WO2019189194A1 - Electrochromic element, smart window, and method for driving electrochromic element - Google Patents

Electrochromic element, smart window, and method for driving electrochromic element Download PDF

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Publication number
WO2019189194A1
WO2019189194A1 PCT/JP2019/012882 JP2019012882W WO2019189194A1 WO 2019189194 A1 WO2019189194 A1 WO 2019189194A1 JP 2019012882 W JP2019012882 W JP 2019012882W WO 2019189194 A1 WO2019189194 A1 WO 2019189194A1
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voltage
applied voltage
transparent electrode
case
period
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PCT/JP2019/012882
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French (fr)
Japanese (ja)
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佐藤　英次
伸之 伊藤
智彦 中川
知輝 鴻池
ひなつ 大鐘
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シャープ株式会社
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/15—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on an electrochromic effect

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  • the present disclosure relates to an electrochromic device, and more particularly, to an electrochromic device including a nanocrystal layer including metal oxide nanoparticles.
  • the present disclosure also relates to a smart window including such an electrochromic element and a method for driving such an electrochromic element.
  • An electrochromic element whose optical properties reversibly change when a voltage is applied is known.
  • a smart window capable of electrically controlling light transmittance.
  • Patent Document 1 discloses an electrochromic element used for an infrared type smart window.
  • a nanocrystal layer is provided as an electrochromic layer in which a light transmission spectrum is changed by application of a voltage.
  • This nanocrystal layer expresses electrochromism using localized surface plasmon resonance (LSPR) of metal oxide nanoparticles.
  • LSPR localized surface plasmon resonance
  • Non-Patent Document 1 discloses various nanocrystals used as electrochromic materials.
  • the inventor of the present application has conducted various studies on the type of electrochromic device using the nanocrystal layer as described above. As a result, in an electrochromic device provided with a nanocrystal layer, there is a risk that the operation failure described below may occur due to repeated voltage application (that is, the magnitude and polarity of the applied voltage change several times). I found a problem.
  • the present disclosure has been made in view of the above problems, and an object thereof is to suppress deterioration and malfunction in an electrochromic device including a nanocrystal layer.
  • An electrochromic device is provided on a surface of a first transparent electrode and a second transparent electrode facing each other, and a surface of the first transparent electrode on the second transparent electrode side, and includes a plurality of metal oxide nanoparticles.
  • a nanocrystal layer containing particles, an electrolyte layer provided between the nanocrystal layer and the second transparent electrode, and a control unit for controlling an applied voltage between the first transparent electrode and the second transparent electrode The control unit is configured to switch the applied voltage from a predetermined first voltage V A to a second voltage V B different from the first voltage V A.
  • the applied voltage is gradually changed from the first voltage V A to the second voltage V B , and the applied voltage is changed from the second voltage V B to the second voltage V B. switch to the first voltage V A
  • the second case of changing the transmission spectrum of the nanocrystal layer by gradually changing the applied voltage from the second voltage V B to the first voltage V A.
  • control unit changes the applied voltage stepwise in each of the first case and the second case.
  • control unit continuously changes the applied voltage in each of the first case and the second case.
  • the polarity of the first voltage V A and the polarity of the second voltage V B are different from each other.
  • control unit includes a period during which a voltage having a magnitude between the first voltage V A and 0 V is held as the applied voltage in each of the first case and the second case.
  • the applied voltage is controlled so that there is a period during which a voltage having a magnitude between the second voltage V B and 0 V is held as the applied voltage.
  • control unit has a magnitude between 0 V and one of the first voltage V A and the second voltage V B as the applied voltage in each of the first case and the second case. There is a period during which the voltage is held, and there is no period during which a voltage having a magnitude between 0 V and the other of the first voltage V A and the second voltage V B is held as the applied voltage.
  • the applied voltage is controlled as follows.
  • control unit applies the application in a period in which the applied voltage is positive and a period in which the applied voltage is negative in each of the first case and the second case.
  • the applied voltage is controlled so that the amount of change in voltage per unit time is different.
  • control unit controls the applied voltage so that the amount of change per unit time decreases as the absolute value of the applied voltage increases in each of the first case and the second case. To do.
  • control unit changes the applied voltage per unit time in a first period which is a predetermined period immediately after switching of the applied voltage in each of the first case and the second case.
  • the applied voltage is controlled so that the amount is larger than the amount of change per unit time of the applied voltage in the second period, which is a predetermined period immediately after the first period.
  • a smart window according to an embodiment of the present disclosure includes an electrochromic element having any one of the configurations described above.
  • An electrochromic device driving method includes a first transparent electrode and a second transparent electrode facing each other, a surface of the first transparent electrode on the second transparent electrode side, and a plurality of metals.
  • a method for driving an electrochromic device comprising: a nanocrystal layer containing oxide nanoparticles; and an electrolyte layer provided between the nanocrystal layer and the second transparent electrode, wherein the first transparent electrode Changing the transmission spectrum of the nanocrystal layer by switching the voltage applied between the second transparent electrodes from a predetermined first voltage V A to a second voltage V B different from the first voltage V A.
  • step (B) for changing the transmission spectrum of the nanocrystal layer by switching the applied voltage from the second voltage V B to the first voltage V a
  • step (a ) The applied voltage is gradually changed from the first voltage V A to the second voltage V B
  • step (B) changes the applied voltage from the second voltage V B to the first voltage. This is done by gradually changing to V A.
  • the applied voltage changes stepwise in each of the steps (A) and (B).
  • the applied voltage continuously changes in each of the steps (A) and (B).
  • the polarity of the first voltage V A and the polarity of the second voltage V B are different from each other.
  • each of the steps (A) and (B) includes a step of holding a voltage having a magnitude between the first voltage V A and 0 V as the applied voltage, and the applied voltage as the first voltage.
  • a voltage having a magnitude between 0 V and one of the first voltage V A and the second voltage V B is held as the applied voltage.
  • a step of holding a voltage having a magnitude between 0 V and the other of the first voltage V A and the second voltage V B as the applied voltage is held in each of the steps (A) and (B).
  • a change per unit time of the applied voltage between a period in which the applied voltage is positive and a period in which the applied voltage is negative. The amount is different.
  • each of the steps (A) and (B) is performed such that the amount of change per unit time decreases as the absolute value of the applied voltage increases.
  • the amount of change per unit time of the applied voltage in a first period that is a predetermined period immediately after switching of the applied voltage is the first period. Is performed so as to be larger than the amount of change per unit time of the applied voltage in the second period, which is a predetermined period immediately after.
  • an electrochromic device including a nanocrystal layer.
  • (A) And (b) is a figure for demonstrating the mechanism in which generation
  • 6 is a graph showing still another example of voltage control by the control unit 7.
  • 6 is a graph showing still another example of voltage control by the control unit 7.
  • 6 is a graph showing still another example of voltage control by the control unit 7.
  • 6 is a graph showing still another example of voltage control by the control unit 7.
  • 6 is a graph showing still another example of voltage control by the control unit 7.
  • (A) And (b) is a figure which shows the example of the structure by which the 1st transparent electrode 1 was divided
  • 2 is a cross-sectional view schematically showing an electrochromic device 100 including a spacer 8.
  • FIG. It is a figure which shows the example of the other structure of the seal part.
  • FIG. 1 is a cross-sectional view schematically showing an electrochromic device 100.
  • the electrochromic element 100 includes a first transparent electrode 1, a second transparent electrode 2, a nanocrystal layer 3, an electrolyte layer 4, and a seal portion 5.
  • the electrochromic element 100 further includes a power supply unit 6 and a control unit 7.
  • the first transparent electrode 1 and the second transparent electrode 2 are arranged so as to face each other.
  • the first transparent electrode 1 and the second transparent electrode 2 are each transparent and substantially colorless.
  • the first transparent electrode 1 and the second transparent electrode 2 are electrically connected to the power supply unit 6.
  • the first transparent electrode 1 is supported on the first substrate 11.
  • the second transparent electrode 2 is supported on the second substrate 12.
  • the first substrate 11 and the second substrate 12 are each transparent and substantially colorless.
  • the nanocrystal layer 3 is provided on the surface of the first transparent electrode 1 on the second transparent electrode 2 side.
  • the nanocrystal layer 3 includes a plurality of metal oxide nanoparticles.
  • the metal oxide nanoparticles are particulate crystals (nanocrystals) having a particle size of several nm to several tens of nm.
  • the electrolyte layer 4 is provided between the nanocrystal layer 3 and the second transparent electrode 2.
  • the electrolyte layer 4 is surrounded by the seal portion 5.
  • the metal oxide nanoparticles contained in the nanocrystal layer 3 are electrochromic materials. Therefore, the transmission spectrum of the nanocrystal layer 3 changes according to the voltage applied between the first transparent electrode 1 and the second transparent electrode 2. This change in the transmission spectrum is accompanied by a change in transmittance in the near infrared region. Therefore, the electrochromic element 100 of this embodiment can control the transmittance of near infrared light.
  • the near-infrared region refers to a wavelength range of about 800 nm or more and about 2500 nm or less.
  • the acquisition rate of solar heat from sunlight can be controlled by controlling the transmittance of the near-infrared light.
  • near-infrared light can be prevented from entering the room in summer, and near-infrared light can be taken into the room in winter.
  • the principle that the nanocrystal layer 3 exhibits electrochromism will be described later. Note that the change in the transmission spectrum of the nanocrystal layer 3 may be accompanied by not only the change in transmittance in the near-infrared region but also the change in transmittance in the visible region (range of about 400 nm or more and about 800 nm or less).
  • the power supply unit 6 applies a predetermined voltage between the first transparent electrode 1 and the second transparent electrode.
  • the control unit 7 controls the voltage applied between the first transparent electrode 1 and the second transparent electrode 2.
  • the control unit 7 controls the power supply unit 6 so that a voltage having a desired magnitude and polarity is applied between the first transparent electrode 1 and the second transparent electrode 2.
  • the applied voltage between the first transparent electrode 1 and the second transparent electrode 2 is the potential of the first transparent electrode 1 when the potential of the second transparent electrode 2 is set as a reference potential. Equivalent to. For example, when the potential of the second transparent electrode 2 is 0V and the potential of the first transparent electrode 1 is + 3V, the applied voltage between the first transparent electrode 1 and the second transparent electrode 2 is + 3V.
  • the control unit 7 uses a predetermined voltage (hereinafter referred to as “first voltage”) V A to a different voltage (hereinafter referred to as “second voltage”) different from the first voltage V A.
  • first voltage a predetermined voltage
  • second voltage a different voltage
  • the applied voltage is changed from the first voltage V A to the second voltage V B. Change gradually.
  • control unit 7 changes the transmission spectrum of the nanocrystal layer 3 by switching the applied voltage from the second voltage V B to the first voltage V A (hereinafter referred to as “second case”).
  • the applied voltage is gradually changed from the second voltage V B to the first voltage V A.
  • the transmission spectrum when -V3 is applied is a state in which the near-infrared transmittance is relatively low (that is, the state where the near-infrared is shielded), and the transmission spectrum when + V3 is applied has a relatively high near-infrared transmittance.
  • a state that is, a state that transmits near infrared rays.
  • FIG. 2 is a graph in which the horizontal axis represents time and the vertical axis represents the voltage applied between the first transparent electrode 1 and the second transparent electrode 2.
  • the deterioration and the malfunction as described above may occur.
  • the deterioration there may be mentioned one caused by warpage at the end of the electrochromic element when a flexible film substrate is used as the first substrate 11 and the second substrate 12.
  • FIG. 3 shows a state in which the first substrate 11 is warped at the end of the electrochromic element due to the influence of cutting and bonding of the film substrate.
  • the first transparent electrode 1, the second transparent electrode 2, and the nanocrystal layer 3 are not shown.
  • FIG. 3 shows equipotential lines eq and electric lines of force ef generated when a voltage is applied between the first transparent electrode 1 and the second transparent electrode 2.
  • there is a portion where electric lines of force ef concentrate (a portion where electric field concentrates and a portion surrounded by a dotted line in the figure) near the region where the warp occurs.
  • side reactions are likely to occur. Once a side reaction occurs, the side reaction at that portion is more likely to occur, and as a result, the electrical resistance of the upper and lower substrates is locally reduced.
  • FIG. 4 is a photograph showing a portion where deterioration has occurred as a result of the voltage control as shown in FIG. 2 being performed once at the end of the electrochromic element.
  • the left end portion in FIG. 4 is a portion that has deteriorated due to the side reaction as described above, and has turned black.
  • An electrochromic element (a kind of dimming cell) can be considered as a set of a plurality of minute cells sc electrically connected in parallel as shown in FIG.
  • Each micro cell sc includes a capacitance component C1 and a resistance component R1 between the electrodes, and is connected in parallel with each other by a resistance component R2 of the transparent electrode.
  • the resistance component R1 decreases in the minute cell (deteriorated cell) sc ′ (lower center in the example shown in FIG. 5) that has deteriorated due to the progress of the side reaction
  • the set value is set in the minute cell sc downstream of the deteriorated cell sc ′.
  • the street voltage is no longer applied. Therefore, it is preferable to apply a voltage so as to suppress the side reaction at the deteriorated portion as much as possible.
  • the control unit 7 of the present embodiment changes the transmission spectrum of the nanocrystal layer 3 by switching the applied voltage from the first voltage V A to the second voltage V B (“first case”). ]), The applied voltage is gradually changed from the first voltage V A to the second voltage V B.
  • the control unit 7 changes the transmission spectrum of the nanocrystal layer 3 by switching the applied voltage from the second voltage V B to the first voltage V A (“second case”). The voltage is gradually changed from the second voltage V B to the first voltage V A.
  • FIG. 6 shows an example of voltage control by the control unit 7.
  • the applied voltage when the applied voltage is switched from -V3 to + V3, the applied voltage is -V3, -V2, -V1, 0, + V1, + V2, + V3 (which is needless to say -V3, -V2,- V1, + V1, + V2, and + V3 are changed stepwise as follows: ⁇ V3 ⁇ V2 ⁇ V1 ⁇ 0 ⁇ + V1 ⁇ + V2 ⁇ V3.
  • the applied voltage is switched from + V3 to -V3, the applied voltage is changed stepwise from + V3, + V2, + V1, 0, -V1, -V2, and -V3.
  • the notations “ ⁇ V3” and “+ V3” do not necessarily mean that the absolute values are the same voltage. That is, “ ⁇ V3” and “+ V3” may have the same absolute value or different values. Similarly, “ ⁇ V2” and “+ V2” do not necessarily mean that the absolute values are the same voltage, and “ ⁇ V1” and “+ V1” indicate that the absolute values are the same voltage. It doesn't necessarily mean.
  • the holding times t1 to t10 after changing the applied voltage to each voltage value are set to be equal to the response speed tr at the time of each voltage change, for example.
  • the response speed here is the time for the amount of change in transmittance at the reference wavelength to reach 90% at each voltage change.
  • the reference wavelength is a wavelength at which the transmittance changes most when the applied voltage is switched from ⁇ V3 to + V3 (or from + V3 to ⁇ V3).
  • the lengths of the holding times t1 to t10 are not limited to those illustrated here. Among the holding times t1 to t10, the amount of change in transmittance that serves as a reference for the length may be different between the holding times t1 to t5 and the holding times t6 to t10.
  • the holding times t1 to t10 are set as times when the transmittance change amount reaches 50%, and the holding times t6 to t10 are set as times when the transmittance change amount reaches 90%. Also good. Further, in order to shorten the switching time, the holding times t1 to t10 may be set as the time when the transmittance change amount reaches 50%.
  • the applied voltage is switched from the first voltage V A (here, ⁇ V3) to the second voltage V B (here, + V3), and from the second voltage V B to the first voltage V.
  • the applied voltage is changed in six steps, but the change in the applied voltage may be two steps or more, and may be seven steps or more.
  • the stepwise change in the applied voltage does not necessarily divide the first voltage V A and the second voltage V B equally. For example, after the polarity of the applied voltage is changed, it is more than before the change.
  • the applied voltage may be changed at fine intervals.
  • first voltage V A and the second voltage V B do not necessarily have to have different polarities.
  • the first voltage V A and the second voltage V B may be voltages having the same polarity and different magnitudes. Further, either the first voltage V A or the second voltage V B may be 0V.
  • the embodiment of the present disclosure is significantly used when the first voltage V A and the second voltage V B are voltages having different polarities. More specifically, it is preferable that the first voltage V A is ⁇ 5 V or more and 0 V or less, and the second voltage V B is more than 0 V and +5 V or less.
  • electrochromism is expressed by utilizing localized surface plasmon resonance (LSPR) of metal oxide nanoparticles contained in the nanocrystal layer 3. Therefore, when changing the transmission spectrum, the free electron density of the metal oxide nanoparticles is changed as will be described in detail later.
  • LSPR localized surface plasmon resonance
  • the state retention characteristics are not mainly due to redox reaction but due to the formation of an electric double layer at the nanoparticle interface.
  • the transmission spectrum is changed by reversing the polarity of the applied voltage, the electrolyte ions diffuse.
  • FIG. 7A shows that when switching from a state where a negative voltage is applied to the nanocrystal layer to a state where a positive voltage is applied, a sufficient amount of time has passed and positive ions have moved away from the nanoparticle interface due to negative ions.
  • the state where the electric double layer was formed is shown.
  • the lower side of FIG. 7A shows the relationship between the distance from the nanoparticle surface and the potential in that state. As shown in the lower side of FIG. 7A, the potential difference near the interface is Va.
  • the upper side of FIG. 7B shows a state in which the polarity of the voltage applied to the nanocrystal layer is suddenly changed when the electrolyte ions are difficult to move (for example, when the viscosity of the electrolyte is very high). Yes.
  • the positive ions forming the electric double layer when a negative voltage is applied to the nanocrystal layer are not sufficiently diffused but are present in the vicinity of the nanoparticle interface.
  • the lower side of FIG. 7B shows the relationship between the distance from the nanoparticle surface and the potential in that state. As shown in the lower side of FIG. 7B, the potential in the vicinity of the interface is slightly increased by the positive ions, so that the potential difference in the vicinity of the interface becomes Vb larger than Va. For this reason, it is considered that side reactions (unnecessary oxidation-reduction reactions) easily occur due to a large potential difference generated near the interface.
  • Non-Patent Document 1 by injecting electrons into a transparent conductive oxide (TCO) nanostructure such as an ITO (Tin-doped Indium-Oxide) nanocrystal layer, near-infrared It is known that the transmission spectrum of a region can be changed. In short, the principle is to shift the absorption wavelength by localized surface plasmon resonance (LSPR) of the TCO nanostructure by applying a voltage. This will be described in more detail below.
  • TCO transparent conductive oxide
  • ITO Tin-doped Indium-Oxide
  • the resonance frequency of LSPR is proportional to the plasma frequency ⁇ p .
  • N is the electron density
  • e is the charge of the electron
  • m is the effective mass of the electron
  • ⁇ 0 is the dielectric constant of the vacuum. Therefore, when a negative voltage is applied to the TCO nanostructure to increase the electron density, the plasma frequency ⁇ p increases, and the resonance frequency of the LSPR also increases. Therefore, the resonance wavelength of LSPR becomes short (that is, shifts to the short wavelength side).
  • the resonance wavelength of the LSPR can be set in the near infrared region, so that the transmission spectrum in the near infrared region can be changed.
  • the function of changing the transmission spectrum in this way is not unique to the ITO nanocrystal layer containing ITO nanoparticles.
  • the above-described functions can be achieved if the nanoparticles are sized so as to cause LSPR (for example, 100 nm or less), and the nanocrystal layer can inject electrons from the transparent electrode.
  • nanoparticles nanoparticles of various metal oxides such as ATO, PTO (phosphorus-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide) can be used.
  • Example 10 An example of the electrochromic device 100 was manufactured as follows and the optical characteristics thereof were verified. The repeated operation characteristics were also evaluated.
  • glass substrates were prepared as the first substrate 11 and the second substrate 12, respectively.
