JP7438509B2 - Light emitting device, light emitting method and organic light emitting device - Google Patents

Light emitting device, light emitting method and organic light emitting device Download PDF

Info

Publication number
JP7438509B2
JP7438509B2 JP2020097798A JP2020097798A JP7438509B2 JP 7438509 B2 JP7438509 B2 JP 7438509B2 JP 2020097798 A JP2020097798 A JP 2020097798A JP 2020097798 A JP2020097798 A JP 2020097798A JP 7438509 B2 JP7438509 B2 JP 7438509B2
Authority
JP
Japan
Prior art keywords
light emitting
organic light
electrode
period
emitting layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
JP2020097798A
Other languages
Japanese (ja)
Other versions
JP2021027330A (en
Inventor
千波矢 安達
一 中野谷
孝彦 山中
滋郎 原
徹 廣畑
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hamamatsu Photonics KK
Kyushu University NUC
Original Assignee
Hamamatsu Photonics KK
Kyushu University NUC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hamamatsu Photonics KK, Kyushu University NUC filed Critical Hamamatsu Photonics KK
Priority to US16/942,283 priority Critical patent/US11925046B2/en
Publication of JP2021027330A publication Critical patent/JP2021027330A/en
Application granted granted Critical
Publication of JP7438509B2 publication Critical patent/JP7438509B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Electroluminescent Light Sources (AREA)

Description

本発明は、発光装置、発光方法及び有機発光素子に関する。 The present invention relates to a light emitting device, a light emitting method, and an organic light emitting element.

特許文献１には、有機色素薄膜と、有機色素薄膜に電圧を印加するように配置された一対の電極と、有機色素薄膜を励起して蛍光を発生させる光源と、を備える蛍光装置が記載されている。特許文献１に記載の蛍光装置は、一対の電極に印加する電圧を変化させることで有機色素薄膜内の電荷量を変化させ、それにより蛍光の効率を増減させる。 Patent Document 1 describes a fluorescent device that includes an organic dye thin film, a pair of electrodes arranged to apply a voltage to the organic dye thin film, and a light source that excites the organic dye thin film to generate fluorescence. ing. The fluorescent device described in Patent Document 1 changes the amount of charge within the organic dye thin film by changing the voltage applied to a pair of electrodes, thereby increasing or decreasing the efficiency of fluorescence.

特許３３０３４７０号公報Patent No. 3303470

ところで、有機発光層には、様々な可能性が期待されている。そこで、本発明者らは、未知の発光形態を鋭意検討し、本発明を完成させるに至った。 By the way, various possibilities are expected for organic light-emitting layers. Therefore, the present inventors conducted intensive studies on unknown light emission forms and completed the present invention.

本発明は、新たな発光形態を実現することができる発光装置、発光方法及び有機発光素子を提供することを目的とする。 An object of the present invention is to provide a light emitting device, a light emitting method, and an organic light emitting element that can realize a new light emitting form.

本発明の発光装置は、有機発光素子と、有機発光素子を制御する制御部と、を備え、有機発光素子は、第１電極と、第２電極と、第１電極と第２電極との間に配置され、励起光の入射によって電荷の分離が起こる有機発光層と、を有し、制御部は、有機発光層に励起光が入射した第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極と第２電極との間の電位差を変化させる。 The light emitting device of the present invention includes an organic light emitting element and a control unit that controls the organic light emitting element, and the organic light emitting element has a first electrode, a second electrode, and a space between the first electrode and the second electrode. an organic light-emitting layer disposed in the organic light-emitting layer in which charges are separated by the incidence of excitation light; In this step, the potential difference between the first electrode and the second electrode is changed so that charge recombination occurs.

この発光装置では、励起光の入射によって電荷の分離が起こる有機発光層が用いられ、有機発光層に励起光が入射した第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極と第２電極との間の電位差が変化させられる。これにより、有機発光層に励起光が入射した第１期間から遅延期間が経過した後の第２期間において、有機発光層から発光を得ることができる。このように、この発光装置によれば、新たな発光形態を実現することができる。 This light-emitting device uses an organic light-emitting layer in which charges are separated by the incidence of excitation light, and in a second period after a delay period has elapsed from a first period in which the excitation light is incident on the organic light-emission layer, charges are regenerated. The potential difference between the first and second electrodes is changed such that binding occurs. Thereby, light emission can be obtained from the organic light emitting layer in the second period after the delay period has elapsed from the first period in which the excitation light was incident on the organic light emitting layer. Thus, according to this light emitting device, a new light emitting form can be realized.

本発明の発光装置では、制御部は、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加してもよい。これにより、簡易な電圧の印加の仕方で、第２期間において有機発光層から発光を得ることができる。 In the light emitting device of the present invention, the control unit sets the potential difference between the first electrode and the second electrode to 0 in the first period and the delay period, and in the second period, controls the forward direction to cause charge recombination. A voltage may be applied between the first and second electrodes such that an electric field is created in the organic light emitting layer. Thereby, light emission can be obtained from the organic light emitting layer in the second period by applying a simple voltage.

本発明の発光装置では、制御部は、第１期間及び遅延期間において、電荷の再結合を起こさせる順方向の電界とは逆方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加し、第２期間において、順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加してもよい。これにより、簡易な電圧の印加の仕方で、第２期間において有機発光層から発光を得ることができる。 In the light emitting device of the present invention, the control unit controls the first electrode and the second electrode so that an electric field in the opposite direction to the forward electric field that causes charge recombination is generated in the organic light emitting layer in the first period and the delay period. A voltage may be applied between the first electrode and the second electrode such that a forward electric field is generated in the organic light emitting layer during the second period. Thereby, light emission can be obtained from the organic light emitting layer in the second period by applying a simple voltage.

本発明の発光装置では、制御部は、遅延期間の長さを調整可能であってもよい。これにより、有機発光層から外部に光が出射するタイミングを調整することができる。 In the light emitting device of the present invention, the control section may be able to adjust the length of the delay period. Thereby, the timing at which light is emitted from the organic light emitting layer to the outside can be adjusted.

本発明の発光装置は、励起光を出射する光源を更に備え、制御部は、第１期間において、有機発光層に励起光が入射するように光源を制御してもよい。これにより、外部から有機発光層に励起光が入射するタイミングを調整することができる。 The light emitting device of the present invention may further include a light source that emits excitation light, and the control unit may control the light source so that the excitation light enters the organic light emitting layer during the first period. Thereby, the timing at which excitation light enters the organic light emitting layer from the outside can be adjusted.

本発明の発光装置では、有機発光層に含まれる有機発光体のダイポールモーメントは、０Ｄよりも大きくてもよい。これにより、例えば、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層から十分な発光を得ることができる。 In the light emitting device of the present invention, the dipole moment of the organic light emitter included in the organic light emitting layer may be greater than 0D. As a result, for example, in the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0, and in the second period, a forward electric field that causes charge recombination is applied to the organic light emitting layer. If a voltage is applied between the first electrode and the second electrode so as to occur, sufficient light emission can be obtained from the organic light emitting layer even if the delay period is lengthened.

本発明の発光装置では、有機発光体のダイポールモーメントは、３Ｄ以上であってもよい。これにより、例えば、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層から、より十分な発光を得ることができる。 In the light emitting device of the present invention, the dipole moment of the organic light emitter may be 3D or more. As a result, for example, in the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0, and in the second period, a forward electric field that causes charge recombination is applied to the organic light emitting layer. When applying a voltage between the first electrode and the second electrode to cause the delay period to be longer, more sufficient light emission can be obtained from the organic light emitting layer.

本発明の発光装置では、有機発光体のダイポールモーメントは、１０Ｄ以上であってもよい。これにより、例えば、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層から、より十分な発光を得ることができる。 In the light emitting device of the present invention, the dipole moment of the organic light emitter may be 10D or more. As a result, for example, in the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0, and in the second period, a forward electric field that causes charge recombination is applied to the organic light emitting layer. When applying a voltage between the first electrode and the second electrode to cause the delay period to be longer, more sufficient light emission can be obtained from the organic light emitting layer.

本発明の発光方法は、第１電極と、第２電極と、第１電極と第２電極との間に配置され、励起光の入射によって電荷の分離が起こる有機発光層と、を有する有機発光素子を用いた発光方法であって、第１期間において、有機発光層に励起光が入射するステップと、第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極と第２電極との間の電位差を変化させるステップと、を備える。 The light emitting method of the present invention includes a first electrode, a second electrode, and an organic light emitting layer disposed between the first electrode and the second electrode, in which charges are separated by incidence of excitation light. A light emitting method using a device, which includes a step in which excitation light is incident on an organic light emitting layer in a first period, and a second period after a delay period has elapsed from the first period, in which charge recombination occurs. and changing the potential difference between the first electrode and the second electrode.

この発光方法では、励起光の入射によって電荷の分離が起こる有機発光層が用いられ、有機発光層に励起光が入射した第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極と第２電極との間の電位差が変化させられる。これにより、有機発光層に励起光が入射した第１期間から遅延期間が経過した後の第２期間において、有機発光層から発光を得ることができる。このように、この発光方法によれば、新たな発光形態を実現することができる。 This light emitting method uses an organic light-emitting layer in which charges are separated by the incidence of excitation light, and in a second period after a delay period has elapsed from the first period in which the excitation light is incident on the organic light-emission layer, the charges are regenerated. The potential difference between the first and second electrodes is changed such that binding occurs. Thereby, light emission can be obtained from the organic light emitting layer in the second period after the delay period has elapsed from the first period in which the excitation light was incident on the organic light emitting layer. In this way, according to this light emission method, a new light emission form can be realized.

本発明の有機発光素子は、第１電極と、第２電極と、第１電極と第２電極との間に配置され、励起光の入射によって電荷の分離が起こる有機発光層と、第１電極と有機発光層との間、及び第２電極と有機発光層との間の少なくとも一方に配置された電荷流入阻止層と、を備える。 The organic light-emitting device of the present invention includes a first electrode, a second electrode, an organic light-emitting layer disposed between the first electrode and the second electrode, and in which charges are separated by incidence of excitation light, and a first electrode. and a charge influx blocking layer disposed between the second electrode and the organic light emitting layer, and at least one between the second electrode and the organic light emitting layer.

この有機発光素子では、励起光の入射によって有機発光層において電荷の分離が起こると、分離した電荷が、第１電極及び第２電極の少なくとも一方から有機発光層への電荷の流入に起因して減少することが、電荷流入阻止層によって抑制される。したがって、有機発光層に励起光が入射した第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極と第２電極との間の電位差を変化させることで、第２期間において有機発光層から発光を得ることができる。このように、この有機発光素子によれば、新たな発光形態を実現することができる。 In this organic light emitting device, when charge separation occurs in the organic light emitting layer due to the incidence of excitation light, the separated charges are caused by the inflow of charges from at least one of the first electrode and the second electrode into the organic light emitting layer. This decrease is suppressed by the charge inflow blocking layer. Therefore, in the second period after the delay period has elapsed from the first period in which the excitation light is incident on the organic light emitting layer, the potential difference between the first electrode and the second electrode is changed so that charge recombination occurs. By doing so, light emission can be obtained from the organic light emitting layer in the second period. In this way, this organic light-emitting device can realize a new form of light emission.

本発明の有機発光素子では、第２電極の仕事関数は、第１電極の仕事関数よりも小さく、電荷流入阻止層は、少なくとも第２電極と有機発光層との間に配置されていてもよい。これにより、第２期間において有機発光層から発光を確実に得ることができる。 In the organic light emitting device of the present invention, the work function of the second electrode is smaller than the work function of the first electrode, and the charge influx blocking layer may be disposed at least between the second electrode and the organic light emitting layer. . Thereby, light emission can be reliably obtained from the organic light emitting layer in the second period.

本発明の有機発光素子では、電荷流入阻止層は、第１電極と有機発光層との間、及び第２電極と有機発光層との間の両方に配置されていてもよい。これにより、第２期間において有機発光層から発光をより確実に得ることができる。 In the organic light emitting device of the present invention, the charge influx blocking layer may be disposed both between the first electrode and the organic light emitting layer and between the second electrode and the organic light emitting layer. Thereby, light emission can be more reliably obtained from the organic light emitting layer in the second period.

本発明の有機発光素子では、第１電極、及び第１電極と有機発光層との間に配置された電荷流入阻止層は、有機発光層に入射する励起光、及び有機発光層から出射する光に対して光透過性を有してもよい。これにより、有機発光層に励起光を確実に入射させることができると共に、有機発光層から光を確実に出射させることができる。 In the organic light emitting device of the present invention, the first electrode and the charge influx blocking layer disposed between the first electrode and the organic light emitting layer prevent excitation light entering the organic light emitting layer and light emitting from the organic light emitting layer. It may have optical transparency. Thereby, excitation light can be reliably made to enter the organic light-emitting layer, and light can also be reliably emitted from the organic light-emitting layer.

本発明の有機発光素子では、第２電極の仕事関数は、第１電極の仕事関数よりも小さく、電荷流入阻止層は、第１電極と有機発光層との間、及び第２電極と有機発光層との間の両方に配置されており、第１電極と有機発光層との間に配置された電荷流入阻止層は、有機発光層に含まれる有機発光体のＨＯＭＯ準位よりも深いＨＯＭＯ準位を有し、第２電極と有機発光層との間に配置された電荷流入阻止層は、有機発光体のＬＵＭＯ準位よりも浅いＬＵＭＯ準位を有してもよい。これにより、第１期間及び遅延期間において、有機発光層から第１電極への正孔の流出を防ぐと共に、有機発光層から第２電極への電子の流出を防ぐことができるため、第２期間において有機発光層から発光をより確実に得ることができる。 In the organic light emitting device of the present invention, the work function of the second electrode is smaller than the work function of the first electrode, and the charge influx blocking layer is provided between the first electrode and the organic light emitting layer and between the second electrode and the organic light emitting layer. The charge influx blocking layer is disposed between the first electrode and the organic light emitting layer, and the charge influx blocking layer is disposed between the first electrode and the organic light emitting layer. The charge influx blocking layer, which is disposed between the second electrode and the organic light-emitting layer, may have a LUMO level shallower than the LUMO level of the organic light-emitting material. This prevents the outflow of holes from the organic light-emitting layer to the first electrode during the first period and the delay period, and also prevents the outflow of electrons from the organic light-emitting layer to the second electrode. In this method, light emission can be more reliably obtained from the organic light emitting layer.

