Transparent conductive material, preparation method and application

Abstract

The present application relates to the field of organic electrochromic materials, and particularly relates to a kind of transparent conductive material, preparation method and application.The transparent conductive material introduces imide-functionalized polar side chain in PBDF main chain, by intramolecular donor-acceptor regulation, polar group introduction and in-situ doping polymerization combined strategy, while keeping n-type conductivity, significantly improve interface ion affinity and bulk capacitance, reduce neutral state residual absorption and enhance moisture and heat stability, overall realize low voltage driving, high optical modulation, low color difference and long-term stability, significantly better than existing electrode material.At the same time, the material of the present application is suitable for solution method roll-to-roll film, can be directly applied to building energy-saving light control glass, automobile anti-dazzle rearview mirror, flexible electrochromic display and energy storage-EC integrated window / mirror and other fields, provides a new working electrode solution for electrochromic products with high performance and industrialization feasibility.

Description

Technical Field

[0001] This invention relates to the field of organic electrochromic materials, specifically to a transparent conductive material, its preparation method, and its application. Background Technology

[0002] Electrochromic (EC) devices are widely used in smart dimming architectural glass, automotive anti-glare rearview mirrors, flexible display and energy storage-EC integrated windows, etc. The requirements for the working electrode are neutral color, high transmittance, low driving voltage, fast response, long cycle life and roll-to-roll processing.

[0003] Traditional transparent conductive material ITO has high conductivity, but it is brittle, expensive and difficult to use in flexible processes; PEDOT:PSS can be solution processed, but it has strong intrinsic blue absorption and poor stability and limited lifespan in humid heat and strong redox cycles.

[0004] In recent years, n-type polybenzodifurandione (n-PBDF) has rapidly developed as a transparent conductive polymer. Early studies have demonstrated that conductivity in the range of 10³–10⁻⁶ can be obtained through a one-step in-situ redox doping method. 4 S cm - ¹ The high transparency of n-PBDF films lays the foundation for flexible transparent electrodes. Subsequently, different teams have proposed polymerization methods using ppm-level metal oxides as catalysts, significantly improving polymerization yield and molecular weight, and enhancing the compactness and uniformity of the film. Further research has revealed that the doped state can be reversibly adjusted through "de-doping-re-doping," thereby achieving dynamic control of crystal form and conductivity. Another direction explores wet spinning processes to prepare n-PBDF fibers, achieving a combination of high conductivity and mechanical flexibility; other works have shown that reduction doping can suppress main chain isomerization defects, improving structural stability and cycle life. The latest synthetic route proposes using α-TQ to suppress catalyst aggregation, achieving one-step, dialysis-free polymerization with a conductivity exceeding 10³ S cm⁻¹. - ¹It also possesses excellent flexibility, further lowering the threshold for industrial preparation.

[0005] In addition to improvements in the material itself, n-PBDF has been applied to various devices such as sterilizable vertical OECT-ECG, bioelectronic sensors, and transparent front electrodes for perovskite solar cells, demonstrating its advantages in low-voltage drive, interfacial ion exchange, and resistance to humid and hot environments.

[0006] While the aforementioned progress has laid the foundation for n-PBDF in terms of conductivity, solution processability, and stability, current research has primarily focused on thermoelectric, OECT, or photovoltaic applications, and has not yet undertaken dedicated optimization of molecular structure and performance specifically for electrochromic applications. Existing linear or alkyl-substituted PBDFs typically exhibit large neutral color differences (ΔE*>5) and limited dimming contrast under EC conditions; key EC performance indicators such as low color difference (ΔE* ≤ 3) and high volume capacitance (C* ≥ 350 F cm⁻¹) are also limited. - ³) System solutions are still lacking for interfacial ion exchange efficiency and hydrothermal cycling stability. Summary of the Invention

[0007] Existing transparent electrode materials used in electrochromic devices (such as ITO, PEDOT:PSS, and existing n-PBDF derivatives) generally suffer from problems such as large color difference, insufficient volume capacitance, high driving voltage, poor stability in humid and hot environments and cycling, making it difficult to meet the comprehensive requirements of low color difference, high dimming contrast, fast response and long life for large-area electrochromic applications such as smart dimming windows and automotive anti-glare mirrors.

[0008] This invention provides a transparent conductive material with the following molecular formula:

[0009]

[0010] R is selected from H, ether chain, fluorinated ether chain, phosphate ester chain or quaternary ammonium salt chain;

[0011] n is an integer between 1 and 50.

