Preparation and application of electrochromic material based on propylene dioxythiophene and triphenylamine derivative

Abstract

The invention relates to the field of electrochromic materials, in particular to a blue and second near-infrared (NIR-II) transmission electrochromic high polymer material based on propene dioxythiophene (ProDOT) and a triphenylamine derivative, and particularly relates to an electrochromic high polymer material based on propene dioxythiophene (ProDOT) and a triphenylamine derivative. The method is suitable for multiple fields of display screens, building glass, coating invisible materials and the like. The invention relates to an electrochromic material based on propenyldioxythiophene (ProDOT) and a triphenylamine derivative, which has a structure shown in the following I-III: # imgabs0, and an electrochromic polymer with red oxygen electrochemical and electrochromic characteristics is prepared by carrying out electrochemical polymerization on three monomers (ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA). According to the present invention, the electrochemical research results show that the ProDOT-TPA has low initial oxidation potential (0.59 V), such that the high-quality polymer can be easily obtained; the optimized polymer [P (ProDOT-TPA)] shows the optical contrast ratio of 14.38% at the position of 400 nm and the optical contrast ratio of 49.55% at the position of 1100 nm in an electrochromic device, and has remarkable electrochromic performance.

Description

Technical Field

[0001] The present invention relates to the field of electrochromic materials, and specifically to a blue and second near-infrared (NIR-II) transmissive electrochromic polymer material based on propylenedioxythiophene (ProDOT) and triphenylamine derivatives, which is applicable to multiple fields such as display screens, building glass, and coating stealth materials. Background Art

[0002] Electrochromic Materials (ECMs) are a class of materials whose color can reversibly change under the action of an external electric field. With the increasing application demands in high-tech fields such as smart windows, automotive rearview mirrors, wearable devices, and coating materials, electrochromic materials have become a research hotspot due to their unique tunable optical properties and broad application prospects. Electrochromic materials achieve color regulation by causing changes in optical properties (such as absorption, transmittance, or color) through electron transfer. Their working principle is based on electrochemical reactions. When a voltage is applied, redox reactions occur on the surface of the material, resulting in a change in the charge state of the material, thereby altering its optical properties.

[0003] Electrochromic materials can be divided into two major categories: inorganic materials and organic materials. Inorganic materials such as tungsten oxide (WO3) and bismuth tungstate (Bi2WO6) have long dominated the electrochromic field. The advantages of inorganic electrochromic materials are their high stability, durability, and long service life, making them suitable for large-scale practical applications. Taking tungsten oxide as an example, it can undergo significant color changes under the action of voltage, usually changing from transparent to blue. Although inorganic electrochromic materials have excellent properties, they have certain limitations, such as slower response times, lower optical contrast, and dependence on environmental conditions (such as temperature and humidity). In addition, the processing technology of these materials is relatively complex, and they usually need to be synthesized at high temperatures, which makes their manufacturing costs relatively high.

[0004] Compared with inorganic electrochromic materials, organic electrochromic materials have been widely studied and applied in recent years due to their lower processing temperature, higher tunability, and wide adaptability in different application fields. Especially conjugated polymer materials have become the focus of research on organic electrochromic materials due to their excellent performance in electrochemical and optical properties. Compared with inorganic materials, organic electrochromic materials have faster response speeds, higher optical contrast, and a wider range of color changes. In addition, the flexibility and processability of organic materials enable them to show great potential in emerging fields such as wearable devices and flexible display technologies.