本発明の有機発光素子では、第２電極の仕事関数は、第１電極の仕事関数よりも小さく、第１電極と有機発光層との間、及び第２電極と有機発光層との間の少なくとも一方に配置された電荷流入阻止層は、有機発光層に含まれる有機発光体のＨＯＭＯ準位よりも深いＨＯＭＯ準位を有してもよい。これにより、第１期間及び遅延期間において、有機発光層から外部への正孔の流出を防ぐことができるため、第２期間において有機発光層から発光をより確実に得ることができる。 In the organic light emitting device of the present invention, the work function of the second electrode is smaller than the work function of the first electrode, and the work function of the second electrode is smaller than the work function of the first electrode, and the work function of the second electrode is smaller than that of the first electrode. The charge influx blocking layer disposed on one side may have a HOMO level deeper than the HOMO level of the organic light emitter included in the organic light emitting layer. Thereby, in the first period and the delay period, it is possible to prevent holes from flowing out from the organic light emitting layer, so that light emission can be more reliably obtained from the organic light emitting layer in the second period.

本発明の有機発光素子では、第２電極の仕事関数は、第１電極の仕事関数よりも小さく、第１電極と有機発光層との間、及び第２電極と有機発光層との間の少なくとも一方に配置された電荷流入阻止層は、有機発光層に含まれる有機発光体のＬＵＭＯ準位よりも浅いＬＵＭＯ準位を有してもよい。これにより、第１期間及び遅延期間において、有機発光層から外部への電子の流出を防ぐことができるため、第２期間において有機発光層から発光をより確実に得ることができる。 In the organic light emitting device of the present invention, the work function of the second electrode is smaller than the work function of the first electrode, and the work function of the second electrode is smaller than that of the first electrode. The charge influx blocking layer disposed on one side may have a LUMO level shallower than the LUMO level of the organic light emitter included in the organic light emitting layer. Thereby, in the first period and the delay period, it is possible to prevent electrons from flowing out from the organic light emitting layer, so that light emission can be more reliably obtained from the organic light emitting layer in the second period.

本発明の有機発光素子では、有機発光層に含まれる有機発光体のダイポールモーメントは、０Ｄよりも大きくてもよい。これにより、例えば、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層から十分な発光を得ることができる。 In the organic light emitting device of the present invention, the dipole moment of the organic light emitter included in the organic light emitting layer may be larger than 0D. As a result, for example, in the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0, and in the second period, a forward electric field that causes charge recombination is applied to the organic light emitting layer. If a voltage is applied between the first electrode and the second electrode so as to occur, sufficient light emission can be obtained from the organic light emitting layer even if the delay period is lengthened.

本発明の有機発光素子では、有機発光体のダイポールモーメントは、３Ｄ以上であってもよい。これにより、例えば、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層から、より十分な発光を得ることができる。 In the organic light emitting device of the present invention, the dipole moment of the organic light emitter may be 3D or more. As a result, for example, in the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0, and in the second period, a forward electric field that causes charge recombination is applied to the organic light emitting layer. When applying a voltage between the first electrode and the second electrode to cause the delay period to be longer, more sufficient light emission can be obtained from the organic light emitting layer.

本発明の有機発光素子では、有機発光体のダイポールモーメントは、１０Ｄ以上であってもよい。これにより、例えば、第１期間及び遅延期間において、第１電極と第２電極との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層に生じるように第１電極と第２電極との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層から、より十分な発光を得ることができる。 In the organic light emitting device of the present invention, the dipole moment of the organic light emitter may be 10D or more. As a result, for example, in the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0, and in the second period, a forward electric field that causes charge recombination is applied to the organic light emitting layer. When applying a voltage between the first electrode and the second electrode to cause the delay period to be longer, more sufficient light emission can be obtained from the organic light emitting layer.

本発明によれば、新たな発光形態を実現することができる発光装置、発光方法及び有機発光素子を提供することが可能となる。 According to the present invention, it is possible to provide a light emitting device, a light emitting method, and an organic light emitting element that can realize a new light emission form.

一実施形態の発光装置の構成図である。FIG. 1 is a configuration diagram of a light emitting device according to an embodiment. 図１に示される有機発光素子の模式図である。2 is a schematic diagram of the organic light emitting device shown in FIG. 1. FIG. 図１に示される有機発光素子のエネルギー図である。2 is an energy diagram of the organic light emitting device shown in FIG. 1. FIG. 図１に示される有機発光素子のエネルギー図である。2 is an energy diagram of the organic light emitting device shown in FIG. 1. FIG. 実施例１の有機発光素子についての実験結果を示すグラフである。3 is a graph showing experimental results regarding the organic light emitting device of Example 1. 実施例２の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 2. 実施例３の有機発光素子についての実験結果を示すグラフである。3 is a graph showing experimental results regarding the organic light emitting device of Example 3. 実施例４の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 4. 実施例５の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 5. 実施例６の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 6. 実施例７の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 7. 実施例１の有機発光素子についての実験結果を示すグラフである。3 is a graph showing experimental results regarding the organic light emitting device of Example 1. 実施例８の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 8. 変形例の発光装置の構成図である。It is a block diagram of the light emitting device of a modification. 実施例１の有機発光素子についての実験結果を示すグラフである。3 is a graph showing experimental results regarding the organic light emitting device of Example 1. 実施例２の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 2. 実施例９の有機発光素子についての実験結果を示すグラフである。7 is a graph showing experimental results regarding the organic light emitting device of Example 9.

以下、本発明の実施形態について、図面を参照して詳細に説明する。なお、各図において同一又は相当部分には同一符号を付し、重複する説明を省略する。
［発光装置の構成］ Embodiments of the present invention will be described in detail below with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations will be omitted.
[Configuration of light emitting device]

図１に示されるように、発光装置１は、有機発光素子２と、制御部３と、を備えている。有機発光素子２は、光透過基板２０と、第１電極２１と、第２電極２２と、第１電荷流入阻止層（電荷流入阻止層）２３と、第２電荷流入阻止層（電荷流入阻止層）２４と、有機発光層２５と、を有している。有機発光素子２では、第１電極２１、第１電荷流入阻止層２３、有機発光層２５、第２電荷流入阻止層２４及び第２電極２２が、この順序で光透過基板２０上に積層されている。つまり、有機発光素子２では、第２電極２２が第１電極２１と対向するように配置されており、有機発光層２５が第１電極２１と第２電極２２との間に配置されている。更に、有機発光素子２では、第１電荷流入阻止層２３が第１電極２１と有機発光層２５との間に配置されており、第２電荷流入阻止層２４が第２電極２２と有機発光層２５との間に配置されている。 As shown in FIG. 1, the light emitting device 1 includes an organic light emitting element 2 and a control section 3. The organic light emitting device 2 includes a light transmitting substrate 20, a first electrode 21, a second electrode 22, a first charge influx blocking layer (charge influx blocking layer) 23, and a second charge influx blocking layer (charge influx blocking layer). ) 24 and an organic light emitting layer 25. In the organic light emitting device 2, a first electrode 21, a first charge inflow blocking layer 23, an organic light emitting layer 25, a second charge inflow blocking layer 24, and a second electrode 22 are laminated in this order on a light transmitting substrate 20. There is. That is, in the organic light emitting device 2, the second electrode 22 is arranged to face the first electrode 21, and the organic light emitting layer 25 is arranged between the first electrode 21 and the second electrode 22. Further, in the organic light emitting device 2, the first charge influx blocking layer 23 is disposed between the first electrode 21 and the organic light emitting layer 25, and the second charge influx blocking layer 24 is disposed between the second electrode 22 and the organic light emitting layer. It is located between 25 and 25.

光透過基板２０は、光透過性を有する材料（例えば、ガラス等）からなる基板である。第１電極２１は、導電性及び光透過性を有する材料（例えば、ＩＴＯ等）からなる層である。光透過基板２０及び第１電極２１は、外部から有機発光層２５に入射する励起光、及び有機発光層２５から外部に出射する光（詳細については、後述する）に対して光透過性を有している。第２電極２２は、導電性を有する材料（例えば、アルミニウム等）からなる層である。本実施形態では、第２電極２２の仕事関数（真空準位からの深さ（絶対値））は、第１電極２１の仕事関数よりも小さい。例えば、第１電極２１がＩＴＯからなり、第２電極２２がアルミニウムからなる場合には、第１電極２１の仕事関数は４．８ｅＶ程度であり、第２電極２２の仕事関数は４．２ｅＶである。 The light-transmitting substrate 20 is a substrate made of a light-transmitting material (eg, glass, etc.). The first electrode 21 is a layer made of a material (for example, ITO, etc.) having conductivity and light transmittance. The light-transmitting substrate 20 and the first electrode 21 have a light-transmitting property for excitation light that enters the organic light-emitting layer 25 from the outside and light that exits from the organic light-emitting layer 25 to the outside (details will be described later). are doing. The second electrode 22 is a layer made of a conductive material (for example, aluminum, etc.). In this embodiment, the work function (depth (absolute value) from the vacuum level) of the second electrode 22 is smaller than the work function of the first electrode 21. For example, when the first electrode 21 is made of ITO and the second electrode 22 is made of aluminum, the work function of the first electrode 21 is about 4.8 eV, and the work function of the second electrode 22 is about 4.2 eV. be.

第１電荷流入阻止層２３は、第１電極２１から有機発光層２５への電荷の流入を阻止する層である。第１電荷流入阻止層２３は、光透過基板２０及び第１電極２１と同様に、外部から有機発光層２５に入射する励起光、及び有機発光層２５から外部に出射する光（詳細については、後述する）に対して光透過性を有している。第２電荷流入阻止層２４は、第２電極２２から有機発光層２５への電荷の流入を阻止する層である。一例として、第１電荷流入阻止層２３がいわゆる電子輸送材料（例えば、Ｔ２Ｔ、ＢＣＰ、ＴＰＢｉ、Ｂｐｈｅｎ等）からなる場合には、第１電荷流入阻止層２３によって、第１電極２１から有機発光層２５への正孔の流入が阻止される。また、第２電荷流入阻止層２４がいわゆる正孔輸送材料（例えば、ＣＢＰ、ＴＡＰＣ、Ｔｒｉｓ－ＰＣｚ、ＮＰＤ等）からなる場合には、第２電荷流入阻止層２４によって、第２電極２２から有機発光層２５への電子の流入が阻止される。 The first charge inflow blocking layer 23 is a layer that prevents charges from flowing into the organic light emitting layer 25 from the first electrode 21 . Like the light-transmitting substrate 20 and the first electrode 21, the first charge influx blocking layer 23 protects against excitation light that enters the organic light-emitting layer 25 from the outside and light that exits from the organic light-emitting layer 25 to the outside (for details, see (described later) has optical transparency. The second charge inflow blocking layer 24 is a layer that blocks charges from flowing into the organic light emitting layer 25 from the second electrode 22 . For example, when the first charge influx blocking layer 23 is made of a so-called electron transporting material (for example, T2T, BCP, TPBi, Bphen, etc.), the first charge influx blocking layer 23 allows the first electrode 21 to be connected to the organic light emitting layer. Holes are prevented from flowing into 25. Furthermore, when the second charge influx blocking layer 24 is made of a so-called hole transport material (for example, CBP, TAPC, Tris-PCz, NPD, etc.), the second charge influx blocking layer 24 allows organic matter to flow from the second electrode 22. Electrons are prevented from flowing into the light emitting layer 25.

有機発光層２５は、励起光の入射によって電荷の分離が起こる層である。本実施形態では、有機発光層２５は、励起光の入射によって電荷の分離が起こる有機発光体を含むホスト材料によって、構成されている。有機発光層２５では、励起光の入射によって電荷の分離が起こる有機発光体として、例えば、ＴＰＡ－ＤＣＰＰ、４ＣｚＩＰＮ、Ａｌｑ３、ＴＢＲｂ、４ＣｚＴＰＮ－Ｐｈ等が用いられている。有機発光層２５では、ホスト材料として、例えば、ＣＢＰ、ｍＣＢＰ，Ｔ２Ｔ，ｍＣＰ，ＰＰＴ，ＤＰＥＰＯ等が用いられている。ホスト材料は、有機発光体よりも大きい励起三重項エネルギーを有するものであることが好ましい。 The organic light-emitting layer 25 is a layer in which charges are separated by incidence of excitation light. In this embodiment, the organic light-emitting layer 25 is made of a host material containing an organic light-emitting material whose charge is separated by the incidence of excitation light. In the organic light-emitting layer 25, for example, TPA-DCPP, 4CzIPN, Alq3, TBRb, 4CzTPN-Ph, etc. are used as organic light-emitting materials whose charges are separated by the incidence of excitation light. In the organic light emitting layer 25, for example, CBP, mCBP, T2T, mCP, PPT, DPEPO, etc. are used as the host material. Preferably, the host material has a higher excited triplet energy than the organic emitter.

制御部３は、有機発光素子２を制御する。具体的には、制御部３は、第１電極２１と第２電極２２との間に印加する電圧の値、第１電極２１と第２電極２２との間に電圧を印加するタイミング等を制御する。制御部３は、後述する遅延期間の長さを調整可能である。一例として、制御部３は、ファンクションジェネレーター（任意波形出力装置）、ＦＰＧＡ等の集積回路等によって、構成されている。
［発光装置において実施される発光方法］ The control unit 3 controls the organic light emitting device 2 . Specifically, the control unit 3 controls the value of the voltage applied between the first electrode 21 and the second electrode 22, the timing of applying the voltage between the first electrode 21 and the second electrode 22, etc. do. The control unit 3 can adjust the length of the delay period, which will be described later. As an example, the control unit 3 is configured by a function generator (arbitrary waveform output device), an integrated circuit such as an FPGA, and the like.
[Light emission method implemented in light emitting device]

発光装置１において実施される発光方法（すなわち、有機発光素子２を用いた発光方法）について、図２、図３及び図４を参照して説明する。なお、図２では、有機発光素子２において、光透過基板２０の図示が省略されている。また、図３及び図４には、一例として、第１電極２１がＩＴＯからなり、第２電極２２がアルミニウムからなり、第１電荷流入阻止層２３がＴ２Ｔからなり、第２電荷流入阻止層２４がＣＢＰからなり、有機発光層２５がＴＰＡ－ＤＣＰＰ（有機発光体）及びＣＢＰ（ホスト材料）からなる場合のエネルギー図が示されている。 A light emitting method implemented in the light emitting device 1 (that is, a light emitting method using the organic light emitting element 2) will be described with reference to FIGS. 2, 3, and 4. Note that in FIG. 2, illustration of the light-transmitting substrate 20 in the organic light-emitting element 2 is omitted. Further, in FIGS. 3 and 4, as an example, the first electrode 21 is made of ITO, the second electrode 22 is made of aluminum, the first charge inflow blocking layer 23 is made of T2T, and the second charge inflow blocking layer 24 is made of T2T. is made of CBP, and an energy diagram is shown in which the organic light emitting layer 25 is made of TPA-DCPP (organic light emitter) and CBP (host material).