[0012] In a preferred embodiment of the present invention, R is selected from the following:

[0013]

[0014] Among them, R1, R2 and R3 are independent alkyl groups;

[0015] X is selected from fluorine, chlorine, bromine, iodine, or phosphate;

[0016] y is an integer from 1 to 10.

[0017] In a preferred embodiment of the present invention, the structure is selected from the following:

[0018] .

[0019] In another aspect of the present invention, a method for preparing the aforementioned transparent conductive material is also provided, comprising the following steps:

[0020]

[0021] Specifically, the steps include the following:

[0022] S1, 2,5-diamino-1,4-phenyldiboronic acid (A-1) and diethyl 2,3-dibromofumarate (A-2) were polymerized by Suzuki coupling reaction in a 1:1 molar ratio under a catalyst to obtain intermediate A-3;

[0023] S2. The intermediate A-3 undergoes esterification under strong acid catalysis to form a lactam compound A-4.

[0024] In a preferred embodiment of the present invention, the following steps are further included:

[0025] S3. The lactam compound A-4 reacts with a halogen-substituted compound to obtain the target product A-5, as follows:

[0026] .

[0027] In a preferred embodiment of the present invention, in step S1, the catalyst is tetratriphenylphosphine palladium.

[0028] In a third aspect of the invention, the application of the aforementioned transparent conductive material in electrochromic devices is also provided.

[0029] In a preferred embodiment of the present invention, the electrochromic device is a p-n type complementary electrochromic device, with a ProDOT derivative as the p-type electrochromic layer and the transparent conductive material as the n-type ion storage layer.

[0030] In a preferred embodiment of the present invention, the electrochromic device further includes a gel electrolyte serving as an ion-conducting medium, located between the p-type electrochromic layer and the n-type ion storage layer.

[0031] This invention proposes a novel n-PBDF-imide functionalized polymer by introducing an imide-functionalized polar side chain into the PBDF backbone. Through a strategy combining intramolecular donor-acceptor regulation, introduction of polar groups, and in-situ doping polymerization, the interfacial ion affinity and volume capacitance are significantly improved while maintaining n-type conductivity, the residual absorption in the neutral state is reduced, and the hygrothermal stability is enhanced.

[0032] This strategy allows the resulting material to maintain a transmittance of over 80% at 550 nm, a neutral color difference ΔE ≤ 3, and a volume capacitance C ≥ 350 F cm⁻¹. -3 Drive voltage ≤ 1 V, cycle life exceeds 3×10 4After 1000 hours of damp heat aging (85 ℃ / 85 %RH), it still retains more than 90% of its performance. Overall, it achieves a combination of low voltage drive, high optical modulation, low color difference and long-term stability, which is significantly better than existing n-PBDF and PEDOT:PSS electrodes.

[0033] The material of this invention is suitable for solution-based roll-to-roll film fabrication and can be directly applied to fields such as building energy-saving dimming glass, automotive anti-glare rearview mirrors, flexible electrochromic displays, and energy storage-EC integrated windows / mirrors, providing a new working electrode solution for electrochromic products that combines high performance and industrial feasibility. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0035] The present invention will be further described in detail below with reference to the embodiments.

[0036] Example 1: Synthesis of representative compound T-1

[0037]

[0038] Under nitrogen protection, 0.1 mol (19.5 g) of (2,5-diamino-1,4-phenylene)diboronic acid (T-1-1) and 0.1 mol (32.9 g) of diethyl 2,3-dibromofumarate (T-1-2) were dissolved in a mixed solvent of toluene, ethanol, and deionized water in a volume ratio of 5:1:1. K₂CO₃ (3 equivalents) was added as a base and Pd(PPh₃)₄ (1 mol%) as a catalyst. After degassing three times under nitrogen atmosphere, the mixture was refluxed and stirred at 85–90 °C for 24 h for alternating copolymerization. After the reaction was completed, the mixture was cooled to room temperature, neutralized with dilute hydrochloric acid, and washed with water to remove inorganic salts. The organic layer was concentrated under reduced pressure and added dropwise to a large amount of methanol to precipitate the polymer. The precipitate was filtered, washed with methanol and acetone, and dried under vacuum at 60 °C to obtain a dark solid intermediate A-3 (ester), with a yield of approximately 70%. 1 H NMR (500 MHz, Chloroform ) δ 6.41 (s, 1H), 6.33 (s, 1H), 4.17 (s, 2H), 4.09 – 3.76 (m, 4H), 3.55 (q, J= 22.1 Hz, 2H), 3.03 (s, 2H), 1.08 (td, J = 22.1, 14.8 Hz, 6H).

