阅读说明：本技术 一种电化学变色器件 (Electrochemical color-changing device ) 是由 谷建民 徐銘 袁一鸣 屈年瑞 钟金玲 王德松 于 2021-08-04 设计创作，主要内容包括：本发明提供了一种电化学变色器件,其包括导电玻璃和变色材料,两块导电玻璃的导电层相对设置,且两块导电玻璃用绝缘物质隔开并用胶枪固定形成空腔,在空腔内填充有变色材料；变色材料为溶于有机良溶剂的铅卤化物溶液或铅卤化物钙钛矿溶液。对器件施加0-3.0V的外在电压,能够在无色和黑色之间转变。本发明电化学变色器件具有很高的颜色对比度,可逆性好且较稳定,制备方法简单快捷,成本较低。(The invention provides an electrochemical color-changing device which comprises conductive glass and a color-changing material, wherein conductive layers of the two pieces of conductive glass are arranged oppositely, the two pieces of conductive glass are separated by an insulating substance and are fixed by a glue gun to form a cavity, and the cavity is filled with the color-changing material; the color-changing material is lead halide solution or lead halide perovskite solution dissolved in good organic solvent. An external voltage of 0-3.0V is applied to the device, enabling a transition between colorless and black. The electrochemical color-changing device has the advantages of high color contrast, good reversibility, stability, simple and quick preparation method and low cost.)

1. An electrochromism device, comprising: the color-changing glass comprises conductive glass and a color-changing material, wherein conductive layers of the two pieces of conductive glass are arranged oppositely, the two pieces of conductive glass are separated by insulating substances and are fixed by a glue gun to form a cavity, and the cavity is filled with the color-changing material;

the color-changing material is a lead halide solution or a lead halide perovskite solution dissolved in a good organic solvent;

the electrochemical color-changing device can realize the conversion between the colorless state and the black state by applying external voltage, and the applied voltage range is 0-3.0V.

2. An organo-metal halide electrochromism device as claimed in claim 1, wherein: the lead halide is PbBr₂And PbCl₂One kind of (1).

3. An organo-metal halide electrochromism device as claimed in claim 1, wherein: the lead halide perovskite is CH₃NH₃PbBr₃。

4. An organo-metal halide electrochromism device as claimed in claim 1, wherein: the concentration of the color-changing material is 10-50 mmol/L.

5. An organo-metal halide electrochromism device as claimed in claim 1, wherein: the organic good solvent is one of N, N-dimethylformamide, dimethyl sulfoxide and gamma-butyrolactone.

Technical Field

The invention relates to the field of optical devices and electrochemistry, in particular to an electrochemical color-changing device.

Technical Field

At present, the realization of device color change is mainly realized by an electrochromic method. Electrochromic reversible color change refers to reversible optical absorption/transmittance change in response to an externally applied voltage, which has been applied to optical switches, electronic paper, smart windows, displays, data storage, military security, optical communication, and thermal control. In the development of electrochromic systems, a great deal of research has been conducted on electrochromic devices of different three primary colors, violet and magenta, etc. In recent years, black electrochromism has attracted attention because it can expand the applicability of electrochromic technology. In many applications of black electrochromic in displays (e.g., electronic books), colorless to black electrochromic devices may ensure privacy as they may transition from a completely colorless state to a nearly opaque state at the appropriate application voltage. However, achieving colorless to black electrochromic devices with ultra-high contrast across the visible region remains a strategic challenge due to the extreme difficulty of designing a complete reverse absorption (transmittance) in the transmissive and colored states.