まず、定常状態では、図３に示されるように、有機発光層２５において電荷の分離が起こっておらず、電荷の分離によって生成された正孔及び電子が有機発光層２５内に存在していない。この状態で、図２の（ａ）に示されるように、第１期間において、外部から光透過基板２０（図１参照）、第１電極２１及び第１電荷流入阻止層２３を介して有機発光層２５に励起光Ｌ１が入射すると（励起光が入射するステップ）、有機発光層２５において電荷の分離が起こり、正孔及び電子が生成される。 First, in a steady state, as shown in FIG. 3, no charge separation occurs in the organic light emitting layer 25, and holes and electrons generated by charge separation do not exist in the organic light emitting layer 25. . In this state, as shown in FIG. 2(a), in the first period, organic light is emitted from the outside through the light transmitting substrate 20 (see FIG. 1), the first electrode 21, and the first charge influx blocking layer 23. When the excitation light L1 is incident on the layer 25 (excitation light incident step), charge separation occurs in the organic light emitting layer 25, and holes and electrons are generated.

より具体的には、励起光Ｌ１の入射によって、有機発光層２５中のＴＰＡ－ＤＣＰＰの分子が励起状態となり、励起状態となった分子のうち、一部の分子は発光して基底状態に戻るが、残りの分子は発光せずに電荷の分離を起こす。図２の（ｂ）及び図４の（ａ）に示されるように、電荷の分離によって生成された正孔は、有機発光層２５と第１電荷流入阻止層２３との界面に移動する。電荷の分離によって生成された電子は、有機発光層２５中のＴＰＡ－ＤＣＰＰ中にトラップされる。 More specifically, upon incidence of the excitation light L1, the molecules of TPA-DCPP in the organic light emitting layer 25 become excited, and some of the excited molecules emit light and return to the ground state. However, the remaining molecules undergo charge separation without emitting light. As shown in FIGS. 2(b) and 4(a), holes generated by the charge separation move to the interface between the organic light emitting layer 25 and the first charge inflow blocking layer 23. Electrons generated by charge separation are trapped in the TPA-DCPP in the organic light emitting layer 25.

続いて、制御部３が、第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極２１と第２電極２２との間の電位差を変化させる（電位差を変化させるステップ）。これにより、図２の（ｃ）及び図４の（ｂ）に示されるように、有機発光層２５において正孔と電子とが再結合することで、有機発光層２５から第１電荷流入阻止層２３、第１電極２１及び光透過基板２０（図１参照）を介して外部に光Ｌ２が出射する。ここで、遅延期間は、第１期間の終了時から第２期間の開始時までの期間である。 Subsequently, the control unit 3 changes the potential difference between the first electrode 21 and the second electrode 22 so that charge recombination occurs in a second period after a delay period has elapsed from the first period ( step of changing the potential difference). As a result, as shown in FIG. 2C and FIG. 23, the light L2 is emitted to the outside via the first electrode 21 and the light transmitting substrate 20 (see FIG. 1). Here, the delay period is a period from the end of the first period to the start of the second period.

なお、制御部３は、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界（以下、単に「順方向の電界」という）が有機発光層２５に生じるように（図３に示される一例では、第２電極２２の電位を基準として第１電極２１の電位が正となるように）第１電極２１と第２電極２２との間に電圧を印加する。或いは、制御部３は、第１期間及び遅延期間において、順方向の電界とは逆方向の電界（以下、単に「逆方向の電界」という）が有機発光層２５に生じるように（図３に示される一例では、第２電極２２の電位を基準として第１電極２１の電位が負となるように）第１電極２１と第２電極２２との間に電圧を印加し、第２期間において、順方向の電界が有機発光層２５に生じるように（図３に示される一例では、第２電極２２の電位を基準として第１電極２１の電位が正となるように）第１電極２１と第２電極２２との間に電圧を印加する。
［作用及び効果］ Note that the control unit 3 sets the potential difference between the first electrode 21 and the second electrode 22 to 0 in the first period and the delay period, and applies a forward electric field ( (hereinafter simply referred to as a "forward electric field") is generated in the organic light emitting layer 25 (in the example shown in FIG. 3, the potential of the first electrode 21 is positive with respect to the potential of the second electrode 22). ) A voltage is applied between the first electrode 21 and the second electrode 22. Alternatively, the control unit 3 may generate an electric field in the opposite direction to the forward electric field (hereinafter simply referred to as "reverse electric field") in the organic light emitting layer 25 during the first period and the delay period (as shown in FIG. 3). In the illustrated example, a voltage is applied between the first electrode 21 and the second electrode 22 (so that the potential of the first electrode 21 is negative with respect to the potential of the second electrode 22), and in the second period, The first electrode 21 and the first electrode 21 are connected so that a forward electric field is generated in the organic light emitting layer 25 (in the example shown in FIG. 3, the potential of the first electrode 21 is positive with respect to the potential of the second electrode 22). A voltage is applied between the two electrodes 22.
[Action and effect]

発光装置１では、励起光Ｌ１の入射によって電荷の分離が起こる有機発光層２５が用いられ、有機発光層２５に励起光Ｌ１が入射した第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極２１と第２電極２２との間の電位差が変化させられる。これにより、有機発光層２５に励起光Ｌ１が入射した第１期間から遅延期間が経過した後の第２期間において、有機発光層２５から発光（光Ｌ２の出射）を得ることができる。このように、発光装置１（及び有機発光素子２を用いた発光方法）によれば、新たな発光形態を実現することができる。発光装置１（及び有機発光素子２を用いた発光方法）による発光形態は、光照射履歴を記憶する光記憶装置等への応用が期待される。 The light-emitting device 1 uses an organic light-emitting layer 25 in which charges are separated by the incidence of the excitation light L1, and in a second period after a delay period has elapsed from the first period in which the excitation light L1 was incident on the organic light-emission layer 25. , the potential difference between the first electrode 21 and the second electrode 22 is changed so that charge recombination occurs. Thereby, light emission (emission of light L2) can be obtained from the organic light emitting layer 25 in the second period after the delay period has elapsed from the first period in which the excitation light L1 was incident on the organic light emitting layer 25. In this way, according to the light emitting device 1 (and the light emitting method using the organic light emitting element 2), a new light emitting form can be realized. The light emitting form of the light emitting device 1 (and the light emitting method using the organic light emitting element 2) is expected to be applied to optical storage devices and the like that store light irradiation history.

また、発光装置１では、制御部３が、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０とし、第２期間において、順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加する。或いは、発光装置１では、制御部３が、第１期間及び遅延期間において、逆方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加し、第２期間において、順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加する。いずれの場合にも、簡易な電圧の印加の仕方で、第２期間において有機発光層２５から発光を得ることができる。 Further, in the light emitting device 1, the control unit 3 sets the potential difference between the first electrode 21 and the second electrode 22 to 0 in the first period and the delay period, and in the second period, the forward electric field is A voltage is applied between the first electrode 21 and the second electrode 22 so as to occur in the layer 25 . Alternatively, in the light emitting device 1, the control unit 3 applies a voltage between the first electrode 21 and the second electrode 22 so that an electric field in the opposite direction is generated in the organic light emitting layer 25 during the first period and the delay period. , during the second period, a voltage is applied between the first electrode 21 and the second electrode 22 so that a forward electric field is generated in the organic light emitting layer 25 . In either case, light emission can be obtained from the organic light emitting layer 25 in the second period by applying a simple voltage.

また、発光装置１では、制御部３が遅延期間の長さを調整可能である。これにより、有機発光層２５から外部に光Ｌ２が出射するタイミングを調整することができる。 Further, in the light emitting device 1, the control unit 3 can adjust the length of the delay period. Thereby, the timing at which the light L2 is emitted from the organic light emitting layer 25 to the outside can be adjusted.

また、有機発光素子２では、励起光Ｌ１の入射によって有機発光層２５において電荷の分離が起こると、分離した電荷が、第１電極２１及び第２電極２２のそれぞれから有機発光層２５への電荷の流入に起因して減少することが、第１電荷流入阻止層２３及び第２電荷流入阻止層２４によって抑制される。したがって、有機発光層２５に励起光Ｌ１が入射した第１期間から遅延期間が経過した後の第２期間において、電荷の再結合が起こるように第１電極２１と第２電極２２との間の電位差を変化させることで、第２期間において有機発光層２５から発光を得ることができる。このように、有機発光素子２によれば、新たな発光形態を実現することができる。有機発光素子２による発光形態は、光照射履歴を記憶する光記憶装置等への応用が期待される。 Further, in the organic light emitting device 2, when charge separation occurs in the organic light emitting layer 25 due to the incidence of the excitation light L1, the separated charges are transferred from each of the first electrode 21 and the second electrode 22 to the organic light emitting layer 25. The first charge inflow blocking layer 23 and the second charge inflow blocking layer 24 suppress the decrease due to the inflow of the charge inflow. Therefore, in the second period after the delay period has elapsed from the first period in which the excitation light L1 is incident on the organic light emitting layer 25, the relationship between the first electrode 21 and the second electrode 22 is such that recombination of charges occurs. By changing the potential difference, light emission can be obtained from the organic light emitting layer 25 in the second period. In this way, the organic light emitting device 2 can realize a new light emission form. The light emission form of the organic light emitting element 2 is expected to be applied to optical storage devices that store light irradiation history.

また、有機発光素子２では、第１電極２１及び第１電荷流入阻止層２３が、有機発光層２５に入射する励起光Ｌ１、及び有機発光層２５から出射する光Ｌ２に対して光透過性を有している。これにより、有機発光層２５に励起光Ｌ１を確実に入射させることができると共に、有機発光層２５から光Ｌ２を確実に出射させることができる。
［電荷流入阻止層についての考察］ Further, in the organic light emitting device 2, the first electrode 21 and the first charge influx blocking layer 23 have optical transparency for the excitation light L1 entering the organic light emitting layer 25 and the light L2 emitted from the organic light emitting layer 25. have. Thereby, the excitation light L1 can be reliably made to enter the organic light emitting layer 25, and the light L2 can be reliably emitted from the organic light emitting layer 25.
[Considerations about charge inflow blocking layer]

順方向の電界を有機発光層２５に生じさせるために、第２期間において、第２電極２２の電位を基準として第１電極２１の電位が正となるように第１電極２１と第２電極２２との間に電圧を印加する場合は、第１電極２１を陽極として機能させ、第２電極２２を陰極として機能させる場合に相当する。したがって、そのような場合には、第２電極２２の仕事関数が第１電極２１の仕事関数よりも小さくなるように、第１電極２１の材料及び第２電極２２の材料を選択することが一般的である。 In order to generate a forward electric field in the organic light emitting layer 25, in the second period, the first electrode 21 and the second electrode 22 are connected so that the potential of the first electrode 21 is positive with respect to the potential of the second electrode 22. When a voltage is applied between the two electrodes, the first electrode 21 functions as an anode and the second electrode 22 functions as a cathode. Therefore, in such a case, it is common to select the material of the first electrode 21 and the material of the second electrode 22 so that the work function of the second electrode 22 is smaller than the work function of the first electrode 21. It is true.

ここで、第１期間及び遅延期間において、第１電極２１から有機発光層２５への電荷の流入を防ぐためには、基本的には、第１電荷流入阻止層２３の材料として、第１電極２１の仕事関数に対して注入障壁が大きくなる材料を選択する必要がある。同様に、第２電極２２から有機発光層２５への電荷の流入を防ぐためには、基本的には、第２電荷流入阻止層２４の材料として、第２電極２２の仕事関数に対して注入障壁が大きくなる材料を選択する必要がある。 Here, in order to prevent charges from flowing into the organic light emitting layer 25 from the first electrode 21 during the first period and the delay period, basically, the first electrode 21 is It is necessary to select a material that has a large injection barrier for the work function of . Similarly, in order to prevent charges from flowing into the organic light emitting layer 25 from the second electrode 22, basically the material of the second charge influx blocking layer 24 is an injection barrier with respect to the work function of the second electrode 22. It is necessary to select a material that has a large value.

図３に示される一例では、ＩＴＯからなる第１電極２１の仕事関数が４．８ｅＶ程度であるから、第１電荷流入阻止層２３の材料として、正孔の注入障壁が高い（すなわち、ＨＯＭＯ準位が深い）Ｔ２Ｔ（ＨＯＭＯ準位：６．５ｅＶ）が選択されている。しかも、Ｔ２Ｔは、電子移動度の高い電子輸送材料であるため、流入する正孔に対して高抵抗を保つことができる。なお、逆方向の電界を有機発光層２５に生じさせるために、第１期間及び遅延期間において、第２電極２２の電位を基準として第１電極２１の電位が負となるように第１電極２１と第２電極２２との間に電圧を印加する場合には、第１電極２１から電子が流入しようとする。しかし、第２期間において陽極として機能する第１電極２１の仕事関数が大きい上に、電子が注入され難いという特性を有機発光体が本質的に有しているため、その場合を考慮して第１電荷流入阻止層２３の材料の条件を限定する必要はない。 In the example shown in FIG. 3, since the work function of the first electrode 21 made of ITO is about 4.8 eV, the material of the first charge influx blocking layer 23 has a high hole injection barrier (that is, HOMO level). T2T (HOMO level: 6.5 eV) is selected. Moreover, since T2T is an electron transport material with high electron mobility, it can maintain high resistance to inflowing holes. Note that, in order to generate an electric field in the opposite direction in the organic light emitting layer 25, the first electrode 21 is adjusted so that the potential of the first electrode 21 becomes negative with respect to the potential of the second electrode 22 in the first period and the delay period. When applying a voltage between the first electrode 21 and the second electrode 22, electrons tend to flow in from the first electrode 21. However, since the work function of the first electrode 21 that functions as an anode in the second period is large and the organic light emitting material inherently has the property that electrons are difficult to be injected, the There is no need to limit the conditions for the material of the one-charge inflow blocking layer 23.