[0039] The product was detected by FT-IR at 1735 cm⁻¹. -1 A clear C=O absorption peak of the ester was observed, confirming the successful progress of Suzuki polymerization. 10.0 g of the obtained T-1-3 (ester) from the previous step was placed under nitrogen protection and m-cresol / NMP (1:1, 100 mL) was added as a high-boiling solvent. Acetic anhydride (8–10 equivalents based on the diester in the repeating unit) and a small amount of sodium acetate / imidazolium were added as a catalytic dehydrating agent. The mixture was stirred at 140–160 °C for 6–8 h to first complete the lactamation of the ortho-ester with the amine and release ethanol. The temperature was then raised to 180 °C and reacted for another 1–2 h to promote cyclization and dehydration to form an amide ring. After the reaction was completed, the mixture was cooled, and the solvent and excess acetic anhydride were removed under reduced pressure. The concentrate was added dropwise to a large amount of methanol to precipitate the solid. The precipitate was filtered and thoroughly washed with methanol / acetone, then dried under vacuum at 60 °C to obtain A-3 (imide) / T-1, a dark solid (yield 84%). 1 ¹H NMR (500 MHz, Chloroform) δ 8.93 (s, 2H), 7.57 (s, 2H). FT-IR showed the ester C=O ( 1735 cm - ¹) disappears, and the characteristic bimodal peaks of imide appear ( 1775 and 1715 cm - ¹) and C–N absorption ( 1375 cm - ¹), confirming that "endoimideation without an external ammonia source" has been completed. GPC (DMF + 0.05 M LiBr, 40 °C, flow rate 1.0 mL min) - ¹), Polystyrene standard: Mn = 2.9 × 10 4 g mol - ¹, Mw = 7.2 × 10 4 g mol - ¹, Ð = 2.48.

[0040] Example 2: Synthesis of representative compound T-2

[0041]

[0042] Take T-1 obtained in Example 1, and measure it according to the imide N=1 in the repeating unit. Place it in a dry three-necked flask and add anhydrous DMF (solid content 5–10 mg / mL). -1 NaH (60% dispersion, 1.2–1.5 equivalents / repeat unit) was added in batches under ice bath to fully deprotonate for 30 min; then 1-bromo-2-(2-(2-methoxyethoxy)ethoxy)ethane (1.5–2.0 equivalents / repeat unit, with 5 mol% KI added as a catalyst if necessary to promote halogenation conversion) was added dropwise. The ice bath was removed and the reaction was stirred at 40–60 °C for 8–12 h (nitrogen protection was maintained during this period, and the increase in viscosity was normal). After the reaction was completed, excess NaH was slowly quenched with anhydrous methanol, the solvent was removed under reduced pressure, and the concentrate was added dropwise to a large amount of stirred, ice-cold diethyl ether / methanol (4:1) to precipitate and filtered. The resulting solid was washed successively with methanol → acetonitrile → acetone to remove unreacted small molecules and salts, and then purified by Soxhlet with methanol / acetonitrile for 6–8 h each. The solid was dried under vacuum at 60 °C to obtain the N-alkylated product (T-2) as a dark solid (typical yield 70–85%, depending on polymer solubility and degree of substitution). 1 H NMR (500 MHz, Chloroform) δ7.57 (s, 2H), 4.00 – 3.76 (m, 4H), 3.73 – 3.29 (m, 26H).

[0043] FT-IR imide N–H (~3300 cm⁻¹) -1 The peaks disappeared, while the imide bimodal peaks (~1775 / 1715 cm⁻¹) remained. -1 And significant C–O–C absorption (~1100 cm⁻¹) was observed. -1 XPS N1s showed a slight shift from imide-NH to N-alkylimide. GPC (DMF + 0.05 M LiBr, 40 °C, flow rate 1.0 mL min) -1 Polystyrene standard: Mn = 3.8 × 10⁻⁶ 4 gmol -1 Mw = 8.6 × 10 4 g mol -1 , Ð = 2.26.