To date, the following strategies have been used primarily to achieve this goal. The most widely used strategy to achieve a colorless to black conversion is based on the principle of "color mixing" by carrying a blend or multilayers to achieve complementary absorption. However, in addition to the complexity of these systems, the larger number of layers/electrodes may cause problems such as loss of transparency of the device or difficulty in controlling the redox potential. In addition, a monomeric polymer or copolymer is synthesized to achieve color change by combining twisted structure, donor-acceptor design and tuning of conjugated chromophores. However, long conjugation also shows low light transmittance, and the synthesis method is more complicated and is prone to side reactions. The thick film can be a colorless to black material, but in a neutral state, the light transmittance of the thick film is low. Therefore, developing a full-colorless color changing device, especially in the colorless to black domain, remains the most challenging problem in the current electrochromic domain.

Disclosure of Invention

In order to overcome the disadvantages of the prior art, the present invention provides an electrochemical color-changing device capable of switching between colorless and black colors depending on an applied voltage, the color-changing device having little absorption of the visible spectrum in a bleached state, having high transmittance throughout the visible spectrum, and having excellent optical contrast.

The invention is realized by the following technical scheme:

an electrochemical color-changing device comprises conductive glass and a color-changing material, wherein conductive layers of the two pieces of conductive glass are oppositely arranged, the two pieces of conductive glass are separated by an insulating substance and are fixed by a glue gun to form a cavity, and the color-changing material is filled in the cavity; the color-changing material is a lead halide solution or a lead halide perovskite solution dissolved in a good organic solvent; the electrochemical color-changing device can realize the conversion between the colorless state and the black state by applying external voltage, and the applied voltage range is 0-3.0V.

Preferably, the lead halide is PbBr₂,PbCl₂One kind of (1).

Preferably, the lead halide perovskite is CH₃NH₃PbBr₃。

Preferably, the concentration of the color-changing material is 10-50 mmol/L.

Preferably, the organic good solvent is one of N, N-dimethylformamide, dimethyl sulfoxide and γ -butyrolactone.

The preparation method of the electrochemical color-changing device comprises the following steps: the method comprises the following steps of enabling the conductive surface of one piece of conductive glass to face upwards, padding a certain height at the edge positions of two symmetrical sides of the conductive glass by using an insulating tape, enabling the conductive surface of the other piece of conductive glass to cover the conductive surface of the other piece of conductive glass downwards on the first piece of conductive glass which is tiled, fixing the second piece of conductive glass by using a glue gun, and injecting a color-changing material between the two pieces of conductive glass through a gap without the insulating tape on two sides.

Compared with the prior art, the invention has the following advantages:

the electrochromism device provided by the invention can realize a conversion process from colorless to black by applying external voltage, and can realize a conversion process from black to colorless by cutting off the voltage. When a voltage is applied to the device, CH₃NH₃PbBr₃Br formation on the surface of the anode ITO₂Pb is generated on the surface of the cathode ITO, so that the device is changed from colorless to black; br in solution when the voltage is switched off₂And [ MAPbBr ]]²⁺Pb and[MABr₃]^2-is changed into CH again₃NH₃PbBr₃Causing the device to change from black to colorless. By changing the voltage or the concentration of the color-changing material, the situation that the appearance of the generated black substance is small and uniform is found, and higher contrast can be achieved. Wherein the voltage mainly influences the size of the product, and the concentration mainly influences the uniformity of the appearance.

The electrochemical color-changing device is simple in structure, a color-changing material layer is sandwiched between two transparent conductive layers, so that a sandwich structure with the color-changing material in the middle is formed, wherein the color-changing material layer is formed by injecting lead halide or lead halide calcium titanium organic good solvent solution into the manufactured color-changing device from a gap on the side surface of conductive glass through capillary action. The color-changing material has high transmittance in the whole visible light region in a bleached state, and has absorption in the whole visible spectrum in a colored state after a certain voltage is applied to the color-changing material. The electrochemical color-changing device can be converted from colorless to black, has good contrast in the whole visible light region, and has good light shading effect.