また、図３に示される一例では、アルミニウムからなる第２電極２２の仕事関数が４．２ｅＶであるから、第２電荷流入阻止層２４の材料として、電子の注入障壁が高い（すなわち、ＬＵＭＯ準位が浅い）ＣＢＰ（ＬＵＭＯ準位：２．４ｅＶ）が選択されている。なお、逆方向の電界を有機発光層２５に生じさせるために、第１期間及び遅延期間において、第２電極２２の電位を基準として第１電極２１の電位が負となるように第１電極２１と第２電極２２との間に電圧を印加する場合には、第２電極２２から正孔が流入する可能性がある。そのため、その場合を考慮して、第２電荷流入阻止層２４の材料として、正孔の注入障壁が高い（すなわち、ＨＯＭＯ準位が深い）材料を選択してもよい。 In addition, in the example shown in FIG. 3, the work function of the second electrode 22 made of aluminum is 4.2 eV, so the material for the second charge influx blocking layer 24 has a high electron injection barrier (that is, LUMO quasi- CBP (LUMO level: 2.4 eV) is selected. Note that, in order to generate an electric field in the opposite direction in the organic light emitting layer 25, the first electrode 21 is adjusted so that the potential of the first electrode 21 becomes negative with respect to the potential of the second electrode 22 in the first period and the delay period. When applying a voltage between the second electrode 22 and the second electrode 22, holes may flow from the second electrode 22. Therefore, in consideration of this case, a material having a high hole injection barrier (that is, a deep HOMO level) may be selected as the material for the second charge inflow blocking layer 24.

また、第１電荷流入阻止層２３の材料及び第２電荷流入阻止層２４の材料を選択する場合に、電流密度－電圧（Ｊ－Ｖ）特性に着目してもよい。第２電極２２の電位を基準として第１電極２１の電位が＋１０Ｖとなるように第１電極２１と第２電極２２との間に電圧を印加した場合、及び、第２電極２２の電位を基準として第１電極２１の電位が－１０Ｖとなるように第１電極２１と第２電極２２との間に電圧を印加した場合の両方の場合において、有機発光層２５における電流密度が０．１ｍＡ／ｃｍ２未満となるように、第１電荷流入阻止層２３の材料及び第２電荷流入阻止層２４の材料を選択してもよい。なお、この場合の電流密度としては、暗状態で＋１０Ｖ及び－１０Ｖを印加した際の電流密度をケースレー製のソースメーター２４００シリーズによって測定した値（アベレージング回数２以上）を用いることができる。 Further, when selecting the material of the first charge inflow blocking layer 23 and the material of the second charge inflow blocking layer 24, attention may be paid to current density-voltage (JV) characteristics. When a voltage is applied between the first electrode 21 and the second electrode 22 such that the potential of the first electrode 21 is +10V with the potential of the second electrode 22 as a reference, and the potential of the second electrode 22 as a reference In both cases, when a voltage is applied between the first electrode 21 and the second electrode 22 so that the potential of the first electrode 21 is -10V, the current density in the organic light emitting layer 25 is 0.1 mA/ The material of the first charge inflow blocking layer 23 and the material of the second charge inflow blocking layer 24 may be selected so that the charge inflow blocking layer 24 is less than cm 2 . Note that as the current density in this case, a value obtained by measuring the current density when applying +10 V and -10 V in a dark state using a Keithley Sourcemeter 2400 series (averaging times 2 or more) can be used.

更に、第１期間及び遅延期間において、有機発光層２５から第１電極２１への正孔の流出を防ぐためには、第１電荷流入阻止層２３の材料として、有機発光層２５の有機発光体のＨＯＭＯ準位よりも深いＨＯＭＯ準位を有する材料を選択してもよい。また、第１期間及び遅延期間において、有機発光層２５から第２電極２２への電子の流出を防ぐためには、第２電荷流入阻止層２４の材料として、有機発光層２５の有機発光体のＬＵＭＯ準位よりも浅いＬＵＭＯ準位を有する材料を選択してもよい。これらにより、第２期間において有機発光層２５から発光をより確実に得ることができる。なお、第１電荷流入阻止層２３の材料及び第２電荷流入阻止層２４の少なくとも一方が、有機発光層２５の有機発光体のＨＯＭＯ準位よりも深いＨＯＭＯ準位を有していれば、第１期間及び遅延期間において、有機発光層２５から外部への正孔の流出を防ぐことができる。或いは、第１電荷流入阻止層２３の材料及び第２電荷流入阻止層２４の少なくとも一方が、有機発光層２５の有機発光体のＬＵＭＯ準位よりも浅いＬＵＭＯ準位を有していれば、第１期間及び遅延期間において、有機発光層２５から外部への電子の流出を防ぐことができる。これらの場合にも、第２期間において有機発光層２５から発光をより確実に得ることができる。 Furthermore, in order to prevent the holes from flowing out from the organic light-emitting layer 25 to the first electrode 21 during the first period and the delay period, the material of the first charge influx blocking layer 23 is an organic light-emitting material of the organic light-emitting layer 25. A material having a HOMO level deeper than the HOMO level may be selected. In addition, in order to prevent electrons from flowing out from the organic light-emitting layer 25 to the second electrode 22 during the first period and the delay period, LUMO of the organic light-emitting body of the organic light-emitting layer 25 is used as the material of the second charge influx blocking layer 24. A material having a LUMO level shallower than the LUMO level may be selected. Due to these, light emission can be more reliably obtained from the organic light emitting layer 25 in the second period. Note that if at least one of the material of the first charge influx blocking layer 23 and the second charge influx blocking layer 24 has a HOMO level deeper than the HOMO level of the organic light emitter of the organic light emitting layer 25, In the one period and the delay period, holes can be prevented from flowing out from the organic light emitting layer 25 to the outside. Alternatively, if at least one of the material of the first charge influx blocking layer 23 and the second charge influx blocking layer 24 has a LUMO level shallower than the LUMO level of the organic light emitter of the organic light emitting layer 25, In the one period and the delay period, it is possible to prevent electrons from flowing out from the organic light emitting layer 25 to the outside. In these cases as well, light emission can be more reliably obtained from the organic light emitting layer 25 in the second period.

本明細書中、有機発光体及び電荷流入阻止層のＨＯＭＯ準位及びＬＵＭＯ準位は、以下に示す方法で測定することができる。 In this specification, the HOMO level and LUMO level of the organic light emitter and the charge influx blocking layer can be measured by the method shown below.

表面ミラー仕上げ、抵抗率０．００３０－０．００６０Ω・ｃｍ、結晶方位＜１００＞のＡｓドープｎ型ベアＳｉウェハ上に有機発光体又は電荷流入阻止層をそれぞれ単独で成膜し、大気下光電子分光測定装置ＡＣ－３Ｅ（ＲＩＫＥＮ ＫＥＩＫＩ社製）によってＨＯＭＯ準位を測定する。膜厚は１００ｎｍとすることが好ましいが、スピンコート法で成膜する場合、厚膜化困難であるため約３０ｎｍで測定を行う。 An organic light emitter or a charge inflow blocking layer was formed independently on an As-doped n-type bare Si wafer with a surface mirror finish, a resistivity of 0.0030-0.0060 Ωcm, and a crystal orientation of <100>. The HOMO level is measured using a spectrometer AC-3E (manufactured by RIKEN KEIKI). The film thickness is preferably 100 nm, but when the film is formed by spin coating, it is difficult to increase the film thickness, so the measurement is performed at about 30 nm.

石英基板上に有機発光体又は電荷流入阻止層をそれぞれ単独で成膜し、ＵＶ－ＶＩＳ－ＮＩＲ分光光度計ＬＡＭＢＤＡ９５０（ＰｅｒｋｉｎＥｌｍｅｒ社製）によって吸収スペクトルを測定する。この際、最も長波長側の吸収ピークが光学濃度（ＯＤ）０．１～１．０となるように膜厚を調整する。また、発光体に関しては、最も長波長側にある吸収極大値をＰＡｂｓとする。ＬＵＭＯ準位に関しては、それぞれ得られた吸収スペクトルの最も長波長側のピークの、長波長側の立ち下がりに対して引いた接線と横軸（波長軸）との交点の波長λｅｄｇｅ[ｎｍ]とし、上述の方法で得られるＨＯＭＯ［ｅＶ］の値を用いて、ＬＵＭＯ［ｅＶ］＝ＨＯＭＯ＋（１２４０／λｅｄｇｅ）によって算出する。なお、立ち下がりの接線は以下のようにして引く。吸収ピークの長波長側から極大値までスペクトル曲線上を移動する際に、スペクトル曲線上の各点における接線を考える。この接線は、曲線が立ち上がるにつれ（つまり縦軸が増加するにつれ）、傾きが増加する。この傾きの値が極大値をとる点において引いた接線を、吸収スペクトルの長波長側の立ち下がりに対する接線とする。
［有機発光層についての考察］ An organic light emitter or a charge inflow blocking layer is individually formed on a quartz substrate, and the absorption spectrum is measured using a UV-VIS-NIR spectrophotometer LAMBDA950 (manufactured by PerkinElmer). At this time, the film thickness is adjusted so that the absorption peak on the longest wavelength side has an optical density (OD) of 0.1 to 1.0. Regarding the light emitter, the maximum absorption value on the longest wavelength side is defined as P Abs . Regarding the LUMO level, the wavelength λ edge [nm] of the intersection of the horizontal axis (wavelength axis) and a tangent drawn to the fall of the longest wavelength side of the peak on the longest wavelength side of the obtained absorption spectrum LUMO[eV]=HOMO+(1240/λ edge ) using the value of HOMO[eV] obtained by the method described above. Note that the falling tangent line is drawn as follows. When moving on the spectral curve from the long wavelength side of the absorption peak to the maximum value, consider the tangents at each point on the spectral curve. The slope of this tangent line increases as the curve rises (ie, as the vertical axis increases). The tangent line drawn at the point where the value of this slope takes the maximum value is defined as the tangent line to the falling edge on the long wavelength side of the absorption spectrum.
[Considerations about organic light emitting layer]

有機発光層２５には、励起光の入射によって電荷の分離が起こる有機発光体として、ダイポールモーメント（μ）が０Ｄよりも大きい有機発光体を用いることができる。ダイポールモーメントは、量子化学計算によって算出可能な値であり、一般的には、ハートリーフォック（ＨＦ）法又は密度汎関数（ＤＦＴ）法と称される計算手法によって算出される値である。その中でも最もよく使用されている条件（汎関数と基底関数との組み合わせ）は、Ｂ３ＬＹＰ／６－３１（ｄ）というものである。一例として、ＴＰＡ－ＤＣＰＰのダイポールモーメントは１３．０５Ｄであり、４ＣｚＩＰＮのダイポールモーメントは３．８５Ｄであり、Ａｌｑ３のダイポールモーメントは４．４０Ｄであり、ＴＢＲｂのダイポールモーメントは０．１６Ｄであり、４ＣｚＴＰＮ－Ｐｈのダイポールモーメントは０Ｄである。なお、ＴＢＲｂ又は４ＣｚＴＰＮ－Ｐｈのように、ダイポールモーメントが３Ｄ未満の有機発光体であっても、逆方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加した状態とすれば、励起光の入射によって電荷の分離が起こる。 For the organic light-emitting layer 25, an organic light-emitting material whose dipole moment (μ) is larger than 0D can be used as an organic light-emitting material whose charges are separated by the incidence of excitation light. The dipole moment is a value that can be calculated by quantum chemical calculation, and is generally a value calculated by a calculation method called the Hartree-Fock (HF) method or the density functional (DFT) method. Among them, the most commonly used condition (combination of functional and basis functions) is B3LYP/6-31(d). As an example, the dipole moment of TPA-DCPP is 13.05D, the dipole moment of 4CzIPN is 3.85D, the dipole moment of Alq3 is 4.40D, the dipole moment of TBRb is 0.16D, and the dipole moment of 4CzTPN is 4.40D. The dipole moment of -Ph is 0D. Note that even if the organic light emitting material has a dipole moment of less than 3D, such as TBRb or 4CzTPN-Ph, the distance between the first electrode 21 and the second electrode 22 is such that an electric field in the opposite direction is generated in the organic light emitting layer 25. When a voltage is applied to , charge separation occurs due to the incidence of excitation light.

ただし、有機発光層２５に含まれる有機発光体のダイポールモーメントが０Ｄよりも大きいと、例えば、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０（又は０に近い値）とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層２５から十分な発光を得ることができる。好ましくは、有機発光体のダイポールモーメントが３Ｄ以上であると（より好ましくは、有機発光体のダイポールモーメントが１０Ｄ以上であると）、例えば、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０（又は０に近い値）とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層２５から、より十分な発光を得ることができる。 However, if the dipole moment of the organic light emitter included in the organic light emitting layer 25 is larger than 0D, for example, the potential difference between the first electrode 21 and the second electrode 22 is reduced to 0 (or (a value close to 0), and in the second period, a voltage is applied between the first electrode 21 and the second electrode 22 so that a forward electric field that causes charge recombination is generated in the organic light emitting layer 25. Furthermore, even if the delay period is lengthened, sufficient light emission can be obtained from the organic light emitting layer 25. Preferably, the dipole moment of the organic light emitter is 3D or more (more preferably, the dipole moment of the organic light emitter is 10D or more), for example, in the first period and the delay period, the first electrode 21 and the first electrode 21 The potential difference between the first electrode 21 and the second electrode 22 is set to 0 (or a value close to 0), and the first electrode 21 and the When applying a voltage between the two electrodes 22, even if the delay period is lengthened, more sufficient light emission can be obtained from the organic light emitting layer 25.

上述したように、有機発光層２５に含まれる有機発光体のダイポールモーメントが３Ｄ未満であっても、逆方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加した状態とすれば、励起光の入射によって電荷の分離が起こる。しかし、逆方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加した状態を維持する遅延期間を長くすると、当該遅延期間経過後の第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加しても、有機発光層２５から十分な発光を得ることができない。これは、遅延期間において、逆方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加した状態が維持されると、微小なリーク電流が系に流れ続けることになり、励起光の入射によって分離した電荷が消滅してしまうため、と考えられる。 As described above, even if the dipole moment of the organic light emitter included in the organic light emitting layer 25 is less than 3D, the first electrode 21 and the second electrode 22 are connected so that an electric field in the opposite direction is generated in the organic light emitting layer 25. If a voltage is applied between them, charge separation will occur due to the incidence of excitation light. However, if the delay period in which the voltage is maintained between the first electrode 21 and the second electrode 22 is lengthened so that an electric field in the opposite direction is generated in the organic light emitting layer 25, the second During the period, even if a voltage is applied between the first electrode 21 and the second electrode 22 so that a forward electric field that causes charge recombination is generated in the organic light emitting layer 25, a sufficient amount of energy is removed from the organic light emitting layer 25. Unable to obtain luminescence. This is because during the delay period, if a voltage is maintained between the first electrode 21 and the second electrode 22 so that an electric field in the opposite direction is generated in the organic light emitting layer 25, a small leakage current will be generated in the system. This is thought to be because the separated charges are annihilated by the incidence of excitation light.

