Anthracene series 3, 4-propylene dioxythiophene conjugated polymer and flexible electrochromic device thereof

Abstract

The invention discloses an anthracene series 3, 4-propylene dioxythiophene conjugated polymer and a flexible electrochromic device thereof, and relates to the field of organic photoelectric materials and devices. The anthracene-ProDOT conjugated polymer is prepared through direct arylation condensation polymerization, the transmittance, coloring efficiency, response time and other properties of the polymer are optimized by introducing a phenyl side chain to an anthracene unit, and the anthracene-ProDOT conjugated polymer is a novel electrochromic functional layer material and serves as a functional layer to prepare a flexible electrochromic device. The preparation method has important guiding significance on electrochromic application of the polymer.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials and devices, particularly the application of anthracene-based 3,4-propylene dioxythiophene conjugated polymers and their flexible electrochromic devices in the field of electrochromism. Background Technology

[0002] Electrochromic technology utilizes the reversible redox reaction of materials under an electric field to dynamically adjust their optical properties. This change is persistent and responsive, requiring only a tiny voltage to trigger. By selecting different materials, this technology can achieve independent control of ultraviolet, visible, and near-infrared light, combining the dual functions of thermal management and visual adjustment. Currently, it has been successfully applied in fields such as automatic anti-glare rearview mirrors for automobiles, smart aircraft windows, and energy-saving glass for buildings, effectively reducing building energy consumption. In recent years, its potential as a low-power digital display technology has also become increasingly prominent, demonstrating broad prospects for green and intelligent applications. It is estimated that by 2030, the global market size of electrochromic materials and devices will reach 22.51 billion yuan, with a compound annual growth rate of 7.14% (DIResaerch), indicating that the electrochromic field is full of tremendous opportunities and challenges.

[0003] Transition metal oxides, metal coordination compounds, organic dyes, and π-conjugated polymers all exhibit electrochromic properties. Polymer electrochromic materials offer advantages such as high coloring intensity, easy structural modification, and good film-forming properties. Anthracene, as a linear polycyclic aromatic hydrocarbon, possesses excellent photophysical properties, thermal stability, and charge / energy transfer capabilities, and can participate in reversible cycloaddition and dimerization reactions. Its high fluorescence quantum yield and good carrier migration characteristics make it an ideal candidate material for optoelectronic devices, especially as a blue light-emitting unit in organic light-emitting diodes. However, the potential of anthracene rings in the field of electrochromism is accompanied by challenges. The electrochromic behavior of anthracene rings originates from their reversible redox reactions. In the neutral state, anthracene derivatives absorb ultraviolet light and appear pale yellow or nearly colorless. When electrochemically oxidized, they generate cationic radicals or divalent cations, producing strong absorption in the visible to near-infrared region, thus transforming into deep blue, blue-green, or near-black. However, the chemical reversibility of this process is a key challenge. The oxidized state of pure anthracene rings is unstable and prone to side reactions such as dimerization or degradation. Therefore, stabilizing the active intermediate through precise molecular design (such as introducing substituents or steric hindrance) is crucial for realizing its effective electrochromic applications.

[0004] By introducing substituents such as phenyl side chains onto anthracene units, molecular steric hindrance and polarity can be controlled, thereby improving thin film forming quality and ion transport kinetics, and enhancing their electrochromic properties. Although anthracene has been extensively studied in fields such as organic light-emitting diodes, organic thin-film transistors, and solar cells, its application in electrochromic systems is still in its early stages. The structure-property relationship between the chemical structure of materials and electrochromic properties remains unclear and requires further systematic and in-depth research. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by researching anthracene-based 3,4-propenedioxythiophene conjugated polymers and their preparation methods, and exploring their applications in flexible devices. This series of conjugated polymers, by altering the substituents on the anthracene ring, enhances the optical contrast and color rendering efficiency of electrochromic properties, representing a novel type of electrochromic functional layer material. The flexible devices fabricated from these polymers exhibit excellent electrochromic performance.

[0006] This invention is achieved through the following technical solution:

[0007] A first aspect of the present invention provides an anthracene-based 3,4-propenedioxythiophene conjugated polymer, characterized in that it has the following structure:

[0008]

[0009] Where n is a natural number from 1 to 10000.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned anthracene-3,4-propylene dioxythiophene conjugated polymer, comprising the following steps:

[0011] A conjugated polymer was obtained by direct arylation polycondensation reaction of monomers M1 and M2 in a certain molar ratio with 3,4-propenedioxothiophene derivatives and a certain proportion of pentanoic acid, tris(dibenzylacetone)dipalladium-chloroform adduct, cesium carbonate, tris(2-methoxyphenyl)phosphine and dimethylacetamide.

[0012] Preferably, in the above steps, the molar ratio of monomers M1 and M2 to the 3,4-propenyldioxothiophene derivative is 1:1.

[0013] Preferably, in the above steps, the direct arylation polycondensation reaction is as follows: under nitrogen protection, monomers M1 and M2, 3,4-propenyl dioxythiophene derivatives, and a certain proportion of pentanoic acid, tris(dibenzylideneacetone)dipalladium-chloroform adduct, cesium carbonate, and tris(2-methoxyphenyl)phosphine are dissolved in dimethylacetamide and heated to 120°C and refluxed for 12 hours.

[0014] A third aspect of the present invention provides the application of the above-mentioned conjugated polymer and its flexible device in the field of electrochromism. Attached Figure Description

[0015] Figure 1 The above are the proton NMR spectra of P1 and P2.

[0016] Figure 2 The following are the spectroelectrochemical spectra of P1 and P2.

