CN112067673A

CN112067673A - Electrochemical system and method for changing response mode of plasmon sensor

Info

Publication number: CN112067673A
Application number: CN202010969149.6A
Authority: CN
Inventors: 朱嘉; 周林; 金艳; 梁洁
Original assignee: Nanjing University
Current assignee: Nanjing University
Priority date: 2020-09-15
Filing date: 2020-09-15
Publication date: 2020-12-11
Anticipated expiration: 2040-09-15
Also published as: CN112067673B

Abstract

The invention relates to an electrochemical system and a method for changing a response mode of a plasmon sensor. The electrochemical system comprises a first electrode, a second electrode and electrolyte, wherein the first electrode and the second electrode are respectively contacted with the electrolyte; wherein the first electrode includes: a metal substrate; and a plurality of nano-elements disposed on the metal substrate; each nanometer element comprises a dielectric lower layer and a metal upper layer, wherein the dielectric lower layer is positioned between the metal upper layer and the metal substrate; wherein the second electrode comprises a conductor; wherein the electrolyte contains lithium ions.

Description

Electrochemical system and method for changing response mode of plasmon sensor

Technical Field

The invention relates to the field of materials, in particular to an electrochemical system and a method for changing a response mode of a plasmon sensor.

Background

Due to the capability of dynamically switching plasmon response, the dynamic plasmon micro-nano structure arouses great research interest of people in the fields of physics, chemistry, material science and the like.

The dynamic plasmon realizes dynamic regulation and control of optical response through structure transformation or material phase change, so that huge research heat is excited in the fields of nanophotonics and metamaterials. Because of the inherent self-established electric field function, flexible modulation and compatibility, the electric control means for the metal structure is the most important of various dynamic control means, and is widely used for regulating and controlling the electronic resonance in the topologically continuous metal structure, which is a new electric control path except for the thermal effect and the chemical effect. However, magnetic metamaterials have great challenges in electrical tuning due to discontinuous structures (e.g., open resonant rings, coupled nanoparticles, multiple stacked rods), but researchers have also had a strong desire to enable in-situ tuning of local structures to tune Magnetic Plasmon Resonance (MPR) and significant magnetic field enhancement. Among various electrically-modulated plasmon devices, noble metal materials (including silver and gold) are most widely used so far, having the advantages of both remarkable optical response and stable chemical properties, but all require a continuous supply of external energy to maintain a dynamic plasmon.

Disclosure of Invention

The inventors have recognized that lithium metal, as the lightest negative electrode material for lithium-based batteries, has a higher specific mass capacity and a lower electrochemical potential, i.e., possesses a higher energy density. In addition, lithium metal has a characteristic of low optical loss. Therefore, if the plasmon characteristics and the energy storage characteristics of the lithium metal are combined, the realization of the self-powered dynamic plasmon device can be greatly promoted.

The novel electrochemical system of the present disclosure includes a plasmonic sensor having a particular metal-insulator (dielectric) -metal (MIM) type grid-like structure. In electrolyte containing lithium ions, the electrochemical system is used for electrodeposition of lithium metal, and the MIM-type grid structure can induce metal lithium to be vertically deposited on the side wall of the grid strip to form a side wall, so that the MIM-type grid structure is converted into a semi-infinite metal-type grid structure, and the conversion of the optical mode of the sensor is realized. It is particularly innovative that the above transition is reversible, that is, when a reverse current is applied, the deposited lithium metal will detach from the electrode surface, thus restoring the MIM-type gate-like structure. Through the innovative scheme, reversible transformation of two different plasmon sensor response modes is realized on one device by the scheme disclosed by the invention.

In some aspects, the present disclosure provides an electrochemical system comprising a first electrode, a second electrode, and an electrolyte, the first and second electrodes each being in contact with the electrolyte;

wherein the first electrode includes:

a metal substrate; and

a plurality of nano-elements disposed on a metal substrate;

each nanometer element comprises a dielectric lower layer and a metal upper layer, wherein the dielectric lower layer is positioned between the metal upper layer and the metal substrate;

wherein the second electrode comprises a conductor;

wherein the electrolyte contains lithium ions.

In some embodiments, the nano-cell further includes a lithium metal sidewall abutting at least a portion of the side surfaces of the lower dielectric layer and the upper metal layer, electrically connecting the upper metal layer with the metal substrate.

In some embodiments, the lithium metal sidewall has a thickness of 10 to 300nm, such as 10 to 50nm, such as 50 to 100nm, in a direction perpendicular to the side surface of the dielectric underlayer.

In some embodiments, the thickness of the lithium metal sidewalls is less than the spacing of adjacent nano-elements.