[0044] Example 3: Synthesis of representative compound T-2

[0045]

[0046] Using T-1 obtained in Example 1 as raw material, and based on the imide N=1 in the repeating unit, it was dissolved in anhydrous DMF (solid content approximately 5–10 mg·mL). -1 In a reaction mixture, NaH (60% dispersion, 1.5 equimolars / repeat unit) was slowly added under ice bath conditions for deprotonation for 30 min; then 1-bromo-2-(2-(2-(trifluoromethoxy)ethoxy)ethoxy)ethane (1.5–2.0 equimolars / repeat unit) was added dropwise. A catalytic amount of KI (approximately 5 mol%) could be added to promote the reaction. After removing the ice bath, the reaction mixture was stirred at 50–60 °C for 10–12 h. After the reaction was complete, the remaining NaH was slowly quenched with anhydrous methanol, the solvent was removed under reduced pressure, and the concentrate was added dropwise to a stirred, ice-cold mixture of diethyl ether / methanol (volume ratio 4:1) to precipitate. The precipitate was filtered and washed successively with methanol, acetonitrile and acetone to remove unreacted small molecules and byproducts. It was then further purified by Soxhlet extraction (methanol / acetonitrile for 6–8 h each) and dried under vacuum at 60 °C to obtain the target product T-3 (N-trifluoromethoxy ether oxyalkyl substituted product), which is a blue-gray solid with a typical yield of 75–85%. 1 H NMR (500 MHz, Chloroform) δ 7.55(s, 2H), 3.84 (td, J = 14.5, 1.7 Hz, 4H), 3.61 (td, J = 14.5, 1.6 Hz, 4H), 3.51(s, 16H).

[0047] FT-IR shows N–H absorption (~3300 cm⁻¹) -1 The peaks disappeared, while the imide bimodal peaks (1775 and 1715 cm⁻¹) remained. -1 ), and significant C–O–C absorption (~1100 cm⁻¹) was observed. -1 ) and C–F absorption (~1210–1230 cm⁻¹) -1 XPS analysis revealed an F1s peak of approximately 688 eV, confirming the successful introduction of the trifluoromethoxy ether chain. GPC (DMF + 0.05 M LiBr, 40 °C, flow rate 1.0 mL / min) -1 Polystyrene standard: Mn = 4.5 × 10⁻⁶ 4 g mol -1 Mw = 9.8 × 10 4 g mol -1 , Ð = 2.18.

[0048] Example 4: Synthesis of representative compound T-4

[0049]

[0050] T-1 obtained in Example 1 (10.0 g, approximately 0.02 mol of repeating unit, calculated as imide N) was dissolved in anhydrous DMF / DMSO (volume ratio 1:1, 200 mL). Cs₂CO₃ (13.0 g, 0.04 mol, 2.0 equimolars / repeat unit) was slowly added under ice bath conditions, and the mixture was stirred for 30 min to deprotonate. Subsequently, 5-bromo-N,N,N-trimethylpentan-1-aminium bromide (18.6 g, 0.04 mol, 2.0 equimolars / repeat unit) was added in a single batch, followed by the addition of 18-crown-6 (0.3 g, 5 mol%) to promote phase transfer. After removing the ice bath, the reaction was continuously stirred at 65 °C for 14 h. After the reaction was completed, the mixture was cooled to room temperature, and 50 mL of anhydrous methanol was slowly added dropwise to quench excess base. The solvent was then removed by rotary evaporation. The resulting viscous liquid was slowly added dropwise to 800 mL of a stirred mixture of acetone / ethyl ether (volume ratio 1:4) to precipitate solids, and the product was collected by filtration.

[0051] The crude product was washed three times successively with acetonitrile, methanol, and acetone (100 mL each) to remove residual inorganic salts and byproducts, and then purified by Soxhlet extraction (acetonitrile for 6 h, methanol for 6 h). Drying conditions: 60 ℃ under vacuum for 12 h. The target product T-4 (imide-N-(CH2)5–N) was obtained. + (CH3)3Br - Dark brown solid, yield 8.5 g (approximately 78%). 1 HNMR (500 MHz, Chloroform ) δ 7.57 (s, 2H), 4.34 (t, J = 10.2 Hz, 4H), 2.15 (s,18H), 1.80 – 1.51 (m, 4H), 1.48 – 1.13 (m, 8H).

