Conjugated polymer based on truxene and EDOT and application thereof in electrochromism field

Abstract

The invention relates to a conjugated polymer based on truxene and EDOT and application of the conjugated polymer in the field of electrochromism. The structural formulas of the two conjugated polymers are shown in the specification, and the two conjugated polymers respectively have rich multicolor changes and excellent stability and are two excellent electrochromic functional layers.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronics, specifically to the design and synthesis of triindene and EDOT conjugated polymers and their application in electrochromism. Background Technology

[0002] Electrochromic materials are materials whose optical properties (absorption, reflectivity, and transmittance) undergo stable and reversible changes under the influence of an applied voltage, typically manifested as changes in color and transparency. With increasing doping (oxidation), electrochromic materials can form polaron and bipolaron energy levels with lower band gaps between the valence and conduction bands. The formation of these new energy levels alters the energy required for valence electron transitions, resulting in changes in absorption peaks in spectroelectrochemistry. These materials show broad commercial prospects in low-energy display devices, electronic paper, color-changing skin, and information storage displays, and can be used for the upgrading and functional integration of various wearable electronic devices.

[0003] The evaluation of the performance of electrochromic materials is one of the most important issues. Researchers use the following parameters and indicators to evaluate the electrochromic performance: (1) Optical contrast (ΔT): The optical transmittance (T) of an electrochromic material between its oxidized and neutral states at a single wavelength. ox and T neut。 The difference between the absorbance and transmittance of a material and its oxidized or neutral state is a crucial parameter for evaluating its electrochromic properties. This wavelength is determined based on the material's absorption spectrum (the same material may exhibit multiple wavelengths), specifically the wavelength corresponding to the maximum absorption peak in either the oxidized or neutral state. The absorption spectrum of a material refers to its absorbance or transmittance curves at different wavelengths. The magnitude of the absorbance in the absorption spectrum measures the material's color change. Furthermore, spectroelectrochemical experiments can also detect the generation of monopolarons or bipolarons in a material based on the applied voltage.

[0004] (2) Coloration efficiency (CE): This refers to the ratio between the change in absorbance and the charge density resulting from the transmission conversion when a certain amount of charge is injected into a conductive polymer film per unit area at a specific wavelength. Generally, the coloration efficiency remains constant during the oxidation or reduction process of the same polymer film and is independent of the film thickness. The formula for calculating coloration efficiency is:

[0005]

[0006] in, △ODThe optical density change value refers to the change in optical density of a polymer film at a specific wavelength. λ max The ratio of the transmittance of the oxidized state to that of the reduced state; Q d It is charge density, which refers to the amount of charge injected per unit area.

[0007] (3) Response time: The time required for an electrochromic material or device to complete an oxidation (colored state) or reduction (fading state) conversion process. The oxidation (colored) process corresponds to the coloring response time, and the reduction (fading) process corresponds to the fading response time. The response time is generally calculated using the time required for a 95% change in transmittance. The main factors affecting the conversion time include: the composition of the electrolytic cell (acidity or alkalinity of the solvent, ion conductivity of the supporting electrolyte), the voltage applied during the oxidation-reduction process, and the ease of ion diffusion in the electrochromic material.

[0008] (4) Open circuit optical memory effect: This refers to the ability of an electrochromic material to retain its oxidized or reduced color without the application of an external voltage. Operationally, this involves testing the optical transmittance of the polymer under external pressure for a certain period, then testing the optical transmittance again after the external pressure is removed. This change represents the memory effect of the material or device. A related application is that light-emitting diodes (LEDs) can retain their displayed content even when power is off. It is worth noting that for electrochromic materials or devices that exhibit color in solution, the color will fade quickly due to ion diffusion or exchange, while all-solid-state electrochromic devices have a better memory effect.

[0009] Current requirements for electrochromic materials and devices mainly include high optical contrast, high coloring efficiency, short response time, good memory effect, rich color changes, and good stability. Professors such as Reynolds from Georgia Institute of Technology, Professor Toppare from Turkey, Professor Xu Chunye from the University of Science and Technology of China, Professor Meng Hong from Peking University, Professor Jia Chunyang from the University of Electronic Science and Technology of China, and Professor Xu Jingkun from Jiangxi University of Science and Technology have made significant contributions to the field of electrochromism. The pursuit of high-performance electrochromic materials and devices has always been a crucial mission for researchers. On the one hand, researchers optimize the performance of existing materials to achieve breakthroughs; on the other hand, they continuously develop new electrochromic materials to obtain more efficient and stable electrochromic performance. Summary of the Invention

[0010] The primary objective of this invention is to provide two types of conjugated polymers based on triindene and EDOT.