Based on the above embodiment, by charging/discharging the above electrochemical system or spontaneously discharging the above electrochemical system, lithium metal is deposited on (or detached from) the surface of the first electrode, thereby enabling the change of the optical mode of the first electrode by the electromagnetic wave.

In some embodiments, the first electrode is configured as a Surface Plasmon Polarization (SPP) sensor.

In some embodiments, the first electrode is configured as a Magnetic Plasmon Resonance (MPR) sensor.

In some embodiments, the one or more nano-elements are in the shape of stripes.

In some embodiments, the plurality of nano-elements are spaced apart from each other, optionally by an average distance of 10 to 1000nm, such as 10 to 100nm, such as 100 to 200nm, such as 200 to 400nm, such as 400 to 600nm, such as 600 to 800 nm.

In some embodiments, the plurality of nano-elements are arranged periodically.

In some embodiments, the plurality of nano-elements are arranged parallel to each other.

In some embodiments, the plurality of nano-elements have the same size.

In some embodiments, the plurality of nano-elements have the same shape.

In some embodiments, the thickness of the metal overlayer is from 10 nm to 1000nm, such as from 50nm to 200 nm.

In some embodiments, the dielectric underlayer has a thickness of 10 to 1000nm, such as 10 to 100nm, such as 30 to 70 nm.

In some embodiments, the metal substrate has a thickness of 10 to 1000nm, such as 10 to 100nm, such as 100 to 200 nm.

In some embodiments, the metal upper layer coincides with a projection of the dielectric lower layer onto the metal substrate.

In some embodiments, the dimension of the metal overlayer is k in a first direction (e.g., the width direction)₁nm，k₁The first direction is parallel to the metal substrate, 10 to 1000, for example, 10 to 100.

In some embodiments, the dimension of the metal overlayer is k in the second direction (e.g., the length direction)₂μm，k₂>10, e.g. k₂The second direction is parallel to the metal substrate and perpendicular to the first direction, which is 10-100.

In some embodiments, the dimension of the dielectric underlayer in a first direction (e.g., width direction) is k₃nm，k₃The first direction is parallel to the metal substrate, 10 to 1000, for example, 10 to 100.

In some embodiments, the dimension of the dielectric underlayer in the second direction (e.g., the length direction)Is k₄μm，k₄>10, e.g. k₄The second direction is parallel to the metal substrate and perpendicular to the first direction, which is 10-100.

In some embodiments, the composition of the metal substrate includes one or more of: au and its alloy, Ag and its alloy, Cu and its alloy.

In some embodiments, the composition of the metallic overlayer includes one or more of: au and its alloy, Ag and its alloy, Cu and its alloy.

In some embodiments, the composition of the dielectric underlayer comprises one or more of: SiO 2₂、MgF₂。

In some embodiments, the concentration of lithium ions in the electrolyte is 0.1 to 10 mol/L;

in some embodiments, the electrolyte includes a solvent (e.g., a carbonate-based solvent) and a solvent-soluble lithium salt (e.g., LiPF)₆Salt).

In some embodiments, the electrolyte includes an electrolyte salt and a solvent. The electrolyte salt may be selected from LiPF₆(lithium hexafluorophosphate), LiBF₄Lithium tetrafluoroborate (LiClO), LiClO₄(lithium perchlorate) LiAsF₆(lithium hexafluoroarsenate), LiFSI (lithium bis (fluorosulfonylimide), LiTFSI (lithium bis (trifluoromethanesulfonylimide)), LiTFS (lithium trifluoromethanesulfonate), LiDFOB (lithium difluorooxalato borate), LiBOB (lithium dioxaoxalato borate), LiPO₂F₂One or more of (lithium difluorophosphate), LiDFOP (lithium difluorooxalate phosphate) and LiTFOP (lithium tetrafluorooxalate phosphate). The solvent may be one of Ethylene Carbonate (EC), Propylene Carbonate (PC), Ethyl Methyl Carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), Methyl Propyl Carbonate (MPC), Ethyl Propyl Carbonate (EPC), Butylene Carbonate (BC), fluoroethylene carbonate (FEC), Methyl Formate (MF), Methyl Acetate (MA), Ethyl Acetate (EA), Propyl Acetate (PA), Methyl Propionate (MP), Ethyl Propionate (EP), Propyl Propionate (PP), Methyl Butyrate (MB), Ethyl Butyrate (EB), 1, 4-butyrolactone (GBL), Sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulfone (ESE), Vinylene Carbonate (VC), ethylene glycol dimethyl ether (DME), triethyl phosphate (TEP)One or more of them.

