Conjugated polymers containing dibenzofuran (thiophene) and carbazole units, their preparation methods and applications

Abstract

This invention relates to conjugated polymers containing dibenzofuran (thiophene) and carbazole units, their preparation methods, and applications. To address the problems of poor optical contrast, slow response time, and poor cycling stability of existing conjugated polymers as electrochromic materials, this invention uses 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene as reactants, reacting them with 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole to form conjugated polymers with dibenzofuran (thiophene) and carbazole units in the main chain. The conjugated polymers of this invention exhibit excellent electrochromic properties, including excellent cycling stability, fast switching time, high optical contrast, and low voltage start-up. This invention is expected to be applied in fields such as smart windows, rearview mirrors, military camouflage, and electronic tags in the construction and automotive industries.

Description

Technical Field

[0001] This invention relates to a conjugated polymer containing dibenzofuran (thiophene) and carbazole units, its preparation method, and its applications. Background Technology

[0002] Electrochromic materials are characterized by redox reactions or charge injection / extraction within their molecular structure under external voltage, resulting in reversible changes in their optical properties, manifested as color or transparency variations. With advancements in technology and the continuous upgrading of electronic products, higher demands are being placed on electrochromic materials: higher optical contrast, richer colors, and faster response times, among others. However, designing and synthesizing high-performance electrochromic materials remains a significant challenge.

[0003] Dibenzofuran (thiophene) is an oxygen-containing (sulfur-containing) heterocyclic aromatic hydrocarbon formed by the fusion of two benzene rings through an oxygen (sulfur) atom. Due to its unique atomic arrangement and electronic structure, its heterocyclic skeleton combines the stability of aromatic rings with the electronic regulation characteristics of heteroatoms. It is easy to form charge transfer with other conjugated units, making it a classic structural unit in the fields of organic optoelectronics, electrochemistry, and polymer synthesis.

[0004] Carbazole compounds possess excellent hole transport capabilities, high photoluminescence efficiency, and good thermal stability, while also exhibiting flexible modification sites and the ability to easily form amorphous, uniform thin films. Various functional groups can be precisely introduced into carbazole compounds according to application requirements, enabling targeted regulation of material properties and resulting in materials with superior overall optical performance.

[0005] This invention designs and synthesizes a novel conjugated polymer with a carbazole compound as the central core of a dibenzofuran (thiophene) containing an oxygen (sulfur) heterocycle, thereby obtaining electrochromic materials and devices with good film-forming properties, fast response time, and good cycle stability. Summary of the Invention

[0006] To address the problems of poor optical contrast, slow response time, and poor cycle stability of conjugated polymers in electrochromic materials, this invention proposes a method for preparing conjugated polymers containing dibenzofuran (thiophene) and carbazole units and their application in electrochromic devices. The structural formulas of the conjugated polymers obtained by overcondensation of commercially available 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene with 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoboron-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoboron-2-yl)-carbazole or other compounds with hydrogen or alkyl substitution at the 9-position (using 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoboron-2-yl)-9-hydro-carbazole are as follows:

[0007] In the formula, n is an integer from 3 to 20. When R1=O and R2=hexyl, the polymer is simply referred to as DBF-Cz-6C; when R1=O and R2=phenyl, the polymer is simply referred to as DBF-Cz-Ph; when R1=S and R2=hexyl, the polymer is simply referred to as DBT-Cz-6C; when R1=S and R2=phenyl, the polymer is simply referred to as DBT-Cz-Ph.

[0008] 2. The method for preparing the conjugated polymer synthesized in this invention using 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene and 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoboron-2-yl)-carbazole, 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoboron-2-yl)-carbazole or other 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoboron-2-yl)-9-hydro-carbazole compounds with hydrogen or alkyl substitution at the 9-position is carried out according to the following steps: I. Preparation of conjugated polymers containing dibenzofuran (thiophene) and carbazole units: Under a nitrogen atmosphere, 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole, 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene, tetra(triphenylphosphine)palladium, potassium carbonate, quaternary ammonium chloride, and tetrahydrofuran: an aqueous solution were added to a three-necked round-bottom flask. The reaction system was slowly heated to 100°C with continuous stirring, and the reaction was determined to be complete by thin-plate chromatography. After the reaction was complete, the resulting filtrate was cooled to room temperature and poured into a large amount of anhydrous methanol with continuous stirring to precipitate. The precipitate was filtered off and washed with a large amount of hot distilled water and anhydrous methanol. The product was dried under vacuum. The product was obtained by Soxhlet extraction with anhydrous methanol followed by vacuum drying.