  • titanium-doped indium oxide Tianium-doped Indium Oxide: InTiO
  • InTiO titanium-doped Indium Oxide
  • the second transparent electrode 2 was formed on the second substrate 12.
  • a dispersion of ATO nanoparticles is applied on the first transparent electrode 1 by spin coating, dried on a hot plate at 140 ° C. for 1 minute, and then fired at 200 ° C. for 60 minutes, A nanocrystal layer 3 was formed.
  • the ATO nanoparticle dispersion used is commercially available for the formation of an antistatic film (manufactured by Dainippon Paint Co., Ltd.).
  • the particle size of the ATO nanoparticles is 8-30 nm, and the dispersion medium is methyl isobutyl ketone and isoform. It is a mixed solution with butanol.
  • FIG. 8 shows a transmission spectrum when the potential of the second transparent electrode 2 is 0 V and voltages of ⁇ 3 V and +3 V are applied to the first transparent electrode 1. From FIG. 8, it can be seen that the transmission spectrum in the near-infrared region changes greatly according to the switching of the polarity of the applied voltage.
  • the applied voltage was controlled as shown in FIG. 9 to evaluate the repeated operation characteristics of the electrochromic device 100 of the example.
  • the applied voltage is switched between -3V and + 3V.
  • the applied voltage is changed stepwise from -3V, -2V, -1V, 0V, + 1V, + 2V, + 3V, and when switching from + 3V to -3V, the applied voltage is + 3V , + 2V, + 1V, 0V, -1V, -2V, and -3V.
  • the holding time at each voltage was set based on the response speed tr at 1800 nm, which is the wavelength with the largest transmittance change.
  • the holding time t1 when the applied voltage is changed from -3V to -2V is almost zero.
  • the holding times t2 and t3 when the applied voltage is changed from -2V to -1V and when the applied voltage is changed from -1V to 0V are 1 minute and 1 minute, respectively.
  • the holding times t4 and t5 when the applied voltage is changed from 0V to + 1V and from + 1V to + 2V are 3 minutes and 6 minutes, respectively.
  • the holding times t6, t7 and t8 are 3 minutes, 3 minutes and 1 minute.
  • the holding times t9 and t10 when the applied voltage is changed from 0V to -1V and when the applied voltage is changed from -1V to -2V are 1 minute and 3 minutes, respectively.
  • the holding time at each voltage gradually increases, and it can be seen that such control is preferable.
  • the holding time at each voltage is not switched before the change in transmittance during the actual measurement is almost completed. Is set to That is, the holding time at each voltage is preferably set so that the change in transmittance at each voltage is almost completed.
  • FIGS. 6 and 9 show the case where the applied voltage is switched from the first voltage V A to the second voltage V B (first case) and the case where the applied voltage is switched from the second voltage V B to the first voltage V A (second case). In each case, the applied voltage changes step by step.
  • the control of the applied voltage is not limited to this example.
  • FIG. 10 shows another example of applied voltage control.
  • the applied voltage when the applied voltage is switched from ⁇ V3 (first voltage V A ) to + V3 (second voltage V B ) and from + V3 to ⁇ V3, the applied voltage continuously changes. To do.
  • the time for changing the applied voltage from ⁇ V3 to + V3 is, for example, the sum of the holding times when changing stepwise (holding times t1, t2, t3, t4 in the example shown in FIG. 6 and the sum of t5).
  • the time for changing the applied voltage from + V3 to ⁇ V3 is the same as the total of the holding times when changing in stages (the total of holding times t6, t7, t8, t9 and t10 in the example shown in FIG. 6). It may be.
  • FIG. 10 shows an example in which the rising speed and the falling speed of the applied voltage are constant (that is, the time change of the applied voltage is linear).
  • the rising speed and the falling speed of the applied voltage are, for example, 0.001 V / second to 6 V / second.
  • the rising speed and the falling speed of the applied voltage are not necessarily constant.
  • the change with time of the applied voltage may be curved.
  • “gradually changing the applied voltage” means that the applied voltage is changed stepwise in two or more steps, continuously changed, or a combination thereof. Means. When the applied voltage is changed suddenly (at once) as in the example shown in FIG. 2, the time required for switching the applied voltage is substantially zero, whereas when the applied voltage is gradually changed, for example, response The applied voltage is switched in a time on the same order as the speed.
  • each of the negative polarity side and the positive polarity side has a period during which an intermediate applied voltage is maintained.
  • the embodiment of the present disclosure is not limited to such an example.
  • FIG. 11 shows still another example of applied voltage control.
  • the applied voltage when the applied voltage is switched from + V3 to ⁇ V3 (second case), the applied voltage is changed stepwise from + V3, + V2, + V1, 0V, and ⁇ V3, and the applied voltage is ⁇
  • the applied voltage is changed stepwise from ⁇ V3, 0, + V1, + V2, and + V3.
  • the ease of deterioration may vary depending on the polarity of the applied voltage.
  • an electrochromic device using ATO nanoparticles as metal oxide nanoparticles and an ionic liquid (specifically 1-Butylpyridinium bis (trifluoromethylsulfonyl) amide) as an electrolyte a black color is applied when a voltage of +3 V is applied.
  • an ionic liquid specifically 1-Butylpyridinium bis (trifluoromethylsulfonyl) amide
  • each of the first case and the second case there is a period in which a voltage having a magnitude between one of the first voltage V A and the second voltage V B and 0 V is held as the applied voltage, and
  • the applied voltage may be controlled so that there is no period in which the voltage between the other of the first voltage V A and the second voltage V B and 0 V is held as the applied voltage.
  • the applied voltage is changed stepwise, but the same can be said when the applied voltage is continuously changed.
  • 12 and 13 show still another example of the control of the applied voltage.
  • the applied voltage is continuously changed in each of the case where the applied voltage is switched from + V3 to ⁇ V3 (second case) and the case where the applied voltage is switched from ⁇ V3 to + V3 (first case).
  • the time change of the applied voltage is linear, whereas in the example shown in FIG. 13, the time change of the applied voltage is curved.
  • the change amount per unit time of the applied voltage (average voltage change in a certain period) between the period in which the applied voltage is positive and the period in which it is negative. Speed may be different).
  • the amount of voltage change per unit time is relatively small, and on the negative polarity side (between 0V and ⁇ V3), the voltage change per unit time.
  • the amount is relatively large.
  • the change amount per unit time of the applied voltage is relatively set on the polarity side where deterioration is likely to occur.
  • the first voltage V A to the second voltage V are suppressed while suppressing deterioration of the element.
  • the time required for switching the applied voltage to B (or from the second voltage V B to the first voltage V A ) (that is, switching the transmission spectrum) can be shortened.
  • FIG. 14 shows still another example of applied voltage control.
  • the applied voltage when the applied voltage is switched from + V3 to -V3 (second case), the applied voltage changes stepwise from + V3, + V2, + V1, 0V, -V1, -V2, and -V3.
  • the applied voltage is switched from ⁇ V3 to + V3 (first case)
  • the applied voltage is changed stepwise from ⁇ V3, ⁇ V2, ⁇ V1, 0, + V1, + V2, and + V3.
  • the holding time is longer as the absolute value of the applied voltage is larger. That is, the larger the absolute value of the applied voltage, the smaller the amount of voltage change per unit time. Deterioration of the element may occur more easily as the absolute value of the applied voltage is larger. As in the example shown in FIG. 14, by reducing the amount of voltage change per unit time as the absolute value of the applied voltage increases, degradation that tends to occur when the absolute value of the applied voltage is large is effectively suppressed. be able to.
  • the applied voltage is changed stepwise, but the same can be said when the applied voltage is continuously changed.
  • 15 and 16 show still another example of control of the applied voltage.
  • the applied voltage is continuously changed when the applied voltage is switched from + V3 to -V3 (second case) and when the applied voltage is switched from -V3 to + V3 (first case).
  • the time change of the applied voltage is linear, whereas in the example shown in FIG. 16, the time change of the applied voltage is curved.
  • the amount of voltage change per unit time decreases as the absolute value of the applied voltage increases. Therefore, by controlling the applied voltage as in the examples shown in FIGS. 15 and 16, it is possible to effectively suppress deterioration that easily occurs when the absolute value of the applied voltage is large.
  • 17 and 18 show still another example of applied voltage control.
  • the applied voltage when the applied voltage is switched from + V3 to ⁇ V3 (second case), the applied voltage is stepped as + V3, + V2, + V1, 0V, ⁇ V1, ⁇ V2, and ⁇ V3.
  • the applied voltage is switched from ⁇ V3 to + V3 (first case)
  • the applied voltage is changed stepwise from ⁇ V3, ⁇ V2, ⁇ V1, 0, + V1, + V2, and + V3.
  • the amount of voltage change per unit time immediately after switching of the applied voltage is relatively large.
  • the change amount per unit time of the applied voltage in the first period for example, the period t1 + t2 from immediately after switching to the end of the + V1 holding period
  • Is larger than the change amount per unit time of the applied voltage in the second period for example, the period t3 + t4 from the end of the + V1 holding period to the end of the ⁇ V1 holding period
  • the change per unit time of the applied voltage in the first period (for example, the period t6 + t7 from immediately after switching to the end of the holding period of ⁇ V1) which is a predetermined period immediately after switching of the applied voltage.
  • the amount is larger than the change amount per unit time of the applied voltage in the second period (for example, the period t8 + t9 from the end of the holding period of ⁇ V1 to the end of the holding period of + V1) which is a predetermined period immediately after the first period. It is getting bigger.
  • the time required for the voltage response of the electrolyte or the like in the element is such that the amount of voltage change per unit time in the vicinity of 0 V is reduced as shown in FIG. 17, or the ultimate voltage (first case as shown in FIG. 18). This can be ensured by reducing the voltage change amount per unit time in the vicinity of the second voltage V B in the first case and the first voltage V A in the second case.
  • the length of the first period is preferably 0.1 minute or more and 3 minutes or less, and the length of the second period is preferably 2 minutes or more and 5 minutes or less.
  • the change amount of the applied voltage from + V3 to + V1 is preferably 1 ⁇ 4 or more of the change amount from + V3 to ⁇ V3, and preferably 1 ⁇ 4 or more and 1 ⁇ 2 or less. Is more preferable.
  • the change amount of the applied voltage from + V1 to ⁇ V1 is preferably 1 ⁇ 4 or more of the change amount from + V3 to ⁇ V3, and is 1 ⁇ 4 or more and 1 ⁇ 2 or less. It is more preferable.
  • the length of the first period is preferably 0.1 minute or more and 3 minutes or less, and the length of the second period is preferably 2 minutes or more and 5 minutes or less.
  • the change amount of the applied voltage from ⁇ V3 to ⁇ V1 is preferably 1 ⁇ 4 or more of the change amount from ⁇ V3 to + V3, and is 1 ⁇ 4 or more and 1 ⁇ 2 or less. More preferably.
  • the change amount of the applied voltage from ⁇ V1 to + V1 is preferably 1 ⁇ 4 or more of the change amount from ⁇ V3 to + V3, and is 1 ⁇ 4 or more and 1 ⁇ 2 or less. It is more preferable.
  • the holding times t1 to t5 after changing the applied voltage to each voltage value are gradually increased. It is preferable.
  • in the first case in the process of changing the applied voltage from ⁇ V3 to + V3, it is preferable to gradually increase the holding times t6 to t10 after the applied voltage is changed to each voltage value.
  • the applied voltage is changed stepwise, but the same can be said when the applied voltage is continuously changed.
  • 19 and 20 show still another example of control of the applied voltage.
  • the applied voltage is continuously changed in each of the case where the applied voltage is switched from + V3 to ⁇ V3 (second case) and the case where the applied voltage is switched from ⁇ V3 to + V3 (first case). Change.
  • the amount of voltage change per unit time immediately after switching of the applied voltage is relatively large. Therefore, by controlling the applied voltage as in the examples shown in FIGS. 19 and 20, it is possible to clarify the change when the switching is performed manually.
  • the time required for the voltage response of the electrolyte or the like in the element is small per unit time near 0 V as shown in FIG. 19, or per unit time near the ultimate voltage as shown in FIG. This can be ensured by reducing the amount of voltage change.
  • the metal oxide used as the material for the metal oxide nanoparticles is not limited to ATO as used in the examples.
  • ATO an almost transparent material such as ITO, AZO (Aluminum-doped Zinc Oxide), and GZO (Gallium-doped Zinc Oxide) can be used.
  • a material that absorbs light in the visible region such as a composite tungsten oxide or lanthanum hexaboride represented by Cs X W Y O 3 (x and y indicate composition ratios) may be used. it can.
  • the method for forming the nanocrystal layer 3 is not particularly limited.
  • the nanocrystal layer 3 can be formed by applying a liquid or semi-solid in which metal oxide nanoparticles are dispersed on the first substrate 11 and performing baking.
  • the dispersion of metal oxide nanoparticles may be applied by a spin coating method, or may be applied by a printing method using a paste to which a vehicle is appropriately added. Further, the coating may be performed by a bar coating method, a slit coating method, a gravure coating method or a die coating method. If the firing temperature is such that organic components on the nanocrystal surface are removed and sintering is suitably performed, sufficient solvent resistance can be obtained.
  • baking may be performed at a temperature of 200 ° C. to 300 ° C. for 30 minutes.
  • first substrate 11 and the second substrate 12 for example, glass substrates can be used.
  • plastic substrate formed from resin materials such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and a polyimide, may be sufficient.
  • These illustrated substrates may be provided with a gas barrier layer formed from an inorganic material or an organic material. In the case where a glass substrate is used, it may be thinned by etching after the two substrates are bonded together.
  • Transparent electrode As the material of the first transparent electrode 1 and the second transparent electrode 2, in addition to InTiO, a material that transmits near-infrared light such as tantalum-substituted tin oxide using anatase-type titanium dioxide as a seed layer or ITO with adjusted carrier density Can be used.
  • the first transparent electrode 1 and the second transparent electrode 2 can be formed by depositing these materials on the first substrate 11 and the second substrate 12 by sputtering, vapor deposition, coating, or the like.
  • the material of the first transparent electrode 1 and the second transparent electrode 2 has a characteristic of reflecting far-infrared light.
  • Infrared light radiated from the room is classified as far-infrared light having a wavelength of about 10 ⁇ m. Therefore, if the first transparent electrode 1 and the second transparent electrode 2 have the characteristic of reflecting far-infrared light, the state of the nanocrystal layer 3 is controlled so that the transmittance of near-infrared light is increased.
  • the indoor heat does not escape to the outdoors as radiant heat, and an ideal state can be realized. Further, even when control is performed so that the transmittance of near-infrared light is lowered in summer, it is possible to prevent the far-infrared light from the outside from entering the room, so that an ideal state can be realized.
  • the electrode extraction (connection to the external wiring) of the first transparent electrode 1 may be performed at one place or at a plurality of places. .
  • the assembly process of the electrochromic element 100 can be simplified and the routing of the wiring can be simplified.
  • a partial response speed delay can be prevented even when there is a resistance component between the first transparent electrode 1 and the second transparent electrode 2, that is, when a current flows.
  • the first transparent electrode 1 may be divided into a plurality of electrically independent sub-electrodes.
  • the transmission spectrum can be changed for each region corresponding to the sub-electrodes.
  • FIGS. 21A and 21B show examples of a configuration in which the first transparent electrode 1 is divided into a plurality of sub-electrodes 1a.
  • the electrode lead-out portions EP are gathered in one place by routing the plurality of sub-electrodes 1a. An unnecessary voltage drop can be prevented by disposing the lead-out portion of the sub electrode 1a away from the operation portion of the electrochromic element 100 such as the outside of the seal portion 5 or under the seal portion 5.
  • the plurality of sub-electrodes 1a are directly connected to the wiring without being routed. That is, the electrode extraction part EP is dispersed in a plurality of places.
  • the second transparent electrode 2 may be divided into a plurality of electrically independent sub-electrodes or may not be divided.
  • the electrolyte layer 4 is made of, for example, an electrolytic solution.
  • an electrolytic solution a material that is easily ionized, such as lithium hexafluorophosphate (LiPF 6 ), sodium hexafluorophosphate (NaPF 6 ), or lithium borofluoride (LiBF 4 ) can be used.
  • ethylene carbonate (EC), diethyl carbonate (DEC), a mixture of EC and DC, propylene carbonate, or the like can be used.
  • an ionic liquid composed of a cyclic quaternary ammonium cation and an imide anion may be used.
  • the electrolyte layer 4 may be composed of a solid electrolyte.
  • a solid electrolyte such as polyethylene oxide containing a lithium salt may be used, or a plastic crystal may be used.
  • the electrochromic element 100 defines the distance (cell thickness) between the first substrate 11 and the second substrate 12 as shown in FIG. It is preferable to provide a spacer 8 for the purpose.
  • the spacer 8 is provided between the nanocrystal layer 3 and the second transparent electrode 2.
  • the spacer 8 can be formed by a photolithography process using a photosensitive resin material.
  • the spacer 8 is, for example, 10 ⁇ m square and 10 ⁇ m high.
  • the formation method of the spacer 8 is not limited to the photolithography process, but may be, for example, a screen printing method.
  • the spacer 8 is preferably formed on the second substrate 12 side (on the second transparent electrode 2).
  • the spacer 8 is provided on the first substrate 11 side, if the spacer 8 is formed before the nanocrystal layer 3 is formed, the thickness of the nanocrystal layer 3 may be uneven due to the influence of the spacer 8, or the spacer 8 may be There is a possibility that leakage with the second transparent electrode 2 occurs due to the covering of 3.
  • the spacer 8 is formed on the nanocrystal layer 3, the residue of the photolithographic process remains on the nanocrystal layer 3, and there is a possibility that the change in the transmission spectrum is hindered.
  • the electrolyte layer 4 is composed of a solid electrolyte, it is not necessary to provide the spacer 8 if the solid electrolyte has appropriate elasticity.
  • seal portion 5 As a material of the seal portion 5, for example, a UV curable resin material can be used.
  • FIG. 23 shows an example of another configuration of the seal portion 5.
  • the seal portion 5 has two regions 5a and 5b formed from different materials (seal materials).
  • the region 5a positioned relatively inside is referred to as “inside region”
  • the region 5b positioned relatively outside is referred to as “outside region”.
  • the inner region 5a is formed from a sealing material having higher solvent resistance than the sealing material forming the outer region 5b.
  • the outer region 5b is formed of a sealing material having a stronger adhesive force than the sealing material forming the inner region 5a.
  • the inner region 5a that is in contact with the electrolyte layer 4 is formed of a sealing material having high solvent resistance
  • the outer region 5b is formed of a sealing material having a strong adhesive force. High reliability and strong adhesion can be achieved at the same time.
  • the power supply unit 6 is a power supply circuit that supplies electric power (applies a predetermined voltage between the first transparent electrode 1 and the second transparent electrode 2).
  • the power supply unit 6 may include a removable primary battery, a secondary battery, and the like.
  • the control unit 7 controls the power supply unit 6 so that a voltage having a desired magnitude and polarity is applied between the first transparent electrode 1 and the second transparent electrode 2.
  • the control unit 7 is a circuit board including, for example, a calculation unit such as a CPU (Central Processing Unit) or a dedicated processor, and a storage unit such as a RAM (Random Access Memory) or a ROM (Read Only Memory).
  • a calculation unit such as a CPU (Central Processing Unit) or a dedicated processor
  • a storage unit such as a RAM (Random Access Memory) or a ROM (Read Only Memory).
  • a RAM Random Access Memory
  • ROM Read Only Memory
  • the electrochromic element 100 does not include a counter electrode on the second transparent electrode 2.
  • the first transparent electrode 1, the second transparent electrode 2, and the nanocrystal layer 3 apply a voltage between the first transparent electrode 1 and the second transparent electrode 2 in order to change the transmission spectrum of the nanocrystal layer 3.
  • the redox reaction does not occur, and the electrochromic device 100 does not include an electrode in which a transmission spectrum changes due to the redox reaction by applying a voltage.