[0005] One of the advantages of organic electrochromic materials is their excellent electrochromic properties. Many organic conjugated polymers (such as poly(aniline) and poly(thiophene)) exhibit high optical contrast and a wide color tuning range, making them ideal materials for applications such as displays and smart windows. In addition, the electronic structures of many organic materials can be adjusted through molecular design, enabling color tuning under different voltages. This designability gives organic electrochromic materials great flexibility in developing new applications. However, compared with inorganic materials, organic electrochromic materials still face many challenges. First, since organic materials usually tend to aggregate, agglomerate, or form crystals, this may lead to poor stability and reliability in practical applications. Aggregation of the materials may cause performance degradation during the electrochromic process and even irreversible electrochromic effects after long-term use. In addition, organic electrochromic materials usually have relatively low redox potentials, which limits their applications under certain extreme environmental conditions. To overcome these challenges, researchers have adopted various strategies, such as introducing electronegative groups into the molecular structure, to optimize the electronic properties of the materials and improve their stability under high-voltage conditions.

[0006] Meanwhile, the application fields of electrochromic materials are constantly expanding. From the initial smart windows and automotive rearview mirrors to today's smart displays, flexible displays, and wearable devices, electrochromic materials have gradually become an important part of electronic devices. With the continuous development of new electrochromic materials, future electrochromic technologies are expected to play a greater role in fields such as smart homes, intelligent transportation, and environmental protection and energy conservation. Electrochromic materials, especially organic electrochromic polymer materials, have become the research focus in the electrochromic field due to their good tunability, response speed, and diverse application prospects. With the continuous progress of technology, it is expected to achieve wide applications in multiple fields in the future, providing stronger support for the development of smart technologies. Summary of the Invention

[0007] To overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary objective of the present invention is a blue and second near-infrared (NIR-II) transmissive electrochromic polymer material system based on propylene dioxythiophene (ProDOT) and triphenylamine derivatives.

[0008] To achieve the above objective, the present invention provides the following technical solution: The preparation and application of a blue and second near-infrared (NIR-II) transmissive electrochromic polymer material based on propylene dioxythiophene (ProDOT) and triphenylamine derivatives, and its preparation method includes the following steps:

[0009]

[0010] Add neopentyl glycol, 3,4 - dimethoxythiophene, and p - TSA into a two - necked round - bottom flask. Evacuate the reaction flask under vacuum, rinse it with dry nitrogen, and then add toluene. Reflux the reaction mixture for 24 hours. After cooling to room temperature, pour the mixture into water and extract it 3 times with dichloromethane. The combined organic layers are dried over anhydrous magnesium sulfate, filtered, and the solvent is evaporated under reduced pressure. Purify the crude product by silica gel column chromatography using petroleum ether:dichloromethane (3:1, v:v) as the eluent to obtain the white solid product 1. Dissolve compound 1 in 40 mL of dry THF solution, add n - BuLi and stir at 0 °C for 2 hours. After adding Bu3SnCl, slowly heat the solution to room temperature and stir for 3 hours. The reaction mixture is repeatedly extracted 3 times with H2O and CH2Cl2, and the organic layer is dried to obtain the yellow mixture 2.

[0011] Transfer the above - mentioned mixture to a new three - necked flask, add 4,4'-dibromotriphenylamine, Pd(PPh3)4, and toluene, and reflux for 24 hours. Extract the reaction mixture 3 times with a mixture of H2O and CH2Cl2. The obtained organic layer is concentrated under reduced pressure and purified by silica gel column chromatography using petroleum ether:dichloromethane (7:1, v:v) as the eluent to obtain the white solid product ProDOT - TPA.