In some embodiments, an electrochemical system includes a housing enclosing at least a portion of a first electrode, at least a portion of a second electrode, and an electrolyte therein;

in some embodiments, the enclosure encloses a plurality of nano-cells disposed on a metal substrate therein.

In some embodiments, the housing comprises a transparent region;

in some embodiments, the transparent region is configured to enable viewing of the first electrode through the transparent region;

in some embodiments, the transparent region is at least transparent to light in the range of 380-3000 nm.

In some embodiments, the electrochemical system further comprises a first tab and a second tab extending from the housing, the first tab and the second tab sealingly penetrating the housing and coupled to the first electrode and the second electrode, respectively;

in some embodiments, the first tab is connected to the metal substrate of the first electrode;

in some embodiments, the first tab is not in contact with the metallic upper layer of the first electrode.

In some embodiments, the second electrode comprises a lithium-containing active material, such as a lithium transition metal oxide.

In some embodiments, the lithium active material is lithium metal or a lithium alloy.

In some embodiments, the lithium active material is a lithium intercalation material, i.e., lithium ions are capable of reversibly intercalating/deintercalating in the material.

In some embodiments, the lithium active material refers to a lithium-element-containing lithium ion battery positive active material or a lithium-element-containing lithium ion battery negative active material.

In some embodiments, the lithium transition metal oxide comprises one or more of: lithium cobaltate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium titanate.

In some embodiments, the electrochemical system is an electrolytic cell or battery;

in some embodiments, the electrochemical system is a lithium battery.

wherein the first electrode includes:

the metal substrate is made of Ag and an alloy thereof; and

a plurality of nano-elements disposed on a metal substrate;

wherein each nanometer element comprises a dielectric lower layer and a metal upper layer, the dielectric lower layer is arranged between the metal upper layer and the metal substrate, and the dielectric lower layer is made of SiO₂Or MgF₂The material of the metal upper layer is Ag and alloy thereof or Cu and alloy thereof;

wherein, a plurality of nanometer elements are arranged periodically;

wherein the second electrode is a lithium transition metal oxide;

wherein the electrolyte contains lithium ions.

In some aspects, the present disclosure provides a method of altering a plasmon sensor response mode, comprising the steps of:

(1) providing an electrochemical system of any one of the above;

(2) applying an external current to the first and second electrodes, or spontaneously discharging the electrochemical system.

In some embodiments, the operations by step (2) are such that:

(a) reducing lithium ions to lithium metal at the nano-elements and depositing; or

(b) So that the lithium metal at the nano-unit is oxidized into lithium ions and is separated.

In some embodiments, the deposited lithium metal forms lithium metal sidewalls that abut at least portions of the side surfaces of the lower dielectric layer and the upper metal layer and electrically connect the upper metal layer to the metal substrate in item (a).

In some embodiments, "comprising," "including," "containing," or "containing" may refer to a weight content greater than zero, such as greater than 1%, such as greater than 10%, such as greater than 20%, such as greater than 30%, such as greater than 40%, such as greater than 50%, such as greater than 60%, such as greater than 70%, such as greater than 80%, such as greater than 90%, such as 100%. The meaning of "comprising", "including" and "containing" corresponds to "consisting of …" when the content is 100%.

Description of terms:

the term Surface Plasmon Polarization (SPP) refers to a coupling mode of an incident electromagnetic wave with collective oscillations of free electrons on the surface of a metal, characterized by the ability to propagate along a metal-dielectric interface, with the electromagnetic field strength decaying exponentially in the direction perpendicular to the interface.

The term Magnetic Plasmon Resonance (MPR) refers to a magnetic field component of an incident electromagnetic wave exciting a circular current mode (or magnetic dipole) in a metal nanostructure, and this local resonance propagates in the metal nanostructure as well to form another transverse polarized wave (since the direction of propagation of the wave is also perpendicular to the direction of oscillation of the magnetic dipole). The coupling is called magnetic plasmon resonance.

The term "dielectric" refers to a substance having a resistivity in excess of 10 ohm-cm, such as 10 ohm-cm, for example 1000 ohm-cm.

The term "nano" means a size of 1000nm or less in at least one dimension, for example, 1 to 100nm, 100 to 200nm, 200 to 300nm, 300 to 400nm, 400 to 500nm, 500 to 600nm, 600 to 700nm, 700 to 800nm, 800 to 900nm, 900 to 1000 nm.

The term "electrolytic cell" is a device used for electrolysis that converts electrical energy into chemical energy. An electrolytic cell generally comprises an electrolyte and two electrodes. When an external electric field is applied to the electrode, ions in the electrolyte are attracted by the electrode with opposite charges, migrate to the electrode and are adsorbed on the electrode, and then reduction or oxidation reaction of getting electrons or losing electrons occurs on the electrode.