[0009] The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole and 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole in step one is 1:1. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to tetra(triphenylphosphine)palladium in step one is 1:0.06. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to potassium carbonate in step one is 1:10. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to quaternary ammonium chloride salt in step one is 1:0.05; The volume ratio of tetrahydrofuran to water in step one is 3:1; The vacuum drying temperature in step one is 45°C, the vacuum drying time is 36 hours, and the vacuum drying pressure is -30~-29KPa.

[0010] The present invention has the following beneficial effects: I. Polymers formed from 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene with 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole possess a conjugated structure, which facilitates charge transport. The nitrogen atom at the center of the carbazole is readily oxidized at lower voltages to form stable cationic radicals, thereby improving cycle stability.

[0011] II. The conjugated polymer of this invention exhibits excellent electrochromic properties. The conjugated polymer of this invention exhibits a significant color change, transitioning from colorless in the neutral state to a deep blue in the oxidized state. When the applied voltage varies between 0 and 1.6V, the coloring time of the conjugated polymer is 1.8–2.8 seconds, and the bleaching time is 0.6–1.1 seconds; it also exhibits high optical contrast, reaching a maximum of 55%. The conjugated polymer prepared by this invention demonstrates excellent cycling stability; after 5000 seconds of cycling, the optical contrast decreases by only 20%, exhibiting superior electrochromic stability. Attached Figure Description

[0012] Figure 1 Fourier transform infrared (FTIR) images of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4; Figure 2 The hydrogen nuclear magnetic resonance spectra of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4 are shown. Figure 3 Thermogravimetric curves of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4 are shown. Figure 4 Cyclic voltammetry diagrams of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4; Figure 5Electrochromic images of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4; Figure 6 Optical contrast images of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4; Figure 7 The switching time diagrams are for the conjugated polymers containing dibenzofuran (thiophene) and carbazole units prepared in Examples 1 to 4. Detailed Implementation

[0013] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0014] Specific Implementation Method 1: The structural formulas of the conjugated polymers containing dibenzofuran (thiophene) and carbazole units in this implementation method are as follows:

[0015] In the formula, n is an integer from 3 to 20.

[0016] The present invention has the following beneficial effects: First, the polymer of dibenzofuran (thiophene) and carbazole units possesses a conjugated structure, which facilitates electron transport. The nitrogen atom at the center of the carbazole atom is readily oxidized at lower voltages to form a stable cationic radical, thereby improving cycle stability.

[0017] II. The conjugated polymer of this invention exhibits excellent electrochromic properties. The conjugated polymer of this invention exhibits a significant color change, transitioning from colorless in the neutral state to a deep blue in the oxidized state. When the applied voltage varies between 0 and 1.6V, the coloring time of the conjugated polymer is 1.8–2.8 seconds, and the bleaching time is 0.6–1.1 seconds; it also exhibits high optical contrast, reaching a maximum of 55%. The conjugated polymer prepared by this invention demonstrates excellent cycling stability; after 5000 seconds of cycling, the optical contrast decreases by only 20%, exhibiting superior electrochromic stability.

[0018] Specific Implementation Method Two: The preparation method of the conjugated polymer containing 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene and 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole in this implementation method is as follows: I. Preparation of conjugated polymers containing 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene and 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole: Under a nitrogen atmosphere, 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole, 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene, tetra(triphenylphosphine)palladium, potassium carbonate, quaternary ammonium chloride, and tetrahydrofuran: an aqueous solution were added to a three-necked round-bottom flask. The reaction system was slowly heated to 100°C with continuous stirring, and the reaction was determined to be complete by thin-plate chromatography. After the reaction was complete, the resulting filtrate was cooled to room temperature and poured into a large amount of anhydrous methanol with continuous stirring to precipitate. The precipitate was filtered off and washed with a large amount of hot distilled water and anhydrous methanol. The product was dried under vacuum. The product was obtained by Soxhlet extraction with anhydrous methanol followed by vacuum drying.

[0019] The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole in step one is 1:1. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to tetra(triphenylphosphine)palladium in step one is 1:0.06. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to potassium carbonate in step one is 1:10. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to quaternary ammonium chloride salt in step one is 1:0.05; The volume ratio of tetrahydrofuran to water in step one is 3:1; The vacuum drying temperature in step one is 45°C, the vacuum drying time is 36 hours, and the vacuum drying pressure is -30~-29KPa.

[0020] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that the carbazole compound monomer mentioned in step one is 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-2-yl)-carbazole.

[0021] Specific Implementation Method 4: This implementation method describes the application of a conjugated polymer containing dibenzofuran / dibenzothiophene and carbazole units as an electrochromic layer in an electrochromic device.