[0012] The present invention provides an electrochromic polymer material based on ProDOT (3,4 - ethylenedioxythiophene) and triphenylamine (TPA) derivatives, which has excellent electrochromic properties and can exhibit significant optical contrast in the blue and second near - infrared (NIR - II) regions. The polymer material is prepared by an electrochemical polymerization method, which successfully overcomes the deficiencies of traditional electrochromic materials in terms of response time, stability, and optical contrast. The combination of ProDOT and TPA derivatives not only improves the electro - chemical reactivity of the material but also effectively optimizes the molecular structure, enhances the efficiency of electron transfer, and thus improves the rate and stability of the electrochromic process. The material provides optical contrasts of 14.38% and 49.55% at wavelengths of 400 nm and 1100 nm respectively, showing excellent dimming ability, and is particularly suitable for fields such as smart windows, automotive rear - view mirrors, and wearable devices. In terms of applications, the material of the present invention has a low initial oxidation potential, good electrochemical stability, and a long service life, making it suitable for practical applications that require long - term stable performance. Compared with existing electrochromic materials, the innovation of this material lies in the efficient regulation of the blue and NIR - II regions through reasonable molecular structure design, providing broad prospects for future applications in multiple high - tech fields such as smart buildings, flexible displays, and energy conservation.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0014] (1) Based on the combination of ProDOT and TPA derivatives, the present invention optimizes the electron transfer path through molecular design, enabling the material to exhibit a faster response speed and higher optical contrast during the electrochemical reaction process. In particular, its ability to regulate light transmission in the blue and second near-infrared regions far exceeds that of existing materials.

[0015] (2) The present invention prepares the material by an electrochemical polymerization method, which is simple and efficient in operation. It avoids the high-temperature and high-energy-consuming synthesis process required for traditional inorganic materials, not only reducing the manufacturing cost but also improving the processing flexibility of the material, making it suitable for large-scale applications.

[0016] (3) By adjusting the chain length and electron-donating groups of the TPA derivative, the electrochromic polymer of the present invention can flexibly regulate its optical properties, meeting the requirements for color change and optical contrast in different application scenarios and showing stronger adaptability.

[0017] (4) The material of the present invention has a low initial oxidation potential, effectively avoiding the performance degradation caused by over-oxidation in traditional materials. After multiple cycles, it can still maintain a high electrochromic effect, greatly improving the long-term reliability of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 are the normalized ultraviolet-visible (UV-Vis) absorption spectra of (A) ProDOT-TPA, ProDOT-TPPA, and ProDOT-2TPA in 10⁻ 5 M THF solution; (B) their photoluminescence (PL) spectra.

[0019] Figure 2 are the optimized molecular configurations of (A) ProDOT-TPA, ProDOT-TPPA, and ProDOT-2TPA; (B) the frontier molecular orbital (HOMO / LUMO) energy levels; (C) the molecular electrostatic potential (ESP) surface (calculated based on the B3LYP / 6-31G(d,p) theory).

[0020] Figure 3 are the linear sweep voltammetry (LSV) curves of (A) ProDOT-TPA, ProDOT-TPPA, and ProDOT-2TPA; (B-D) the cyclic voltammetry (CV) curves of 10⁻² M ProDOT-TPA (B), ProDOT-TPPA (C), and ProDOT-2TPA (D) in CH2Cl2-Bu4NPF6 (10⁻¹M).

[0021] Figure 4(A) Cyclic voltammograms of P(ProDOT-TPA) in 0.10 M CH2Cl2 - Bu4NPF6 solution without monomers at different scan rates; (B) Linear relationship between the oxidation / reduction peak current density of P(ProDOT-TPA) and the scan rate; (C) Spectroelectrochemical curves of P(ProDOT-TPA) on ITO glass (in 0.10 M CH3CN - Bu4NPF6 solution); (D) Optical transmittance curve of P(ProDOT-TPA) at 400 nm (switching time from 10 s to 1 s); (E) Time - transmittance curve at 400 nm (cycle time 10 s); (F) Time - transmittance curve at 1100 nm (cycle time 10 s). Detailed implementation mode

[0022] The present invention will be further described in detail below in conjunction with examples and drawings, but the implementation mode of the present invention is not limited thereto.

[0023] Example 1 Preparation of Based on Propylenedioxythiophene and Triphenylamine Derivative [ProDOT - TPA]

[0024]

[0025] The synthesis route is as follows:

[0026]

[0027] (1) All chemicals and reagents were purchased from commercial channels and used without further purification. All reagents and drugs were sealed before use and not processed.