The term "battery" refers to a device capable of converting chemical energy into electrical energy. The battery may be a primary battery or a secondary battery.

The term "silver alloy" refers to alloys with a silver content > 50 wt.%, preferably > 70 wt.%, and even more preferably > 90%. "gold alloy" means an alloy with a gold content > 50 wt.%, preferably > 70 wt.%, more preferably > 90%. "copper alloy" means an alloy having a copper content of > 50 wt.%, preferably > 70 wt.%, more preferably > 90%.

The term "transparent" is a transmission of 85% or more, for example 95% or more, for light of a predetermined wavelength range.

Advantageous effects

One or more technical schemes of the present disclosure have one or more of the following beneficial effects:

(1) the novel electrochemical system of the present disclosure enables on/off of a Magnetic Plasmon Resonance (MPR) mode of a plasmon sensor;

(2) the novel electrochemical system of the present disclosure enables red/blue shifting of the Surface Plasmon Polarization (SPP) mode of the plasmonic sensor;

(3) the novel electrochemical system of the present disclosure enables reversible switching of optical modes;

(4) the novel electrochemical systems disclosed have unique Magnetic Plasmon Resonance (MPR) modes that generally have longer resonance wavelengths (far from intrinsic band-to-band absorption) in favor of higher signal contrast.

(5) The disclosed novel electrochemical system can obtain different angle-dependent spectral characteristics of MPR (before lithium deposition) and SPP (after lithium deposition), and can provide a unique optical detection method for detecting the evolution process of electrochemical metallic lithium.

Drawings

Fig. 1 shows a side view of the plasmon sensor of embodiment 1.

Fig. 2 shows a top view of the metal upper layer of the plasmon sensor of embodiment 1.

Fig. 3 shows an electrochemical system (containing argon) comprising the plasmonic sensor.

Fig. 4 (a) and (b) respectively show a scanning electron microscope photograph and a schematic view of the first grid-like structure 100 before deposition of lithium metal; (c) and (d) a scanning electron micrograph and a schematic view, respectively, of the second grid structure 200 after deposition of lithium metal.

Fig. 5 (a) and (b) show the reflection spectra of the first grating structure and the second grating structure, respectively.

Fig. 6 shows an electrochemical system (containing an electrolyte) comprising the plasmonic sensor.

Fig. 7 (a) shows an in-situ reflectance spectrum during deposition of lithium at 300 μ a, and (b) shows an in-situ reflectance spectrum during deintercalation of lithium at 100 μ a.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The medicines or instruments used are not indicated by manufacturers, and are all conventional products which can be obtained commercially.

The following examples used instrumentation as shown in the following table:

TABLE 1

Example 1

This example prepared a magnetic plasmon sensor.

Fig. 1 shows a side view of the plasmon sensor of embodiment 1. Fig. 2 shows a top view of the metal upper layer of the plasmon sensor of embodiment 1. Fig. 3 shows an electrochemical system comprising the plasmonic sensor.

As shown in fig. 1 and 2, the plasmon sensor 10 is prepared as follows:

(1) providing a quartz plate 50 with the thickness of 1mm, dividing a first area 51 and a second area 52 on the quartz plate 50, wherein the first area 51 is used for arranging the plasmon sensor 10, and the second area 52 is subsequently used for configuring a second electrode when assembling the electrochemical system;

(2) depositing a metal substrate 13 (material: Ag) with the thickness of 100nm on the first region 51 by adopting a physical vapor deposition method;

(3) dividing a third region 131 and a fourth region 132 on the metal substrate 13 by physical vapor deposition, and depositing a dielectric underlayer 12 (material: SiO) with a thickness of 50nm on the third region 131 of the metal substrate 13₂) The fourth region 132 is not deposited and the fourth region 132 is subsequently used to connect tabs during assembly of the electrochemical system;

(4) depositing a metal upper layer 11 (material: Ag) with the thickness of 50nm on the dielectric lower layer 12 by adopting a physical vapor deposition method;

(5) etching the product of step (4) from the side of metal upper layer 11 by a focused ion beam etching (FIB) method to prepare first grid-like structure 100, i.e., plasmon sensor 10 of example 1 is obtained.