  • the electrochromic device 100 that does not include a counter electrode made of a substance that causes an oxidation-reduction reaction can avoid deterioration in repetitive characteristics due to a side reaction of the oxidation-reduction reaction.
  • the wavelength of plasmon absorption in the near infrared region can be changed by the charge movement on the first transparent electrode 1 and the second transparent electrode 2 that occurs when a voltage is applied.
  • the electrochromic device 100 in the embodiment of the present disclosure is suitably used for a smart window.
  • the electrochromic element 100 itself may be a smart window, or a laminated structure in which the electrochromic element 100 is bonded to a plate glass may function as a smart window.
  • one of the plurality of plate glasses constituting the multilayer glass may be replaced with the electrochromic element 100.
  • an electrochromic element 100 may be substituted for a central plate glass among three plate glasses constituting a double glass having a triple glass structure.
  • six interfaces between a solid such as glass and a gas such as air are formed. At these interfaces, since interface reflection occurs, the transmittance of light including visible light is lowered. Therefore, it is preferable to provide an antireflection film such as an AR (Anti-Reflective) film, an LR (Low-Reflective) film, or a Moseye (registered trademark) film on these interfaces (including both surfaces of the electrochromic element 100).
  • an electrochromic device including a nanocrystal layer it is possible to suppress deterioration and malfunction in an electrochromic device including a nanocrystal layer.
  • the electrochromic device according to the embodiment of the present disclosure is suitably used for a smart window.

Abstract

This electrochromic element is provided with: a first transparent electrode and a second transparent electrode that face each other; a nanocrystal layer that is provided on the second transparent electrode-side surface of the first transparent electrode and that contains a plurality of metal oxide nanoparticles; an electrolytic layer that is provided between the nanocrystal layer and the second transparent electrode; and a control unit that controls a voltage to be applied between the first transparent electrode and the second transparent electrode. In a first case for changing the transmission spectrum of the nanocrystal layer by switching the voltage to be applied from a prescribed first voltage VA to a second voltage VB which is different from the first voltage VA, the control unit gradually changes the voltage to be applied from the first voltage VA to the second voltage VB. In a second case for changing the transmission spectrum of the nanocrystal layer by switching the transmission spectrum of the nanocrystal layer by switching the voltage to be applied from the second voltage VB to the first voltage VA, the control unit gradually changes the voltage to be applied from the second voltage VB to the first voltage VA.

Description

エレクトロクロミック素子、スマートウィンドウおよびエレクトロクロミック素子の駆動方法Electrochromic device, smart window and driving method of electrochromic device
　本開示は、エレクトロクロミック素子に関し、特に、金属酸化物ナノ粒子を含むナノ結晶層を備えたエレクトロクロミック素子に関する。また、本開示は、そのようなエレクトロクロミック素子を備えたスマートウィンドウやそのようなエレクトロクロミック素子の駆動方法にも関する。 The present disclosure relates to an electrochromic device, and more particularly, to an electrochromic device including a nanocrystal layer including metal oxide nanoparticles. The present disclosure also relates to a smart window including such an electrochromic element and a method for driving such an electrochromic element.
　電圧の印加によりその光学的性質が可逆的に変化するエレクトロクロミック素子が知られている。エレクトロクロミック素子を用いた製品の１つとして、電気的に光透過率を制御することができるスマートウィンドウが挙げられる。 An electrochromic element whose optical properties reversibly change when a voltage is applied is known. As one of products using an electrochromic element, there is a smart window capable of electrically controlling light transmittance.
　スマートウィンドウの一種として、赤外光の透過率を制御可能なタイプ（以下では「赤外タイプ」と呼ぶこともある。）が提案されている。特許文献１は、赤外タイプのスマートウィンドウに用いられるエレクトロクロミック素子を開示している。 As a kind of smart window, a type capable of controlling the transmittance of infrared light (hereinafter sometimes referred to as “infrared type”) has been proposed. Patent Document 1 discloses an electrochromic element used for an infrared type smart window.
　特許文献１に開示されているエレクトロクロミック素子では、電圧の印加により光の透過スペクトルが変化するエレクトロクロミック層として、ナノ結晶層が設けられている。このナノ結晶層は、金属酸化物ナノ粒子の局在表面プラズモン共鳴（ＬＳＰＲ）を利用してエレクトロクロミズムを発現する。 In the electrochromic element disclosed in Patent Document 1, a nanocrystal layer is provided as an electrochromic layer in which a light transmission spectrum is changed by application of a voltage. This nanocrystal layer expresses electrochromism using localized surface plasmon resonance (LSPR) of metal oxide nanoparticles.
　非特許文献１は、エレクトロクロミック材料として用いられる種々のナノ結晶を開示している。 Non-Patent Document 1 discloses various nanocrystals used as electrochromic materials.
国際公開第２０１７／１４１５２８号International Publication No. 2017/141528
　本願発明者は、上述したようなナノ結晶層を用いるタイプのエレクトロクロミック素子について様々な検討を行った。その結果、ナノ結晶層を備えたエレクトロクロミック素子において、電圧印加の繰り返し（つまり印加電圧の大きさや極性が幾度も変化すること）により、以下に説明するような動作不良が発生するおそれがあるという問題を見出した。 The inventor of the present application has conducted various studies on the type of electrochromic device using the nanocrystal layer as described above. As a result, in an electrochromic device provided with a nanocrystal layer, there is a risk that the operation failure described below may occur due to repeated voltage application (that is, the magnitude and polarity of the applied voltage change several times). I found a problem.
　エレクトロクロミック素子を実際に製造する際、エレクトロクロミック素子内を全く均質に作製することは不可能である。例えば、セル厚ムラやナノ結晶層の厚さムラ、シール部付近におけるシール剤の溶け込みや水分の侵入、さらには、基板としてフィルム基板を用いたときにはフィルム基板の曲げに起因するナノ結晶層のクラックやセル厚異常などが生じることが考えられる。そのような部分においては、設定通りの電圧が印加されても局所的に他の部分と異なる現象が起こり、劣化の原因となる副反応が促進される場合がある。そのような劣化が発生すると、正常な部分にも所望の電圧が印加されず、エレクトロクロミック素子全体が動作不良となってしまう。 When actually manufacturing an electrochromic device, it is impossible to make the inside of the electrochromic device completely homogeneous. For example, cell thickness unevenness, nanocrystal layer thickness unevenness, penetration of sealing agent in the vicinity of the seal and penetration of moisture, and cracks in the nanocrystal layer due to bending of the film substrate when the film substrate is used as the substrate It is possible that an abnormal cell thickness or the like occurs. In such a portion, even when a voltage as set is applied, a phenomenon that differs locally from other portions occurs, and a side reaction that causes deterioration may be promoted. When such deterioration occurs, a desired voltage is not applied to a normal part, and the entire electrochromic element becomes defective.
　本開示は、上記問題に鑑みてなされたものであり、その目的は、ナノ結晶層を備えたエレクトロクロミック素子における劣化および動作不良を抑制することにある。 The present disclosure has been made in view of the above problems, and an object thereof is to suppress deterioration and malfunction in an electrochromic device including a nanocrystal layer.
　本開示の実施形態によるエレクトロクロミック素子は、互いに対向する第１透明電極および第２透明電極と、前記第１透明電極の前記第２透明電極側の表面上に設けられ、複数の金属酸化物ナノ粒子を含むナノ結晶層と、前記ナノ結晶層と前記第２透明電極の間に設けられた電解質層と、前記第１透明電極と前記第２透明電極の間への印加電圧を制御する制御部と、を備えたエレクトロクロミック素子であって、前記制御部は、前記印加電圧を所定の第１電圧ＶAから前記第１電圧ＶAとは異なる第２電圧ＶBに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる第１の場合には、前記印加電圧を前記第１電圧ＶAから前記第２電圧ＶBまで徐々に変化させ、前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる第２の場合には、前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAまで徐々に変化させる。 An electrochromic device according to an embodiment of the present disclosure is provided on a surface of a first transparent electrode and a second transparent electrode facing each other, and a surface of the first transparent electrode on the second transparent electrode side, and includes a plurality of metal oxide nanoparticles. A nanocrystal layer containing particles, an electrolyte layer provided between the nanocrystal layer and the second transparent electrode, and a control unit for controlling an applied voltage between the first transparent electrode and the second transparent electrode The control unit is configured to switch the applied voltage from a predetermined first voltage V A to a second voltage V B different from the first voltage V A. In the first case of changing the transmission spectrum of the layer, the applied voltage is gradually changed from the first voltage V A to the second voltage V B , and the applied voltage is changed from the second voltage V B to the second voltage V B. switch to the first voltage V A In the second case of changing the transmission spectrum of the nanocrystal layer by gradually changing the applied voltage from the second voltage V B to the first voltage V A.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧を段階的に変化させる。 In one embodiment, the control unit changes the applied voltage stepwise in each of the first case and the second case.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧を連続的に変化させる。 In one embodiment, the control unit continuously changes the applied voltage in each of the first case and the second case.
　ある実施形態では、前記第１電圧ＶAの極性と、前記第２電圧ＶBの極性とが互いに異なる。 In one embodiment, the polarity of the first voltage V A and the polarity of the second voltage V B are different from each other.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧として前記第１電圧ＶAと０Ｖの間の大きさの電圧が保持される期間と、前記印加電圧として前記第２電圧ＶBと０Ｖの間の大きさの電圧が保持される期間とが存在するように前記印加電圧を制御する。 In one embodiment, the control unit includes a period during which a voltage having a magnitude between the first voltage V A and 0 V is held as the applied voltage in each of the first case and the second case. The applied voltage is controlled so that there is a period during which a voltage having a magnitude between the second voltage V B and 0 V is held as the applied voltage.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの一方と０Ｖの間の大きさの電圧が保持される期間が存在し、且つ、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの他方と０Ｖの間の大きさの電圧が保持される期間が存在しないように前記印加電圧を制御する。 In one embodiment, the control unit has a magnitude between 0 V and one of the first voltage V A and the second voltage V B as the applied voltage in each of the first case and the second case. There is a period during which the voltage is held, and there is no period during which a voltage having a magnitude between 0 V and the other of the first voltage V A and the second voltage V B is held as the applied voltage. The applied voltage is controlled as follows.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧が正極性である期間と、前記印加電圧が負極性である期間とで、前記印加電圧の単位時間当たりの変化量が異なるように前記印加電圧を制御する。 In one embodiment, the control unit applies the application in a period in which the applied voltage is positive and a period in which the applied voltage is negative in each of the first case and the second case. The applied voltage is controlled so that the amount of change in voltage per unit time is different.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧の絶対値が大きくなるほど単位時間当たりの変化量が小さくなるように前記印加電圧を制御する。 In one embodiment, the control unit controls the applied voltage so that the amount of change per unit time decreases as the absolute value of the applied voltage increases in each of the first case and the second case. To do.
　ある実施形態では、前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧の切り替え直後の所定の期間である第１期間における前記印加電圧の単位時間当たりの変化量が、前記第１期間の直後の所定の期間である第２期間における前記印加電圧の単位時間当たりの変化量よりも大きくなるように前記印加電圧を制御する。 In one embodiment, the control unit changes the applied voltage per unit time in a first period which is a predetermined period immediately after switching of the applied voltage in each of the first case and the second case. The applied voltage is controlled so that the amount is larger than the amount of change per unit time of the applied voltage in the second period, which is a predetermined period immediately after the first period.
　本開示の実施形態によるスマートウィンドウは、上述したいずれかの構成を有するエレクトロクロミック素子を備える。 A smart window according to an embodiment of the present disclosure includes an electrochromic element having any one of the configurations described above.
　本開示の実施形態によるエレクトロクロミック素子の駆動方法は、互いに対向する第１透明電極および第２透明電極と、前記第１透明電極の前記第２透明電極側の表面上に設けられ、複数の金属酸化物ナノ粒子を含むナノ結晶層と、前記ナノ結晶層と前記第２透明電極の間に設けられた電解質層と、を備えたエレクトロクロミック素子の駆動方法であって、前記第１透明電極と前記第２透明電極の間への印加電圧を、所定の第１電圧ＶAから前記第１電圧ＶAとは異なる第２電圧ＶBに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる工程（Ａ）と、前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる工程（Ｂ）と、を包含し、前記工程（Ａ）は、前記印加電圧を前記第１電圧ＶAから前記第２電圧ＶBまで徐々に変化させることによって行われ、前記工程（Ｂ）は、前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAまで徐々に変化させることによって行われる。 An electrochromic device driving method according to an embodiment of the present disclosure includes a first transparent electrode and a second transparent electrode facing each other, a surface of the first transparent electrode on the second transparent electrode side, and a plurality of metals. A method for driving an electrochromic device comprising: a nanocrystal layer containing oxide nanoparticles; and an electrolyte layer provided between the nanocrystal layer and the second transparent electrode, wherein the first transparent electrode Changing the transmission spectrum of the nanocrystal layer by switching the voltage applied between the second transparent electrodes from a predetermined first voltage V A to a second voltage V B different from the first voltage V A. and (a), it includes a step (B) for changing the transmission spectrum of the nanocrystal layer by switching the applied voltage from the second voltage V B to the first voltage V a, the step (a ) The applied voltage is gradually changed from the first voltage V A to the second voltage V B , and the step (B) changes the applied voltage from the second voltage V B to the first voltage. This is done by gradually changing to V A.
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれにおいて、前記印加電圧が段階的に変化する。 In one embodiment, the applied voltage changes stepwise in each of the steps (A) and (B).
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれにおいて、前記印加電圧が連続的に変化する。 In one embodiment, the applied voltage continuously changes in each of the steps (A) and (B).
　ある実施形態では、前記第１電圧ＶAの極性と、前記第２電圧ＶBの極性とが互いに異なる。 In one embodiment, the polarity of the first voltage V A and the polarity of the second voltage V B are different from each other.
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧として前記第１電圧ＶAと０Ｖの間の大きさの電圧が保持される工程と、前記印加電圧として前記第２電圧ＶBと０Ｖの間の大きさの電圧が保持される工程とを含む。 In one embodiment, each of the steps (A) and (B) includes a step of holding a voltage having a magnitude between the first voltage V A and 0 V as the applied voltage, and the applied voltage as the first voltage. A step of holding a voltage having a magnitude between two voltages V B and 0 V.
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの一方と０Ｖの間の大きさの電圧が保持される工程を含み、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの他方と０Ｖの間の大きさの電圧が保持される工程を含まない。 In one embodiment, in each of the steps (A) and (B), a voltage having a magnitude between 0 V and one of the first voltage V A and the second voltage V B is held as the applied voltage. And a step of holding a voltage having a magnitude between 0 V and the other of the first voltage V A and the second voltage V B as the applied voltage.
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれにおいて、前記印加電圧が正極性である期間と、前記印加電圧が負極性である期間とで、前記印加電圧の単位時間当たりの変化量が異なる。 In one embodiment, in each of the steps (A) and (B), a change per unit time of the applied voltage between a period in which the applied voltage is positive and a period in which the applied voltage is negative. The amount is different.
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧の絶対値が大きくなるほど単位時間当たりの変化量が小さくなるように行われる。 In one embodiment, each of the steps (A) and (B) is performed such that the amount of change per unit time decreases as the absolute value of the applied voltage increases.
　ある実施形態では、前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧の切り替え直後の所定の期間である第１期間における前記印加電圧の単位時間当たりの変化量が、前記第１期間の直後の所定の期間である第２期間における前記印加電圧の単位時間当たりの変化量よりも大きくなるように行われる。 In one embodiment, in each of the steps (A) and (B), the amount of change per unit time of the applied voltage in a first period that is a predetermined period immediately after switching of the applied voltage is the first period. Is performed so as to be larger than the amount of change per unit time of the applied voltage in the second period, which is a predetermined period immediately after.
　本開示の実施形態によれば、ナノ結晶層を備えたエレクトロクロミック素子における劣化および動作不良を抑制することができる。 According to the embodiment of the present disclosure, it is possible to suppress deterioration and malfunction in an electrochromic device including a nanocrystal layer.
本開示の実施形態におけるエレクトロクロミック素子１００を模式的に示す断面図である。It is sectional drawing which shows typically the electrochromic element 100 in embodiment of this indication. 比較例の電圧制御を示すグラフである。It is a graph which shows the voltage control of a comparative example. フィルム基板の切断や貼り合せ時の影響により、エレクトロクロミック素子の端部において第１基板１１に反りが生じた状態を示す図である。It is a figure which shows the state which the curvature generate | occur | produced in the 1st board | substrate 11 in the edge part of an electrochromic element by the influence at the time of a cutting | disconnection and bonding of a film board | substrate. エレクトロクロミック素子の端部において劣化が発生している部分を示す写真である。It is a photograph which shows the part which degradation has generate | occur | produced in the edge part of an electrochromic element. エレクトロクロミック素子（調光セル）を、複数の微小セルｓｃの集合として表わしたモデル図である。It is a model figure showing an electrochromic element (light control cell) as a set of a plurality of minute cells sc. エレクトロクロミック素子１００の制御部７による電圧制御の例を示すグラフである。5 is a graph showing an example of voltage control by the control unit 7 of the electrochromic element 100. （ａ）および（ｂ）は、印加電圧を徐々に変化させることによって劣化および動作不良の発生が抑制されるメカニズムを説明するための図である。(A) And (b) is a figure for demonstrating the mechanism in which generation | occurrence | production of deterioration and a malfunctioning is suppressed by changing an applied voltage gradually. 実施例の透過スペクトルを示すグラフである。It is a graph which shows the transmission spectrum of an Example. 実施例の繰り返し動作特性を評価したときの電圧制御を示すグラフである。It is a graph which shows voltage control when the repeated operation characteristic of an Example is evaluated. 制御部７による電圧制御の他の例を示すグラフである。7 is a graph showing another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. 制御部７による電圧制御のさらに他の例を示すグラフである。6 is a graph showing still another example of voltage control by the control unit 7. （ａ）および（ｂ）は、第１透明電極１が複数のサブ電極１ａに分割された構成の例を示す図である。(A) And (b) is a figure which shows the example of the structure by which the 1st transparent electrode 1 was divided | segmented into the some sub electrode 1a. スペーサ８を備えるエレクトロクロミック素子１００を模式的に示す断面図である。2 is a cross-sectional view schematically showing an electrochromic device 100 including a spacer 8. FIG. シール部５の他の構成の例を示す図である。It is a figure which shows the example of the other structure of the seal part.
　以下、図面を参照しながら本発明の実施形態を説明する。なお、本発明は以下の実施形態に限定されるものではない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.
　［エレクトロクロミック素子の全体構成］
　図１を参照しながら、本実施形態におけるエレクトロクロミック素子１００を説明する。図１は、エレクトロクロミック素子１００を模式的に示す断面図である。 [Overall structure of electrochromic element]
With reference to FIG. 1, an electrochromic device 100 according to this embodiment will be described. FIG. 1 is a cross-sectional view schematically showing an electrochromic device 100.
　エレクトロクロミック素子１００は、図１に示すように、第１透明電極１、第２透明電極２、ナノ結晶層３および電解質層４およびシール部５を備える。また、エレクトロクロミック素子１００は、電源部６および制御部７をさらに備える。 As shown in FIG. 1, the electrochromic element 100 includes a first transparent electrode 1, a second transparent electrode 2, a nanocrystal layer 3, an electrolyte layer 4, and a seal portion 5. The electrochromic element 100 further includes a power supply unit 6 and a control unit 7.
　第１透明電極１および第２透明電極２は、互いに対向するように配置されている。第１透明電極１および第２透明電極２は、それぞれ透明であり、実質的に無色である。第１透明電極１および第２透明電極２は、電源部６に電気的に接続されている。第１透明電極１は、第１基板１１に支持されている。第２透明電極２は、第２基板１２に支持されている。第１基板１１および第２基板１２は、それぞれ透明であり、実質的に無色である。 The first transparent electrode 1 and the second transparent electrode 2 are arranged so as to face each other. The first transparent electrode 1 and the second transparent electrode 2 are each transparent and substantially colorless. The first transparent electrode 1 and the second transparent electrode 2 are electrically connected to the power supply unit 6. The first transparent electrode 1 is supported on the first substrate 11. The second transparent electrode 2 is supported on the second substrate 12. The first substrate 11 and the second substrate 12 are each transparent and substantially colorless.