[0028] (2) Add neopentyl glycol (3.30 g, 32.00 mmol), 3,4 - dimethoxythiophene (2.40 g, 16.00 mmol), and p - TSA (0.30 g, 1.60 mmol) to a 125 mL two - necked round - bottom flask. Evacuate the reaction flask under vacuum, flush it with dry nitrogen three times, and then add 40 mL of toluene. The reaction mixture was refluxed for 24 hours. After cooling to room temperature, the mixture was poured into water and extracted three times with dichloromethane. The combined organic layers were dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure, and the crude product was purified by silica gel column chromatography using petroleum ether : dichloromethane (3 : 1, v : v) as the eluent to obtain 2.35 g of a white solid product 1, with a yield of 80%. 1 H NMR (500 MHz, CDCl3) δ 6.48 (s, 2H), 3.73 (s, 4H), 1.03(s, 6H). 1313C NMR (125 MHz, CDCl3), δ (ppm): 150.01, 105.53, 80.10, 38.90, 21.70.

[0029] (3) Under a nitrogen atmosphere, compound 1 (1 g, 5.80 mmol) was dissolved in 40 mL of dry THF solution, and then n-BuLi (2.30 mL, 5.70 mmol, 2.40 M hexane solution) was added and stirred at 0 o °C for 2 hours. After adding Bu3SnCl (1.90 mL, 7.08 mmol), the solution was slowly heated to room temperature and stirred for 3 hours. The reaction mixture was repeatedly extracted 3 times with H2O and CH2Cl2, and the organic layer was dried to obtain a yellow mixture 2. The above mixture was transferred to a new three-necked flask, 4,4'-dibromotriphenylamine (0.53 g, 1.32 mmol), Pd(PPh3)4 (0.06 g, 0.05 mmol), and 35 mL of toluene were added, and the mixture was refluxed at 110 o °C for 24 hours. The reaction mixture was extracted 3 times with a mixture of H2O and CH2Cl2. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using petroleum ether : dichloromethane (7:1, v:v) as the eluent to obtain 0.20 g of a white solid product ProDOT-TPA. The yield was 25%. 1 1H NMR (500 MHz, CDCl3) δ 7.56 (d, J = 8.9 Hz, 4H), 7.27 (d, J = 10.0 Hz, 2H), 7.14 (d, J = 7.9 Hz, 2H), 7.08 (d, J = 8.7 Hz, 5H), 6.41 (s, 2H), 3.81 (d, J = 23.1 Hz, 8H), 1.06 (s, 12H). 13 13C NMR (125 MHz, CDCl3), δ (ppm): 150.65, 147.29, 146.27, 145.50, 129.30, 127.77, 127.45, 124.63, 123.85, 123.16, 122.41, 102.38, 80.08, 79.97, 38.96, 21.79.

[0030] Example 2 Preparation of Based on Propylenedioxythiophene and Triphenylamine Derivative [ProDOT-TPPA]

[0031]

[0032] The synthetic route is as follows:

[0033] (1) Under a nitrogen atmosphere, compound 1 (1 g, 5.80 mmol) was dissolved in 40 mL of dry THF solution, and then n-BuLi (2.30 mL, 5.70 mmol, 2.40 M hexane solution) was added and stirred at 0 °C for 2 hours. After adding Bu3SnCl (1.90 mL, 7.08 mmol), the solution was slowly heated to room temperature and stirred for 3 hours. The reaction mixture was repeatedly extracted 3 times with H2O and CH2Cl2, and the organic layer was dried to obtain yellow mixture 2. The above mixture was transferred to a new three-necked flask, and 4,4'-dibromotriphenylamine (0.66 g, 2.64 mmol), Pd(PPh3)4 (0.12 g, 0.11 mmol), and 35 mL of toluene were added. The reactants were stirred at 110 o °C for 24 hours and then cooled to room temperature. The reaction mixture was repeatedly extracted 3 times with H2O and CH2Cl2. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using petroleum ether : dichloromethane (5:1, v:v) as the eluent to obtain 0.48 g of a white solid product 5. The yield was 52%. 1 H NMR (500 MHz, CDCl3) δ 7.59 (d, J = 6.9 Hz, 2H), 7.29 (d, J = 6.9 Hz, 2H), 7.09 (dd, J = 16.8, 6.9 Hz, 4H), 6.96 (s, 1H), 6.39 (s, 1H), 3.81 (d, J = 21.9 Hz, 4H), 1.06 (s, 6H). 13 C NMR (125 MHz, CDCl3), δ(ppm): 150.65, 145.22, 142.61, 141.82, 129.42, 127.80, 126.32, 122.67, 121.42, 118.15, 117.66, 101.98, 80.10, 79.98, 38.97, 21.79.