In the step (5), the specific parameters of the focused ion beam etching are as follows:

a) etching is carried out with an etching depth of 100nm, namely, only the metal upper layer 11 and the dielectric lower layer 12 are etched;

b) for the metal upper layer 11 and the dielectric lower layer 12, firstly, an island-shaped area 110 isolated from a peripheral area 120 is obtained through etching, and then, a first grid-shaped structure 100 is etched on the island-shaped area 110;

c) the first grid-like structure 100 comprises grid bars 101 and gaps 102 arranged in parallel, the width (d) of the gaps 102₂) 390nm, the width (d) of the grid 101₁) Is 400nm, and thus, the period width (d) of the first gate-like structure 100₃) At 790nm (400nm +390 nm). The length (L) of the bars 101 and the gaps 102 was 40 μm.

The above-prepared member, i.e., quartz plate 50 and plasmon sensor 10 disposed thereon, is named member I. The dimensional parameters of part I are shown in the table below:

TABLE 2

	Long and long	Width of	Thickness of	Material of
					Quartz plate	5cm	2.5cm	1mm	SiO₂
Island region of metal substrate	60μm	60μm	100nm	Ag
					Grid of dielectric lower layer	40μm	400nm	50nm	SiO₂
Grid of metal upper layer	40μm	400nm	50nm	Ag
					Gaps between adjacent bars	40μm	390nm	100nm	×

Example 2

This example prepares an electrochemical system containing a plasmonic sensor.

Fig. 3 shows a schematic view of the electrochemical system of example 2.

As shown, the electrochemical system includes component I of example 1, i.e., quartz plate 50 and plasmonic sensor 10 disposed thereon. Plasmon sensor 10 serves here as the first electrode of the electrochemical system.

On this basis, the electrochemical system further comprises a second electrode 20. The second electrode 20 includes an active material 21 (lithium iron phosphate LiFePO)₄) The active material 21 is disposed at a second region 52 of the quartz plate 50. The second electrode 20 also includes a tab 22 connected to the active material 21.

On the basis, the electrochemical system further comprises a power supply 40 and a wire 45, the third region 132 of the metal substrate 13 of the plasmon resonance sensor 10 is connected with the power supply through the wire 45, and the tab 22 of the second electrode 20 is connected with the power supply through the wire 45.

On the basis, the electrochemical system also comprises an electrolyte. The electrolyte comprises the following components: the solvent is a mixed solution of Ethylene Carbonate (EC) and diethyl carbonate (DEC) according to a volume ratio of 1:1, and the solute is LiPF with a concentration of 1M₆2% by weight of Vinylene Carbonate (VC) were used as solvent additive.

In this embodiment, in a glove box of an inert gas argon gas, a container containing an electrolyte is provided, and the first electrode (i.e., plasmon sensor 10) and the second electrode 20 provided on the quartz plate 50 are immersed in the electrolyte. For the first electrode, the island regions 110 are targeted to deposit lithium regions.

Power is supplied to the first electrode (i.e., plasmonic sensor 10) and the second electrode 20 by power supply 40. With the first electrode as the cathode and the second electrode as the anode, deposition of lithium metal at the island regions 110 at the first electrode can be achieved. After depositing metal lithium on the island regions 110, the metal lithium changes the microstructure of the first grid-like structure 100 of the plasmonic sensor 10 to form a new second grid-like structure 200 (as shown in fig. 4).

After electrodeposition, quartz plate 50, and plasmon sensor 10 and second electrode 20 provided thereon were taken out from electrolyte solution 30, washed with DEC in a glove box, and dried. It is encapsulated. Specifically, as shown in fig. 3, the opposite sides of the quartz plate 50 are covered with the glass plate 60 with the island region 110 and the active material 21 sandwiched therebetween, and the gaps around the glass plate 60 and the quartz plate 50 are sealed with epoxy resin to form a sealed cavity filled with the inert gas argon 35. The product of example 2, part II, was obtained for subsequent analytical testing.

Analysis and detection 1: analysis by scanning electron microscope

The part I of example 1 and the part II of example 2 were each observed using a scanning electron microscope.

For plasmon sensor 10, (a) and (b) of fig. 4 show a scanning electron microscope photograph and a schematic view, respectively, of first grid-like structure 100 before deposition of lithium metal. Fig. 4 (c) and (d) respectively show a scanning electron microscope photograph and a schematic view of the second grid structure 200 after deposition of lithium metal.

As shown in fig. 4 (a) to (b), before the deposition of the metal lithium, the first grid structure 100 has a grid width of 400nm, a gap width of about 390nm, and a period width of about 790 nm. Before the deposition of the metal lithium, the metal substrate and the metal upper layer of the first gate structure 100 are separated by the dielectric lower layer, i.e. it has a sandwich structure of "metal substrate-dielectric lower layer-metal upper layer" (hereinafter referred to as MIM structure). Analyzing the field distribution of the local electric field and the magnetic field, the dielectric layer in the middle of the double metal layer of the MIM can generate magnetic dipole moment, and the grid-shaped structure with the MIM structure can show obvious Magnetic Plasmon Resonance (MPR) under the action of electromagnetic waves.