　ナノ結晶層３は、第１透明電極１の第２透明電極２側の表面上に設けられている。ナノ結晶層３は、複数の金属酸化物ナノ粒子を含む。金属酸化物ナノ粒子は、数ｎｍ～数十ｎｍの粒径を有する粒子状の結晶体（ナノ結晶）である。 The nanocrystal layer 3 is provided on the surface of the first transparent electrode 1 on the second transparent electrode 2 side. The nanocrystal layer 3 includes a plurality of metal oxide nanoparticles. The metal oxide nanoparticles are particulate crystals (nanocrystals) having a particle size of several nm to several tens of nm.
　電解質層４は、ナノ結晶層３と第２透明電極２の間に設けられている。電界質層４は、シール部５によって包囲されている。 The electrolyte layer 4 is provided between the nanocrystal layer 3 and the second transparent electrode 2. The electrolyte layer 4 is surrounded by the seal portion 5.
　ナノ結晶層３に含まれる金属酸化物ナノ粒子は、エレクトロクロミック材料である。そのため、ナノ結晶層３の透過スペクトルは、第１透明電極１と第２透明電極２の間に印加された電圧に応じて変化する。この透過スペクトルの変化は、近赤外領域における透過率変化を伴っている。従って、本実施形態のエレクトロクロミック素子１００は、近赤外光の透過率を制御することができる。本願明細書において、近赤外領域は、波長が約８００ｎｍ以上約２５００ｎｍ以下の範囲を指す。太陽から放射される赤外光の大部分は近赤外光であるので、近赤外光の透過率を制御することにより、太陽光による日射熱の取得率を制御することができる。例えば、夏期には近赤外光の室内への入射を防ぐことができ、冬期には近赤外光を室内に取り込むことができる。ナノ結晶層３がエレクトロクロミズムを示す原理については後述する。なお、ナノ結晶層３の透過スペクトルの変化は、近赤外領域における透過率変化だけでなく、可視領域（約４００ｎｍ以上約８００ｎｍ以下の範囲）における透過率変化を伴っていてもよい。 The metal oxide nanoparticles contained in the nanocrystal layer 3 are electrochromic materials. Therefore, the transmission spectrum of the nanocrystal layer 3 changes according to the voltage applied between the first transparent electrode 1 and the second transparent electrode 2. This change in the transmission spectrum is accompanied by a change in transmittance in the near infrared region. Therefore, the electrochromic element 100 of this embodiment can control the transmittance of near infrared light. In the specification of the present application, the near-infrared region refers to a wavelength range of about 800 nm or more and about 2500 nm or less. Since most of the infrared light radiated from the sun is near-infrared light, the acquisition rate of solar heat from sunlight can be controlled by controlling the transmittance of the near-infrared light. For example, near-infrared light can be prevented from entering the room in summer, and near-infrared light can be taken into the room in winter. The principle that the nanocrystal layer 3 exhibits electrochromism will be described later. Note that the change in the transmission spectrum of the nanocrystal layer 3 may be accompanied by not only the change in transmittance in the near-infrared region but also the change in transmittance in the visible region (range of about 400 nm or more and about 800 nm or less).
　電源部６は、第１透明電極１と第２透明電極の間に所定の電圧を印加する。 The power supply unit 6 applies a predetermined voltage between the first transparent electrode 1 and the second transparent electrode.
　制御部７は、第１透明電極１と第２透明電極２の間への印加電圧を制御する。例えば、制御部７は、第１透明電極１と第２透明電極２の間に所望の大きさおよび極性の電圧が印加されるように電源部６を制御する。なお、本願明細書では、「第１透明電極１と第２透明電極２の間への印加電圧」は、第２透明電極２の電位を基準電位としたときの第１透明電極１の電位に相当する。例えば、第２透明電極２の電位が０Ｖ、第１透明電極１の電位が＋３Ｖである場合、第１透明電極１と第２透明電極２の間への印加電圧は＋３Ｖである。 The control unit 7 controls the voltage applied between the first transparent electrode 1 and the second transparent electrode 2. For example, the control unit 7 controls the power supply unit 6 so that a voltage having a desired magnitude and polarity is applied between the first transparent electrode 1 and the second transparent electrode 2. In the present specification, “the applied voltage between the first transparent electrode 1 and the second transparent electrode 2” is the potential of the first transparent electrode 1 when the potential of the second transparent electrode 2 is set as a reference potential. Equivalent to. For example, when the potential of the second transparent electrode 2 is 0V and the potential of the first transparent electrode 1 is + 3V, the applied voltage between the first transparent electrode 1 and the second transparent electrode 2 is + 3V.
　本実施形態の制御部７は、印加電圧を所定のある電圧（以下では「第１電圧」と呼ぶ）ＶAから第１電圧ＶAとは異なる別のある電圧（以下では「第２電圧」と呼ぶ）ＶBに切り替えることによってナノ結晶層３の透過スペクトルを変化させる場合（以下では「第１の場合」と呼ぶ）には、印加電圧を第１電圧ＶAから第２電圧ＶBまで徐々に変化させる。 The control unit 7 according to the present embodiment uses a predetermined voltage (hereinafter referred to as “first voltage”) V A to a different voltage (hereinafter referred to as “second voltage”) different from the first voltage V A. When the transmission spectrum of the nanocrystal layer 3 is changed by switching to V B (hereinafter referred to as “first case”), the applied voltage is changed from the first voltage V A to the second voltage V B. Change gradually.
　また、制御部７は、印加電圧を第２電圧ＶBから第１電圧ＶAに切り替えることによってナノ結晶層３の透過スペクトルを変化させる場合（以下では「第２の場合」と呼ぶ）には、印加電圧を第２電圧ＶBから第１電圧ＶAまで徐々に変化させる。 In addition, the control unit 7 changes the transmission spectrum of the nanocrystal layer 3 by switching the applied voltage from the second voltage V B to the first voltage V A (hereinafter referred to as “second case”). The applied voltage is gradually changed from the second voltage V B to the first voltage V A.
　以下、制御部７による印加電圧の制御を、第１電圧ＶAが－Ｖ３、第２電圧ＶBが＋Ｖ３である例を用いて説明する。－Ｖ３印加時の透過スペクトルは、近赤外線の透過率が相対的に低い状態（つまり近赤外線を遮蔽する状態）であり、＋Ｖ３印加時の透過スペクトルは、近赤外線の透過率が相対的に高い状態（つまり近赤外線を透過する状態）であるとする。 Hereinafter, the control of the applied voltage by the control unit 7 will be described using an example in which the first voltage V A is −V3 and the second voltage V B is + V3. The transmission spectrum when -V3 is applied is a state in which the near-infrared transmittance is relatively low (that is, the state where the near-infrared is shielded), and the transmission spectrum when + V3 is applied has a relatively high near-infrared transmittance. Suppose that it is in a state (that is, a state that transmits near infrared rays).
　まず、図２を参照しながら、比較例の電圧制御を説明する。図２は、横軸を時間とし、縦軸を第１透明電極１と第２透明電極２の間への印加電圧としたグラフである。 First, the voltage control of the comparative example will be described with reference to FIG. FIG. 2 is a graph in which the horizontal axis represents time and the vertical axis represents the voltage applied between the first transparent electrode 1 and the second transparent electrode 2.
　図２に示す例では、印加電圧を－Ｖ３から＋Ｖ３に切り替える場合には、印加電圧を－Ｖ３から＋Ｖ３まで一気に（急に）変化させ、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合には、印加電圧を＋Ｖ３から－Ｖ３まで一気に（急に）変化させる。印加電圧を－Ｖ３と＋Ｖ３の間で切り替えて透過スペクトルを変化させる場合、図２に示した比較例のような電圧制御が従来通りの自然な態様として考えられる。 In the example shown in FIG. 2, when the applied voltage is switched from −V3 to + V3, the applied voltage is changed suddenly from −V3 to + V3, and when the applied voltage is switched from + V3 to −V3, the applied voltage is applied. The voltage is changed suddenly from + V3 to -V3. When changing the transmission spectrum by switching the applied voltage between −V3 and + V3, voltage control as in the comparative example shown in FIG. 2 is considered as a natural mode as before.
　しかしながら、このような制御を行った場合、既に説明したような劣化や動作不良が発生するおそれがある。劣化の例として、第１基板１１および第２基板１２として可撓性を有するフィルム基板を用いた場合のエレクトロクロミック素子端部における反りに起因するものが挙げられる。 However, when such control is performed, there is a possibility that the deterioration and the malfunction as described above may occur. As an example of the deterioration, there may be mentioned one caused by warpage at the end of the electrochromic element when a flexible film substrate is used as the first substrate 11 and the second substrate 12.
　図３は、フィルム基板の切断や貼り合せ時の影響により、エレクトロクロミック素子の端部において第１基板１１に反りが生じた状態を示している。なお、図３では、第１透明電極１、第２透明電極２およびナノ結晶層３の図示を省略している。また、図３には、第１透明電極１と第２透明電極２の間に電圧が印加されたときに生じる等電位線ｅｑおよび電気力線ｅｆを示している。図３に示すように、反りが生じている領域付近には、電気力線ｅｆが集中する部分（電界が集中する部分であり、図中の点線で囲まれた部分）が存在し、この部分では副反応が起こりやすくなる。一度副反応が起こると、その部分における副反応はいっそう起こりやすくなり、結果として上下基板の電気抵抗が局所的に低下した状態となる。 FIG. 3 shows a state in which the first substrate 11 is warped at the end of the electrochromic element due to the influence of cutting and bonding of the film substrate. In FIG. 3, the first transparent electrode 1, the second transparent electrode 2, and the nanocrystal layer 3 are not shown. FIG. 3 shows equipotential lines eq and electric lines of force ef generated when a voltage is applied between the first transparent electrode 1 and the second transparent electrode 2. As shown in FIG. 3, there is a portion where electric lines of force ef concentrate (a portion where electric field concentrates and a portion surrounded by a dotted line in the figure) near the region where the warp occurs. Then side reactions are likely to occur. Once a side reaction occurs, the side reaction at that portion is more likely to occur, and as a result, the electrical resistance of the upper and lower substrates is locally reduced.
　図４は、エレクトロクロミック素子の端部において、図２に示すような電圧制御が１回行われた結果、劣化が発生している部分を示す写真である。図４中の左端の部分は、上述したような副反応により劣化した部分であり、黒く変色している。 FIG. 4 is a photograph showing a portion where deterioration has occurred as a result of the voltage control as shown in FIG. 2 being performed once at the end of the electrochromic element. The left end portion in FIG. 4 is a portion that has deteriorated due to the side reaction as described above, and has turned black.
　エレクトロクロミック素子（一種の調光セルである）は、図５に示すように、電気的に並列に接続された複数の微小セルｓｃの集合であると考えることもできる。各微小セルｓｃは、電極間の容量成分Ｃ１および抵抗成分Ｒ１を含んでおり、透明電極の抵抗成分Ｒ２で互いに並列に接続されている。副反応が進むことによって劣化した微小セル（劣化セル）ｓｃ’（図５に示す例では下段中央）で抵抗成分Ｒ１が小さくなると、劣化セルｓｃ’よりも下流にある微小セルｓｃには設定値通りの電圧は印加されなくなる。そのため、劣化部分の副反応を可能な限り抑制できるように電圧を印加することが好ましい。 An electrochromic element (a kind of dimming cell) can be considered as a set of a plurality of minute cells sc electrically connected in parallel as shown in FIG. Each micro cell sc includes a capacitance component C1 and a resistance component R1 between the electrodes, and is connected in parallel with each other by a resistance component R2 of the transparent electrode. When the resistance component R1 decreases in the minute cell (deteriorated cell) sc ′ (lower center in the example shown in FIG. 5) that has deteriorated due to the progress of the side reaction, the set value is set in the minute cell sc downstream of the deteriorated cell sc ′. The street voltage is no longer applied. Therefore, it is preferable to apply a voltage so as to suppress the side reaction at the deteriorated portion as much as possible.
　既に説明したように、本実施形態の制御部７は、印加電圧を第１電圧ＶAから第２電圧ＶBに切り替えることによってナノ結晶層３の透過スペクトルを変化させる場合（「第１の場合」）には、印加電圧を第１電圧ＶAから第２電圧ＶBまで徐々に変化させる。また、制御部７は、印加電圧を第２電圧ＶBから第１電圧ＶAに切り替えることによってナノ結晶層３の透過スペクトルを変化させる場合（「第２の場合」）には、印加電圧を第２電圧ＶBから第１電圧ＶAまで徐々に変化させる。このことにより、上述したような副反応を抑制することができ、繰り返し動作特性を改善することができる。 As already described, the control unit 7 of the present embodiment changes the transmission spectrum of the nanocrystal layer 3 by switching the applied voltage from the first voltage V A to the second voltage V B (“first case”). ]), The applied voltage is gradually changed from the first voltage V A to the second voltage V B. In addition, the control unit 7 changes the transmission spectrum of the nanocrystal layer 3 by switching the applied voltage from the second voltage V B to the first voltage V A (“second case”). The voltage is gradually changed from the second voltage V B to the first voltage V A. As a result, the side reaction as described above can be suppressed, and the repeated operation characteristics can be improved.
　図６に、制御部７による電圧制御の例を示す。図６に示す例では、印加電圧を－Ｖ３から＋Ｖ３に切り替える場合には、印加電圧を－Ｖ３、－Ｖ２、－Ｖ１、０、＋Ｖ１、＋Ｖ２、＋Ｖ３（言うまでもないが－Ｖ３、－Ｖ２、－Ｖ１、＋Ｖ１、＋Ｖ２、＋Ｖ３は、－Ｖ３＜－Ｖ２＜－Ｖ１＜０＜＋Ｖ１＜＋Ｖ２＜Ｖ３の関係を満足する）と段階的に変化させる。また、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合には、印加電圧を＋Ｖ３、＋Ｖ２、＋Ｖ１、０、－Ｖ１、－Ｖ２、－Ｖ３と段階的に変化させる。なお、ここで、「－Ｖ３」と「＋Ｖ３」という表記は、絶対値が同じ電圧であることを必ずしも意味していない。つまり、「－Ｖ３」と「＋Ｖ３」とは、絶対値が同じであってもよいし、異なっていてもよい。同様に、「－Ｖ２」と「＋Ｖ２」とは、絶対値が同じ電圧であることを必ずしも意味しておらず、「－Ｖ１」と「＋Ｖ１」とは、絶対値が同じ電圧であることを必ずしも意味していない。 FIG. 6 shows an example of voltage control by the control unit 7. In the example shown in FIG. 6, when the applied voltage is switched from -V3 to + V3, the applied voltage is -V3, -V2, -V1, 0, + V1, + V2, + V3 (which is needless to say -V3, -V2,- V1, + V1, + V2, and + V3 are changed stepwise as follows: −V3 <−V2 <−V1 <0 <+ V1 <+ V2 <V3. When the applied voltage is switched from + V3 to -V3, the applied voltage is changed stepwise from + V3, + V2, + V1, 0, -V1, -V2, and -V3. Here, the notations “−V3” and “+ V3” do not necessarily mean that the absolute values are the same voltage. That is, “−V3” and “+ V3” may have the same absolute value or different values. Similarly, “−V2” and “+ V2” do not necessarily mean that the absolute values are the same voltage, and “−V1” and “+ V1” indicate that the absolute values are the same voltage. It doesn't necessarily mean.
　印加電圧を各電圧値に変化させた後の保持時間ｔ１～ｔ１０は、例えば、それぞれの電圧変化時の応答速度ｔｒと同等に設定される。ここでの応答速度は、それぞれの電圧変化時に参照波長における透過率の変化量が９割に達する時間である。参照波長は、印加電圧を－Ｖ３から＋Ｖ３に切り替えたとき（または＋Ｖ３から－Ｖ３に切り替えたとき）にもっとも透過率が大きく変化する波長である。なお、保持時間ｔ１～ｔ１０の長さは、ここで例示したものに限定されるわけではない。保持時間ｔ１～ｔ１０のうち、保持時間ｔ１～ｔ５と保持時間ｔ６～ｔ１０とで、長さの基準となる透過率変化量が異なっていてもよい。例えば、保持時間ｔ１～ｔ１０のうち、保持時間ｔ１～ｔ５を、透過率の変化量が５割に達する時間とするとともに、保持時間ｔ６～ｔ１０を透過率の変化量が９割に達する時間としてもよい。さらに、切り替え時間を短縮するために、保持時間ｔ１～ｔ１０を、透過率の変化量が５割に達する時間としてもよい。 The holding times t1 to t10 after changing the applied voltage to each voltage value are set to be equal to the response speed tr at the time of each voltage change, for example. The response speed here is the time for the amount of change in transmittance at the reference wavelength to reach 90% at each voltage change. The reference wavelength is a wavelength at which the transmittance changes most when the applied voltage is switched from −V3 to + V3 (or from + V3 to −V3). Note that the lengths of the holding times t1 to t10 are not limited to those illustrated here. Among the holding times t1 to t10, the amount of change in transmittance that serves as a reference for the length may be different between the holding times t1 to t5 and the holding times t6 to t10. For example, among the holding times t1 to t10, the holding times t1 to t5 are set as times when the transmittance change amount reaches 50%, and the holding times t6 to t10 are set as times when the transmittance change amount reaches 90%. Also good. Further, in order to shorten the switching time, the holding times t1 to t10 may be set as the time when the transmittance change amount reaches 50%.
　また、図６に示す例では、印加電圧を第１電圧ＶA（ここでは－Ｖ３）から第２電圧ＶB（ここでは＋Ｖ３）に切り替える場合、および、第２電圧ＶBから第１電圧ＶAに切り替える場合のそれぞれにおいて、印加電圧を６段階に変化させているが、印加電圧の変化は２段階以上であればよく、７段階以上であってもよい。また、印加電圧の段階的な変化は、第１電圧ＶAと第２電圧ＶBとの間を必ずしも等分割する必要はなく、例えば、印加電圧の極性が変化した後には、変化前よりも細かい間隔で印加電圧を変化させてもよい。 In the example shown in FIG. 6, the applied voltage is switched from the first voltage V A (here, −V3) to the second voltage V B (here, + V3), and from the second voltage V B to the first voltage V. In each case of switching to A , the applied voltage is changed in six steps, but the change in the applied voltage may be two steps or more, and may be seven steps or more. Further, the stepwise change in the applied voltage does not necessarily divide the first voltage V A and the second voltage V B equally. For example, after the polarity of the applied voltage is changed, it is more than before the change. The applied voltage may be changed at fine intervals.
　さらに、第１電圧ＶAと第２電圧ＶBとは、必ずしも互いに極性が異なる電圧である必要はない。第１電圧ＶAと第２電圧ＶBとは、互いに極性が同じで大きさが異なる電圧であってもよい。また、第１電圧ＶAと第２電圧ＶBのどちらかが０Ｖであってもよい。ただし、第１電圧ＶAと第２電圧ＶBの極性が互いに異なる場合、印加電圧の切り替え時の電圧差が大きくなりやすいことや、極性反転を伴うことなどから、上述したようなエレクトロクロミック素子の劣化等が発生しやすい。そのため、本開示の実施形態は、第１電圧ＶAと第２電圧ＶBとが、互いに極性が異なる電圧である場合に用いる意義が大きいといえる。より具体的には、第１電圧ＶAが－５Ｖ以上０Ｖ以下であり、第２電圧ＶBが０Ｖ超＋５Ｖ以下であることが好ましい。 Furthermore, the first voltage V A and the second voltage V B do not necessarily have to have different polarities. The first voltage V A and the second voltage V B may be voltages having the same polarity and different magnitudes. Further, either the first voltage V A or the second voltage V B may be 0V. However, when the polarities of the first voltage V A and the second voltage V B are different from each other, the voltage difference at the time of switching the applied voltage is likely to increase, and the polarity reversal is accompanied. It is easy for deterioration to occur. Therefore, it can be said that the embodiment of the present disclosure is significantly used when the first voltage V A and the second voltage V B are voltages having different polarities. More specifically, it is preferable that the first voltage V A is −5 V or more and 0 V or less, and the second voltage V B is more than 0 V and +5 V or less.