[0022] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Two in that the application of the conjugated polymer containing dibenzofuran / dibenzothiophene and carbazole units as the electrochromic layer in the electrochromic device is carried out according to the following steps: A conjugated polymer containing dibenzofuran / dibenzothiophene and carbazole units is used as the electrochromic layer in the electrochromic device. The electrochromic layer is coated on a conductive substrate to prepare the electrochromic device. The electrochromic layer produces electrochromic changes under the action of an external electric field. Other steps and parameters are the same as in specific implementation scheme two.

[0023] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the conductive substrate is conductive glass, ITO conductive resin film, transparent silver nanowires, or transparent carbon nanotube electrodes. Other steps and parameters are the same as in Specific Implementation Method Two or Three.

[0024] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Five in that the voltage of the external electric field is 0~3V.

[0025] The beneficial effects of the present invention are verified using the following embodiments: Example 1: The structural formula of the conjugated polymer DBF-Cz-6C synthesized from 2,8-dibromodibenzofuran is as follows:

[0026] In the formula, n is an integer from 3 to 20.

[0027] The preparation method of the conjugated polymer DBF-Cz-6C synthesized from 2,8-dibromodibenzofuran in this embodiment is as follows: I. Preparation of conjugated polymers containing dibenzofuran and carbazole units: Under a nitrogen atmosphere, 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-2-yl)-carbazole, 2,8-dibromodibenzofuran, tetra(triphenylphosphine)palladium, potassium carbonate, quaternary ammonium chloride, and tetrahydrofuran aqueous solution were added to a three-necked round-bottom flask. The reaction system was slowly heated to 100°C with continuous stirring, and the reaction was determined to be complete by thin-plate chromatography. After the reaction was complete, the resulting filtrate was cooled to room temperature and poured into a large amount of anhydrous methanol with continuous stirring to precipitate. The precipitate was filtered off and washed with a large amount of hot distilled water and anhydrous methanol. The product was dried under vacuum. The product was obtained by Soxhlet extraction with anhydrous methanol followed by vacuum drying.

[0028] The molar ratio of 2,8-dibromodibenzofuran to carbazole compounds in step one is 1:1; The molar ratio of 2,8-dibromodibenzofuran to tetra(triphenylphosphine)palladium in step one is 1:0.06; The molar ratio of 2,8-dibromodibenzofuran to potassium carbonate in step one is 1:10; The molar ratio of 2,8-dibromodibenzofuran to quaternary ammonium chloride salt in step one is 1:0.05; The volume ratio of tetrahydrofuran to water in step one is 3:1; The vacuum drying temperature in step one is 45°C, the vacuum drying time is 36 hours, and the vacuum drying pressure is -30~-29KPa.

[0029] The structural formula of the conjugated polymer DBT-Cz-6C synthesized from 2,8-dibromodibenzothiophene in Example 2 is similar to that of DBF-Cz-6C in Example 1.

[0030] The specific preparation method of DBT-Cz-6C is the same as that of DBF-Cz-6C in Example 1. The difference is that in Example 2, 2,8-dibromodibenzothiophene is used instead of 2,8-dibromodibenzofuran.

[0031] The structural formula of the conjugated polymer DBF-Cz-Ph synthesized in Example 3 using 2,8-dibromodibenzofuran is similar to that of DBF-Cz-6C in Example 1.

[0032] The specific preparation method of DBF-Cz-Ph is the same as that of DBF-Cz-6C in Example 1, except that the three-purpose raw material 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole is used instead of 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole.

[0033] The structure of DBT-Cz-Ph synthesized from 2,8-dibromodibenzothiophene in Example 4 is similar to that of DBF-Cz-6C in Example 1.

[0034] The specific preparation method of DBT-Cz-Ph is the same as that of DBF-Cz-6C in Example 1. The difference is that in Example 4, 2,8-dibromodibenzothiophene is used instead of 2,8-dibromodibenzofuran, and 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole is used instead of 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole.

[0035] Figure 1Fourier transform infrared (FTIR) images of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4 demonstrate the successful synthesis of the conjugated polymers.

[0036] Figure 2 The hydrogen nuclear magnetic resonance spectra of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4 are shown. Figure 2 The characteristic peaks for aromatic compounds are at 8.0–9.0 ppm, for methoxy compounds at 3.5–4.0 ppm, and for long alkyl chains at 1.0–3.0 ppm. This indicates that the conjugated polymers were successfully synthesized in Examples 1–4.

[0037] Figure 3 The thermogravimetric analysis (TGA) curves of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4 are shown. The thermal decomposition temperatures of the conjugated polymers at a weight loss of 5% under nitrogen atmosphere are all above 431°C, indicating that these conjugated polymers possess good thermodynamic stability. When the conjugated polymers are heated to 800°C, the char residue is above 71%, demonstrating the good thermal stability of the conjugated polymers.