As shown in fig. 4 (c) to (d), after the deposition of the metal lithium, the MIM type first gate structure is changed to the semi-infinite metal type second gate structure 200. During the deposition of the metal lithium, the first grid-like structure 100 induces the metal lithium to be vertically deposited on the sidewalls 14 of the grid bars 101 to form the sidewalls 14, the sidewalls 14 connect the metal upper layer and the metal substrate, and the width of the grid bars 101 is widened, so that the average width of the grid bars 101 is increased from about 400nm before deposition to about 500nm, i.e., the thickness of the sidewalls 14 is about 50 nm. After the plasmonic sensor 10 deposits lithium metal, the metallic lithium sidewall 14 will connect the metallic upper layer and the metallic substrate, shorting the MIM structure and the discontinuous MIM structure will become a continuous semi-infinite metal structure. Analyzing the field distribution of the local electric and magnetic fields, the Magnetic Plasmon Resonance (MPR) of the sensor under the action of the electromagnetic wave will be attenuated to disappear, and in turn will exhibit surface plasmon resonance (SPP) characteristics.

And (3) analysis and detection 2: fourier infrared transform spectroscopy

Reflection spectra of the first and second grating structures were observed using a fourier transform infrared spectrometer (Bruker vertex 60) with the surrounding area 120 of the metallic upper layer 11 of the plasmonic sensor 10 as a reference for the reflection test, the spectral lines being shown in fig. 5 (a) and (b), respectively.

As shown in fig. 5 (a), the reflection spectrum of the first grating-like structure before the deposition of metallic lithium has a significant reflection valley at 1.85 μm, and the wide and symmetrical reflection valley proves to belong to a Magnetic Plasmon Resonance (MPR) mode. The reflective valley of the first grating-like structure corresponding to the non-localized Surface Plasmon Polariton (SPP) of the periodic structure is at about 790nm, which is not apparent in this figure because 790nm is somewhat outside the instrumental measurement range.

As shown in fig. 5 (b), for the second grating-like structure, the reflection valley at 1.85 μm representing the Magnetic Plasmon Resonance (MPR) mode disappears, while the reflection valley representing the Surface Plasmon Polarization (SPP) mode is red-shifted to a wavelength of about 1 μm.

As shown in fig. 4 to 5, the first grid structure 100 is transformed into the second grid structure 200 by electrodeposition of lithium metal, and the optical mode changes as follows:

(1) the intensity of the Magnetic Plasmon Resonance (MPR) mode is attenuated to substantially disappear;

(2) the wavelength of the Surface Plasmon Polarization (SPP) mode is red-shifted.

Example 3

Example 3 differs from example 2 in the location of the electrolyte. Fig. 6 shows a schematic view of the electrochemical system of the present embodiment.

In this embodiment, the opposite sides of the quartz piece 50 are covered with the glass piece 60, the peripheral gaps of the glass piece 60 and the quartz piece 50 are sealed with epoxy resin, the island region 110 and the active material 21 are sandwiched therebetween, and the peripheral gaps of the glass piece 60 and the quartz piece 50 are sealed with epoxy resin to form a cavity in which the island region 110 and the active material 21 are sealed. The third region 132 of the metal upper layer 13 and a portion of the tab 22 are not sealed within the cavity and are subsequently used to connect to the power source 40 via the wire 45.

A small hole is reserved for injecting electrolyte when the sealing is carried out. After the epoxy resin adhesive is dried and stabilized, the sample is transferred to an inert gas glove box, the electrolyte 30 is injected into the cavity from the small hole by a needle, so that the cavity is filled with the electrolyte, and the island-shaped area 110 and the active substance 21 are immersed in the electrolyte 30. Finally the hole was sealed with epoxy and the resulting product was named part III as shown in fig. 6.

On this basis, the electrochemical system further comprises a power source 40 and a lead 45, the third region 132 of the metal substrate 13 is connected with the power source 40 through the lead 45, and the tab 22 of the second electrode 20 is connected with the power source 40 through the lead 45.

Power is supplied to the first electrode (i.e., plasmonic sensor 10) and the second electrode 20 by power supply 40. The charging or discharging of the electrochemical system can be realized by adjusting the current direction.