なお、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０とすることには、次のようなメリットもある。すなわち、逆方向の電界が有機発光層２５に生じることが繰り返されないため、有機発光層２５の長寿命化を図ることができる。また、逆方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加するための専用の電源が不要となるため、発光装置１の構造の簡易化を図ることができる。 Note that setting the potential difference between the first electrode 21 and the second electrode 22 to 0 in the first period and the delay period also has the following merits. That is, since an electric field in the opposite direction is not repeatedly generated in the organic light emitting layer 25, the life of the organic light emitting layer 25 can be extended. Further, since a dedicated power source for applying a voltage between the first electrode 21 and the second electrode 22 so that an electric field in the opposite direction is generated in the organic light emitting layer 25 is not required, the structure of the light emitting device 1 can be simplified. It is possible to aim for

以上により、遅延期間の長短によらず安定した発光を得るためには、有機発光体のダイポールモーメントが０Ｄよりも大きければよいが、有機発光体のダイポールモーメントが３Ｄ以上であることが好ましく、有機発光体のダイポールモーメントが１０Ｄ以上であることがより好ましい。ただし、有機発光体のダイポールモーメントが３０Ｄよりも大きくなると、十分な遷移双極子モーメントが得られず、発光量子収率が上がり難い（つまり、大きな発光強度が得られない）ため、有機発光体のダイポールモーメントが３０Ｄよりも小さいことが好ましい。
［実験結果］ As described above, in order to obtain stable light emission regardless of the length of the delay period, it is sufficient that the dipole moment of the organic light emitter is larger than 0D, but it is preferable that the dipole moment of the organic light emitter is 3D or more. It is more preferable that the dipole moment of the light emitter is 10D or more. However, if the dipole moment of the organic light emitter is larger than 30D, a sufficient transition dipole moment will not be obtained and the luminescence quantum yield will be difficult to increase (that is, a large emission intensity cannot be obtained). Preferably, the dipole moment is smaller than 30D.
[Experimental result]

以下、実験結果について、時間と発光強度との関係を示す図５～図１３を参照して説明する。以下の説明では、第１電極２１と第２電極２２との間の電位差を単に「電位差」という。また、有機発光層２５に順方向の電界を生じさせるために、第２電極２２の電位を基準として第１電極２１の電位が例えば＋５Ｖとなるように第１電極２１と第２電極２２との間に電圧を印加することを、「＋５Ｖの順方向電圧を印加する」と表現する。また、有機発光層２５に逆方向の電界を生じさせるために、第２電極２２の電位を基準として第１電極２１の電位が例えば－１０Ｖとなるように第１電極２１と第２電極２２との間に電圧を印加することを、「－１０Ｖの逆方向電圧を印加する」と表現する。 The experimental results will be explained below with reference to FIGS. 5 to 13, which show the relationship between time and luminescence intensity. In the following description, the potential difference between the first electrode 21 and the second electrode 22 will be simply referred to as "potential difference." Further, in order to generate a forward electric field in the organic light emitting layer 25, the first electrode 21 and the second electrode 22 are connected so that the potential of the first electrode 21 is, for example, +5V with respect to the potential of the second electrode 22. Applying a voltage between them is expressed as "applying a forward voltage of +5V". Further, in order to generate an electric field in the opposite direction in the organic light emitting layer 25, the first electrode 21 and the second electrode 22 are connected so that the potential of the first electrode 21 is, for example, -10V with respect to the potential of the second electrode 22. Applying a voltage between them is expressed as "applying a reverse voltage of -10V."

実施例１の有機発光素子２を次のように製造した。まず、厚さ１００ｎｍのＩＴＯからなる第１電極２１が形成されたガラス基板を準備し、真空蒸着法によって、Ｔ２Ｔからなる第１電荷流入阻止層２３を第１電極２１上に形成した。続いて、異なる蒸着源からの共蒸着法によって、ＣＢＰ（ホスト材料）及びＴＰＡ－ＤＣＰＰ（有機発光体）からなる有機発光層２５を第１電荷流入阻止層２３上に形成した。このとき、ＣＢＰとＴＰＡ－ＤＣＰＰとの質量比を５０：５０とした。続いて、真空蒸着法によって、ＣＢＰからなる第２電荷流入阻止層２４を有機発光層２５上に形成した。第１電荷流入阻止層２３、有機発光層２５及び第２電荷流入阻止層２４の全体の厚さは１６０ｎｍであった。続いて、真空蒸着法によって、厚さ１００ｎｍのアルミニウムからなる第２電極２２を第２電荷流入阻止層２４上に形成した。 Organic light emitting device 2 of Example 1 was manufactured as follows. First, a glass substrate on which a first electrode 21 made of ITO with a thickness of 100 nm was formed was prepared, and a first charge inflow blocking layer 23 made of T2T was formed on the first electrode 21 by a vacuum evaporation method. Subsequently, an organic light-emitting layer 25 made of CBP (host material) and TPA-DCPP (organic light-emitting material) was formed on the first charge influx blocking layer 23 by co-evaporation using different deposition sources. At this time, the mass ratio of CBP and TPA-DCPP was set to 50:50. Subsequently, a second charge inflow blocking layer 24 made of CBP was formed on the organic light emitting layer 25 by vacuum evaporation. The total thickness of the first charge inflow blocking layer 23, the organic light emitting layer 25, and the second charge inflow blocking layer 24 was 160 nm. Subsequently, a second electrode 22 made of aluminum and having a thickness of 100 nm was formed on the second charge inflow blocking layer 24 by vacuum evaporation.

以上のように製造された実施例１の有機発光素子２についての実験結果は、次のとおりである。図５の（ａ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光（発光スパイク）が観測された。なお、０～１．０ｍ秒の遅延期間において発光強度が得られているのは、分離した電荷の一部が自然に再結合しているためと考えられる。また、図５の（ｂ）に示されるように、－０．００２～０秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０秒の遅延期間において電位差を０に維持し、１．０～１．００００５秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。１秒というように遅延期間を長くしても、分離した電荷が有機発光層２５内に残存し続け、電荷の再結合による発光に繋がることが分かった。また、図５の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が図５の（ａ）の場合に比べて強く観測された。なお、図５の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 The experimental results for the organic light emitting device 2 of Example 1 manufactured as described above are as follows. As shown in (a) of FIG. 5, in a first period of -0.5 to 0 msec, the potential difference is set to 0 and the excitation light L1 is incident on the organic light emitting layer 25, and in a delay period of 0 to 1.0 msec. When the potential difference was maintained at 0 and a forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission (light emission spike) from the organic light emitting layer 25 was observed during the second period. Note that the reason why the luminescence intensity is obtained during the delay period of 0 to 1.0 msec is considered to be that some of the separated charges are naturally recombined. Further, as shown in FIG. 5(b), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 during the first period from -0.002 to 0 seconds, and the excitation light L1 is delayed from 0 to 1.0 seconds. When the potential difference was maintained at 0 during the period and a forward voltage of +5 V was applied during the second period of 1.0 to 1.00005 seconds, light emission from the organic light emitting layer 25 was observed during the second period. It has been found that even if the delay period is increased to 1 second, the separated charges continue to remain in the organic light emitting layer 25, leading to light emission due to charge recombination. Further, as shown in FIG. 5(c), in the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer The emission from 25 was observed more strongly than in the case of FIG. 5(a). Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG.

次に、実施例２の有機発光素子２を用意した。実施例２の有機発光素子２は、有機発光体が４ＣｚＩＰＮである点で、実施例１の有機発光素子２と異なっている。実施例２の有機発光素子２についての実験結果は、次のとおりである。まず、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、その後、電位差を０に維持したままにすると、発光強度は、図６の（ａ）に示されるとおりとなった。これに対し、図６の（ｂ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。また、図６の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が図６の（ｂ）の場合に比べて強く観測された。なお、図６の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 Next, the organic light emitting device 2 of Example 2 was prepared. The organic light emitting device 2 of Example 2 differs from the organic light emitting device 2 of Example 1 in that the organic light emitter is 4CzIPN. The experimental results for the organic light emitting device 2 of Example 2 are as follows. First, in a first period of -0.5 to 0 msec, the potential difference is set to 0 and the excitation light L1 is made to enter the organic light emitting layer 25. After that, when the potential difference is maintained at 0, the emission intensity is as shown in FIG. The result was as shown in a). On the other hand, as shown in FIG. 6(b), the potential difference is set to 0 during the first period of -0.5 to 0 msec, and the excitation light L1 is incident on the organic light emitting layer 25, and When the potential difference was maintained at 0 during the delay period and a forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission from the organic light emitting layer 25 was observed during the second period. Further, as shown in FIG. 6(c), in the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, and the excitation light L1 is applied to the organic light emitting layer 25. When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer The light emission from 25 was observed more strongly than in the case of FIG. 6(b). Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG.

次に、実施例３の有機発光素子２を用意した。実施例３の有機発光素子２は、有機発光体がＡｌｑ３である点で、実施例１の有機発光素子２と異なっている。実施例３の有機発光素子２についての実験結果は、次のとおりである。まず、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、その後、電位差を０に維持したままにすると、発光強度は、図７の（ａ）に示されるとおりとなった。これに対し、図７の（ｂ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。また、図７の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が図７の（ｂ）の場合に比べて強く観測された。なお、図７の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 Next, the organic light emitting device 2 of Example 3 was prepared. The organic light emitting device 2 of Example 3 differs from the organic light emitting device 2 of Example 1 in that the organic light emitter is Alq3. The experimental results for the organic light emitting device 2 of Example 3 are as follows. First, in a first period of -0.5 to 0 msec, the potential difference is set to 0 and the excitation light L1 is made to enter the organic light emitting layer 25. After that, when the potential difference is maintained at 0, the emission intensity is as shown in FIG. The result was as shown in a). On the other hand, as shown in FIG. 7(b), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in the first period of -0.5 to 0 msec, and When the potential difference was maintained at 0 during the delay period and a forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission from the organic light emitting layer 25 was observed during the second period. Further, as shown in FIG. 7(c), during the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, and the excitation light L1 is applied to the organic light emitting layer 25. When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer The light emission from 25 was observed more strongly than in the case of FIG. 7(b). Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG.

次に、実施例４の有機発光素子２を用意した。実施例４の有機発光素子２は、有機発光体がＴＢＲｂである点で、実施例１の有機発光素子２と異なっている。実施例４の有機発光素子２についての実験結果は、次のとおりである。まず、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、その後、電位差を０に維持したままにすると、発光強度は、図８の（ａ）に示されるとおりとなった。これに対し、図８の（ｂ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加しても、第２期間において、有機発光層２５からの発光が顕著には観測されなかった。また、図８の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。なお、図８の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 Next, the organic light emitting device 2 of Example 4 was prepared. The organic light emitting device 2 of Example 4 differs from the organic light emitting device 2 of Example 1 in that the organic light emitter is TBRb. The experimental results for the organic light emitting device 2 of Example 4 are as follows. First, in a first period of -0.5 to 0 msec, the potential difference is set to 0 and the excitation light L1 is made to enter the organic light emitting layer 25. After that, when the potential difference is maintained at 0, the emission intensity is as shown in FIG. The result was as shown in a). On the other hand, as shown in FIG. 8(b), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in the first period of -0.5 to 0 msec, and Even if the potential difference is maintained at 0 during the delay period of was not observed. Further, as shown in FIG. 8(c), in the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer Luminescence from 25 was observed. Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG.

以上の実施例１～実施例４の有機発光素子についての結果から、励起光Ｌ１の入射によって電荷の分離が起こる有機発光体を用い、少なくとも第１期間及び遅延期間において逆方向電圧を印加すれば、第２期間において有機発光層２５からの発光が観測されると考えられる。 From the above results regarding the organic light emitting devices of Examples 1 to 4, it is clear that if an organic light emitting body is used in which charges are separated by the incidence of the excitation light L1, and a reverse voltage is applied at least during the first period and the delay period. It is considered that light emission from the organic light emitting layer 25 is observed in the second period.

次に、実施例５の有機発光素子２を用意した。実施例５の有機発光素子２は、第２電荷流入阻止層２４を有しない点で、実施例１の有機発光素子２と異なっている。実施例５の有機発光素子２についての実験結果は、次のとおりである。図９の（ａ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。また、図９の（ｂ）に示されるように、－０．００２～０秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０秒の遅延期間において電位差を０に維持し、１．０～１．００００５秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が顕著には観測されなかった。また、図９の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。なお、図９の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 Next, the organic light emitting device 2 of Example 5 was prepared. The organic light emitting device 2 of Example 5 differs from the organic light emitting device 2 of Example 1 in that it does not have the second charge influx blocking layer 24. The experimental results for the organic light emitting device 2 of Example 5 are as follows. As shown in (a) of FIG. 9, the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in the first period of -0.5 to 0 msec, and in the delay period of 0 to 1.0 msec. When the potential difference was maintained at 0 and a forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission from the organic light emitting layer 25 was observed during the second period. Further, as shown in FIG. 9(b), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in the first period from -0.002 to 0 seconds, and the excitation light L1 is delayed from 0 to 1.0 seconds. When the potential difference is maintained at 0 during the period and a forward voltage of +5V is applied during the second period of 1.0 to 1.00005 seconds, no significant light emission from the organic light emitting layer 25 is observed during the second period. Ta. Further, as shown in FIG. 9(c), in the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, and the excitation light L1 is applied to the organic light emitting layer 25. When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer Luminescence from 25 was observed. Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG.