[0011] Another object of the present invention is to provide the above-mentioned preparation method based on triindene and EDOT conjugated polymer.

[0012] Another object of the present invention is to provide the above-mentioned application of the triindene and EDOT conjugated polymer in the field of electrochromism.

[0013] The objective of this invention is achieved through the following solution: Based on the conjugated polymers of triindene and EDOT and their applications in the field of electrochromism, the invention is characterized by having the following structure:

[0014] The product based on the tri-indene and EDOT conjugated polymer is characterized by potentially having a porous structure. This provides ion transport channels, which is beneficial for ion transport.

[0015] The product based on triindene and EDOT conjugated polymer is characterized in that PTr-EDOT exhibits distinct multicolor variations of yellow, green, blue, and violet, and PTr-ProDOT demonstrates excellent stability.

[0016] The method for preparing the polymer material is characterized by the following steps: 2,7,12-tribromo-5,5',10,10',15,15'-hexylindene (Tr-3Br) with a calculated molar ratio is reacted with 3,4-ethylenedioxythiophene (EDOT) and 3,3-bis((((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane-heptene (ProDOT) monomers via direct (hetero)arylation polymerization (DHAP) to obtain the polymer.

[0017] The aforementioned tri-indene and EDOT conjugated polymer has been applied in the field of electrochromism.

[0018] Compared with the prior art, the present invention has the following advantages: (1) This invention designs and synthesizes two novel polymers based on triindene and EDOT conjugated polymers; (2) The present invention realizes two electrochromic polymers with excellent multicolor changes and excellent stability respectively. Attached Figure Description

[0019] Figure 1 The image shows the spectroelectrochemical spectra of two conjugated polymers based on triindene and EDOT in a specific implementation.

[0020] Figure 2 This is a dynamic stability diagram.

[0021] Figure 3 For the triindene and EDOT conjugated polymer Detailed Implementation

[0022] The present invention will be further described below through specific embodiments, the purpose of which is to help to better understand the content of the present invention. Specifically, these embodiments include polymer synthesis and device fabrication methods, but these specific embodiments do not limit the scope of protection of the present invention in any way.

[0023] The present invention can be practiced using conventional techniques of polymer chemistry within the art. In the following examples, efforts have been made to ensure the accuracy of the figures used (including quantities, temperatures, reaction times, etc.), but some experimental errors and deviations should be considered. Temperatures used in the following examples are expressed in °C, and pressures are at or near atmospheric pressure. Solvents used were purchased of analytical or chromatographic grade, and all reactions were carried out under a nitrogen atmosphere. Unless otherwise stated, all reagents were commercially available. Specific implementation methods Example 1

[0024] Preparation of polymers PTr-EDOT and PTr-ProDOT The chemical reaction process is shown below, with specific reaction steps and conditions as follows:

[0025] (1) The raw materials described in the above reaction formula, hydrogenated hexane and NN-dimethylacetamide (DMAc), were purchased from Aladdin Reagent (Shanghai) Co., Ltd. Tris(4-methoxyphenyl)phosphine ((o-CH3OC6H4)3P), tris(dibenzylacetone)dipalladium-chloroform adduct (Pd(dba)3-CHCl3), and cesium carbonate (Cs2CO3) were purchased from Energy Chemical Company. 2,7,12-tribromo-5,5',10,10',15,15'-hexanetriindenyl terpinene (Tr-3Br), 3,4-ethylenedioxythiophene (EDOT), and 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane-heptene (ProDOT) were purchased from Suzhou Nakai Company. Pteropenic acid was purchased from Tokyo Chemical Industry Co., Ltd. All commercial chemicals are used directly without further processing.

[0026] (2) Preparation of polymers Add 2,7,12-tribromo-5,5',10,10',15,15'-hexylindene (270.11 mg, 0.25 mmol), 3,4-ethylenedioxythiophene (53.325 mg, 0.375 mmol), terpentine (32.75 mg, 0.32 mmol), palladium catalyst (25.57 mg, 0.025 mmol), cesium carbonate (203.67 mg, 0.625 mmol), and tris(4-methoxyphenyl)phosphine (8.8 mg, 0.025 mmol) to a pressure-resistant flask. Then, purge the air by injecting nitrogen gas into the pressure-resistant flask for 20 minutes, and then close the flask. The pressure-resistant flask is then magnetically stirred in a constant-temperature oil bath at 120°C for 12 hours to carry out the reaction. After cooling to room temperature, the precipitate was washed with anhydrous ethanol and precipitated. The precipitate was then washed sequentially with anhydrous ethanol, n-hexane, and chloroform in a Soxhlet extractor until colorless. Finally, rotary evaporation was performed to remove excess solvent, yielding the polymer product. Yield: 62%.