In this embodiment, the first electrode is used as a cathode, and the second electrode is used as an anode, so that the lithium metal is deposited at the first electrode. The current parameters are: the deposition current is 300 muA, and the electrifying time period is 0-15 min. After the metal lithium is deposited on the island regions 110, the metal lithium changes the microstructure of the first grid-like structure 100 of the plasmonic sensor 10 to form a new second grid-like structure 200 (as shown in fig. 4).

Then, with the first electrode as an anode and the second electrode as a cathode, the detachment of lithium metal from the first electrode is achieved. The current parameters are: the current is 100 muA, and the electrifying time period is 15-40 min. After the lithium metal is removed, the second grid structure 200 on the first electrode is transformed back to the first grid structure 100.

Analyzing and detecting: fourier infrared transform spectroscopy

The reflection spectra of the plasmonic sensor of example 3 under the effect of electromagnetic waves at different stages of lithium deposition were observed using a fourier transform infrared spectrometer (Bruker vertex 60) with the surrounding area 120 of the metallic upper layer 11 of the plasmonic sensor 10 as reference for the reflection test, the spectral lines being shown in fig. 7. FIG. 7 (a) shows an in-situ reflectance spectrum during lithium deposition at a current of 300. mu.A, and (b) shows an in-situ reflectance spectrum during lithium desorption at a current of 100. mu.A.

From fig. 7 (a), the reflection spectrum before the metal lithium deposition (0min) has two reflection valleys (≈ 1.2 and ≈ 1.6 μm) corresponding to the SPP (on metal/dielectric interface) mode and the MPR mode, respectively, similar to the spectral features of the previous ex-situ experiment.

When a current of 300 μ A was applied, the metallic lithium began to deposit (period: 0 → 3 → 9min), and when a reverse current of 100 μ A was applied, the metallic lithium began to detach (period: 15 → 38 → 40 min). In the above cycle, two representative dynamic evolution laws (attenuation/disappearance of MPR and red-shift of SPP) in the experimental phenomenon of example 2 were also observed in this experiment of example 3.

For example, in the entire electrochemical cycle (original surface → lithium deposition → lithium detachment), on/off/on switching of the reflection valley at about 1.6 μm corresponding to the MPR mode can be observed. With the deposition of lithium metal, the MPR reflection valley at 1.6 μm gradually weakens to almost disappear, and when the lithium metal is sufficiently detached, the MPR reflection valley at 1.6 μm reappears.

For another example, during the entire electrochemical cycle (original surface → lithium deposition → lithium detachment), a slight red shift of the reflective valley corresponding to the SPP can be observed and returns to the original position after the complete cycle is over.

The above embodiments show an electrochemical system for realizing electric field dynamic regulation of plasmon resonance modes by metal lithium deposition. The system adopts an electric field regulation and control means for the first time, and realizes regulation and/or switching of Magnetic Plasmon Resonance (MPR) and Surface Plasmon Polarization (SPP) modes through selective deposition of metal lithium on a metal-insulator-metal (MIM) structure.

The electrochemical system disclosed by the invention can generate reversible structural transformation from a discontinuous MIM structure to the single-interface grating in the electrochemical charge-discharge process, so that dynamic optical regulation between magnetic plasmon resonance and surface plasmon polarization is realized. The reflection spectrum related to the morphology can be used as a research platform for electric field regulation and control of dynamic plasmons, and an idea is provided for an electric control and self-powered compatible dynamic plasmons device and an electrochemical in-situ nondestructive optical detection device.

The experimental result disclosed by the invention provides an effective method for realizing the reconfigurable magnetic metamaterial, and also creates a new idea for an electrically compatible self-powered dynamic plasmon device and an in-situ nondestructive optical detection device of electrochemical reaction.

While specific embodiments of the invention have been described in detail, those skilled in the art will understand that: various modifications may be made in the details within the teachings of the disclosure, and these variations are within the scope of the invention. The full scope of the invention is given by the appended claims and any equivalents thereof.

Claims

1. An electrochemical system comprising a first electrode, a second electrode and an electrolyte, the first electrode and the second electrode being in contact with the electrolyte, respectively;

wherein the first electrode comprises:

a metal substrate; and

a plurality of nano-elements disposed on the metal substrate;

wherein the second electrode comprises an electrical conductor;

wherein the electrolyte contains lithium ions.

2. The electrochemical system of claim 1, the nano-cell further comprising a lithium metal sidewall abutting at least a portion of a side surface of the lower dielectric layer and the upper metal layer electrically connecting the upper metal layer with the metal substrate;

optionally, the thickness of the lithium metal side wall is 10-300 nm along the direction vertical to the side surface of the dielectric lower layer.

3. Electrochemical system according to claim 1 or 2, characterized by any of the following:

the first electrode is configured as a Surface Plasmon Polariton (SPP) sensor;

the first electrode is configured as a Magnetic Plasmon Resonance (MPR) sensor.