次に、実施例６の有機発光素子２を用意した。実施例６の有機発光素子２は、第１電荷流入阻止層２３を有しない点で、実施例１の有機発光素子２と異なっている。実施例６の有機発光素子２についての実験結果は、次のとおりである。図１０の（ａ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。また、図１０の（ｂ）に示されるように、－０．００２～０秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０秒の遅延期間において電位差を０に維持し、１．０～１．００００５秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が顕著には観測されなかった。また、図１０の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。なお、図１０の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 Next, the organic light emitting device 2 of Example 6 was prepared. The organic light emitting device 2 of Example 6 differs from the organic light emitting device 2 of Example 1 in that it does not have the first charge influx blocking layer 23. The experimental results for the organic light emitting device 2 of Example 6 are as follows. As shown in FIG. 10(a), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in a first period of -0.5 to 0 msec, and in a delay period of 0 to 1.0 msec. When the potential difference was maintained at 0 and a forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission from the organic light emitting layer 25 was observed during the second period. In addition, as shown in FIG. 10(b), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in the first period from -0.002 to 0 seconds, and the excitation light L1 is delayed from 0 to 1.0 seconds. When the potential difference is maintained at 0 during the period and a forward voltage of +5V is applied during the second period of 1.0 to 1.00005 seconds, no significant light emission from the organic light emitting layer 25 is observed during the second period. Ta. Further, as shown in FIG. 10(c), in the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, and the excitation light L1 is applied to the organic light emitting layer 25. When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer Luminescence from 25 was observed. Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG. 10.

次に、実施例７の有機発光素子２を用意した。実施例７の有機発光素子２は、第１電荷流入阻止層２３及び第２電荷流入阻止層２４を有しない点で、実施例１の有機発光素子２と異なっている。実施例７の有機発光素子２についての実験結果は、次のとおりである。図１１の（ａ）に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。また、図１１の（ｂ）に示されるように、－０．００２～０秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０秒の遅延期間において電位差を０に維持し、１．０～１．００００５秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が顕著には観測されなかった。また、図１１の（ｃ）に示されるように、－０．５～０ｍ秒の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。なお、図１１の（ａ）、（ｂ）及び（ｃ）のいずれの場合も、励起光Ｌ１の強度は同一である。 Next, the organic light emitting device 2 of Example 7 was prepared. The organic light emitting device 2 of Example 7 differs from the organic light emitting device 2 of Example 1 in that it does not have the first charge inflow blocking layer 23 and the second charge inflow blocking layer 24. The experimental results for the organic light emitting device 2 of Example 7 are as follows. As shown in FIG. 11(a), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in a first period of -0.5 to 0 msec, and in a delay period of 0 to 1.0 msec. When the potential difference was maintained at 0 and a forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission from the organic light emitting layer 25 was observed during the second period. Further, as shown in FIG. 11(b), the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in the first period from -0.002 to 0 seconds, and the excitation light L1 is delayed from 0 to 1.0 seconds. When the potential difference is maintained at 0 during the period and a forward voltage of +5V is applied during the second period of 1.0 to 1.00005 seconds, no significant light emission from the organic light emitting layer 25 is observed during the second period. Ta. Further, as shown in FIG. 11(c), in the first period of -0.5 to 0 msec, a reverse voltage of -10V is applied to make the excitation light L1 enter the organic light emitting layer 25, and the excitation light L1 is applied to the organic light emitting layer 25. When maintaining the application of a reverse voltage of -10 V during a delay period of 1.0 msec and applying a forward voltage of +5 V during a second period of 1.0 to 1.05 msec, the organic light emitting layer Luminescence from 25 was observed. Note that the intensity of the excitation light L1 is the same in all cases of (a), (b), and (c) in FIG. 11.

以上の実施例１及び実施例５～実施例７の結果から、有機発光素子２が第１電荷流入阻止層２３及び第２電荷流入阻止層２４を有する場合（実施例１の場合）には、有機発光素子２が第１電荷流入阻止層２３のみを有する場合（実施例５の場合）、有機発光素子２が第２電荷流入阻止層２４のみを有する場合（実施例６の場合）、並びに、第１電荷流入阻止層２３及び第２電荷流入阻止層２４を有しない場合（実施例７の場合）に比べて、遅延期間を長くしても、有機発光層２５からの発光が得られることが分かった。また、遅延期間が短ければ、有機発光素子２が第１電荷流入阻止層２３のみを有する場合（実施例５の場合）及び有機発光素子２が第２電荷流入阻止層２４のみを有する場合（実施例６の場合）にも、有機発光層２５からの発光が得られることが分かった。 From the results of Example 1 and Examples 5 to 7 above, when the organic light emitting device 2 has the first charge inflow blocking layer 23 and the second charge inflow blocking layer 24 (in the case of Example 1), When the organic light emitting device 2 has only the first charge inflow blocking layer 23 (in the case of Example 5), when the organic light emitting device 2 has only the second charge inflow blocking layer 24 (in the case of Example 6), and Compared to the case where the first charge inflow blocking layer 23 and the second charge inflow blocking layer 24 are not provided (in the case of Example 7), light emission from the organic light emitting layer 25 can be obtained even if the delay period is lengthened. Do you get it. Further, if the delay period is short, the organic light emitting device 2 has only the first charge inflow blocking layer 23 (in the case of Example 5) and the organic light emitting device 2 has only the second charge inflow blocking layer 24 (in the case of the embodiment). It was found that light emission from the organic light-emitting layer 25 was also obtained in the case of Example 6).

なお、遅延期間が短ければ、有機発光素子２が第２電荷流入阻止層２４のみを有する場合（実施例６の場合）には、有機発光素子２が第１電荷流入阻止層２３のみを有する場合（実施例５の場合）に比べて有機発光層２５からの発光が強く得られることが分かった。このことから、第１電極２１の仕事関数よりも小さい仕事関数を有する第２電極２２と有機発光層２５との間に第２電荷流入阻止層２４が配置された構成は、第２電極２２の仕事関数よりも大きい仕事関数を有する第１電極２１と有機発光層２５との間に第１電荷流入阻止層２３が配置された構成に比べて、有機発光層２５からの発光を得る上で有利であると考えられる。 In addition, if the delay period is short, when the organic light emitting device 2 has only the second charge inflow blocking layer 24 (in the case of Example 6), when the organic light emitting device 2 has only the first charge inflow blocking layer 23 It was found that stronger light emission from the organic light-emitting layer 25 was obtained than in the case of Example 5. From this, the configuration in which the second charge influx blocking layer 24 is disposed between the second electrode 22 and the organic light emitting layer 25, which has a work function smaller than that of the first electrode 21, is similar to that of the second electrode 22. This is advantageous in obtaining light emission from the organic light emitting layer 25 compared to a configuration in which the first charge influx blocking layer 23 is disposed between the first electrode 21 and the organic light emitting layer 25 having a work function larger than the work function. It is thought that.

また、有機発光素子２が第１電荷流入阻止層２３及び第２電荷流入阻止層２４を有する場合（実施例１の場合）には、図１２の（ａ）、（ｂ）及び（ｃ）に示されるように、遅延期間を３０秒間、１分間、１時間としても、有機発光層２５からの発光が観測された。図１２の（ａ）、（ｂ）及び（ｃ）に示される実験結果は、２．０ｍ秒間の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、上述した各遅延期間において電位差を０に維持し、上述した各遅延期間が経過した後の０．０５ｍ秒間の第２期間において＋５Ｖの順方向電圧を印加した場合の実験結果であり、いずれの場合も、励起光Ｌ１の強度は同一である。なお、図１２の（ａ）、（ｂ）及び（ｃ）に示される発光スパイクは、第２期間における発光スパイクであり、図１２の（ａ）、（ｂ）及び（ｃ）には第１期間は図示されていない。 In addition, when the organic light emitting device 2 has the first charge inflow blocking layer 23 and the second charge inflow blocking layer 24 (in the case of Example 1), (a), (b) and (c) of FIG. As shown, light emission from the organic light emitting layer 25 was observed even when the delay period was 30 seconds, 1 minute, and 1 hour. The experimental results shown in FIGS. 12(a), (b), and (c) were obtained by injecting the excitation light L1 into the organic light emitting layer 25 with the potential difference set to 0 during the first period of 2.0 msec, and each of the above-mentioned delays. These are the experimental results when the potential difference was maintained at 0 during the period, and a forward voltage of +5V was applied during the second period of 0.05 msec after each delay period described above, and in both cases, the excitation light The strength of L1 is the same. Note that the light emission spikes shown in (a), (b), and (c) of FIG. 12 are the light emission spikes in the second period, and the light emission spikes shown in (a), (b), and (c) of FIG. Periods are not shown.

次に、実施例８の有機発光素子２を用意した。実施例８の有機発光素子２は、有機発光層２５がＴＰＡ－ＤＣＰＰのみからなる点（すなわち、有機発光層２５がホスト材料を含まない点）で、実施例１の有機発光素子２と異なっている。実施例６についての実験結果は、次のとおりである。図１３に示されるように、－０．５～０ｍ秒の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、０～１．０ｍ秒の遅延期間において電位差を０に維持し、１．０～１．０５ｍ秒の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。このことから、有機発光層２５がホスト材料を含まなくても、有機発光層２５からの発光が得られることが分かった。 Next, the organic light emitting device 2 of Example 8 was prepared. The organic light emitting device 2 of Example 8 differs from the organic light emitting device 2 of Example 1 in that the organic light emitting layer 25 is made only of TPA-DCPP (that is, the organic light emitting layer 25 does not contain a host material). There is. The experimental results for Example 6 are as follows. As shown in FIG. 13, the excitation light L1 is made to enter the organic light emitting layer 25 with the potential difference set to 0 in a first period of -0.5 to 0 msec, and the potential difference is set to 0 in a delay period of 0 to 1.0 msec. When the forward voltage of +5 V was applied during the second period of 1.0 to 1.05 msec, light emission from the organic light emitting layer 25 was observed during the second period. From this, it was found that light emission from the organic light emitting layer 25 can be obtained even if the organic light emitting layer 25 does not contain a host material.

次に、実施例１の有機発光素子２を再び用意した。実施例１の有機発光素子２では、ダイポールモーメントが１３．０５ＤであるＴＰＡ－ＤＣＰＰが有機発光体として用いられている。図１５の（ａ）の左側のグラフでは、０．５ｍ秒間（－０．５～０ｍ秒）の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、１．０ｍ秒間（０～１．０ｍ秒）の遅延期間において電位差を０に維持し、０．０５ｍ秒間（１．０～１．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１５の（ａ）の右側のグラフでは、０．５ｍ秒間（－１０００．５～－１０００．０ｍ秒）の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、１秒間（－１０００．０～０ｍ秒）の遅延期間において電位差を０に維持し、０．０５秒間（０～０．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１５の（ａ）の右側のグラフに示される場合の遅延期間は、図１５の（ａ）の左側のグラフに示される場合の遅延期間の１０００倍に相当する。この場合、図１５の（ａ）の右側のグラフに示される場合の発光強度は、図１５の（ａ）の左側のグラフに示される場合の発光強度に比べ、１桁も減衰しなかった。 Next, the organic light emitting device 2 of Example 1 was prepared again. In the organic light emitting device 2 of Example 1, TPA-DCPP having a dipole moment of 13.05D is used as the organic light emitter. In the graph on the left side of FIG. 15(a), excitation light L1 is incident on the organic light emitting layer 25 with the potential difference set to 0 in the first period of 0.5 msec (-0.5 to 0 msec), and the excitation light L1 is incident on the organic light emitting layer 25 for 1.0 msec. If the potential difference is maintained at 0 during the delay period (0 to 1.0 msec) and a forward voltage of +5V is applied during the second period of 0.05 msec (1.0 to 1.05 msec), the second period In this case, light emission from the organic light emitting layer 25 was observed. In the graph on the right side of (a) of FIG. 15, in the first period of 0.5 msec (-1000.5 to -1000.0 msec), the potential difference is set to 0 and the excitation light L1 is incident on the organic light emitting layer 25. If the potential difference is maintained at 0 during a delay period of seconds (-1000.0 to 0 msec) and a forward voltage of +5V is applied during a second period of 0.05 seconds (0 to 0.05 msec), the second period In this case, light emission from the organic light emitting layer 25 was observed. The delay period in the case shown in the graph on the right side of FIG. 15(a) corresponds to 1000 times the delay period in the case shown in the graph on the left side in FIG. 15(a). In this case, the emission intensity in the case shown in the graph on the right side of FIG. 15(a) was not attenuated by one order of magnitude compared to the emission intensity in the case shown in the graph on the left side in FIG. 15(a).

同様に、実施例１の有機発光素子２を再び用意した。図１５の（ｂ）の左側のグラフでは、０．５ｍ秒間（－０．５～０ｍ秒）の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、１．０ｍ秒間（０～１．０ｍ秒）の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、０．０５ｍ秒間（１．０～１．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１５の（ｂ）の右側のグラフでは、０．５ｍ秒間（－１０００．５～－１０００．０ｍ秒）の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、１秒間（－１０００．０～０ｍ秒）の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、０．０５秒間（０～０．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１５の（ｂ）の右側のグラフに示される場合の遅延期間は、図１５の（ｂ）の左側のグラフに示される場合の遅延期間の１０００倍に相当する。この場合、図１５の（ｂ）の右側のグラフに示される場合の発光強度は、図１５の（ｂ）の左側のグラフに示される場合の発光強度に比べ、１桁以上減衰した。 Similarly, the organic light emitting device 2 of Example 1 was again prepared. In the graph on the left side of FIG. 15(b), excitation light L1 is applied to the organic light emitting layer 25 by applying a reverse voltage of -10V in the first period of 0.5 msec (-0.5 to 0 msec). and maintain the application of a reverse voltage of -10V during a delay period of 1.0 msec (0 to 1.0 msec), and +5V during a second period of 0.05 msec (1.0 to 1.05 msec). When a forward voltage of 1 was applied, light emission from the organic light emitting layer 25 was observed in the second period. In the graph on the right side of FIG. 15(b), excitation light is applied to the organic light emitting layer 25 by applying a reverse voltage of -10V during the first period of 0.5 msec (-1000.5 to -1000.0 msec). L1 is input, and a reverse voltage of -10V is maintained during a delay period of 1 second (-1000.0 to 0 msec), and +5V is applied during a second period of 0.05 seconds (0 to 0.05 msec). When a forward voltage of 1 was applied, light emission from the organic light emitting layer 25 was observed in the second period. The delay period in the case shown in the graph on the right side of FIG. 15(b) corresponds to 1000 times the delay period in the case shown in the graph on the left side in FIG. 15(b). In this case, the emission intensity in the case shown in the graph on the right side of FIG. 15(b) was attenuated by more than one order of magnitude compared to the emission intensity in the case shown in the graph on the left side in FIG. 15(b).