Drawings

FIG. 1 is a schematic view of the preparation of an electrochromism device according to the present invention;

FIG. 2 is a schematic diagram of a color changing device at different voltages;

FIG. 3(a) is a photograph of color-changing materials of different concentrations in example 1;

FIG. 3(b) is a graph showing the UV-VIS absorption spectra of the color-changing materials of different concentrations in example 1;

FIG. 4(a) is a UV-VIS absorption spectrum of the anode product in example 2;

FIG. 4(b) is an X-ray diffraction spectrum of the cathode product in example 2;

FIG. 5 is a UV-VIS diffuse reflectance spectrum of lead at a voltage of 2.5V for a color-changing device of different concentrations of color-changing material in example 3;

FIG. 6 is a topographical map of lead formation at a voltage of 2.5V for color-changing devices of varying concentrations of color-changing material in example 3;

FIG. 7 is a contrast curve of the color changing device of example 3 with different concentrations of the color changing material;

FIG. 8 is a UV-VIS diffuse reflectance spectrum of lead in a color changing device of example 4 at different voltages;

FIG. 9 is a topographical view of lead formation in a color changing device at different voltages in example 4;

FIG. 10 is a transmission curve of the color-changing device in example 4 at different voltages upon coloring and discoloring;

FIG. 11(a) is an absorption diagram of a device constructed in example 5 with a concentration of 20mmol/L of the discoloring material at 0V and a voltage of 2.5V applied;

FIG. 11(b) is a transmission graph of 0V and 2.5V applied voltage for the device constructed in example 5 when the concentration of the discoloring material is 20 mmol/L;

FIG. 12(a) is a graph showing the contrast ratio with time at a voltage of 2.5V at different wavelengths for the device constructed in example 5 with a concentration of 20mmol/L of the discoloring material;

FIG. 12(b) is a graph showing the time-dependent change of the contrast at a voltage of 0V for the devices constructed in example 5 at a concentration of 20mmol/L of the discoloring material at different wavelengths;

FIG. 13 is a graph showing the change in transmittance at different wavelengths when the voltage of 0V and 2.5V are switched in a device constructed in example 5 with a concentration of 20mmol/L of the discoloring material.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art 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 reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Embodiments of the present invention are described below with reference to the accompanying drawings:

the invention provides an electrochemical color-changing device, which has a three-layer structure: two transparent conductive layers and a color-changing material layer; the color-changing material layer is an organic good solvent solution of lead halide or lead halide calcium titanium.

Example 1

(1) Weighing CH with different masses₃NH₃PbBr₃Respectively dissolving in N, N-Dimethylformamide (DMF) to obtain solutions of 10mmol/L, 20mmol/L, 30mmol/L, 40mmol/L and 50mmol/L for later use.

(2) Conducting ultrasonic cleaning on the conductive glass by using toluene, acetone, absolute ethyl alcohol and water in sequence, and then drying the conductive glass in a nitrogen atmosphere for later use. One piece of conductive glass is used for upwards facing the conductive surface and is padded at the edge positions of two ends of the conductive glass by an insulating tape to a certain height, the other piece of conductive glass is covered on the first piece of conductive glass which is tiled downwards, and the first piece of conductive glass is fixed by a glue gun. Will CH₃NH₃The DMF solution of PbBr was injected into the electrochromic device through the gap without insulating tape on both sides.

The prepared color-changing device is characterized and tested for performance, and the result is as follows:

according to FIG. 3(a), the concentrations of CH₃NH₃The photograph of the DMF solution of PbBr confirms that the prepared color-changing material is colorless and transparent.

According to FIG. 3 (right) for different concentrations of CH₃NH₃The UV absorption of a DMF solution of PbBr, which has no absorption in the visible region, indicates a very high transmittance.

Example 2

Will CH₃NH₃Putting a DMF solution of PbBr into a beaker, connecting the three electrodes with an electrochemical workstation for testing, connecting conductive glass with a working electrode, connecting Ag/AgCl with a reference electrode, connecting a Pt sheet with a counter electrode, and applying forward and reverse voltages to the device.