[0034] (2) Under a nitrogen atmosphere, compound 5 (1.60 g, 4.57 mmol), 1,4-diiodobenzene (0.60 g, 1.82 mmol), 1,10-phenanthroline (0.02 g, 0.11 mmol), CuI (0.02 g, 0.11 mmol), KOH (1.30 g, 23.20 mmol), and 30 mL of toluene were added to a three-necked flask. The reaction was carried out at 110 oStir at 12 h under C, then cool to room temperature. The reaction mixture was extracted 3 times with a mixture of H2O and CH2Cl2. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using petroleum ether:dichloromethane (7:1, v:v) as the eluent to obtain 0.28 g of white solid ProDOT-TPPA in 20% yield. 1 1H NMR (500 MHz, CDCl3) δ 7.53 (dd, J = 26.3, 8.2 Hz, 8H), 7.10 (d, J = 7.9 Hz,4H), 7.04 (d, J = 8.5 Hz, 6H), 6.85 (d, J = 8.9 Hz, 4H), 6.41 (s, 2H), 3.81(d, J = 22.1 Hz, 8H), 1.06 (s, 12H). 13 13C NMR (125 MHz, CDCl3), δ (ppm):150.64, 147.47, 147.00, 145.91, 145.61, 138.11, 129.44, 128.24, 127.55,125.55, 124.74, 124.08, 123.56, 122.19, 102.56, 85.11, 80.07, 79.98, 38.96,21.79.

[0035] Example 3 Preparation of a Novel Spatially Conjugated Organic Single-Molecule Wire Based on Hexaphenylbenzene [ZL-03]

[0036]

[0037] The synthetic route is as follows:

[0038] (1) The synthesis of intermediate 5 was the same as the steps in Example 2

[0039] (2) Under a nitrogen atmosphere, compound 5 (1.60 g, 4.57 mmol), 4,4'-diiodobiphenyl (0.60 g, 1.47 mmol), 1,10-phenanthroline (0.02 g, 0.11 mmol), CuI (0.02 g, 0.11 mmol), KOH (1.30 g, 23.20 mmol) and 30 mL of toluene were added to a three-necked flask. The reaction was carried out at 110 oStir at 12 h under C, and then cool to room temperature. The reaction mixture was extracted three times with a mixture of H2O and CH2Cl2. The organic layer was concentrated under reduced pressure, and the crude product was purified by silica gel column chromatography using petroleum ether:dichloromethane (7:1, v:v) as the eluent to obtain 0.25 g of white solid ProDOT-2TPA with a yield of 20%. 1 HNMR (500 MHz, CDCl3) δ 7.74 (d, J = 8.4 Hz, 4H), 7.58 (d, J = 8.3 Hz, 4H),7.43 (d, J = 8.4 Hz, 4H), 7.30 (s, 4H), 7.15 (d, J = 6.9 Hz, 6H), 7.10 (d, J= 8.2 Hz, 4H), 6.42 (s, 2H), 3.81 (d, J = 23.2 Hz, 8H), 1.06 (s, 12H). 13 C NMR(125 MHz, CDCl3), δ (ppm): 150.65, 147.33, 147.27, 146.21, 145.56, 140.14,137.82, 133.90, 129.39, 128.50, 128.00, 127.56, 127.51, 124.78, 124.05,123.94, 123.37, 122.31, 102.47, 92.36, 80.07, 79.98, 38.96, 21.79.