[0017] Figure 3 The diagram shows the flexible electrochromic devices P1 and P2. Detailed Implementation

[0018] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0019] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions of this application will be described in detail below with reference to specific embodiments. Unless otherwise specified, experimental conditions not detailed in the embodiments are generally based on conventional conditions or conditions recommended by the reagent company; reagents, consumables, etc., used in the following embodiments can be obtained commercially unless otherwise specified.

[0020] Example 1

[0021] Preparation of anthracene-based 3,4-propene dioxythiophene conjugated polymer P1

[0022] The chemical reaction process is shown below, with specific reaction steps and conditions as follows:

[0023]

[0024] Under nitrogen protection, dibromoanthracene (M1) (336 mg, 1 mmol), 3,4-propenylatedioxythiophene derivative (440 mg, 1 mmol), pentylamino acid (15.15 mg, 0.15 mmol), palladium catalyst (22.23 mg, 0.025 mmol), and cesium carbonate (407.50 mg, 1.25 mmol) were added to a pressure-resistant flask, followed by the addition of N,N-dimethylacetamide (10 mL). The mixture was stirred thoroughly and refluxed at 120 °C for 12 h. After cooling to room temperature, the polymer was washed with anhydrous ethanol and precipitated. The polymer was then extracted sequentially with anhydrous ethanol, n-hexane, and chloroform using a Soxhlet extractor. Finally, rotary evaporation was performed to remove excess solvent, yielding the chloroform-containing polymer, P1. Nuclear magnetic resonance (NMR) spectra were then analyzed. Figure 1 ).

[0025] Example 2

[0026] Preparation of anthracene-ProDOT conjugated polymer P2

[0027] The chemical reaction process is shown below, with specific reaction steps and conditions as follows:

[0028] Under nitrogen protection, 9,10-dibromo-2-phenylanthracene (M2) (412 mg, 1 mmol), 3,4-propenylatedioxythiophene derivative (440 mg, 1 mmol), pentanoic acid (15.15 mg, 0.15 mmol), palladium catalyst (22.23 mg, 0.025 mmol), and cesium carbonate (407.50 mg, 1.25 mmol) were added to a pressure-resistant flask, and N,N-dimethylacetamide (10 mL) was added. The mixture was stirred thoroughly and refluxed at 120 °C for 12 h. After cooling to room temperature, the polymer was washed with anhydrous ethanol and precipitated. The polymer was then extracted sequentially with anhydrous ethanol, n-hexane, and chloroform using a Soxhlet extractor. Finally, the excess solvent was removed by rotary evaporation to obtain the chloroform-containing polymer, yielding P2. Nuclear magnetic resonance (NMR) spectra were then measured. Figure 1 ).

[0029] Example 3

[0030] Taking the polymer materials obtained in Examples 1 and 2 as examples, their application in the field of electrochromic materials.

[0031] The following examples will illustrate the polymer provided by the present invention and its application process in the field of electrochromic technology, but the present invention is not limited to the examples given.

[0032] (1) Spectroelectrochemistry

[0033] The polymers obtained in Examples 1 and 2 were sprayed onto ITO conductive glass to form a polymer film. The ITO conductive glass coated with the polymer film was 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 by an electrochemical workstation, and the changes in the absorption spectrum of the polymer at different voltages were recorded using a UV-Vis spectrometer, thus obtaining the electrochemical spectrogram of the polymer. (See figure) Figure 2 .

[0034] (2) Dynamics

[0035] 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, response time, and other parameters. 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.

[0036] (3) Fabrication and testing of flexible electrochromic devices

[0037] To prepare the gel electrolyte required for flexible electrochromic devices, polymethyl methacrylate (PMMA), lithium perchlorate (LiClO4), propylene carbonate (PC), and acetonitrile (ACN) were used as raw materials. The specific preparation process is as follows: LiClO4 and PMMA were dried at 100 °C for 12 hours to remove moisture and reach constant weight. LiClO4, PC, and ACN were added sequentially to a pressure-resistant bottle equipped with a magnet. PMMA was slowly added under magnetic stirring. The mass fractions of PC, PMMA, LiClO4, and ACN were 85.5%, 5.5%, 3.5%, and 5.5%, respectively. Nitrogen gas was purged into the bottle for 30 minutes to ensure nitrogen protection. The reaction was then carried out in a constant-temperature oil bath at 65 °C with stirring for 12 hours. The prepared gel electrolyte was cooled to room temperature and then stored at 4 °C for later use. It is important to note that the amount of ACN used needs to be appropriate. An appropriate amount of ACN can increase the fluidity of the gel electrolyte, facilitating uniform coverage of the electrochromic device. The device undergoes an electrochemical oxidation-reduction reaction under positive and negative voltages, resulting in a color change (e.g. Figure 3 ).

[0038] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. Anthracene-based 3,4-propene dioxythiophene conjugated polymer, characterized in that, It has the following structure: ， Where n is a natural number from 1 to 10000.

2. The method for preparing the conjugated polymer according to claim 1, characterized in that, Includes the following steps: ，， A conjugated polymer was obtained by direct arylation polycondensation reaction of monomers M1 and M2 in a certain molar ratio with 3,4-propenedioxothiophene derivatives and a certain proportion of pentanoic acid, tris(dibenzylideneacetone)dipalladium-chloroform adduct, cesium carbonate, tris(2-methoxyphenyl)phosphine and dimethylacetamide.

3. The anthracene-3,4-propylene dioxythiophene conjugated polymer and its flexible devices according to any one of claims 1 have been applied in the field of electrochromism.

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