次に、実施例２の有機発光素子２を再び用意した。実施例２の有機発光素子２では、ダイポールモーメントが３．８５Ｄである４ＣｚＩＰＮが有機発光体として用いられている。図１６の（ａ）の左側のグラフでは、０．５ｍ秒間（－０．５～０ｍ秒）の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、１．０ｍ秒間（０～１．０ｍ秒）の遅延期間において電位差を０に維持し、０．０５ｍ秒間（１．０～１．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１６の（ａ）の右側のグラフでは、０．５ｍ秒間（－１０００．５～－１０００．０ｍ秒）の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、１秒間（－１０００．０～０ｍ秒）の遅延期間において電位差を０に維持し、０．０５秒間（０～０．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１６の（ａ）の右側のグラフに示される場合の遅延期間は、図１６の（ａ）の左側のグラフに示される場合の遅延期間の１０００倍に相当する。この場合、図１６の（ａ）の右側のグラフに示される場合の発光強度は、図１６の（ａ）の左側のグラフに示される場合の発光強度に比べ、１桁も減衰しなかった。 Next, the organic light emitting device 2 of Example 2 was prepared again. In the organic light emitting device 2 of Example 2, 4CzIPN having a dipole moment of 3.85D is used as the organic light emitter. In the graph on the left side of (a) of FIG. 16, the excitation light L1 is incident on the organic light emitting layer 25 with the potential difference set to 0 in the first period of 0.5 msec (-0.5 to 0 msec), and the excitation light L1 is incident on the organic light emitting layer 25 for 1.0 msec. If the potential difference is maintained at 0 during the delay period (0 to 1.0 msec) and a forward voltage of +5V is applied during the second period of 0.05 msec (1.0 to 1.05 msec), the second period In this case, light emission from the organic light emitting layer 25 was observed. In the graph on the right side of (a) of FIG. 16, in the first period of 0.5 msec (-1000.5 to -1000.0 msec), the potential difference is set to 0 and the excitation light L1 is incident on the organic light emitting layer 25. If the potential difference is maintained at 0 during a delay period of seconds (-1000.0 to 0 msec) and a forward voltage of +5V is applied during a second period of 0.05 seconds (0 to 0.05 msec), the second period In this case, light emission from the organic light emitting layer 25 was observed. The delay period in the case shown in the graph on the right side of FIG. 16(a) corresponds to 1000 times the delay period in the case shown in the graph on the left side in FIG. 16(a). In this case, the emission intensity in the case shown in the graph on the right side of FIG. 16(a) did not decrease by one order of magnitude compared to the emission intensity in the case shown in the graph on the left side in FIG. 16(a).

同様に、実施例２の有機発光素子２を再び用意した。図１６の（ｂ）の左側のグラフでは、０．５ｍ秒間（－０．５～０ｍ秒）の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、１．０ｍ秒間（０～１．０ｍ秒）の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、０．０５ｍ秒間（１．０～１．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１６の（ｂ）の右側のグラフでは、０．５ｍ秒間（－１０００．５～－１０００．０ｍ秒）の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、１秒間（－１０００．０～０ｍ秒）の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、０．０５秒間（０～０．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１６の（ｂ）の右側のグラフに示される場合の遅延期間は、図１６の（ｂ）の左側のグラフに示される場合の遅延期間の１０００倍に相当する。この場合、図１６の（ｂ）の右側のグラフに示される場合の発光強度は、図１６の（ｂ）の左側のグラフに示される場合の発光強度に比べ、１桁以上減衰した。 Similarly, the organic light emitting device 2 of Example 2 was prepared again. In the graph on the left side of FIG. 16(b), excitation light L1 is applied to the organic light emitting layer 25 by applying a reverse voltage of -10V in the first period of 0.5 msec (-0.5 to 0 msec). and maintain the application of a reverse voltage of -10V during a delay period of 1.0 msec (0 to 1.0 msec), and +5V during a second period of 0.05 msec (1.0 to 1.05 msec). When a forward voltage of 1 was applied, light emission from the organic light emitting layer 25 was observed in the second period. In the graph on the right side of FIG. 16(b), excitation light is applied to the organic light emitting layer 25 by applying a reverse voltage of -10V during the first period of 0.5 msec (-1000.5 to -1000.0 msec). L1 is input, and a reverse voltage of -10V is maintained during a delay period of 1 second (-1000.0 to 0 msec), and +5V is applied during a second period of 0.05 seconds (0 to 0.05 msec). When a forward voltage of 1 was applied, light emission from the organic light emitting layer 25 was observed in the second period. The delay period in the case shown in the graph on the right side of FIG. 16(b) corresponds to 1000 times the delay period in the case shown in the graph on the left side in FIG. 16(b). In this case, the emission intensity in the case shown in the graph on the right side of FIG. 16(b) was attenuated by more than one order of magnitude compared to the emission intensity in the case shown in the graph on the left side in FIG. 16(b).

次に、実施例９の有機発光素子２を用意した。実施例９の有機発光素子２は、有機発光体が４ＣｚＴＰＮ－Ｐｈである点で、実施例１の有機発光素子２と異なっている。実施例９の有機発光素子２では、ダイポールモーメントが０Ｄである４ＣｚＴＰＮ－Ｐｈが有機発光体として用いられている。図１７の（ａ）の左側のグラフでは、０．５ｍ秒間（－０．５～０ｍ秒）の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、１．０ｍ秒間（０～１．０ｍ秒）の遅延期間において電位差を０に維持し、０．０５ｍ秒間（１．０～１．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測されなかった。図１７の（ａ）の右側のグラフでは、０．５ｍ秒間（－１０００．５～－１０００．０ｍ秒）の第１期間において電位差を０として有機発光層２５に励起光Ｌ１を入射させ、１秒間（－１０００．０～０ｍ秒）の遅延期間において電位差を０に維持し、０．０５秒間（０～０．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測されなかった。図１７の（ａ）の右側のグラフに示される場合の遅延期間は、図１７の（ａ）の左側のグラフに示される場合の遅延期間の１０００倍に相当する。 Next, the organic light emitting device 2 of Example 9 was prepared. The organic light emitting device 2 of Example 9 differs from the organic light emitting device 2 of Example 1 in that the organic light emitter is 4CzTPN-Ph. In the organic light emitting device 2 of Example 9, 4CzTPN-Ph having a dipole moment of 0D is used as the organic light emitter. In the graph on the left side of (a) of FIG. 17, excitation light L1 is incident on the organic light emitting layer 25 with the potential difference set to 0 in the first period of 0.5 msec (-0.5 to 0 msec), and the excitation light L1 is incident on the organic light emitting layer 25 for 1.0 msec. If the potential difference is maintained at 0 during the delay period (0 to 1.0 msec) and a forward voltage of +5V is applied during the second period of 0.05 msec (1.0 to 1.05 msec), the second period In this case, no light emission from the organic light emitting layer 25 was observed. In the graph on the right side of (a) of FIG. 17, in the first period of 0.5 msec (-1000.5 to -1000.0 msec), the potential difference is set to 0 and the excitation light L1 is incident on the organic light emitting layer 25. If the potential difference is maintained at 0 during a delay period of seconds (-1000.0 to 0 msec) and a forward voltage of +5V is applied during a second period of 0.05 seconds (0 to 0.05 msec), the second period In this case, no light emission from the organic light emitting layer 25 was observed. The delay period in the case shown in the graph on the right side of FIG. 17(a) corresponds to 1000 times the delay period in the case shown in the graph on the left side in FIG. 17(a).

同様に、実施例９の有機発光素子２を再び用意した。図１７の（ｂ）の左側のグラフでは、０．５ｍ秒間（－０．５～０ｍ秒）の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、１．０ｍ秒間（０～１．０ｍ秒）の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、０．０５ｍ秒間（１．０～１．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１７の（ｂ）の右側のグラフでは、０．５ｍ秒間（－１０００．５～－１０００．０ｍ秒）の第１期間において－１０Ｖの逆方向電圧を印加して有機発光層２５に励起光Ｌ１を入射させ、１秒間（－１０００．０～０ｍ秒）の遅延期間において－１０Ｖの逆方向電圧の印加を維持し、０．０５秒間（０～０．０５ｍ秒）の第２期間において＋５Ｖの順方向電圧を印加すると、第２期間において、有機発光層２５からの発光が観測された。図１７の（ｂ）の右側のグラフに示される場合の遅延期間は、図１７の（ｂ）の左側のグラフに示される場合の遅延期間の１０００倍に相当する。この場合、図１７の（ｂ）の右側のグラフに示される場合の発光強度は、図１７の（ｂ）の左側のグラフに示される場合の発光強度に比べ、１桁以上減衰した。 Similarly, the organic light emitting device 2 of Example 9 was again prepared. In the left graph of FIG. 17(b), excitation light L1 is applied to the organic light emitting layer 25 by applying a reverse voltage of -10V during the first period of 0.5 msec (-0.5 to 0 msec). and maintain the application of a reverse voltage of -10V during a delay period of 1.0 msec (0 to 1.0 msec), and +5V during a second period of 0.05 msec (1.0 to 1.05 msec). When a forward voltage of 1 was applied, light emission from the organic light emitting layer 25 was observed in the second period. In the graph on the right side of FIG. 17(b), excitation light is applied to the organic light emitting layer 25 by applying a reverse voltage of -10V during the first period of 0.5 msec (-1000.5 to -1000.0 msec). L1 is input, and a reverse voltage of -10V is maintained during a delay period of 1 second (-1000.0 to 0 msec), and +5V is applied during a second period of 0.05 seconds (0 to 0.05 msec). When a forward voltage of 1 was applied, light emission from the organic light emitting layer 25 was observed in the second period. The delay period in the case shown in the graph on the right side of FIG. 17(b) corresponds to 1000 times the delay period in the case shown in the graph on the left side in FIG. 17(b). In this case, the emission intensity in the case shown in the graph on the right side of FIG. 17(b) was attenuated by more than one order of magnitude compared to the emission intensity in the case shown in the graph on the left side in FIG. 17(b).

以上の図１５の（ａ）及び（ｂ）、図１６の（ａ）及び（ｂ）、並びに、図１７の（ａ）及び（ｂ）に示されるグラフから、有機発光層２５に含まれる有機発光体のダイポールモーメントが０Ｄよりも大きいと、例えば、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層２５から十分な発光を得ることができることが分かった。また、好ましくは、有機発光体のダイポールモーメントが３Ｄ以上であると（より好ましくは、有機発光体のダイポールモーメントが１０Ｄ以上であると）、例えば、第１期間及び遅延期間において、第１電極２１と第２電極２２との間の電位差を０とし、第２期間において、電荷の再結合を起こさせる順方向の電界が有機発光層２５に生じるように第１電極２１と第２電極２２との間に電圧を印加する場合に、遅延期間を長くしても、有機発光層２５から、より十分な発光を得ることができることが分かった。なお、図１５の（ａ）及び（ｂ）、図１６の（ａ）及び（ｂ）、並びに、図１７の（ａ）及び（ｂ）のいずれの場合も、励起光Ｌ１の強度は同一であった。
［変形例］ From the graphs shown in FIGS. 15 (a) and (b), FIG. 16 (a) and (b), and FIG. 17 (a) and (b), it is clear that the organic If the dipole moment of the light emitter is larger than 0D, for example, the potential difference between the first electrode 21 and the second electrode 22 is set to 0 in the first period and the delay period, and the recombination of charges is caused in the second period. When applying a voltage between the first electrode 21 and the second electrode 22 so as to generate a forward electric field in the organic light emitting layer 25, even if the delay period is lengthened, a sufficient amount of light is emitted from the organic light emitting layer 25. It was found that luminescence could be obtained. Further, preferably, the dipole moment of the organic light emitter is 3D or more (more preferably, the dipole moment of the organic light emitter is 10D or more), for example, in the first period and the delay period, the first electrode 21 The potential difference between the first electrode 21 and the second electrode 22 is set to 0, and the first electrode 21 and the second electrode 22 are connected in such a way that a forward electric field that causes charge recombination is generated in the organic light emitting layer 25 during the second period. It has been found that even if the delay period is lengthened when a voltage is applied between them, more sufficient light emission can be obtained from the organic light emitting layer 25. Note that the intensity of the excitation light L1 is the same in all cases of (a) and (b) in FIG. 15, (a) and (b) in FIG. 16, and (a) and (b) in FIG. there were.
[Modified example]

本発明は、上記実施形態に限定されない。例えば、図１４に示されるように、発光装置１は、励起光Ｌ１を出射する光源４を更に備えていてもよく、制御部３は、第１期間において、有機発光層２５に励起光Ｌ１が入射するように光源４を制御してもよい。これにより、外部から有機発光層２５に励起光Ｌ１が入射するタイミングを調整することができる。 The present invention is not limited to the above embodiments. For example, as shown in FIG. 14, the light emitting device 1 may further include a light source 4 that emits excitation light L1, and the control unit 3 controls the excitation light L1 to be emitted to the organic light emitting layer 25 in the first period. The light source 4 may be controlled so that the light is incident. Thereby, the timing at which the excitation light L1 enters the organic light emitting layer 25 from the outside can be adjusted.