[0027] Add 2,7,12-tribromo-5,5',10,10',15,15'-hexyltriindene (270.11 mg, 0.25 mmol) and 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxane (165.26 mg, 0.375 mmol), terpentine (32.75 mg, 0.32 mmol), palladium catalyst (25.57 mg, 0.025 mmol), cesium carbonate (203.67 mg, 0.625 mmol), and tris(4-methoxyphenyl)phosphine (8.8 mg, 0.025 mmol) to the pressure vessel. Then inject nitrogen gas into the pressure vessel for 20 minutes to purge air, and then close the valve. The reaction was carried out in a pressure-resistant flask under magnetic stirring in a constant-temperature oil bath at 120°C for 12 hours. After cooling to room temperature, the precipitate was washed with anhydrous ethanol and precipitated. The precipitate was then washed sequentially with anhydrous ethanol, n-hexane, and chloroform in a Soxhlet extractor until colorless. Finally, excess solvent was removed by rotary evaporation to obtain the polymer product. Yield: 65%. Example 2

[0028] The polymer material obtained in Example 1 is applied to electrochromic applications. The following examples will illustrate the process of the tri-indene and EDOT conjugated polymer and its application in the field of electrochromism provided by the present invention, but the present invention is not limited to the examples given.

[0029] (1) Spectroelectrochemistry The material prepared in Example 1 was dissolved in chloroform solution and sprayed onto ITO conductive glass to form a polymer film. The film was then placed in a three-electrode electrolytic cell containing an acetonitrile solution of tetrabutylammonium hexafluoride. The working electrode was the ITO conductive glass with the polymer film, the counter electrode was a platinum sheet, and the reference electrode was an Ag / AgCl electrode. Using a potentiostatic method, the voltage applied to the working electrode was adjusted via an electrochemical workstation, and the changes in the absorption spectra of the polymer at different voltages were recorded using a UV-Vis spectrometer, thus obtaining the spectroelectrochemical spectra of the two polymers. Figure 1 .like Figure 1 As shown in (a), the absorption peak intensity at 550 nm of PTr-ProDOT decreases with increasing voltage, corresponding to the generation of polarons, and the color of the polymer film begins to change. Figure 1 As shown in (b), as the voltage increases, the absorption peak intensity at 400 nm of PTr-EDOT decreases, and a new peak appears at around 600 nm. With the increase of voltage, the absorption spectrum shifts, resulting in changes in the polychromaticity of the film.

[0030] (2) Study on the kinetic stability of polymer films A UV-Vis spectrophotometer is used to measure the transmittance of a polymer film in its oxidized and reduced states at a specific wavelength under a square wave potential, thereby calculating optical contrast and influence time. The UV-Vis spectrophotometer records a time-transmittance curve, while the electrochemical workstation records a time-current curve. The coloring efficiency can also be calculated from these two curves. Figure 2 (a) shows the kinetic stability of PTr-EDOT at 406 nm and 610 nm, with a square wave potential interval of 10 s. The polymer transmittance values ​​are approximately 10% and 12%, respectively. Figure 2 (b) is the kinetic stability spectrum of PTr-ProDOT at 555 nm, with a square wave potential interval of 10 s. The polymer transmittance is approximately 29%.

[0031] The above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A conjugated polymer based on indene and EDOT, characterized in that, It has the following structure:

2. The two polymers according to claim 1, characterized in that, PTr-EDOT features four multi-color variations: yellow, green, blue, and purple, and its color changes gradually, making it highly promising for applications in camouflage. PTr-ProDOT also exhibits excellent dynamic stability.

3. The method for preparing the polymer material according to claim 1, characterized in that, Specifically, the steps are as follows: 2,7,12-tribromo-5,5',10,10',15,15'-hexanetriindene (Tr-3Br) with a calculated molar ratio is reacted with 3,4-ethylenedioxythiophene (EDOT) and 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxaneheptene (ProDOT) monomers and a catalyst, respectively. The two novel electrochromic conjugated polymers based on triindene and EDOT conjugated polymers described in this invention are obtained by direct (hetero)arylation polymerization.

4. The tri-indene and EDOT conjugated polymer as described in any one of claims 1-3 is applied in the field of electrochromism.

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