[0052] FT-IR (KBr, cm -1 ): 1774 (C=O, imide asym), 1715 (C=O, imide sym), 1048 (C–N + stretch), 954 (C–N +–CH3stretch), 3300 (N–H) absorption completely disappeared. GPC (DMF + 0.05 MLiBr, 40 °C, flow rate 1.0 mL min) -1 Polystyrene standard: Mn = 5.1 × 10⁻⁶ 4 g mol -1 Mw = 1.12 × 10 5 g mol -1 , Ð = 2.20.

[0053] XPS: N1s peak at 402.2 eV (quaternary ammonium nitrogen), Br 3d5 / 2 peak at 68.6 eV;

[0054] Elemental analysis (wt%): C 57.2%, H 6.3%, N 4.9%, Br 6.7%, consistent with theoretical values ​​(C 57.4%, H 6.2%, N 5.0%, Br 6.5%).

[0055] Solubility test: T-4 can form a uniform dispersion in ethanol, water and acetonitrile, with stability >72 h;

[0056] Thermogravimetric analysis (TGA): 5% weight loss temperature T5% = 289 ℃, residual carbon content 46 wt%.

[0057] Example 5: Synthesis of representative compound T-5

[0058]

[0059] T-1 obtained in Example 1 (10.0 g, based on repeating unit imide N ≈ 0.02 mol) was dissolved in anhydrous DMF (200 mL). NaH (60% dispersion, 1.2 g, 0.03 mol, 1.5 equivalent) was slowly added under ice bath conditions for deprotonation for 30 min. Then, diethyl (5-bromopentyl)phosphonate (6.9 g, 0.025 mol, 1.25 equivalent) was added in one go. The ice bath was removed under nitrogen protection, and the reaction was stirred at 70 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and 50 mL of anhydrous methanol was slowly added dropwise to quench excess NaH. The solvent was removed by rotary evaporation. The viscous liquid was added dropwise to an acetone / diethyl ether (1:4, 800 mL) mixture to precipitate the solid, which was then collected by filtration.

[0060] The obtained solid was washed three times with acetonitrile, methanol, and acetone (100 mL each) to remove residual salts and byproducts, then purified by Soxhlet extraction (acetonitrile for 6 h, methanol for 6 h), and dried under vacuum at 60 °C for 12 h to obtain the target product T-5 [N-(CH2)5P(O)(OEt)2 substitution], which was a dark blue-gray solid with a yield of 8.1 g (approximately 76%). 1 H NMR (500MHz, Chloroform ) δ 7.57 (s, 2H), 4.49 – 4.11 (m, 4H), 3.50 (q, J = 21.9 Hz,8H), 1.90 – 1.50 (m, 8H), 1.47 – 0.89 (m, 20H).

[0061] FT-IR (KBr, cm -1 ): 1772 (C=O, imide asym), 1715 (C=O, imide sym), 1256 (P=O stretch), 1042 (P–O–C stretch), 3300 (N–H). Absorption completely disappeared. GPC (DMF + 0.05 MLiBr, 40 °C, flow rate 1.0 mL min). -1 Polystyrene standard: Mn = 4.8 × 10⁻⁶ 4 g mol -1 Mw = 1.05 × 10 5 g mol -1 Ð = 2.19;

[0062] ³¹P NMR (162 MHz, CDCl3): δ ≈ 25.3 ppm, single resonance peak, confirming the P(V) structure;

[0063] XPS: P2p peak 133.5 eV (P=O), N1s peak 399.6 eV (imide N);

[0064] Elemental analysis (wt%): C 58.1%, H 6.7%, N 4.3%, P 3.2%, consistent with theoretical values ​​(C 58.4%, H 6.6%, N 4.2%, P 3.3%).

[0065] TGA: 5% weight loss temperature T5% = 302 ℃, residual carbon content ≈ 44 wt%;

[0066] Contact angle test (film, water droplet): θ = 48°, which is significantly lower than T-1 (83°), indicating a significant improvement in ionophilicity.

[0067] Example 6: Fabrication and Performance Testing of Electrochromic Devices Based on the ProDOT / n-PBDF-imide System

[0068] (I) Device Design and Structure Description

[0069] This invention uses ProDOT derivatives as the electrochromic layer (coloring layer) and synthesized n-PBDF-imide functionalized polymers (T-1 to T-5) as the ion storage layer to construct a p-n type complementary bilayer electrochromic device, comprising ITO / ProDOT (electrochromic layer) / electrolyte gel / Tx (n-PBDF-imide ion storage layer) / ITO. The ProDOT film undergoes oxidative coloring under positive bias, while the Tx film undergoes reduction doping under negative bias, serving as a synergistic electron and ion storage layer to achieve charge balance and fast response.