また、上記実施形態では、有機発光素子２において、第１電極２１と有機発光層２５との間に第１電荷流入阻止層２３が配置されており、第２電極２２と有機発光層２５との間に第２電荷流入阻止層２４が配置されていたが、第１電極２１と有機発光層２５との間に第１電荷流入阻止層２３が配置されていなくてもよいし、或いは、第２電極２２と有機発光層２５との間に第２電荷流入阻止層２４が配置されていなくてもよい。ただし、第１電極２１と有機発光層２５との間に第１電荷流入阻止層２３が配置され且つ第２電極２２と有機発光層２５との間に第２電荷流入阻止層２４が配置された構成によれば、第２期間において有機発光層２５から発光をより確実に得ることができる。また、上述したように、第１電極２１の仕事関数よりも小さい仕事関数を有する第２電極２２と有機発光層２５との間に第２電荷流入阻止層２４が配置された構成は、第２電極２２の仕事関数よりも大きい仕事関数を有する第１電極２１と有機発光層２５との間に第１電荷流入阻止層２３が配置された構成に比べて、有機発光層２５からの発光を得る上で有利であると考えられる。 Further, in the above embodiment, in the organic light emitting device 2, the first charge influx blocking layer 23 is disposed between the first electrode 21 and the organic light emitting layer 25, and the first charge influx blocking layer 23 is arranged between the second electrode 22 and the organic light emitting layer 25. Although the second charge inflow blocking layer 24 is arranged between the first electrode 21 and the organic light emitting layer 25, the first charge inflow blocking layer 23 may not be arranged between the first electrode 21 and the organic light emitting layer 25, or the second charge inflow blocking layer 23 may not be arranged between the first electrode 21 and the organic light emitting layer 25. The second charge inflow blocking layer 24 may not be disposed between the electrode 22 and the organic light emitting layer 25. However, a first charge inflow blocking layer 23 is disposed between the first electrode 21 and the organic light emitting layer 25, and a second charge influx blocking layer 24 is disposed between the second electrode 22 and the organic light emitting layer 25. According to the configuration, light emission can be more reliably obtained from the organic light emitting layer 25 in the second period. Furthermore, as described above, the configuration in which the second charge influx blocking layer 24 is disposed between the second electrode 22 having a work function smaller than that of the first electrode 21 and the organic light emitting layer 25 is a Light emission from the organic light emitting layer 25 is obtained compared to a configuration in which the first charge influx blocking layer 23 is disposed between the first electrode 21 and the organic light emitting layer 25 having a work function larger than the work function of the electrode 22. This is considered to be advantageous.

また、有機発光素子２において、第１電荷流入阻止層２３及び第２電荷流入阻止層２４のそれぞれは、電気絶縁性材料によって形成されていてもよい。また、例えば、１枚の光透過基板２０上に複数の有機発光素子２が２次元に配置されていてもよい。また、制御部３は、例えば、第１期間及び遅延期間において逆方向電圧を印加し、第２期間において電位差を０としてもよい。つまり、第２期間において、電荷の再結合が起こるように第１電極２１と第２電極２２との間の電位差を変化させることができれば、第２期間において有機発光層２５からの発光を得ることができる。 Further, in the organic light emitting device 2, each of the first charge inflow blocking layer 23 and the second charge inflow blocking layer 24 may be formed of an electrically insulating material. Further, for example, a plurality of organic light emitting elements 2 may be two-dimensionally arranged on one light-transmitting substrate 20. Further, the control unit 3 may apply a reverse voltage in the first period and the delay period, and set the potential difference to 0 in the second period, for example. In other words, if the potential difference between the first electrode 21 and the second electrode 22 can be changed so that charge recombination occurs in the second period, light emission from the organic light emitting layer 25 can be obtained in the second period. I can do it.

また、有機発光素子２は、第１期間（すなわち、有機発光層２５に励起光Ｌ１が入射するステップ）において、電気的フローティング状態（換言すれば、第１電極２１及び第２電極２２の電位が独立した状態）とされてもよい。例えば、発光装置１において、有機発光素子２を制御部３から物理的に切り離すことで、第１期間において有機発光素子２を電気的フローティング状態としてもよい。これにより、励起光Ｌ１の入射によって有機発光層２５において分離した電荷が、第１電極２１及び第２電極２２から有機発光層２５への電荷の流入に起因して減少するのを抑制することができる。その結果、第２期間において、電荷の再結合が起こるように第１電極２１と第２電極２２との間の電位差を変化させることで、第２期間において有機発光層２５から確実に発光を得ることができる。また、例えば、発光装置１において、第１電極２１及び第２電極２２のそれぞれに接続された配線に設けられたスイッチを制御部３がＯＮからＯＦＦに切り替えることで、第１期間において有機発光素子２を電気的フローティング状態としてもよい。なお、有機発光素子２における第１電荷流入阻止層２３及び第２電荷流入阻止層２４の少なくとも一方の存在は、第１電極２１と第２電極２２との間の電位差を変化させるための配線を第１電極２１及び第２電極２２の少なくとも一方に接続しただけで有機発光層２５に電荷が流入するのを抑制する上で、有効である。 Further, the organic light emitting device 2 is in an electrically floating state (in other words, the potentials of the first electrode 21 and the second electrode 22 are (independent state). For example, in the light emitting device 1, the organic light emitting element 2 may be placed in an electrically floating state during the first period by physically separating the organic light emitting element 2 from the control unit 3. This suppresses the charge separated in the organic light emitting layer 25 due to the incidence of the excitation light L1 from decreasing due to the inflow of charges from the first electrode 21 and the second electrode 22 into the organic light emitting layer 25. can. As a result, in the second period, by changing the potential difference between the first electrode 21 and the second electrode 22 so that charge recombination occurs, light emission is reliably obtained from the organic light emitting layer 25 in the second period. be able to. Further, for example, in the light emitting device 1, the control unit 3 switches from ON to OFF a switch provided in the wiring connected to each of the first electrode 21 and the second electrode 22, so that the organic light emitting element is activated in the first period. 2 may be in an electrically floating state. Note that the presence of at least one of the first charge inflow blocking layer 23 and the second charge inflow blocking layer 24 in the organic light emitting device 2 makes it possible to connect wiring for changing the potential difference between the first electrode 21 and the second electrode 22. Simply connecting to at least one of the first electrode 21 and the second electrode 22 is effective in suppressing charges from flowing into the organic light emitting layer 25.

１…発光装置、２…有機発光素子、３…制御部、４…光源、２１…第１電極、２２…第２電極、２３…第１電荷流入阻止層（電荷流入阻止層）、２４…第２電荷流入阻止層（電荷流入阻止層）、２５…有機発光層、Ｌ１…励起光。 DESCRIPTION OF SYMBOLS 1... Light emitting device, 2... Organic light emitting element, 3... Control part, 4... Light source, 21... First electrode, 22... Second electrode, 23... First charge inflow blocking layer (charge inflow blocking layer), 24... Third 2 Charge inflow blocking layer (charge inflow blocking layer), 25...Organic light emitting layer, L1...Excitation light.

Claims (9)

有機発光素子と、
前記有機発光素子を制御する制御部と、を備え、
前記有機発光素子は、
第１電極と、
第２電極と、
前記第１電極と前記第２電極との間に配置され、励起光の入射によって電荷の分離が起こる有機発光層と、を有し、
前記制御部は、前記有機発光層に前記励起光が入射した第１期間から遅延期間が経過した後の第２期間において、前記電荷の再結合が起こるように前記第１電極と前記第２電極との間の電位差を変化させる、発光装置。 an organic light emitting device;
A control unit that controls the organic light emitting element,
The organic light emitting device is
a first electrode;
a second electrode;
an organic light-emitting layer disposed between the first electrode and the second electrode, in which charges are separated by incidence of excitation light;
The control unit controls the first electrode and the second electrode so that the charges recombine in a second period after a delay period has elapsed from the first period in which the excitation light was incident on the organic light emitting layer. A light emitting device that changes the potential difference between 前記制御部は、
前記第１期間及び前記遅延期間において、前記第１電極と前記第２電極との間の前記電位差を０とし、
前記第２期間において、前記電荷の再結合を起こさせる順方向の電界が前記有機発光層に生じるように前記第１電極と前記第２電極との間に電圧を印加する、請求項１に記載の発光装置。 The control unit includes:
In the first period and the delay period, the potential difference between the first electrode and the second electrode is set to 0,
2. In the second period, a voltage is applied between the first electrode and the second electrode so that a forward electric field that causes recombination of the charges is generated in the organic light emitting layer. light emitting device. 前記制御部は、
前記第１期間及び前記遅延期間において、前記電荷の再結合を起こさせる順方向の電界とは逆方向の電界が前記有機発光層に生じるように前記第１電極と前記第２電極との間に電圧を印加し、
前記第２期間において、前記順方向の電界が前記有機発光層に生じるように前記第１電極と前記第２電極との間に電圧を印加する、請求項１に記載の発光装置。 The control unit includes:
in the first period and the delay period, between the first electrode and the second electrode so that an electric field in the opposite direction to the forward electric field that causes the charge recombination is generated in the organic light emitting layer. Apply voltage,
The light emitting device according to claim 1, wherein a voltage is applied between the first electrode and the second electrode so that the forward electric field is generated in the organic light emitting layer during the second period. 前記制御部は、前記遅延期間の長さを調整可能である、請求項１～３のいずれか一項に記載の発光装置。 The light emitting device according to claim 1, wherein the control section is capable of adjusting the length of the delay period. 前記励起光を出射する光源を更に備え、
前記制御部は、前記第１期間において、前記有機発光層に前記励起光が入射するように前記光源を制御する、請求項１～４のいずれか一項に記載の発光装置。 further comprising a light source that emits the excitation light,
The light emitting device according to any one of claims 1 to 4, wherein the control unit controls the light source so that the excitation light is incident on the organic light emitting layer during the first period. 前記有機発光層に含まれる有機発光体のダイポールモーメントは、０Ｄよりも大きい、請求項１～５のいずれか一項に記載の発光装置。 The light emitting device according to any one of claims 1 to 5, wherein the dipole moment of the organic light emitter included in the organic light emitting layer is larger than 0D. 前記有機発光体のダイポールモーメントは、３Ｄ以上である、請求項６に記載の発光装置。 The light emitting device according to claim 6, wherein the dipole moment of the organic light emitter is 3D or more. 前記有機発光体のダイポールモーメントは、１０Ｄ以上である、請求項７に記載の発光装置。 The light emitting device according to claim 7, wherein the organic light emitter has a dipole moment of 10D or more. 第１電極と、第２電極と、前記第１電極と前記第２電極との間に配置され、励起光の入射によって電荷の分離が起こる有機発光層と、を有する有機発光素子を用いた発光方法であって、
第１期間において、前記有機発光層に前記励起光が入射するステップと、
前記第１期間から遅延期間が経過した後の第２期間において、前記電荷の再結合が起こるように前記第１電極と前記第２電極との間の電位差を変化させるステップと、を備える、発光方法。 Light emission using an organic light emitting element having a first electrode, a second electrode, and an organic light emitting layer disposed between the first electrode and the second electrode, in which charges are separated by incidence of excitation light. A method,
In a first period, the excitation light is incident on the organic light emitting layer;
In a second period after a delay period has elapsed from the first period, changing the potential difference between the first electrode and the second electrode so that recombination of the charges occurs. Method.
JP2020097798A 2019-08-02 2020-06-04 Light emitting device, light emitting method and organic light emitting device Active JP7438509B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US16/942,283 US11925046B2 (en) 2019-08-02 2020-07-29 Light-emitting device, light-emitting method, and organic light-emitting element

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019142844 2019-08-02
JP2019142844 2019-08-02

Publications (2)

Publication Number Publication Date
JP2021027330A JP2021027330A (en) 2021-02-22
JP7438509B2 true JP7438509B2 (en) 2024-02-27

Family

ID=74662508

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2020097798A Active JP7438509B2 (en) 2019-08-02 2020-06-04 Light emitting device, light emitting method and organic light emitting device

Country Status (1)

Country Link
JP (1) JP7438509B2 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004054269A (en) 2002-07-23 2004-02-19 Samsung Sdi Co Ltd Image display device for photon emission suppressing element base board and image display method using same
JP2005502086A (en) 2001-08-30 2005-01-20 ケンブリッジ ディスプレイ テクノロジー リミテッド Optoelectronic display
JP2005510025A (en) 2001-11-12 2005-04-14 ネオビューコロン カンパニー リミテッド Organic light emitting device with high luminous efficiency
US20160035993A1 (en) 2013-12-23 2016-02-04 Boe Technology Group Co., Ltd. Organic electroluminescent device and display device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005502086A (en) 2001-08-30 2005-01-20 ケンブリッジ ディスプレイ テクノロジー リミテッド Optoelectronic display
JP2005510025A (en) 2001-11-12 2005-04-14 ネオビューコロン カンパニー リミテッド Organic light emitting device with high luminous efficiency
JP2004054269A (en) 2002-07-23 2004-02-19 Samsung Sdi Co Ltd Image display device for photon emission suppressing element base board and image display method using same
US20160035993A1 (en) 2013-12-23 2016-02-04 Boe Technology Group Co., Ltd. Organic electroluminescent device and display device

Also Published As

Publication number Publication date
JP2021027330A (en) 2021-02-22

Similar Documents

Publication Publication Date Title
Inoue et al. Effect of reverse intersystem crossing rate to suppress efficiency roll-off in organic light-emitting diodes with thermally activated delayed fluorescence emitters
Hasan et al. Exciton–exciton annihilation in thermally activated delayed fluorescence emitter
EP2299786B1 (en) Stacked organic light-emitting diode
JP6482782B2 (en) Organic light emitting device
JP6890784B2 (en) Organic electroluminescence device and biometric device
JP2019068068A (en) Light emitting element
CN108123047B (en) Organic light emitting diode and white organic light emitting diode
Yuan et al. Improvement of the Electroluminescence Performance of Exciplex‐Based OLEDs by Effective Utilization of Long‐Range Coupled Electron–Hole Pairs
US20160093809A1 (en) Organic light emitting device
US11611052B2 (en) Organic light emitting display device and lighting apparatus for vehicles using the same
WO2017115833A1 (en) Organic electroluminescent element
TW201318471A (en) Organic electroluminescent device with space charge/voltage instability stabilization drive
Liu et al. Centimeter-scale hole diffusion and its application in organic light-emitting diodes
JP7438509B2 (en) Light emitting device, light emitting method and organic light emitting device
CN112490376B (en) Novel organic electroluminescent device matched with HIT and EB materials
US11925046B2 (en) Light-emitting device, light-emitting method, and organic light-emitting element
KR101936315B1 (en) Organic light emitting device comprising cohost
US9935285B2 (en) Organic electroluminescent device with multiple phosphorescent emitters
US20230053098A1 (en) Organic light-emitting element, light-emitting device, and light-emitting method
CN112490390B (en) Novel organic electroluminescent device matched with HIT and EB materials
JP2023026999A (en) Organic light-emitting element, light-emitting device and light-emitting method
JP6047416B2 (en) Evaluation method of organic electroluminescence device
Liu et al. Centimeter-scale hole diffusion and its application in organic light-emitting diodes for reducing efficiency roll-off and enhancing operation lifetime
Kajii et al. Current-density dependence of transient properties in green phosphorescent organic light-emitting diodes
CN111200077A (en) Internal light extraction structure, organic light emitting device comprising same and manufacturing method thereof

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20230530

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20231213

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20231221

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20240110

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20240130

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20240205

R150 Certificate of patent or registration of utility model

Ref document number: 7438509

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150