The analysis in FIG. 4(a) shows that elemental bromine is generated on the surface of the anode.

Analysis according to fig. 4(b) revealed that lead was generated on the cathode surface.

Example 3

(1) Using a pipette to suck 10mmol/L, 20mmol/L, 30mmol/L, 40mmol/L and 50mmol/L CH₃NH₃Respectively injecting DMF solution of PbBr into the prepared devices, and spreadingThe whole plane is filled for standby.

(2) And respectively connecting the conductive glass at the two ends of the device injected with the color-changing materials with different concentrations to the anode and the cathode of a power supply through leads, and applying the same voltage.

The prepared color-changing device is characterized and tested for performance, and the result is as follows:

analysis from fig. 5 shows that the absorption intensity of lead produced by the color changing device is different at different concentrations, indicating that the concentration has an effect on the absorption of lead formation.

According to the analysis of FIG. 6, the appearance change of the formed substance of the color-changing device with different concentrations under the same voltage is obtained, which shows that the uniformity of the concentration mainly controls the product to influence the contrast performance of the device.

According to the analysis of fig. 7, the color-changing devices with different concentrations have colorless-to-black conversion in the whole visible light region, which illustrates that the concentration of the color-changing material has control on the contrast performance of the device.

Example 4

(1) Using a pipette to suck CH with the concentration of 20mmol/L₃NH₃And (3) injecting a DMF solution of PbBr into the manufactured device through the gap on the side surface of the device, and paving the solution on the whole plane for later use.

(2) And respectively connecting the conductive glass at the two ends of the device injected with the solution to the anode and the cathode of a power supply through leads, and applying different voltages.

The prepared color-changing device is characterized and tested for performance, and the result is as follows:

analysis from fig. 8 shows that the absorption intensity of lead produced by the color changing device is different at different voltages, indicating that the voltage has an effect on the absorption of lead formation.

The microscopic appearance of the device is observed according to FIG. 9, and the appearance change of the product after voltage is applied illustrates that the voltage mainly regulates the size of the product to influence the contrast performance of the device.

The change curve of the transmittance of the color-changing device under different voltages is obtained by analysis according to fig. 10, which illustrates that the voltage can regulate and control the contrast performance of the device.

Example 5

(1) Using a pipette to suck CH with a concentration of 20mmol/L₃NH₃And (3) injecting a DMF solution of PbBr into the manufactured device through the gap on the side surface of the device, and paving the solution on the whole plane for later use.

(2) And respectively connecting the conductive glass at the two ends of the device injected with the solution to the anode and the cathode of a power supply through leads, and applying a voltage of 2.5V.

The performance of the prepared color-changing device is detected, and the result is as follows:

from FIG. 11(a), a sharp transition in absorption between 0-2.5V can be observed, illustrating the effect of voltage application on the absorption of the device.

From fig. 11(b), it can be observed that there is a large change in transmittance over the entire visible light region between 0 and 2.5V, indicating that the transmittance of the device decreases with an increase in voltage.

The contrast ratio gradually increases with time and the coloring process occurs, as illustrated in FIG. 12(a) for the change of the contrast ratio with time in the case of coloring in the wavelength range of 400-800 nm.

The change of contrast with time in the case of fading in the wavelength range of 400-800nm according to FIG. 12(b) illustrates the fading process that occurs as the contrast gradually decreases with time.

The cycling stability at different wavelengths of 400-800nm in FIG. 13 illustrates that the reversibility of the color-changing device at different visible light wavelengths is better and more stable with the voltage conversion.

The technical features disclosed above are not limited to the combinations with other features disclosed, and other combinations between the technical features can be performed by those skilled in the art according to the purpose of the invention to achieve the aim of the invention, and various modifications made to the technical scheme of the invention by those skilled in the art without departing from the design spirit of the invention shall fall within the protection scope defined by the claims of the invention.