　ここで、本実施形態のように、印加電圧を徐々に変化させることによって、劣化および動作不良の発生が抑制されるメカニズムの一例を説明する。 Here, an example of a mechanism in which the occurrence of deterioration and malfunction is suppressed by gradually changing the applied voltage as in the present embodiment will be described.
　既に説明したように、本実施形態のエレクトロクロミック素子１００では、ナノ結晶層３に含まれる金属酸化物ナノ粒子の局在表面プラズモン共鳴（ＬＳＰＲ）を利用してエレクトロクロミズムを発現させる。そのため、透過スペクトルを変化させる際には、後に詳述するように、金属酸化物ナノ粒子の自由電子密度を変化させる。 As already described, in the electrochromic device 100 of the present embodiment, electrochromism is expressed by utilizing localized surface plasmon resonance (LSPR) of metal oxide nanoparticles contained in the nanocrystal layer 3. Therefore, when changing the transmission spectrum, the free electron density of the metal oxide nanoparticles is changed as will be described in detail later.
　金属酸化物ナノ粒子の自由電子密度を変化させるような系においては、状態保持の特性は、主に酸化還元反応によるものではなく、ナノ粒子界面における電気二重層の形成によるものである。印加電圧の極性を反転させて透過スペクトルを変化させるとき、電解質のイオンは拡散する。 In a system that changes the free electron density of metal oxide nanoparticles, the state retention characteristics are not mainly due to redox reaction but due to the formation of an electric double layer at the nanoparticle interface. When the transmission spectrum is changed by reversing the polarity of the applied voltage, the electrolyte ions diffuse.
　図７（ａ）の上側は、ナノ結晶層に負電圧を印加した状態から正電圧を印加した状態に切り替えたときに、十分に時間が経過してナノ粒子界面から正イオンが遠ざかり負イオンによって電気二重層が形成された状態を示している。図７（ａ）の下側は、その状態における、ナノ粒子表面からの距離と電位との関係を示している。図７（ａ）の下側に示されているように、界面近傍の電位差はＶａとなる。 The upper side of FIG. 7A shows that when switching from a state where a negative voltage is applied to the nanocrystal layer to a state where a positive voltage is applied, a sufficient amount of time has passed and positive ions have moved away from the nanoparticle interface due to negative ions. The state where the electric double layer was formed is shown. The lower side of FIG. 7A shows the relationship between the distance from the nanoparticle surface and the potential in that state. As shown in the lower side of FIG. 7A, the potential difference near the interface is Va.
　図７（ｂ）の上側は、電解質イオンが移動しにくい場合（例えば電解液の粘度が非常に高い場合）に、ナノ結晶層への印加電圧の極性を急激に入れ替えたときの様子を示している。ナノ結晶層に負電圧を印加していたときに電気二重層を形成していた正イオンが十分に拡散されずにナノ粒子界面付近に存在している。図７（ｂ）の下側は、その状態におけるナノ粒子表面からの距離と電位との関係を示している。図７（ｂ）の下側に示されているように、界面近傍の電位は、正イオンによって少し高くなるので、界面付近の電位差はＶａよりも大きなＶｂとなる。そのため、界面付近に生じる大きな電位差によって副反応（不要な酸化還元反応）が起きやすくなると考えられる。 The upper side of FIG. 7B shows a state in which the polarity of the voltage applied to the nanocrystal layer is suddenly changed when the electrolyte ions are difficult to move (for example, when the viscosity of the electrolyte is very high). Yes. The positive ions forming the electric double layer when a negative voltage is applied to the nanocrystal layer are not sufficiently diffused but are present in the vicinity of the nanoparticle interface. The lower side of FIG. 7B shows the relationship between the distance from the nanoparticle surface and the potential in that state. As shown in the lower side of FIG. 7B, the potential in the vicinity of the interface is slightly increased by the positive ions, so that the potential difference in the vicinity of the interface becomes Vb larger than Va. For this reason, it is considered that side reactions (unnecessary oxidation-reduction reactions) easily occur due to a large potential difference generated near the interface.
　これに対し、本開示の実施形態のように、印加電圧を徐々に変化させると、図７（ｂ）に示したような状態となることを防止できるので、副反応に起因する劣化を抑制することができる。 On the other hand, when the applied voltage is gradually changed as in the embodiment of the present disclosure, the state as shown in FIG. 7B can be prevented, so that deterioration due to the side reaction is suppressed. be able to.
　金属酸化物ナノ粒子の自由電子密度を変化させる素子においては、一方の状態から他方の状態に切り替えるとき、電圧を少しでも変化させたときから他方の状態への変化が開始される。そのため、自由電子密度を安定化させる電解質イオンの移動は、電圧を少し変化させたときから起こり始めるので、電気二重層を形成するイオンの確実な移動を実現させるためには、電圧を変化させ始めたときから十分な（本実施形態のような）制御を行うことが好ましいといえる。 In the element that changes the free electron density of the metal oxide nanoparticles, when switching from one state to the other state, the change to the other state starts when the voltage is changed even a little. Therefore, the movement of electrolyte ions that stabilize the free electron density begins to occur when the voltage is slightly changed. Therefore, in order to realize reliable movement of ions that form the electric double layer, the voltage starts to change. Therefore, it can be said that it is preferable to perform sufficient control (as in this embodiment).
　［ナノ結晶層の動作原理］
　ここで、ナノ結晶層３がエレクトロクロミズムを示す原理を説明する。 [Principle of operation of nanocrystal layer]
Here, the principle that the nanocrystal layer 3 exhibits electrochromism will be described.
　非特許文献１に記載されているように、ＩＴＯ（Tin doped Indium Oxide）ナノ結晶層などの透明導電性酸化物（Transparent Conducting Oxide：ＴＣＯ）ナノ構造体に電子を注入することによって、近赤外領域の透過スペクトルを変化させ得ることが知られている。その原理は、端的に言えば、ＴＣＯナノ構造体の局在表面プラズモン共鳴（ＬＳＰＲ）による吸収波長を、電圧印加によってシフトさせることである。以下、より詳細に説明する。 As described in Non-Patent Document 1, by injecting electrons into a transparent conductive oxide (TCO) nanostructure such as an ITO (Tin-doped Indium-Oxide) nanocrystal layer, near-infrared It is known that the transmission spectrum of a region can be changed. In short, the principle is to shift the absorption wavelength by localized surface plasmon resonance (LSPR) of the TCO nanostructure by applying a voltage. This will be described in more detail below.
　ＬＳＰＲの共鳴周波数は、プラズマ周波数ωpに比例する。プラズマ周波数ωpは、下記式で表わされる。
　ωp２＝Ｎ・ｅ2／（ｍ・ε０） The resonance frequency of LSPR is proportional to the plasma frequency ω p . The plasma frequency ω p is expressed by the following equation.
ω p 2 = N · e 2 / (m · ε0)
　ここで、Ｎは電子密度、ｅは電子の電荷、ｍは電子の有効質量、ε０は真空の誘電率である。従って、ＴＣＯナノ構造体に負電圧を印加して電子密度を高くすると、プラズマ周波数ωpが大きくなるので、ＬＳＰＲの共鳴周波数も大きくなる。そのため、ＬＳＰＲの共鳴波長は短くなる（つまり短波長側にシフトする）。ＴＣＯナノ構造体のキャリア密度を調整することにより、ＬＳＰＲの共鳴波長を近赤外領域に設定できるので、近赤外領域における透過スペクトルを変化させることが可能となる。 Here, N is the electron density, e is the charge of the electron, m is the effective mass of the electron, and ε0 is the dielectric constant of the vacuum. Therefore, when a negative voltage is applied to the TCO nanostructure to increase the electron density, the plasma frequency ω p increases, and the resonance frequency of the LSPR also increases. Therefore, the resonance wavelength of LSPR becomes short (that is, shifts to the short wavelength side). By adjusting the carrier density of the TCO nanostructure, the resonance wavelength of the LSPR can be set in the near infrared region, so that the transmission spectrum in the near infrared region can be changed.
　なお、このように透過スペクトルを変化させる機能は、ＩＴＯナノ粒子を含むＩＴＯナノ結晶層だけに特有のものではない。ナノ粒子が、ＬＳＰＲが生じるようなサイズ（例えば１００ｎｍ以下）であり、且つ、ナノ結晶層が透明電極からの電子を注入され得るような構成であれば、原理的には上述した機能を奏し得る。ナノ粒子としては、ＡＴＯ、ＰＴＯ（リンドープ酸化錫）、ＡＺＯ（アルミニウムドープ酸化亜鉛）、ＧＺＯ（ガリウムドープ酸化亜鉛）等の種々の金属酸化物のナノ粒子を用いることができる。 Note that the function of changing the transmission spectrum in this way is not unique to the ITO nanocrystal layer containing ITO nanoparticles. In principle, the above-described functions can be achieved if the nanoparticles are sized so as to cause LSPR (for example, 100 nm or less), and the nanocrystal layer can inject electrons from the transparent electrode. . As nanoparticles, nanoparticles of various metal oxides such as ATO, PTO (phosphorus-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide) can be used.
　［実施例］
　エレクトロクロミック素子１００の実施例を以下のようにして作製し、その光学特性を検証した。また、繰り返し動作特性についても評価を行った。 [Example]
An example of the electrochromic device 100 was manufactured as follows and the optical characteristics thereof were verified. The repeated operation characteristics were also evaluated.
　まず、第１基板１１および第２基板１２としてそれぞれガラス基板を用意した。次に、第１基板１１上に、近赤外領域において透明となるようなチタンドープ酸化インジウム（Titanium-doped Indium Oxide：ＩｎＴｉＯ）をスパッタ法により堆積し、第１透明電極１を形成した。同様にして、第２基板１２上に第２透明電極２を形成した。 First, glass substrates were prepared as the first substrate 11 and the second substrate 12, respectively. Next, titanium-doped indium oxide (Titanium-doped Indium Oxide: InTiO), which becomes transparent in the near infrared region, was deposited on the first substrate 11 by sputtering to form the first transparent electrode 1. Similarly, the second transparent electrode 2 was formed on the second substrate 12.
　続いて、第１透明電極１上に、ＡＴＯナノ粒子の分散液をスピンコート法により塗布し、ホットプレート上で１４０℃で１分間乾燥させた後、２００℃で６０分間焼成を行うことにより、ナノ結晶層３を形成した。使用したＡＴＯナノ粒子分散液は、帯電防止膜形成用に市販されているもの（大日本塗料株式会社製）であり、ＡＴＯナノ粒子の粒径は８ｎｍ～３０ｎｍ、分散媒はメチルイソブチルケトンとイソブタノールとの混合液である。 Subsequently, a dispersion of ATO nanoparticles is applied on the first transparent electrode 1 by spin coating, dried on a hot plate at 140 ° C. for 1 minute, and then fired at 200 ° C. for 60 minutes, A nanocrystal layer 3 was formed. The ATO nanoparticle dispersion used is commercially available for the formation of an antistatic film (manufactured by Dainippon Paint Co., Ltd.). The particle size of the ATO nanoparticles is 8-30 nm, and the dispersion medium is methyl isobutyl ketone and isoform. It is a mixed solution with butanol.
　その後、粒径が１０μｍの樹脂スペーサを２ｗｔ％含むＵＶ硬化型樹脂材料を、ナノ結晶層３または第２透明電極２の外周上に、部分的に注入口が存在するように塗布する。続いて、両基板を重ね合せ、紫外線を照射することによってシール部５を形成した。次に、注入口から電解液として、１ｍｏｌ／ＬのＬｉＢＦ4を含むＥＣ（Ethylene carbonate）・ＤＥＣ（Diethyl Carbonate）混合液（ＥＣ：ＤＥＣ＝１：２）を注入し、その後、ＵＶ硬化型樹脂材料で封止を行って電解質層４を形成した。 Thereafter, a UV curable resin material containing 2 wt% of a resin spacer having a particle size of 10 μm is applied on the outer periphery of the nanocrystal layer 3 or the second transparent electrode 2 so that the injection port partially exists. Subsequently, both the substrates were overlapped and irradiated with ultraviolet rays to form the seal portion 5. Next, an EC (Ethylene carbonate) / DEC (Diethyl Carbonate) mixed solution (EC: DEC = 1: 2) containing 1 mol / L LiBF 4 is injected from the injection port as an electrolytic solution, and then UV curable resin is used. The electrolyte layer 4 was formed by sealing with a material.
　このようにして、実施例のエレクトロクロミック素子１００が得られた。図８に、第２透明電極２の電位を０Ｖとし、第１透明電極１に－３Ｖおよび＋３Ｖの電圧を印加したときの透過スペクトルを示す。図８から、近赤外領域における透過スペクトルが、印加電圧の極性の切り替えに応じて大きく変化していることがわかる。 Thus, the electrochromic device 100 of the example was obtained. FIG. 8 shows a transmission spectrum when the potential of the second transparent electrode 2 is 0 V and voltages of −3 V and +3 V are applied to the first transparent electrode 1. From FIG. 8, it can be seen that the transmission spectrum in the near-infrared region changes greatly according to the switching of the polarity of the applied voltage.
　図９に示すような印加電圧の制御を行って、実施例のエレクトロクロミック素子１００の繰り返し動作特性を評価した。図９に示す例では、印加電圧を－３Ｖと＋３Ｖとの間で切り替える。－３Ｖから＋３Ｖに切り替える場合には、印加電圧を－３Ｖ、－２Ｖ、－１Ｖ、０Ｖ、＋１Ｖ、＋２Ｖ、＋３Ｖと段階的に変化させ、＋３Ｖから－３Ｖに切り替える場合には、印加電圧を＋３Ｖ、＋２Ｖ、＋１Ｖ、０Ｖ、－１Ｖ、－２Ｖ、－３Ｖと段階的に変化させる。 The applied voltage was controlled as shown in FIG. 9 to evaluate the repeated operation characteristics of the electrochromic device 100 of the example. In the example shown in FIG. 9, the applied voltage is switched between -3V and + 3V. When switching from -3V to + 3V, the applied voltage is changed stepwise from -3V, -2V, -1V, 0V, + 1V, + 2V, + 3V, and when switching from + 3V to -3V, the applied voltage is + 3V , + 2V, + 1V, 0V, -1V, -2V, and -3V.
　各電圧での保持時間は、透過率変化がもっとも大きい波長である１８００ｎｍでの応答速度ｔｒに基づいて設定した。印加電圧を－３Ｖから－２Ｖに変化させたときの保持時間ｔ１は、ほぼゼロである。印加電圧を－２Ｖから－１Ｖに変化させたとき、および、－１Ｖから０Ｖに変化させたときの保持時間ｔ２およびｔ３は、それぞれ１分および１分である。印加電圧を０Ｖから＋１Ｖに変化させたとき、および、＋１Ｖから＋２Ｖに変化させたときの保持時間ｔ４およびｔ５は、それぞれ３分および６分である。また、印加電圧を＋３Ｖから＋２Ｖに変化させたとき、＋２Ｖから＋１Ｖに変化させたとき、および、＋１Ｖから０Ｖに変化させたときの保持時間ｔ６、ｔ７およびｔ８は、それぞれ３分、３分および１分である。印加電圧を０Ｖから－１Ｖに変化させたとき、および、－１Ｖから－２Ｖに変化させたときの保持時間ｔ９およびｔ１０は、それぞれ１分および３分である。 The holding time at each voltage was set based on the response speed tr at 1800 nm, which is the wavelength with the largest transmittance change. The holding time t1 when the applied voltage is changed from -3V to -2V is almost zero. The holding times t2 and t3 when the applied voltage is changed from -2V to -1V and when the applied voltage is changed from -1V to 0V are 1 minute and 1 minute, respectively. The holding times t4 and t5 when the applied voltage is changed from 0V to + 1V and from + 1V to + 2V are 3 minutes and 6 minutes, respectively. When the applied voltage is changed from + 3V to + 2V, from + 2V to + 1V, and from + 1V to 0V, the holding times t6, t7 and t8 are 3 minutes, 3 minutes and 1 minute. The holding times t9 and t10 when the applied voltage is changed from 0V to -1V and when the applied voltage is changed from -1V to -2V are 1 minute and 3 minutes, respectively.
　図９に示した電圧制御を３０回以上行ったところ、上述したような素子の端部における劣化（黒く変色する現象）は観察されず、良好な繰り返し動作特性が得られていることが確認された。図９に示した例では、印加電圧を－３Ｖから＋３Ｖに変化させる場合に、各電圧での保持時間が徐々に長くなっており、このような制御が好ましいことがわかる。また、図９に示した例では、印加電圧を＋３Ｖから－３Ｖに変化させる場合の各電圧での保持時間は、実際に測定中の透過率の変化が概ね完了する前に印加電圧を切り換えないように設定されている。つまり、各電圧での保持時間は、各電圧における透過率の変化が概ね完了するように設定されることが好ましい。 When the voltage control shown in FIG. 9 was performed 30 times or more, the above-described deterioration at the end of the element (a phenomenon of black discoloration) was not observed, and it was confirmed that good repeated operation characteristics were obtained. It was. In the example shown in FIG. 9, when the applied voltage is changed from −3V to + 3V, the holding time at each voltage gradually increases, and it can be seen that such control is preferable. In the example shown in FIG. 9, the holding time at each voltage when the applied voltage is changed from +3 V to -3 V is not switched before the change in transmittance during the actual measurement is almost completed. Is set to That is, the holding time at each voltage is preferably set so that the change in transmittance at each voltage is almost completed.
　［電圧制御の他の例］
　図６および図９には、印加電圧を第１電圧ＶAから第２電圧ＶBに切り替える場合（第１の場合）および第２電圧ＶBから第１電圧ＶAに切り替える場合（第２の場合）のそれぞれにおいて、印加電圧が段階的に変化する例を示したが、印加電圧の制御はこの例に限定されるものではない。 [Other examples of voltage control]
FIGS. 6 and 9 show the case where the applied voltage is switched from the first voltage V A to the second voltage V B (first case) and the case where the applied voltage is switched from the second voltage V B to the first voltage V A (second case). In each case, the applied voltage changes step by step. However, the control of the applied voltage is not limited to this example.
　図１０に、印加電圧の制御の他の例を示す。図１０に示す例では、印加電圧を－Ｖ３（第１電圧ＶA）から＋Ｖ３（第２電圧ＶB）に切り替える場合および＋Ｖ３から－Ｖ３に切り替える場合のそれぞれにおいて、印加電圧は連続的に変化する。 FIG. 10 shows another example of applied voltage control. In the example shown in FIG. 10, when the applied voltage is switched from −V3 (first voltage V A ) to + V3 (second voltage V B ) and from + V3 to −V3, the applied voltage continuously changes. To do.
　図１０に示す例において、印加電圧を－Ｖ３から＋Ｖ３まで変化させる時間は、例えば、段階的に変化させる場合の保持時間の合計（図６に示す例における保持時間ｔ１、ｔ２、ｔ３、ｔ４およびｔ５の合計）と同じであってよい。同様に、印加電圧を＋Ｖ３から－Ｖ３まで変化させる時間は、段階的に変化させる場合の保持時間の合計（図６に示す例における保持時間ｔ６、ｔ７、ｔ８、ｔ９およびｔ１０の合計）と同じであってよい。 In the example shown in FIG. 10, the time for changing the applied voltage from −V3 to + V3 is, for example, the sum of the holding times when changing stepwise (holding times t1, t2, t3, t4 in the example shown in FIG. 6 and the sum of t5). Similarly, the time for changing the applied voltage from + V3 to −V3 is the same as the total of the holding times when changing in stages (the total of holding times t6, t7, t8, t9 and t10 in the example shown in FIG. 6). It may be.