[0040] Example 4 UV-Visible Absorption Spectra of ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA

[0041] Figure 1 To measure the optical properties of the molecules in dilute tetrahydrofuran (THF) solution, we investigated the optical absorption characteristics by measuring the UV-visible absorption spectra of three materials, ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA. Figure 1A shows the absorption spectra of three molecules in THF solution. All molecules exhibit significant absorption characteristics in the ultraviolet and visible regions of 240 - 400 nm. The maximum absorption peaks of ProDOT-TPA and ProDOT-2TPA are located at 357 nm and 354 nm respectively, while that of ProDOT-TPPA appears at 343 nm. Compared with ProDOT-TPPA, the absorption peaks of ProDOT-TPA and ProDOT-2TPA show a slight red shift. This phenomenon indicates that with the increase in the TPA chain length (from ProDOT-TPA to ProDOT-2TPA), the intramolecular electronic structure changes, leading to enhanced interaction between electron orbits and thus causing changes in the light absorption properties. ProDOT-TPA has the strongest absorption ability in this region, indicating its higher light absorption efficiency. The absorption peak of ProDOT-TPPA is slightly shorter, which is related to the electronic effect in its molecular structure. The chain length of TPA affects the optical properties of the material.

[0042] Example 5 Theoretical Calculations of ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA

[0043] As Figure 2 shown, we optimized and calculated the molecular structures and electronic properties of three molecules, ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA, by density functional theory (DFT). The calculation results show that ProDOT-TPA has a smaller energy level difference (3.67 eV), and the electron distribution between its HOMO and LUMO is relatively uniform, with smooth electron transfer, showing excellent electrochromic performance. While the energy level difference of ProDOT-TPPA is 3.58 eV, showing a slightly inferior electrochromic effect. The energy level difference of ProDOT-2TPA is 3.59 eV, and its molecular structure is relatively distorted, resulting in a low electron transfer efficiency, which affects its electrochromic performance. The charge distributions of ProDOT-TPA and ProDOT-TPPA are concentrated on the ProDOT unit, while that of ProDOT-2TPA is mainly concentrated on the carbon atoms of the TPA part, showing a strong negative charge. This theoretical calculation provides an important basis for understanding the differences in the optoelectronic properties of these materials.

[0044] Example 6 Study on the Electrochemical Behavior of ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA

[0045] As Figure 3As shown, we performed electrochemical measurements on ProDOT-TPA, ProDOT-TPPA, and ProDOT-2TPA by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The LSV results showed that the initial oxidation potentials of ProDOT-TPA, ProDOT-TPPA, and ProDOT-2TPA were 0.59 V, 0.68 V, and 0.75 V, respectively. ProDOT-TPA had the lowest initial oxidation potential (0.59 V), indicating that this material could initiate the electrochromic reaction at a lower voltage, which was beneficial for avoiding side reactions such as overoxidation and promoting the formation of high-performance electrodeposited polymer films. Compared with ProDOT-TPA, ProDOT-TPPA and ProDOT-2TPA had higher oxidation potentials, indicating that the introduction of TPA derivatives led to a more distorted molecular configuration, thus increasing the oxidation potential of the material. Further, the electrochemical stability of the three materials was analyzed by CV tests. From the second scan, all samples showed new redox peaks, and the current intensity increased with the increase in the number of scans, indicating the extension and deposition of the conjugated polymer backbone on the electrode. The oxidation peak potentials of ProDOT-TPA were 0.50 V / 0.68 V, while the oxidation peaks of ProDOT-TPPA and ProDOT-2TPA were located at 0.68 V and 0.70 V, respectively. Compared with ProDOT-TPA, the increase in the current density of the redox peaks in the CV profiles of ProDOT-TPPA and ProDOT-2TPA was smaller, indicating that the corresponding polymer films were not further generated, and the introduction of TPA derivatives led to a decrease in the conductivity of the material, affecting the formation of the polymer film. Therefore, ProDOT-TPA exhibited excellent electrochemical performance and stability in the electrochemical reaction and was suitable for efficient electrochromic applications.