4. The electrochemical system of claim 1, the nano-elements having one or more of the following characteristics:

-the shape of the one or more nano-elements is a strip;

-the plurality of nano-elements are spaced apart from each other, optionally with an average distance of 10-1000 nm;

-a plurality of nano-elements arranged periodically;

-a plurality of nano-elements are arranged parallel to each other;

-the plurality of nano-elements have the same size;

-the plurality of nano-elements have the same shape.

5. The electrochemical system of claim 1, having one or more of the following features;

the thickness of the metallic upper layer is 10-1000nm, for example 50-200 nm;

the thickness of the dielectric underlayer is 10 to 1000nm, for example 30 to 70 nm;

-the metal substrate has a thickness of 10 to 1000nm, such as 100 to 200 nm;

-the metal upper layer coincides with the projection of the dielectric lower layer on the metal substrate;

in a first direction, the dimension of the metallic upper layer is k₁nm，k₁10-1000, wherein the first direction is parallel to the metal substrate;

in the second direction, the dimension of the metallic upper layer is k₂μm，k₂>10, the second direction being parallel to the metal substrate and perpendicular to the first direction;

in a first direction, the dimension of the dielectric underlayer is k₃nm，k₃10-1000, wherein the first direction is parallel to the metal substrate;

in the second direction, the dimension of the dielectric underlayer is k₄μm，k₄>10, the second direction being parallel to the metal substrate and perpendicular to the first direction.

6. The electrochemical system of claim 1, having one or more of the following features:

-the composition of the metal substrate comprises one or more of: au and its alloy, Ag and its alloy, Cu and its alloy;

-the composition of the metallic upper layer comprises one or more of: au and its alloy, Ag and its alloy, Cu and its alloy;

-the composition of the dielectric underlayer comprises one or more of: SiO 2₂、MgF₂。

7. The electrochemical system of claim 1, having one or more of the following features:

the concentration of lithium ions in the electrolyte is 0.1-10 mol/L;

the electrolyte comprises a solvent (e.g. a carbonate-based solvent) and a lithium salt (e.g. LiPF) soluble in said solvent₆Salt).

8. The electrochemical system of claim 1, comprising a housing that encloses at least a portion of the first electrode, at least a portion of the second electrode, and the electrolyte therein;

optionally, the housing encapsulates a plurality of nano-elements disposed on the metal substrate therein.

9. The electrochemical system of claim 8, wherein the housing comprises a transparent region;

optionally, the transparent region is configured to enable viewing of the first electrode through the transparent region;

optionally, the transparent region is at least transparent to light in a wavelength range of 380-3000 nm.

10. The electrochemical system of claim 8 further comprising first and second tabs extending from the housing, the first and second tabs sealingly penetrating the housing and connecting to the first and second electrodes, respectively;

optionally, the first tab is connected with the metal substrate of the first electrode;

optionally, the first tab is not in contact with the metallic upper layer of the first electrode.

11. The electrochemical system of claim 1, the second electrode comprising a lithium-containing active material, such as a lithium transition metal oxide.

12. The electrochemical system of claim 1, which is an electrolytic cell or battery;

optionally, the electrochemical system is a lithium battery.

13. An electrochemical system comprising a first electrode, a second electrode and an electrolyte, the first electrode and the second electrode being in contact with the electrolyte, respectively;

wherein the first electrode comprises:

the metal substrate is made of Ag and alloy thereof or Cu and alloy thereof; and

a plurality of nano-elements disposed on the metal substrate;

each nanometer element comprises a dielectric medium lower layer and a metal upper layer, the dielectric medium lower layer is positioned between the metal upper layer and the metal substrate, and the dielectric medium lower layer is made of SiO₂Or MgF₂The material of the metal upper layer is Ag and alloy thereof or Cu and alloy thereof;

wherein the plurality of nano-elements are arranged periodically;

wherein the second electrode is a lithium transition metal oxide;

wherein the electrolyte contains lithium ions.

14. A method of altering a plasmon sensor response mode, comprising the steps of:

(1) providing an electrochemical system according to any one of claims 1 to 13;

15. The method of claim 14, such that by operation of step (2):

(a) causing lithium ions to be reduced to lithium metal at the nano-sized unit and deposited; or

(b) And oxidizing the lithium metal at the nano-unit into lithium ions and releasing the lithium ions.

Optionally, in item (a), the deposited lithium metal forms lithium metal sidewalls that abut at least portions of the side surfaces of the lower dielectric layer and the upper metal layer and electrically connect the upper metal layer to the metal substrate.