[0070] (II) Device fabrication process

[0071] 1. Preparation of ProDOT electrochromic layer

[0072] 1.1 Electrochemical polymerization method: 0.01 mol ProDOT was dissolved in an acetonitrile / PC (volume ratio 1:1) solution containing 0.1 mol LiTFSI electrolyte;

[0073] 1.2 Polymerization was carried out on an ITO substrate at a constant potential of +1.25 V for 60 s to obtain a ProDOT film with a thickness of approximately 150 nm;

[0074] 1.3 Clean with acetonitrile and vacuum dry for later use.

[0075] 2. Preparation of n-PBDF-imide ion storage layer (T-1~T-5)

[0076] 2.1 Dissolve each polymer in NMP:IPA (3:1) at a concentration of 10 mg / mL. -1 ;

[0077] 2.2 Spin-coated onto another ITO substrate (1000 rpm, dried at 60 °C for 2 h) to form a film of approximately 120 nm thickness.

[0078] 3. Device Assembly

[0079] 3.1 [EMIM][TFSI] / PMMA gel electrolyte (mass ratio 8:2) was used as the ion conduction medium;

[0080] 3.2 The ProDOT layer and Tx layer were bonded together face to face, pre-cured at 60 °C for 30 min, and then encapsulated into a symmetrical device (effective area 2 cm × 2 cm).

[0081] (III) Performance Testing Methods

[0082] 1. Optical and electrochromic properties

[0083] 1.1 The transmittance of the bleached state (T_bleached), the transmittance of the colored state (T_colored), and the optical modulation amplitude ΔT were measured using a UV-Vis spectrometer. 550 ;

[0084] 1.2 Calculate ΔE*ab using CIE1976 color coordinates;

[0085] 1.3 Timing current (CA) test for coloring and bleaching time;

[0086] 1.4 Cycle life testing was conducted at ±1.0 V for 3 × 10⁻⁶ cycles. 4 Secondary switch.

[0087] 2. Electrochemical and electron transport properties

[0088] 2.1 Cyclic Voltammetry (CV) Test Range 1.0 to +1.0 V, scan rate 50 mV s -1 ;

[0089] 2.2 The volume capacitance C* is calculated from the integrated charge;

[0090] 2.3 The carrier mobility μ is obtained by the transient current response method.

[0091] 3. Environmental stability test

[0092] At 85 °C / 85 %RH, UV (365 nm, 50 mW cm⁻¹) -2 The performance retention rate was tested under irradiation conditions of 200 h and salt spray (5 wt% NaCl, 48 h).

[0093] (iv) Performance test results

[0094]

[0095] (V) Results Analysis

[0096] 1. Verification of the collaborative mechanism:

[0097] The p–n type bilayer system composed of ProDOT and n-PBDF-imide layers can achieve complementary coloring / bleaching at a driving voltage ≤ 1 V, significantly improving optical contrast and energy utilization.

[0098] 2. Optical and colorimetric properties:

[0099] Modified samples (T-3 to T-5) at 550 nm ΔT 550 ≥ 54%, color difference ΔE* ≤ 3, achieving neutral tone conversion, and visual uniformity superior to PEDOT:PSS and unmodified n-PBDF.

[0100] 3. Electrochemical and transport properties:

[0101] Volumetric capacitance C increased by 30%–70%, and carrier mobility μ reached 3×10⁻⁶. -4 cm² V -1 s -1 This indicates that the polar side chains promote bidirectional coupling transport of ions and electrons.

[0102] 4. Stability performance:

[0103] Under conditions of 85 °C / 85 %RH, UV, and salt spray, samples T-3 to T-5 retained more than 90% of their initial optical performance, with a cycle life exceeding 3 × 10⁻⁶. 4 This is far superior to traditional materials.

[0104] (vi) Overall Conclusion

[0105] A bilayer complementary electrochromic device, constructed using ProDOT as the color-changing layer and n-PBDF-imide as the ion storage layer, achieves high transmittance difference, low color difference, and long cycle life under low-voltage driving. The functionalized imide side chain structure effectively improves ion accessibility and volumetric capacitance, enabling the device to possess both excellent electro-optical response and environmental reliability. This provides a novel, industrially viable system for applications such as smart dimming glass, automotive anti-glare mirrors, and flexible wearable displays.