[0046] Example 7 Study on the Electrochemical Behavior and Optical Properties of P(ProDOT-TPA)

[0047] As Figure 4 shown, the redox activity, stability, and electrochromic properties of the electrochemically polymerized P(ProDOT-TPA) were studied by electrochemical tests and optical characterization. Figure 4 A shows the cyclic voltammetry (CV) curves in the scan rate range of 25 mV / s to 300 mV / s. P(ProDOT-TPA) exhibits a broad reversible redox process with a potential window of 0 to 0.80 V. As the scan rate increases, two oxidation reactions occurring simultaneously inside the polymer are shown, indicating that this material has good electrochemical responsiveness. Figure 4 B shows the anodic current density (j p,a ) and the cathodic current density (j p,c)(The) linear relationship with the scanning rate indicates that the redox process is not diffusion-controlled, reflecting the good conductivity and stable electrochemical behavior of P(ProDOT-TPA).

[0048] In a 0.10 M CH3CN-Bu4NPF6 solution without monomers, we measured the absorption spectrum of P(ProDOT-TPA) ( Figure 4 C). At an initial voltage of -0.50 V, P(ProDOT-TPA) shows absorption peaks at 447 nm and 674 nm respectively. As the voltage increases, the absorption peak at 447 nm gradually decreases, while the absorption peak at 674 nm increases, indicating the formation of polarons. When the voltage is further increased to 1.20 V, the 447 nm peak continues to weaken, and the near-infrared absorption at 800 nm increases, indicating the transformation of polarons into bipolarons. Figure 4 D to Figure 4 F shows the optical contrast (∆T%) of P(ProDOT-TPA). At different switching intervals, the ∆T% of P(ProDOT-TPA) slightly decreases after switching from a 10-second to a 1-second interval, but shows excellent cycling stability. After 300 cycles, at 400 nm and 1100 nm, the ∆T% remains at 14.14% and 14.58% respectively. After 1000 cycles, although the ∆T% at 1100 nm decreases, it still remains at a high level. These results indicate that P(ProDOT-TPA) has a high optical contrast, redox activity, and excellent electrochemical cycling stability, making it suitable for electrochromic applications with long-term stable operation.

Claims

1. An electrochromic molecule based on ProDOT and triphenylamine derivatives, which is composed of 3,4-ethylenedioxythiophene (ProDOT) and triphenylamine (TPA), and its characteristic structure As shown in I-III below: 。 2. The preparation method of the electrochromic molecule according to claim 1 specifically includes the following steps: Bromotriphenylamine and tributyltin propylene dioxythiophene react under the catalysis of tetrakis(triphenylphosphine)palladium to form Compound I. 1,4-Diiodobenzene and propylene dioxythiophene diphenylamine form a carbon-nitrogen bond in the presence of potassium hydroxide and copper iodide to synthesize Compound II. 4,4'-Diiodobiphenyl and propylene dioxythiophene diphenylamine form a carbon-nitrogen bond in the presence of potassium hydroxide and copper iodide to synthesize Compound III.

3. The electrochromic polymer according to claim 1, wherein This polymer is obtained by electrochemical polymerization from the following monomers: ProDOT-TPA, ProDOT-TPPA, or ProDOT-2TPA. The polymer has excellent redox electrochemical properties and electrochromic properties and can exhibit optical contrast in both the blue light and the second near-infrared (NIR-II) region simultaneously.

Images