　図１０に示す例のように、印加電圧を連続的に変化させた場合でも、段階的に変化させた場合と同様に、素子の劣化を抑制する効果が得られる。また、印加電圧を連続的に変化させると、微小な時間で見たときの急激な電圧変化がないという利点がある。一方、印加電圧を段階的に変化させると、エレクトロクロミック素子を視認するユーザーにとって切り替わりを体感しやすいという利点がある。 As in the example shown in FIG. 10, even when the applied voltage is continuously changed, the effect of suppressing the deterioration of the element can be obtained as in the case where the applied voltage is changed stepwise. Further, when the applied voltage is continuously changed, there is an advantage that there is no sudden voltage change when viewed in a minute time. On the other hand, when the applied voltage is changed in stages, there is an advantage that the user who views the electrochromic element can easily feel the switching.
　なお、図１０には、印加電圧の上昇速度および下降速度がそれぞれ一定である（つまり印加電圧の時間変化が直線状である）例を示した。印加電圧の上昇速度および下降速度は、例えば、０．００１Ｖ／秒～６Ｖ／秒である。ただし、印加電圧の上昇速度および下降速度は必ずしも一定である必要はない。例えば、印加電圧の時間変化が曲線状であってもよい。 Note that FIG. 10 shows an example in which the rising speed and the falling speed of the applied voltage are constant (that is, the time change of the applied voltage is linear). The rising speed and the falling speed of the applied voltage are, for example, 0.001 V / second to 6 V / second. However, the rising speed and the falling speed of the applied voltage are not necessarily constant. For example, the change with time of the applied voltage may be curved.
　これまでの説明からわかるように、本願明細書において「印加電圧を徐々に変化させる」とは、印加電圧を２段階以上で段階的に変化させるか、連続的に変化させるか、またはこれらの組み合わせを意味している。図２に示す例のように、印加電圧を急に（一気に）変化させる場合、印加電圧の切り替えに要する時間が実質的にゼロであるのに対し、印加電圧を徐々に変化させる場合、例えば応答速度と同程度のオーダーの時間で印加電圧の切り替えが行われる。 As can be seen from the above description, in the present specification, “gradually changing the applied voltage” means that the applied voltage is changed stepwise in two or more steps, continuously changed, or a combination thereof. Means. When the applied voltage is changed suddenly (at once) as in the example shown in FIG. 2, the time required for switching the applied voltage is substantially zero, whereas when the applied voltage is gradually changed, for example, response The applied voltage is switched in a time on the same order as the speed.
　また、これまでの説明で示した例では、第１の場合および第２の場合のそれぞれにおいて、印加電圧として第１電圧ＶAと０Ｖの間の大きさの電圧が保持される期間と、印加電圧として第２電圧ＶBと０Ｖの間の大きさの電圧が保持される期間とが存在する。つまり、負極性側および正極性側のそれぞれにおいて、中間的な大きさの印加電圧（第１電圧ＶAと０Ｖの間、または、第２電圧ＶBと０Ｖの間の電圧）が保持される期間がある。 Further, in the examples shown in the above description, in each of the first case and the second case, a period during which a voltage having a magnitude between the first voltage V A and 0 V is held as the applied voltage, There is a period during which a voltage having a magnitude between the second voltage V B and 0 V is held as the voltage. That is, an applied voltage of intermediate magnitude (a voltage between the first voltage V A and 0 V or a voltage between the second voltage V B and 0 V) is held on each of the negative polarity side and the positive polarity side. There is a period.
　既に説明したように、金属酸化物ナノ粒子のＬＳＰＲを利用するエレクトロクロミック素子１００では、電圧を少しでも変化させると状態変化が開始されるので、素子の劣化を抑制するためには、電圧を変化させ始めたときから十分な制御を行うことが好ましい。そのため、これまで例示したように、負極性側および正極性側のそれぞれにおいて、中間的な大きさの印加電圧が保持される期間があることが好ましいといえる。ただし、本開示の実施形態はこのような例に限定されるものではない。 As described above, in the electrochromic device 100 using the LSPR of the metal oxide nanoparticles, since the state change is started when the voltage is changed even a little, the voltage is changed to suppress the deterioration of the device. It is preferable to perform sufficient control from the beginning. Therefore, as exemplified above, it can be said that it is preferable that each of the negative polarity side and the positive polarity side has a period during which an intermediate applied voltage is maintained. However, the embodiment of the present disclosure is not limited to such an example.
　図１１に、印加電圧の制御のさらに他の例を示す。図１１に示す例では、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合（第２の場合）には、印加電圧を＋Ｖ３、＋Ｖ２、＋Ｖ１、０Ｖ、－Ｖ３と段階的に変化させ、印加電圧を－Ｖ３から＋Ｖ３に切り替える場合（第１の場合）には、印加電圧を－Ｖ３、０、＋Ｖ１、＋Ｖ２、＋Ｖ３と段階的に変化させる。 FIG. 11 shows still another example of applied voltage control. In the example shown in FIG. 11, when the applied voltage is switched from + V3 to −V3 (second case), the applied voltage is changed stepwise from + V3, + V2, + V1, 0V, and −V3, and the applied voltage is − When switching from V3 to + V3 (first case), the applied voltage is changed stepwise from −V3, 0, + V1, + V2, and + V3.
　図１１に示す例では、第１の場合および第２の場合のそれぞれにおいて、印加電圧として第２電圧ＶB（＋Ｖ３）と０Ｖの間の大きさの電圧が保持される期間が存在し、且つ、印加電圧として第１電圧ＶA（－Ｖ３）と０Ｖの間の大きさの電圧が保持される期間が存在しない。 In the example shown in FIG. 11, in each of the first case and the second case, there is a period in which a voltage having a magnitude between the second voltage V B (+ V3) and 0 V is held as the applied voltage, and There is no period during which a voltage having a magnitude between the first voltage V A (−V3) and 0 V is held as the applied voltage.
　エレクトロクロミック素子の構成材料によっては、印加電圧の極性の正負によって劣化の発生しやすさが異なることがある。例えば、金属酸化物ナノ粒子としてＡＴＯナノ粒子を用い、電解質としてイオン液体（具体的には1-Butylpyridinium bis(trifluoromethylsulfonyl)amide）を用いたエレクトロクロミック素子においては、＋３Ｖの電圧を印加したときには黒色の劣化が発生するが、－３Ｖの電圧を印加した時には顕著な劣化は発生しない。 Depending on the constituent material of the electrochromic element, the ease of deterioration may vary depending on the polarity of the applied voltage. For example, in an electrochromic device using ATO nanoparticles as metal oxide nanoparticles and an ionic liquid (specifically 1-Butylpyridinium bis (trifluoromethylsulfonyl) amide) as an electrolyte, a black color is applied when a voltage of +3 V is applied. Although degradation occurs, no significant degradation occurs when a voltage of -3V is applied.
　このような場合には、図１１に示すように、顕著な劣化が発生し得る正極性側において中間的な印加電圧が保持される期間が存在すれば、負極側には中間的な印加電圧が保持される期間が存在しなくても、劣化を十分に抑制することができる。勿論、正極性側では顕著な劣化が発生せず、負極性側で顕著な劣化が発生し得る材料を用いる場合には、顕著な劣化が発生し得る負極性側において中間的な印加電圧が保持される期間が存在すれば、正極側には中間的な印加電圧が保持される期間が存在しなくてもよい。 In such a case, as shown in FIG. 11, if there is a period in which an intermediate applied voltage is maintained on the positive polarity side where significant deterioration may occur, an intermediate applied voltage is present on the negative electrode side. Even if there is no holding period, deterioration can be sufficiently suppressed. Of course, when a material that does not cause significant deterioration on the positive polarity side and that can generate significant deterioration on the negative polarity side is used, an intermediate applied voltage is maintained on the negative polarity side where significant deterioration can occur. If there is a period to be applied, there may be no period in which the intermediate applied voltage is held on the positive electrode side.
　つまり、第１の場合および第２の場合のそれぞれにおいて、印加電圧として第１電圧ＶAおよび第２電圧ＶBの一方と０Ｖの間の大きさの電圧が保持される期間が存在し、且つ、印加電圧として第１電圧ＶAおよび第２電圧ＶBの他方と０Ｖの間の大きさの電圧が保持される期間が存在しないように印加電圧を制御すればよい。 That is, in each of the first case and the second case, there is a period in which a voltage having a magnitude between one of the first voltage V A and the second voltage V B and 0 V is held as the applied voltage, and The applied voltage may be controlled so that there is no period in which the voltage between the other of the first voltage V A and the second voltage V B and 0 V is held as the applied voltage.
　図１１では、印加電圧を段階的に変化させているが、印加電圧を連続的に変化させる場合も同様のことがいえる。図１２および図１３に、印加電圧の制御のさらに他の例を示す。 In FIG. 11, the applied voltage is changed stepwise, but the same can be said when the applied voltage is continuously changed. 12 and 13 show still another example of the control of the applied voltage.
　図１２および図１３に示す例では、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合（第２の場合）および－Ｖ３から＋Ｖ３に切り替える場合（第１の場合）のそれぞれにおいて、印加電圧は連続的に変化する（図１２に示す例では、印加電圧の時間変化が直線状であるのに対し、図１３に示す例では、印加電圧の時間変化が曲線状である）。ただし、第１の場合および第２の場合のそれぞれにおいて、印加電圧が正極性である期間と、負極性である期間とで、印加電圧の単位時間当たりの変化量（ある期間における平均の電圧変化速度といってもよい）が異なっている。より具体的には、正極性側（＋Ｖ３と０Ｖの間）では、単位時間当たりの電圧変化量が相対的に小さく、負極性側（０Ｖと－Ｖ３の間）では、単位時間当たりの電圧変化量が相対的に大きい。このような制御を行うことにより、エレクトロクロミック素子の構成材料として、正極性側で劣化が発生しやすい材料が用いられている場合に、素子の劣化を十分に抑制することができる。 In the example shown in FIGS. 12 and 13, the applied voltage is continuously changed in each of the case where the applied voltage is switched from + V3 to −V3 (second case) and the case where the applied voltage is switched from −V3 to + V3 (first case). In the example shown in FIG. 12, the time change of the applied voltage is linear, whereas in the example shown in FIG. 13, the time change of the applied voltage is curved. However, in each of the first case and the second case, the change amount per unit time of the applied voltage (average voltage change in a certain period) between the period in which the applied voltage is positive and the period in which it is negative. Speed may be different). More specifically, on the positive polarity side (between + V3 and 0V), the amount of voltage change per unit time is relatively small, and on the negative polarity side (between 0V and −V3), the voltage change per unit time. The amount is relatively large. By performing such control, when a material that easily deteriorates on the positive polarity side is used as a constituent material of the electrochromic element, deterioration of the element can be sufficiently suppressed.
　図１１、図１２および図１３に示した例のように、極性に応じた劣化の発生し易さに着目し、劣化の発生しやすい極性側では、印加電圧の単位時間当たりの変化量を相対的に小さくし、劣化の発生しにくい極性側では、印加電圧の単位時間当たりの変化量を相対的に大きくすることにより、素子の劣化を抑制しつつ、第１電圧ＶAから第２電圧ＶBへの（または第２電圧ＶBから第１電圧ＶAへの）印加電圧の切り替え（つまり透過スペクトルの切り替え）に要する時間を短くすることができる。 As in the examples shown in FIGS. 11, 12, and 13, paying attention to the ease of occurrence of deterioration according to the polarity, the change amount per unit time of the applied voltage is relatively set on the polarity side where deterioration is likely to occur. On the polarity side where the deterioration is less likely to occur and the amount of change in applied voltage per unit time is relatively increased, the first voltage V A to the second voltage V are suppressed while suppressing deterioration of the element. The time required for switching the applied voltage to B (or from the second voltage V B to the first voltage V A ) (that is, switching the transmission spectrum) can be shortened.
　図１４に、印加電圧の制御のさらに他の例を示す。図１４に示す例では、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合（第２の場合）には、印加電圧を＋Ｖ３、＋Ｖ２、＋Ｖ１、０Ｖ、－Ｖ１、－Ｖ２、－Ｖ３と段階的に変化させ、印加電圧を－Ｖ３から＋Ｖ３に切り替える場合（第１の場合）には、印加電圧を－Ｖ３、－Ｖ２、－Ｖ１、０、＋Ｖ１、＋Ｖ２、＋Ｖ３と段階的に変化させる。 FIG. 14 shows still another example of applied voltage control. In the example shown in FIG. 14, when the applied voltage is switched from + V3 to -V3 (second case), the applied voltage changes stepwise from + V3, + V2, + V1, 0V, -V1, -V2, and -V3. When the applied voltage is switched from −V3 to + V3 (first case), the applied voltage is changed stepwise from −V3, −V2, −V1, 0, + V1, + V2, and + V3.
　また、図１４に示す例では、第１の場合および第２の場合のそれぞれにおいて、印加電圧の絶対値が大きくなるほど保持時間が長い。つまり、印加電圧の絶対値が大きくなるほど単位時間当たりの電圧変化量が小さくなる。素子の劣化は、印加電圧の絶対値が大きいほど発生しやすいことがある。図１４に示す例のように、印加電圧の絶対値が大きくなるほど単位時間当たりの電圧変化量を小さくすることによって、印加電圧の絶対値が大きいときに発生しやすい劣化を、効果的に抑制することができる。 Further, in the example shown in FIG. 14, in each of the first case and the second case, the holding time is longer as the absolute value of the applied voltage is larger. That is, the larger the absolute value of the applied voltage, the smaller the amount of voltage change per unit time. Deterioration of the element may occur more easily as the absolute value of the applied voltage is larger. As in the example shown in FIG. 14, by reducing the amount of voltage change per unit time as the absolute value of the applied voltage increases, degradation that tends to occur when the absolute value of the applied voltage is large is effectively suppressed. be able to.
　図１４では、印加電圧を段階的に変化させているが、印加電圧を連続的に変化させる場合も同様のことがいえる。図１５および図１６に、印加電圧の制御のさらに他の例を示す。 In FIG. 14, the applied voltage is changed stepwise, but the same can be said when the applied voltage is continuously changed. 15 and 16 show still another example of control of the applied voltage.
　図１５および図１６に示す例では、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合（第２の場合）および－Ｖ３から＋Ｖ３に切り替える場合（第１の場合）のそれぞれにおいて、印加電圧は連続的に変化する（図１５に示す例では、印加電圧の時間変化が直線状であるのに対し、図１６に示す例では、印加電圧の時間変化が曲線状である）。ただし、印加電圧の絶対値が大きくなるほど単位時間当たりの電圧変化量が小さくなる。そのため、図１５および図１６に示す例のように印加電圧を制御することによっても、印加電圧の絶対値が大きいときに発生しやすい劣化を、効果的に抑制することができる。 In the example shown in FIG. 15 and FIG. 16, the applied voltage is continuously changed when the applied voltage is switched from + V3 to -V3 (second case) and when the applied voltage is switched from -V3 to + V3 (first case). In the example shown in FIG. 15, the time change of the applied voltage is linear, whereas in the example shown in FIG. 16, the time change of the applied voltage is curved. However, the amount of voltage change per unit time decreases as the absolute value of the applied voltage increases. Therefore, by controlling the applied voltage as in the examples shown in FIGS. 15 and 16, it is possible to effectively suppress deterioration that easily occurs when the absolute value of the applied voltage is large.
　図１７および図１８に、印加電圧の制御のさらに他の例を示す。図１７および図１８に示す例では、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合（第２の場合）には、印加電圧を＋Ｖ３、＋Ｖ２、＋Ｖ１、０Ｖ、－Ｖ１、－Ｖ２、－Ｖ３と段階的に変化させ、印加電圧を－Ｖ３から＋Ｖ３に切り替える場合（第１の場合）には、印加電圧を－Ｖ３、－Ｖ２、－Ｖ１、０、＋Ｖ１、＋Ｖ２、＋Ｖ３と段階的に変化させる。 17 and 18 show still another example of applied voltage control. In the example shown in FIGS. 17 and 18, when the applied voltage is switched from + V3 to −V3 (second case), the applied voltage is stepped as + V3, + V2, + V1, 0V, −V1, −V2, and −V3. When the applied voltage is switched from −V3 to + V3 (first case), the applied voltage is changed stepwise from −V3, −V2, −V1, 0, + V1, + V2, and + V3.
　また、図１７および図１８に示す例では、印加電圧の切り替え直後の単位時間当たりの電圧変化量が相対的に大きい。言い換えると、第２の場合において、印加電圧の切り替え直後の所定の期間である第１期間（例えば切り換え直後から＋Ｖ１の保持期間の終了時までの期間ｔ１＋ｔ２）における印加電圧の単位時間当たりの変化量が、第１期間の直後の所定の期間である第２期間（例えば＋Ｖ１の保持期間終了時から－Ｖ１の保持期間終了時までの期間ｔ３＋ｔ４）における印加電圧の単位時間当たりの変化量よりも大きくなっている。同様に、第１の場合において、印加電圧の切り替え直後の所定の期間である第１期間（例えば切り換え直後から－Ｖ１の保持期間の終了時までの期間ｔ６＋ｔ７）における印加電圧の単位時間当たりの変化量が、第１期間の直後の所定の期間である第２期間（例えば－Ｖ１の保持期間終了時から＋Ｖ１の保持期間終了時までの期間ｔ８＋ｔ９）における印加電圧の単位時間当たりの変化量よりも大きくなっている。 In the example shown in FIGS. 17 and 18, the amount of voltage change per unit time immediately after switching of the applied voltage is relatively large. In other words, in the second case, the change amount per unit time of the applied voltage in the first period (for example, the period t1 + t2 from immediately after switching to the end of the + V1 holding period) that is a predetermined period immediately after switching of the applied voltage. Is larger than the change amount per unit time of the applied voltage in the second period (for example, the period t3 + t4 from the end of the + V1 holding period to the end of the −V1 holding period), which is a predetermined period immediately after the first period. It has become. Similarly, in the first case, the change per unit time of the applied voltage in the first period (for example, the period t6 + t7 from immediately after switching to the end of the holding period of −V1) which is a predetermined period immediately after switching of the applied voltage. The amount is larger than the change amount per unit time of the applied voltage in the second period (for example, the period t8 + t9 from the end of the holding period of −V1 to the end of the holding period of + V1) which is a predetermined period immediately after the first period. It is getting bigger.
　図１７および図１８に示す例のように、印加電圧の切り替え直後の単位時間当たりの変化量を相対的に大きくすると、手動で切り替えを行った際の変化を明確にすることができる。なお、素子内の電解質等の電圧応答に必要な時間は、図１７に示すように０Ｖ付近における単位時間当たりの電圧変化量を小さくしたり、図１８に示すように到達電圧（第１の場合における第２電圧ＶB、第２の場合における第１電圧ＶA）付近の単位時間当たりの電圧変化量を小さくしたりすることによって確保することができる。 As in the example shown in FIGS. 17 and 18, when the amount of change per unit time immediately after switching of the applied voltage is relatively large, the change when switching manually can be clarified. The time required for the voltage response of the electrolyte or the like in the element is such that the amount of voltage change per unit time in the vicinity of 0 V is reduced as shown in FIG. 17, or the ultimate voltage (first case as shown in FIG. 18). This can be ensured by reducing the voltage change amount per unit time in the vicinity of the second voltage V B in the first case and the first voltage V A in the second case.
　第２の場合において、第１期間の長さは０．１分以上３分以下であり、第２期間の長さは２分以上５分以下であることが好ましい。また、第２の場合において、印加電圧の＋Ｖ３から＋Ｖ１への変化量は、＋Ｖ３から－Ｖ３への変化量の１／４以上であることが好ましく、１／４以上１／２以下であることがより好ましい。さらに、第２の場合において、印加電圧の＋Ｖ１から－Ｖ１への変化量は、＋Ｖ３から－Ｖ３への変化量の１／４以上であることが好ましく、１／４以上１／２以下であることがより好ましい。 In the second case, the length of the first period is preferably 0.1 minute or more and 3 minutes or less, and the length of the second period is preferably 2 minutes or more and 5 minutes or less. In the second case, the change amount of the applied voltage from + V3 to + V1 is preferably ¼ or more of the change amount from + V3 to −V3, and preferably ¼ or more and ½ or less. Is more preferable. Further, in the second case, the change amount of the applied voltage from + V1 to −V1 is preferably ¼ or more of the change amount from + V3 to −V3, and is ¼ or more and ½ or less. It is more preferable.