[0106] (vii) Summary of the innovations of this invention

[0107] 1. Innovative Molecular Structure – Introducing Imidamine Polar Functional Side Chains into the n-PBDF Main Chain

[0108] 1.1 Amide structural units are formed by modifying the conjugated skeleton of benzodifurandione (PBDF), i.e., the n-PBDF-imide copolymer system;

[0109] 1.2 The imide structure provides electron attraction, improving electron mobility and molecular thermal stability;

[0110] 1.3 The side chain can be further introduced with polar groups such as etheroxyalkyl, fluorinated etheroxyalkyl, quaternary ammonium and phosphate groups to achieve controllable adjustment of interfacial ion accessibility and membrane polarization capability.

[0111] 2. Innovation in Synergistic Conduction Mechanism – Bidirectional Enhancement of Electron and Ion Conduction

[0112] 2.1 The synergistic effect of polar side chains and main chain π–π stacking constructs a continuous electronic and ion dual-channel network;

[0113] 2.2 In-situ doping polymerization ensures that the dopant is co-distributed with the main chain, avoiding problems of uneven doping and phase separation;

[0114] 2.3 This mechanism significantly improves the volumetric capacitance C* (≥350 F cm). - ³) and carrier mobility μ (≈3×10) - 4 cm² V - ¹ s - ¹), achieving rapid reversible color change at low voltage (≤0.9 V).

[0115] 3. Device Structure Innovation – Constructing a p–n Type Complementary Electrochromic System

[0116] 3.1 Using ProDOT derivatives as p-type electrochromic layers and n-PBDF-imide as n-type ion storage layers;

[0117] 3.2 Complementary coloring / bleaching is achieved through electron-ion coupling, significantly improving optical modulation amplitude and color neutrality;

[0118] 3.3 This structure achieves ΔT at ±1 V voltage. 550 Neutral tone modulation effect with ≥ 55% and ΔE* ≤ 3.

[0119] 4. Performance and process innovation – low voltage, high stability, roll-to-roll film formation

[0120] 4.1 The material also possesses high conductivity (>10² S cm⁻¹). - ¹) With solution processability;

[0121] 4.2 The device retains >90% of its initial performance after aging at 85 ℃ / 85 %RH, UV and salt spray;

[0122] 4.3 The entire process is based on solution preparation, compatible with flexible substrates and roll-to-roll industrial processes.

[0123] This invention solves key technical problems in traditional electrochromic materials, such as large color difference, slow response, and insufficient stability, through a four-layer innovation logic of "structure-mechanism-performance-application," achieving a balance between low-voltage drive, fast response, high optical contrast, and excellent weather resistance. This system is compatible with flexible solution processes and possesses significant scientific originality and industrial potential.

Claims

1. A transparent conductive material, characterized in that, The molecular formula is as follows: n is an integer from 1 to 50, and n is not 1; R is selected from the following: Among them, R1, R2 and R3 are independent alkyl groups; X is selected from fluorine, chlorine, bromine, and iodine; y is an integer from 1 to 10.

2. The transparent conductive material according to claim 1, characterized in that, Selected from the following structure: 。 3. The method for preparing the transparent conductive material according to claim 1, characterized in that, The process includes the following: Specifically, the steps include the following: S1, 2,5-diamino-1,4-phenyldiboronic acid (A-1) and diethyl 2,3-dibromofumarate (A-2) were polymerized by Suzuki coupling reaction in a 1:1 molar ratio under a catalyst to obtain intermediate A-3; S2. The intermediate A-3 undergoes esterification under strong acid catalysis to form a lactam compound A-4; S3. The lactam compound A-4 reacts with a halogen-substituted compound to obtain the target product A-5, as follows: 。 4. The preparation method according to claim 3, characterized in that, In step S1, the catalyst is tetratriphenylphosphine palladium.

5. The application of the transparent conductive material according to any one of claims 1-2 in electrochromic devices.

6. The application according to claim 5, characterized in that, The electrochromic device is a p-n type complementary electrochromic device, with ProDOT derivative as the p-type electrochromic layer and the transparent conductive material as the n-type ion storage layer.

7. The application according to claim 5, characterized in that, The electrochromic device also includes a gel electrolyte, which serves as an ion-conducting medium, located between the p-type electrochromic layer and the n-type ion storage layer.

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