[0038] Figure 4 Cyclic voltammograms of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4; from Figure 4 It can be seen that DBF-Cz-6C showed an oxidation peak at 1.39V and a reduction peak at 0.95V; DBF-Cz-Ph showed an oxidation peak at 1.08V and a reduction peak at 0.65V; DBT-Cz-6C showed an oxidation peak at 1.27V and a reduction peak at 0.92V; DBT-Cz-Ph showed an oxidation peak at 1.23V and a reduction peak at 1.02V; indicating that the conjugated polymers prepared in Examples 1 to 4 underwent redox reactions under applied voltage.

[0039] Figure 5 Electrochromic images of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4; from Figure 5 It can be seen that the absorption peak at 437 nm of DBT-Cz-Ph gradually increases with the increase of voltage between 0 and 1.6V; when applied to 1.4V, the color of the film turns dark blue.

[0040] Figure 6 Optical contrast images of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4; from Figure 6It can be seen that the optical contrast of DBT-Cz-Ph is 51%, and it still remains at 31% after 5000 seconds of cycling, indicating that the conjugated polymer has high optical contrast and excellent cycling stability.

[0041] Figure 7 This is a switching time diagram of the conjugated polymers containing dibenzofuran / dibenzothiophene and carbazole units prepared in Examples 1 to 4. Figure 7 It can be seen that the coloring time of DBT-Cz-Ph is 1.8 seconds and the bleaching time is 1.1 seconds, indicating that the conjugated polymer has a fast switching response.

Claims

1. A conjugated polymer containing dibenzofuran (thiophene) and carbazole units, characterized in that... The conjugated polymer backbone contains dibenzofuran (thiophene) and carbazole unit structures. The structural formula of the prepared conjugated polymer is as follows: In the formula, n is an integer from 3 to 20.

2. The method for preparing the conjugated polymer containing dibenzofuran (thiophene) and carbazole units as described in claim 1, characterized in that... The preparation method is as follows: I. Preparation of conjugated polymers containing dibenzofuran (thiophene) and carbazole units: Under a nitrogen atmosphere, 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)-carbazole, 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene, tetra(triphenylphosphine)palladium, potassium carbonate, quaternary ammonium chloride, and tetrahydrofuran: an aqueous solution were added to a three-necked round-bottom flask. The reaction system was slowly heated to 100°C with continuous stirring, and the reaction was determined to be complete by thin-plate chromatography. After the reaction was complete, the resulting filtrate was cooled to room temperature and poured into a large amount of anhydrous methanol with continuous stirring to precipitate. The precipitate was filtered off and washed with a large amount of hot distilled water and anhydrous methanol. The product was then dried under vacuum. The product was obtained by Soxhlet extraction with anhydrous methanol and vacuum drying. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to carbazole compounds in step one is 1:1; The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to tetra(triphenylphosphine)palladium in step one is 1:0.

06. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to potassium carbonate in step one is 1:

10. The molar ratio of 2,8-dibromodibenzofuran or 2,8-dibromodibenzothiophene to quaternary ammonium chloride salt in step one is 1:0.05; The volume ratio of tetrahydrofuran to water in step one is 3:1; The vacuum drying temperature in step one is 45°C, the vacuum drying time is 36 hours, and the vacuum drying pressure is -30~-29KPa.

3. The method for preparing the conjugated polymer containing dibenzofuran or dibenzothiophene and carbazole units according to claim 2, characterized in that... The carbazole compound mentioned in step one is a conjugated polymer prepared from 9-hexyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborhecyclopentan-2-yl)-carbazole or 9-phenyl-3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborhecyclopentan-2-yl)-carbazole and other 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborhecyclopentan-2-yl)-carbazole compounds with H or alkyl substitution at the 9-position.

4. The application of the conjugated polymer containing dibenzofuran or dibenzothiophene and carbazole units as described in claim 3 as an electrochromic layer in an electrochromic device.

5. The application of the conjugated polymer containing dibenzofuran or dibenzothiophene and carbazole units according to claim 3, characterized in that: A conjugated polymer containing dibenzofuran or dibenzothiophene and carbazole units is used as the electrochromic layer in an electrochromic device. The electrochromic layer is coated on a conductive transparent electrode to prepare an active electrode, which exhibits electrochromic phenomenon under the action of an external electric field.

6. The application of the conjugated polymer containing dibenzofuran or dibenzothiophene and carbazole units according to claim 3, characterized in that... The voltage of the applied electric field is 0~3V.

7. The application of the conjugated polymer containing dibenzofuran or dibenzothiophene and carbazole units according to claim 3, characterized in that... The transparent electrode is an ITO (indium tin oxide), transparent silver nanowire, or transparent carbon nanotube electrode.

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