　同様に、第１の場合において、第１期間の長さは０．１分以上３分以下であり、第２期間の長さは２分以上５分以下であることが好ましい。また、第１の場合において、印加電圧の－Ｖ３から－Ｖ１への変化量は、－Ｖ３から＋Ｖ３への変化量の１／４以上であることが好ましく、１／４以上１／２以下であることがより好ましい。さらに、第１の場合において、印加電圧の－Ｖ１から＋Ｖ１への変化量は、―Ｖ３から＋Ｖ３への変化量の１／４以上であることが好ましく、１／４以上１／２以下であることがより好ましい。 Similarly, in the first case, the length of the first period is preferably 0.1 minute or more and 3 minutes or less, and the length of the second period is preferably 2 minutes or more and 5 minutes or less. In the first case, the change amount of the applied voltage from −V3 to −V1 is preferably ¼ or more of the change amount from −V3 to + V3, and is ¼ or more and ½ or less. More preferably. Furthermore, in the first case, the change amount of the applied voltage from −V1 to + V1 is preferably ¼ or more of the change amount from −V3 to + V3, and is ¼ or more and ½ or less. It is more preferable.
　また、図１８に示すように、第２の場合において、印加電圧を＋Ｖ３から－Ｖ３まで変化させる過程で、印加電圧を各電圧値に変化させた後の保持時間ｔ１～ｔ５を徐々に長くすることが好ましい。同様に、第１の場合において、印加電圧を－Ｖ３から＋Ｖ３まで変化させる過程で、印加電圧を各電圧値に変化させた後の保持時間ｔ６～ｔ１０を徐々に長くすることが好ましい。 Also, as shown in FIG. 18, in the second case, in the process of changing the applied voltage from + V3 to -V3, the holding times t1 to t5 after changing the applied voltage to each voltage value are gradually increased. It is preferable. Similarly, in the first case, in the process of changing the applied voltage from −V3 to + V3, it is preferable to gradually increase the holding times t6 to t10 after the applied voltage is changed to each voltage value.
　図１７および図１８では、印加電圧を段階的に変化させているが、印加電圧を連続的に変化させる場合も同様のことがいえる。図１９および図２０に、印加電圧の制御のさらに他の例を示す。図１９および図２０に示す例では、印加電圧を＋Ｖ３から－Ｖ３に切り替える場合（第２の場合）および－Ｖ３から＋Ｖ３に切り替える場合（第１の場合）のそれぞれにおいて、印加電圧は連続的に変化する。ただし、印加電圧の切り替え直後の単位時間当たりの電圧変化量が相対的に大きい。そのため、図１９および図２０に示す例のように印加電圧を制御することによっても、手動で切り替えを行った際の変化を明確にすることができる。なお、素子内の電解質等の電圧応答に必要な時間は、図１９に示すように０Ｖ付近における単位時間当たりの電圧変化量を小さくしたり、図２０に示すように到達電圧付近の単位時間当たりの電圧変化量を小さくしたりすることによって確保することができる。 17 and 18, the applied voltage is changed stepwise, but the same can be said when the applied voltage is continuously changed. 19 and 20 show still another example of control of the applied voltage. In the example shown in FIGS. 19 and 20, the applied voltage is continuously changed in each of the case where the applied voltage is switched from + V3 to −V3 (second case) and the case where the applied voltage is switched from −V3 to + V3 (first case). Change. However, the amount of voltage change per unit time immediately after switching of the applied voltage is relatively large. Therefore, by controlling the applied voltage as in the examples shown in FIGS. 19 and 20, it is possible to clarify the change when the switching is performed manually. The time required for the voltage response of the electrolyte or the like in the element is small per unit time near 0 V as shown in FIG. 19, or per unit time near the ultimate voltage as shown in FIG. This can be ensured by reducing the amount of voltage change.
　続いて、エレクトロクロミック素子１００の各構成要素の具体例や好ましい構成を説明する。 Subsequently, specific examples and preferred configurations of each component of the electrochromic element 100 will be described.
　［ナノ結晶層］
　金属酸化物ナノ粒子の材料として用いられる金属酸化物は、実施例で用いたようなＡＴＯに限定されるものではない。例えば、ＩＴＯやＡＺＯ（Aluminum-doped Zinc Oxide：アルミニウムドープ酸化亜鉛）、ＧＺＯ（Gallium-doped Zinc Oxide：ガリウムドープ酸化亜鉛）等の可視領域においてほぼ透明な材料を用いることができる。また、ＣｓXＷYＯ3（ｘ、ｙは組成比を示す）で表されるような複合タングステン酸化物や六ホウ化ランタンなどのような、可視領域の光を吸収する材料を用いることもできる。 [Nanocrystalline layer]
The metal oxide used as the material for the metal oxide nanoparticles is not limited to ATO as used in the examples. For example, an almost transparent material such as ITO, AZO (Aluminum-doped Zinc Oxide), and GZO (Gallium-doped Zinc Oxide) can be used. In addition, a material that absorbs light in the visible region, such as a composite tungsten oxide or lanthanum hexaboride represented by Cs X W Y O 3 (x and y indicate composition ratios) may be used. it can.
　ナノ結晶層３の形成方法に特に限定はない。金属酸化物ナノ粒子が分散された液体または半固体を第１基板１１上に塗布し、焼成を行うことによって、ナノ結晶層３を形成することができる。金属酸化物ナノ粒子の分散液をスピンコート法により塗布してもよいし、ビヒクルを適度に添加されたペーストを用いた印刷法により塗布してもよい。また、バーコート法、スリットコート法、グラビアコート法またはダイコート法により塗布を行ってもよい。焼成温度が、ナノ結晶表面にある有機成分が除去されて焼結が好適に生じる温度であれば、十分な耐溶剤性が得られる。ただし、焼成温度が高すぎ、焼結が過度に進むと、所望の波長のＬＳＰＲが得られないおそれがある。ＡＴＯナノ粒子の分散液を用いたスピンコート法により塗布を行う場合、例えば、２００℃以上３００℃以下の温度で３０分間焼成を行えばよい。 The method for forming the nanocrystal layer 3 is not particularly limited. The nanocrystal layer 3 can be formed by applying a liquid or semi-solid in which metal oxide nanoparticles are dispersed on the first substrate 11 and performing baking. The dispersion of metal oxide nanoparticles may be applied by a spin coating method, or may be applied by a printing method using a paste to which a vehicle is appropriately added. Further, the coating may be performed by a bar coating method, a slit coating method, a gravure coating method or a die coating method. If the firing temperature is such that organic components on the nanocrystal surface are removed and sintering is suitably performed, sufficient solvent resistance can be obtained. However, if the firing temperature is too high and the sintering proceeds excessively, there is a possibility that an LSPR having a desired wavelength cannot be obtained. When coating is performed by a spin coating method using a dispersion of ATO nanoparticles, for example, baking may be performed at a temperature of 200 ° C. to 300 ° C. for 30 minutes.
　［基板］
　第１基板１１および第２基板１２としては、例えばガラス基板を用いることができる。また、ＰＥＴ（ポリエチレンテレフタレート）やＰＥＮ（ポリエチレンナフタレート）、ポリイミドなどの樹脂材料から形成されたプラスチック基板であってもよい。例示したこれらの基板に、無機材料または有機材料から形成されたガスバリア層が設けられたものを用いてもよい。ガラス基板を用いる場合、両基板を貼り合わせた後にエッチング処理により薄型化してもよい。 [substrate]
As the first substrate 11 and the second substrate 12, for example, glass substrates can be used. Moreover, the plastic substrate formed from resin materials, such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and a polyimide, may be sufficient. These illustrated substrates may be provided with a gas barrier layer formed from an inorganic material or an organic material. In the case where a glass substrate is used, it may be thinned by etching after the two substrates are bonded together.
　［透明電極］
　第１透明電極１および第２透明電極２の材料としては、ＩｎＴｉＯの他、アナターゼ型二酸化チタンをシード層としたタンタル置換酸化スズやキャリア密度を調整したＩＴＯ等の近赤外光を透過する材料を用いることができる。これらの材料を、スパッタ法や蒸着法、塗布法などにより第１基板１１および第２基板１２上に堆積することによって、第１透明電極１および第２透明電極２を形成することができる。 [Transparent electrode]
As the material of the first transparent electrode 1 and the second transparent electrode 2, in addition to InTiO, a material that transmits near-infrared light such as tantalum-substituted tin oxide using anatase-type titanium dioxide as a seed layer or ITO with adjusted carrier density Can be used. The first transparent electrode 1 and the second transparent electrode 2 can be formed by depositing these materials on the first substrate 11 and the second substrate 12 by sputtering, vapor deposition, coating, or the like.
　また、第１透明電極１および第２透明電極２の材料は、遠赤外光を反射する特性を有することが好ましい。冬期に室内の温度を高く保つためには、室内から屋外に赤外光が出ることを防ぐ必要がある。室内から輻射される赤外光は、波長が１０μｍ程度の、遠赤外光に分類されるものである。そのため、第１透明電極１および第２透明電極２が遠赤外光を反射する特性を有していると、近赤外光の透過率が高くなるようにナノ結晶層３の状態を制御しても、室内の熱は輻射熱として屋外に逃げない、理想的な状態を実現することができる。また、夏期に近赤外光の透過率が低くなるように制御したときも、屋外からの遠赤外光が室内に入ることを防止できるので、やはり理想的な状態を実現できる。 Moreover, it is preferable that the material of the first transparent electrode 1 and the second transparent electrode 2 has a characteristic of reflecting far-infrared light. In order to keep the room temperature high in winter, it is necessary to prevent infrared light from being emitted from the room to the outdoors. Infrared light radiated from the room is classified as far-infrared light having a wavelength of about 10 μm. Therefore, if the first transparent electrode 1 and the second transparent electrode 2 have the characteristic of reflecting far-infrared light, the state of the nanocrystal layer 3 is controlled so that the transmittance of near-infrared light is increased. However, the indoor heat does not escape to the outdoors as radiant heat, and an ideal state can be realized. Further, even when control is performed so that the transmittance of near-infrared light is lowered in summer, it is possible to prevent the far-infrared light from the outside from entering the room, so that an ideal state can be realized.
　エレクトロクロミック素子１００が表示を目的としないものである場合、第１透明電極１の電極取り出し（外部配線への接続）は、１箇所で行われてもよいし、複数箇所で行われてもよい。１箇所の場合、エレクトロクロミック素子１００の組み立て工程が簡略化されるとともに配線の引き回しを簡素にすることができる。複数箇所の場合、第１透明電極１と第２透明電極２との間に抵抗成分がある、すなわち電流が流れるような場合にも部分的な応答速度の遅延を防ぐことができる。 When the electrochromic element 100 is not intended for display, the electrode extraction (connection to the external wiring) of the first transparent electrode 1 may be performed at one place or at a plurality of places. . In the case of one place, the assembly process of the electrochromic element 100 can be simplified and the routing of the wiring can be simplified. In the case of a plurality of locations, a partial response speed delay can be prevented even when there is a resistance component between the first transparent electrode 1 and the second transparent electrode 2, that is, when a current flows.
　第１透明電極１は、電気的に独立した複数のサブ電極に分割されていてもよい。第１透明電極１が複数のサブ電極に分割されていると、サブ電極に対応する領域ごとに透過スペクトルを変化させることができる。図２１（ａ）および（ｂ）に、第１透明電極１が複数のサブ電極１ａに分割された構成の例を示す。 The first transparent electrode 1 may be divided into a plurality of electrically independent sub-electrodes. When the first transparent electrode 1 is divided into a plurality of sub-electrodes, the transmission spectrum can be changed for each region corresponding to the sub-electrodes. FIGS. 21A and 21B show examples of a configuration in which the first transparent electrode 1 is divided into a plurality of sub-electrodes 1a.
　図２１（ａ）に示す例では、複数のサブ電極１ａの引き回しによって、電極取り出し部ＥＰが１箇所に集約されている。サブ電極１ａの引き回し部分を、シール部５の外側やシール部５の下など、エレクトロクロミック素子１００の動作部から外して配置することによって、不要な電圧降下を防止することができる。 In the example shown in FIG. 21 (a), the electrode lead-out portions EP are gathered in one place by routing the plurality of sub-electrodes 1a. An unnecessary voltage drop can be prevented by disposing the lead-out portion of the sub electrode 1a away from the operation portion of the electrochromic element 100 such as the outside of the seal portion 5 or under the seal portion 5.
　図２１（ｂ）に示す例では、複数のサブ電極１ａが引き回されることなく、直接配線に接続される。つまり、電極取り出し部ＥＰは、複数箇所に分散されている。 In the example shown in FIG. 21B, the plurality of sub-electrodes 1a are directly connected to the wiring without being routed. That is, the electrode extraction part EP is dispersed in a plurality of places.
　第２透明電極２は、第１透明電極１と同様、電気的に独立した複数のサブ電極に分割されていてもよいし、分割されていなくてもよい。 As with the first transparent electrode 1, the second transparent electrode 2 may be divided into a plurality of electrically independent sub-electrodes or may not be divided.
　［電解質層］
　電解質層４は、例えば電解液で構成される。電解液の電解質としては、ヘキサフルオロリン酸リチウム（ＬｉＰＦ6）やヘキサフルオロリン酸ナトリウム（ＮａＰＦ6）、ホウフッ化リチウム（ＬｉＢＦ4）等のイオン化しやすい材料を用いることができる。電解液の溶媒としては、炭酸エチレン（ＥＣ）、炭酸ジエチル（ＤＥＣ）、ＥＣとＤＣとの混合物、炭酸プロピレン等を用いることができる。また、これらにポリビニルブチラール等を溶解させたゲルを用いてもよい。さらに、例えば環状四級アンモニウムカチオンとイミドアニオンからなるイオン液体を用いてもよい。 [Electrolyte layer]
The electrolyte layer 4 is made of, for example, an electrolytic solution. As the electrolyte of the electrolytic solution, a material that is easily ionized, such as lithium hexafluorophosphate (LiPF 6 ), sodium hexafluorophosphate (NaPF 6 ), or lithium borofluoride (LiBF 4 ) can be used. As the solvent for the electrolytic solution, ethylene carbonate (EC), diethyl carbonate (DEC), a mixture of EC and DC, propylene carbonate, or the like can be used. Moreover, you may use the gel which melt | dissolved polyvinyl butyral etc. in these. Further, for example, an ionic liquid composed of a cyclic quaternary ammonium cation and an imide anion may be used.
　電解質層４は、固体電界質から構成されてもよい。例えば、リチウム塩を含むポリエチレンオキサイドのような固体電解質を用いてもよいし、柔粘性結晶を用いてもよい。 The electrolyte layer 4 may be composed of a solid electrolyte. For example, a solid electrolyte such as polyethylene oxide containing a lithium salt may be used, or a plastic crystal may be used.
　［スペーサ］
　電解質層４が、電解液等の低粘度材料から構成される場合、エレクトロクロミック素子１００は、図２２に示すように、第１基板１１と第２基板１２との距離（セル厚）を規定するためのスペーサ８を備えることが好ましい。図２２に例示する構成では、スペーサ８は、ナノ結晶層３と第２透明電極２との間に設けられている。スペーサ８は、感光性樹脂材料を用いてフォトリソ工程により形成することができる。スペーサ８は、例えば１０μｍ角で１０μｍの高さを有する。スペーサ８の形成方法は、フォトリソ工程に限定されず、例えばスクリーン印刷法であってもよい。 [Spacer]
When the electrolyte layer 4 is made of a low-viscosity material such as an electrolytic solution, the electrochromic element 100 defines the distance (cell thickness) between the first substrate 11 and the second substrate 12 as shown in FIG. It is preferable to provide a spacer 8 for the purpose. In the configuration illustrated in FIG. 22, the spacer 8 is provided between the nanocrystal layer 3 and the second transparent electrode 2. The spacer 8 can be formed by a photolithography process using a photosensitive resin material. The spacer 8 is, for example, 10 μm square and 10 μm high. The formation method of the spacer 8 is not limited to the photolithography process, but may be, for example, a screen printing method.
　スペーサ８は、第２基板１２側（第２透明電極２上）に形成されることが好ましい。第１基板１１側にスペーサ８を設ける場合、ナノ結晶層３の形成前にスペーサ８を形成すると、スペーサ８の影響によってナノ結晶層３の厚さにむらが生じたり、スペーサ８をナノ結晶層３が被覆することによって第２透明電極２とのリークが発生するおそれがある。また、ナノ結晶層３上にスペーサ８を形成すると、フォトリソ工程の残渣がナノ結晶層３上に残り、透過スペクトルの変化を阻害する可能性がある。 The spacer 8 is preferably formed on the second substrate 12 side (on the second transparent electrode 2). When the spacer 8 is provided on the first substrate 11 side, if the spacer 8 is formed before the nanocrystal layer 3 is formed, the thickness of the nanocrystal layer 3 may be uneven due to the influence of the spacer 8, or the spacer 8 may be There is a possibility that leakage with the second transparent electrode 2 occurs due to the covering of 3. Moreover, when the spacer 8 is formed on the nanocrystal layer 3, the residue of the photolithographic process remains on the nanocrystal layer 3, and there is a possibility that the change in the transmission spectrum is hindered.
　電解質層４が固体電解質から構成される場合、固体電解質が適度な弾性を有していれば、スペーサ８を設ける必要はない。 When the electrolyte layer 4 is composed of a solid electrolyte, it is not necessary to provide the spacer 8 if the solid electrolyte has appropriate elasticity.
　［シール部］
　シール部５の材料としては、例えばＵＶ硬化型の樹脂材料を用いることができる。 [Seal part]
As a material of the seal portion 5, for example, a UV curable resin material can be used.
　図２３に、シール部５の他の構成の例を示す。図２３に示す例では、シール部５は、異なる材料（シール材）から形成された２つの領域５ａおよび５ｂを有する。以下では、相対的に内側に位置する領域５ａを「内側領域」と呼び、相対的に外側に位置する領域５ｂを「外側領域」と呼ぶ。 FIG. 23 shows an example of another configuration of the seal portion 5. In the example shown in FIG. 23, the seal portion 5 has two regions 5a and 5b formed from different materials (seal materials). Hereinafter, the region 5a positioned relatively inside is referred to as “inside region”, and the region 5b positioned relatively outside is referred to as “outside region”.
　内側領域５ａは、外側領域５ｂを形成するシール材よりも耐溶剤性の高いシール材から形成されている。これに対し、外側領域５ｂは、内側領域５ａを形成するシール材よりも接着力の強いシール材から形成されている。 The inner region 5a is formed from a sealing material having higher solvent resistance than the sealing material forming the outer region 5b. On the other hand, the outer region 5b is formed of a sealing material having a stronger adhesive force than the sealing material forming the inner region 5a.
　このように、電解質層４（電解液）に接触する内側領域５ａを耐溶剤性の高いシール材で形成するとともに、外側領域５ｂを接着力の強いシール材で形成することにより、シール部５の高い信頼性および強い接着力を両立させることができる。 As described above, the inner region 5a that is in contact with the electrolyte layer 4 (electrolyte) is formed of a sealing material having high solvent resistance, and the outer region 5b is formed of a sealing material having a strong adhesive force. High reliability and strong adhesion can be achieved at the same time.
　［電源部］
　電源部６は、電力を供給する（第１透明電極１と第２透明電極２の間に所定の電圧を印加する）電源回路である。電源部６は、脱着可能な一次電池、二次電池等を含み得る。 [Power supply part]
The power supply unit 6 is a power supply circuit that supplies electric power (applies a predetermined voltage between the first transparent electrode 1 and the second transparent electrode 2). The power supply unit 6 may include a removable primary battery, a secondary battery, and the like.
　［制御部］
　制御部７は、第１透明電極１と第２透明電極２の間に所望の大きさおよび極性の電圧が印加されるように電源部６を制御する。制御部７は、例えば、ＣＰＵ（Central Processing Unit）や専用プロセッサ等の演算部と、ＲＡＭ（Random Access Memory）、ＲＯＭ（Read Only Memory）等の記憶部とを備えた回路基板である。制御部７の設置場所（配置）に特に制限はなく、制御部７は、必ずしもエレクトロクロミック素子１００の筐体内に組み込まれている必要はない。 [Control unit]
The control unit 7 controls the power supply unit 6 so that a voltage having a desired magnitude and polarity is applied between the first transparent electrode 1 and the second transparent electrode 2. The control unit 7 is a circuit board including, for example, a calculation unit such as a CPU (Central Processing Unit) or a dedicated processor, and a storage unit such as a RAM (Random Access Memory) or a ROM (Read Only Memory). There is no restriction | limiting in particular in the installation place (arrangement | positioning) of the control part 7, The control part 7 does not necessarily need to be integrated in the housing | casing of the electrochromic element 100. FIG.
　［製造方法］
　エレクトロクロミック素子１００を製造する際、液晶パネルや色素増感型太陽電池等の製造に用いられる種々の方法・工程を用いることができる。第１基板１１および第２基板１２としてプラスチック基板（樹脂基板）を用いる場合には、ロール・ツー・ロール法によって貼り合せ工程を連続的に行うことができるので、製造コストを低減することが可能である。また、一連の工程を脱酸素乾燥雰囲気下で行うことにより、エレクトロクロミック素子１００の信頼性を向上させることができる。 [Production method]
When manufacturing the electrochromic element 100, various methods and processes used for manufacturing a liquid crystal panel, a dye-sensitized solar cell, and the like can be used. When a plastic substrate (resin substrate) is used as the first substrate 11 and the second substrate 12, the bonding process can be continuously performed by a roll-to-roll method, so that the manufacturing cost can be reduced. It is. Further, the reliability of the electrochromic device 100 can be improved by performing a series of steps in a deoxygenated dry atmosphere.
　［対電極を含まない構成の効果］
　従来のエレクトロクロミック素子として、金属酸化物を含む対電極を備えた構成が知られている（例えば非特許文献１の図２）。この構成では、電圧印加によって光学的性質を変化させる際、対電極の酸化還元反応を電気化学的に行っている。これは、ＴＣＯナノ構造体を着色状態に遷移させるために、酸化還元反応に基づいて十分な電荷の出し入れを行うためである。しかしながら、対電極における酸化反応および還元反応の際、例えば酸素のような不純物が存在すると、本来の目的とは異なる副反応が生じることとなる。ＬＳＰＲによるエレクトロクロミックは、明確な電気化学的反応を示さないことが知られているが、上述した副反応の存在により、対電極を含む構成は、光学的性質の変化に対する繰り返し特性が悪くなるという問題がある。 [Effect of the configuration not including the counter electrode]
As a conventional electrochromic element, a configuration including a counter electrode containing a metal oxide is known (for example, FIG. 2 of Non-Patent Document 1). In this configuration, when the optical properties are changed by voltage application, the redox reaction of the counter electrode is performed electrochemically. This is because sufficient charges are taken in and out based on the oxidation-reduction reaction in order to transition the TCO nanostructure to the colored state. However, in the oxidation reaction and reduction reaction at the counter electrode, if an impurity such as oxygen is present, a side reaction different from the original purpose occurs. It is known that electrochromic by LSPR does not show a clear electrochemical reaction, but due to the presence of the side reaction described above, the configuration including the counter electrode has poor repeatability with respect to changes in optical properties. There's a problem.
　図１に例示した構成では、エレクトロクロミック素子１００は、第２透明電極２上に対電極を備えていない。また、第１透明電極１、第２透明電極２およびナノ結晶層３は、ナノ結晶層３の透過スペクトルを変化させるために第１透明電極１と第２透明電極２との間に電圧を印加したとき、酸化還元反応を生じず、エレクトロクロミック素子１００は、電圧印加によって酸化還元反応による透過スペクトルの変化が生じる電極を含まない。 In the configuration illustrated in FIG. 1, the electrochromic element 100 does not include a counter electrode on the second transparent electrode 2. The first transparent electrode 1, the second transparent electrode 2, and the nanocrystal layer 3 apply a voltage between the first transparent electrode 1 and the second transparent electrode 2 in order to change the transmission spectrum of the nanocrystal layer 3. Then, the redox reaction does not occur, and the electrochromic device 100 does not include an electrode in which a transmission spectrum changes due to the redox reaction by applying a voltage.
　既に説明したように、ＬＳＰＲは、明確な電気化学的反応を示さない。従って、酸化還元反応を起こす物質によって構成された対電極を含まないエレクトロクロミック素子１００は、酸化還元反応の副反応による繰り返し特性の悪化を避けることができる。エレクトロクロミック素子１００では、電圧を印加した場合に生じる第１透明電極１および第２透明電極２上の電荷移動によって、近赤外領域でプラズモン吸収される波長を変化させることが可能である。 As already explained, LSPR does not show a clear electrochemical reaction. Therefore, the electrochromic device 100 that does not include a counter electrode made of a substance that causes an oxidation-reduction reaction can avoid deterioration in repetitive characteristics due to a side reaction of the oxidation-reduction reaction. In the electrochromic element 100, the wavelength of plasmon absorption in the near infrared region can be changed by the charge movement on the first transparent electrode 1 and the second transparent electrode 2 that occurs when a voltage is applied.
　［スマートウィンドウ］
　本開示の実施形態におけるエレクトロクロミック素子１００は、スマートウィンドウに好適に用いられる。 [Smart Window]
The electrochromic device 100 in the embodiment of the present disclosure is suitably used for a smart window.
　エレクトロクロミック素子１００自体がスマートウィンドウであってもよいし、板ガラスにエレクトロクロミック素子１００が貼り付けられた積層構造体がスマートウィンドウとして機能してもよい。 The electrochromic element 100 itself may be a smart window, or a laminated structure in which the electrochromic element 100 is bonded to a plate glass may function as a smart window.
　また、複層ガラスを構成する複数の板ガラスのうちの１つが、エレクトロクロミック素子１００に置換されてもよい。例えば、トリプルガラス構造の複層ガラスを構成する３つの板ガラスのうちの中央の板ガラスをエレクトロクロミック素子１００に置換してもよい。ただし、その場合、ガラスのような固体と空気のような気体との界面が６つ形成される。これらの界面においては、界面反射が起こるので、可視光線を含む光の透過率が低くなる。そのため、これらの界面（エレクトロクロミック素子１００の両表面を含む）に、ＡＲ（Anti Reflective）フィルムやＬＲ（Low Reflective）フィルム、モスアイ（登録商標）フィルムのような反射防止膜を設けることが好ましい。 Moreover, one of the plurality of plate glasses constituting the multilayer glass may be replaced with the electrochromic element 100. For example, an electrochromic element 100 may be substituted for a central plate glass among three plate glasses constituting a double glass having a triple glass structure. However, in that case, six interfaces between a solid such as glass and a gas such as air are formed. At these interfaces, since interface reflection occurs, the transmittance of light including visible light is lowered. Therefore, it is preferable to provide an antireflection film such as an AR (Anti-Reflective) film, an LR (Low-Reflective) film, or a Moseye (registered trademark) film on these interfaces (including both surfaces of the electrochromic element 100).
　本開示の実施形態によれば、ナノ結晶層を備えたエレクトロクロミック素子における劣化および動作不良を抑制することができる。本開示の実施形態によるエレクトロクロミック素子は、スマートウィンドウに好適に用いられる。 According to the embodiment of the present disclosure, it is possible to suppress deterioration and malfunction in an electrochromic device including a nanocrystal layer. The electrochromic device according to the embodiment of the present disclosure is suitably used for a smart window.
 ［援用の記載］
　本国際出願は、２０１８年３月３０日に日本国特許庁に出願された特願２０１８－６７８１５号に基づく優先権を主張するものであり、特願２０１８－６７８１５号の開示内容の全てを参照により本国際出願に援用する。 [Description of support]
This international application claims priority based on Japanese Patent Application No. 2018-67815 filed with the Japan Patent Office on March 30, 2018. See the entire disclosure of Japanese Patent Application No. 2018-67815. Is incorporated herein by reference.
　１　　第１透明電極
　１ａ　　サブ電極
　２　　第２透明電極
　３　　ナノ結晶層
　４　　電解質層
　５　　シール部
　５ａ　　内側領域
　５ｂ　　外側領域
　６　　電源部
　７　　制御部
　８　　スペーサ
　１１　　第１基板
　１２　　第２基板
　１００　　エレクトロクロミック素子 DESCRIPTION OF SYMBOLS 1 1st transparent electrode 1a Sub electrode 2 2nd transparent electrode 3 Nanocrystal layer 4 Electrolyte layer 5 Seal part 5a Inner area | region 5b Outer area | region 6 Power supply part 7 Control part 8 Spacer 11 1st board | substrate 12 2nd board | substrate 100 Electrochromic element

Claims (19)

  1. 　互いに対向する第１透明電極および第２透明電極と、
    　前記第１透明電極の前記第２透明電極側の表面上に設けられ、複数の金属酸化物ナノ粒子を含むナノ結晶層と、
    　前記ナノ結晶層と前記第２透明電極の間に設けられた電解質層と、
    　前記第１透明電極と前記第２透明電極の間への印加電圧を制御する制御部と、
    を備えたエレクトロクロミック素子であって、
    　前記制御部は、
    　前記印加電圧を所定の第１電圧ＶAから前記第１電圧ＶAとは異なる第２電圧ＶBに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる第１の場合には、前記印加電圧を前記第１電圧ＶAから前記第２電圧ＶBまで徐々に変化させ、
    　前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる第２の場合には、前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAまで徐々に変化させる、エレクトロクロミック素子。     A first transparent electrode and a second transparent electrode facing each other;
    A nanocrystal layer provided on a surface of the first transparent electrode on the second transparent electrode side and including a plurality of metal oxide nanoparticles;
    An electrolyte layer provided between the nanocrystal layer and the second transparent electrode;
    A control unit for controlling an applied voltage between the first transparent electrode and the second transparent electrode;
    An electrochromic device comprising:
    The controller is
    In the first case where the transmission spectrum of the nanocrystal layer is changed by switching the applied voltage from a predetermined first voltage V A to a second voltage V B different from the first voltage V A , the applied voltage Is gradually changed from the first voltage V A to the second voltage V B ,
    Wherein when the applied voltage from the second voltage V B of the second to change the transmission spectrum of the nanocrystal layer by switching to the first voltage V A, the said applied voltage from said second voltage V B An electrochromic device that gradually changes to the first voltage V A.
  2. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧を段階的に変化させる請求項１に記載のエレクトロクロミック素子。 The electrochromic device according to claim 1, wherein the control unit changes the applied voltage stepwise in each of the first case and the second case.
  3. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧を連続的に変化させる請求項１に記載のエレクトロクロミック素子。 The electrochromic device according to claim 1, wherein the control unit continuously changes the applied voltage in each of the first case and the second case.
  4. 　前記第１電圧ＶAの極性と、前記第２電圧ＶBの極性とが互いに異なる、請求項１から３のいずれかに記載のエレクトロクロミック素子。 4. The electrochromic device according to claim 1, wherein a polarity of the first voltage V A and a polarity of the second voltage V B are different from each other.
  5. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧として前記第１電圧ＶAと０Ｖの間の大きさの電圧が保持される期間と、前記印加電圧として前記第２電圧ＶBと０Ｖの間の大きさの電圧が保持される期間とが存在するように前記印加電圧を制御する、請求項４に記載のエレクトロクロミック素子。 In each of the first case and the second case, the control unit includes a period during which a voltage having a magnitude between the first voltage V A and 0 V is held as the applied voltage, and the applied voltage as the applied voltage. 5. The electrochromic device according to claim 4, wherein the applied voltage is controlled such that there is a period in which a voltage having a magnitude between the second voltage V B and 0 V is maintained.
  6. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの一方と０Ｖの間の大きさの電圧が保持される期間が存在し、且つ、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの他方と０Ｖの間の大きさの電圧が保持される期間が存在しないように前記印加電圧を制御する、請求項４に記載のエレクトロクロミック素子。 In each of the first case and the second case, the control unit holds a voltage having a magnitude between 0 V and one of the first voltage V A and the second voltage V B as the applied voltage. The applied voltage so that there is no period in which a voltage having a magnitude between 0 V and the other of the first voltage V A and the second voltage V B is held as the applied voltage. The electrochromic device according to claim 4, wherein the electrochromic device is controlled.
  7. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧が正極性である期間と、前記印加電圧が負極性である期間とで、前記印加電圧の単位時間当たりの変化量が異なるように前記印加電圧を制御する、請求項４に記載のエレクトロクロミック素子。 In each of the first case and the second case, the control unit is configured so that the applied voltage per unit time is a period in which the applied voltage is positive and a period in which the applied voltage is negative. The electrochromic device according to claim 4, wherein the applied voltage is controlled so that the amount of change in is different.
  8. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧の絶対値が大きくなるほど単位時間当たりの変化量が小さくなるように前記印加電圧を制御する、請求項１から５のいずれかに記載のエレクトロクロミック素子。 The control unit controls the applied voltage so that a change amount per unit time becomes smaller as an absolute value of the applied voltage becomes larger in each of the first case and the second case. To 5. The electrochromic device according to any one of 5 to 5.
  9. 　前記制御部は、前記第１の場合および前記第２の場合のそれぞれにおいて、前記印加電圧の切り替え直後の所定の期間である第１期間における前記印加電圧の単位時間当たりの変化量が、前記第１期間の直後の所定の期間である第２期間における前記印加電圧の単位時間当たりの変化量よりも大きくなるように前記印加電圧を制御する、請求項１から５のいずれかに記載のエレクトロクロミック素子。 In each of the first case and the second case, the control unit is configured so that a change amount per unit time of the applied voltage in a first period that is a predetermined period immediately after switching of the applied voltage is the first time. The electrochromic according to any one of claims 1 to 5, wherein the applied voltage is controlled to be larger than a change amount per unit time of the applied voltage in a second period which is a predetermined period immediately after one period. element.
  10. 　請求項１から９のいずれかに記載のエレクトロクロミック素子を備えたスマートウィンドウ。 A smart window comprising the electrochromic device according to any one of claims 1 to 9.
  11. 　互いに対向する第１透明電極および第２透明電極と、
    　前記第１透明電極の前記第２透明電極側の表面上に設けられ、複数の金属酸化物ナノ粒子を含むナノ結晶層と、
    　前記ナノ結晶層と前記第２透明電極の間に設けられた電解質層と、
    を備えたエレクトロクロミック素子の駆動方法であって、
    　前記第１透明電極と前記第２透明電極の間への印加電圧を、所定の第１電圧ＶAから前記第１電圧ＶAとは異なる第２電圧ＶBに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる工程（Ａ）と、
    　前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAに切り替えることによって前記ナノ結晶層の透過スペクトルを変化させる工程（Ｂ）と、
    を包含し、
    　前記工程（Ａ）は、前記印加電圧を前記第１電圧ＶAから前記第２電圧ＶBまで徐々に変化させることによって行われ、
    　前記工程（Ｂ）は、前記印加電圧を前記第２電圧ＶBから前記第１電圧ＶAまで徐々に変化させることによって行われる、エレクトロクロミック素子の駆動方法。     A first transparent electrode and a second transparent electrode facing each other;
    A nanocrystal layer provided on a surface of the first transparent electrode on the second transparent electrode side and including a plurality of metal oxide nanoparticles;
    An electrolyte layer provided between the nanocrystal layer and the second transparent electrode;
    A method of driving an electrochromic device comprising:
    By switching the voltage applied between the first transparent electrode and the second transparent electrode from a predetermined first voltage V A to a second voltage V B different from the first voltage V A , Changing the transmission spectrum (A);
    (B) changing the transmission spectrum of the nanocrystal layer by switching the applied voltage from the second voltage V B to the first voltage V A ;
    Including
    The step (A) is performed by gradually changing the applied voltage from the first voltage V A to the second voltage V B.
    The step (B) is a method for driving an electrochromic device, wherein the applied voltage is gradually changed from the second voltage V B to the first voltage V A.
  12. 　前記工程（Ａ）および（Ｂ）のそれぞれにおいて、前記印加電圧が段階的に変化する請求項１１に記載の駆動方法。 The driving method according to claim 11, wherein the applied voltage changes stepwise in each of the steps (A) and (B).
  13. 　前記工程（Ａ）および（Ｂ）のそれぞれにおいて、前記印加電圧が連続的に変化する請求項１１に記載の駆動方法。 The driving method according to claim 11, wherein the applied voltage continuously changes in each of the steps (A) and (B).
  14. 　前記第１電圧ＶAの極性と、前記第２電圧ＶBの極性とが互いに異なる、請求項１１から１３のいずれかに記載の駆動方法。 The driving method according to claim 11, wherein a polarity of the first voltage V A and a polarity of the second voltage V B are different from each other.
  15. 　前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧として前記第１電圧ＶAと０Ｖの間の大きさの電圧が保持される工程と、前記印加電圧として前記第２電圧ＶBと０Ｖの間の大きさの電圧が保持される工程とを含む、請求項１４に記載の駆動方法。 Each of the steps (A) and (B) includes a step of holding a voltage having a magnitude between the first voltage V A and 0 V as the applied voltage, and the second voltage V B as the applied voltage. The method according to claim 14, further comprising a step of maintaining a voltage having a magnitude between 0V.
  16. 　前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの一方と０Ｖの間の大きさの電圧が保持される工程を含み、前記印加電圧として前記第１電圧ＶAおよび前記第２電圧ＶBの他方と０Ｖの間の大きさの電圧が保持される工程を含まない、請求項１４に記載の駆動方法。 Each of the steps (A) and (B) includes a step in which a voltage having a magnitude between 0 V and one of the first voltage V A and the second voltage V B is held as the applied voltage, The driving method according to claim 14, wherein the applied voltage does not include a step of holding a voltage having a magnitude between 0 V and the other of the first voltage V A and the second voltage V B.
  17. 　前記工程（Ａ）および（Ｂ）のそれぞれにおいて、前記印加電圧が正極性である期間と、前記印加電圧が負極性である期間とで、前記印加電圧の単位時間当たりの変化量が異なる、請求項１４に記載の駆動方法。 In each of the steps (A) and (B), the amount of change per unit time of the applied voltage differs between a period in which the applied voltage is positive and a period in which the applied voltage is negative. Item 15. The driving method according to Item 14.
  18. 　前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧の絶対値が大きくなるほど単位時間当たりの変化量が小さくなるように行われる、請求項１１から１５のいずれかに記載の駆動方法。 The driving method according to any one of claims 11 to 15, wherein each of the steps (A) and (B) is performed such that the amount of change per unit time decreases as the absolute value of the applied voltage increases.
  19. 　前記工程（Ａ）および（Ｂ）のそれぞれは、前記印加電圧の切り替え直後の所定の期間である第１期間における前記印加電圧の単位時間当たりの変化量が、前記第１期間の直後の所定の期間である第２期間における前記印加電圧の単位時間当たりの変化量よりも大きくなるように行われる、請求項１１から１５のいずれかに記載の駆動方法。 In each of the steps (A) and (B), a change amount per unit time of the applied voltage in a first period, which is a predetermined period immediately after switching of the applied voltage, is a predetermined period immediately after the first period. The driving method according to claim 11, wherein the driving method is performed so as to be larger than a change amount per unit time of the applied voltage in a second period which is a period.
PCT/JP2019/012882 2018-03-30 2019-03-26 Electrochromic element, smart window, and method for driving electrochromic element WO2019189194A1 (en)

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