A method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemistry and its application

Abstract

The application provides a preparation method for preparing a high-density electron transport type electrode film on a non-conductive substrate by electrochemistry, comprising the following steps: S1, placing an oxidizing agent, 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione and / or poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) on a substrate to obtain a conductive film substrate layer; S2, mixing 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, a solvent and an anhydride to obtain an electrolyte; S3, adding the conductive film substrate layer in S1 into the electrolyte, and performing electrochemical polymerization by using a three-electrode system to obtain an electrochemical polymerization treatment film I; and the preparation method further comprises the following step: S4, performing reduction doping treatment on the electrochemical polymerization treatment film I by using a three-electrode system to obtain a final conductive film II. The electrode film has good compactness and stability, can be used as a cathode in an organic electronic device, has the advantages of high conductivity, simple processing and preparation, and suitability for flexible devices.

Description

Technical Field

[0001] This invention relates to the fields of conductive polymer thin film preparation and organic optoelectronic technology, and mainly to a method for preparing a high-density electron transport electrode thin film on a non-conductive substrate using electrochemistry and its application. Background Technology

[0002] With the increasing popularity and demand for electronic products such as smartphones, tablets, and displays, the need for high-performance, low-cost, and flexible electrode materials is also constantly growing. Traditional transparent electrode materials, such as indium tin oxide (ITO), have many drawbacks, including complex manufacturing processes, limited overall resources, and difficulty in achieving flexibility. Conductive polymers, as a promising alternative, are expected to overcome these problems, attracting numerous research institutions and companies to invest in their research and development.

[0003] Conductive polymers, characterized by their conjugated backbones, allow for the movement of charge carriers, resulting in excellent conductivity comparable to or even surpassing that of traditional materials. Furthermore, conductive polymers possess solution processability, enabling the fabrication of electrodes suitable for various electronic products through printing and other methods, facilitating low-cost, large-area fabrication. Secondly, conductive polymers inherit the excellent mechanical properties of traditional organic materials, exhibiting good flexibility. They can be customized into flexible electrodes capable of bending and stretching according to product requirements, making them suitable for curved displays, flexible electronic devices, and other fields. Moreover, the fabrication process of conductive polymer materials is relatively simple, and improvements in this process are expected to reduce production costs and enhance market competitiveness.

[0004] However, the application of conductive polymers in electrodes still faces some challenges. Firstly, the mainstream conductive polymers are currently p-type conductive polymers dominated by hole carriers, such as the commonly used poly(3,4-ethylenedioxythiophene) (PEDOT), which is therefore typically used as an anode in organic electronic devices to collect / transport holes. However, the conductivity and stability of n-type conductive polymer materials dominated by electron carriers still need improvement, requiring further optimization of material formulations and preparation processes. Furthermore, the durability and environmental adaptability of conductive polymer materials also require further research and improvement to ensure the stability and longevity of products in practical applications. In 2022, the n-type conductive polymer poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) (PBFDO), which combines ultra-high conductivity and high stability, was reported (Nature, 2022, 611, 271-277), promoting the application of n-type conductive polymers in organic electronic devices and attracting increasing attention. However, PBFDO is a rigid linear polymer molecule. During the film formation process, the irregular arrangement of the rigid chains in the PBFDO solution prepared by chemical polymerization will result in large voids inside the film. The conductivity and stability of large-area films are greatly affected by the processing technology, which will cause certain difficulties in application.

[0005] Therefore, improving the density and stability of PBFDO films is of great significance for promoting the wide application of n-type conductive polymers, especially their application as electron transport electrodes in organic electronic devices and even flexible electronic devices.

[0006] In conclusion, it is necessary to develop a new technical solution to address the defects and shortcomings of existing technologies. Summary of the Invention

[0007] This invention provides a method for preparing a high-density electron transport electrode film on a non-conductive substrate using electrochemistry and its application. The high-density electron transport electrode film prepared by electrochemistry on a non-conductive substrate has a denser and smoother surface morphology. The electrode film can be used as a cathode in organic electronic devices and has advantages such as high conductivity, simple processing and preparation, and applicability to flexible devices, resulting in significant economic value and social benefits.

[0008] One object of the present invention is to provide a method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry, the method comprising the following steps:

[0009] S1. An oxidant, 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione and / or poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) are disposed on a substrate to obtain a conductive thin film substrate layer;

[0010] S2. Mix 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, solvent, and acid anhydride to obtain an electrolyte;

[0011] S3. The conductive thin film substrate is added to the electrolyte, and electrochemical polymerization is carried out using a three-electrode system to obtain electrochemically polymerized film I.

[0012] Furthermore, in step S1, the solvent of the oxidant is an alcohol and / or an ester solvent.

[0013] Further, in step S1, the solvent for the 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione is dimethyl sulfoxide.

[0014] Furthermore, the method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry may further include the following steps:

[0015] S4. Using a three-electrode system, the electrochemically polymerized thin film I is subjected to reduction doping treatment to obtain the final conductive thin film II.

[0016] Further, in step S1, the step of setting the oxidant, 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione and / or poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) on the substrate is as follows:

[0017] An oxidant and 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione were placed on the substrate surface, heated and dried, and the process was repeated n times to obtain a conductive thin film substrate layer.

[0018] or

[0019] Poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) was deposited on the surface of a substrate and dried by heating to obtain a conductive thin film substrate layer.

[0020] The value of n is 1 to 20.

[0021] Furthermore, the substrate includes, but is not limited to, one or more of glass, quartz, polyimide, and polyurethane.

[0022] Furthermore, the substrate surface is disposed of by immersion or coating.

[0023] Furthermore, in step S2, the solvent is selected from one or more polar aprotic solvents.

[0024] Furthermore, the polar aprotic solvent includes, but is not limited to, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and hexamethylphosphoric triamine.

[0025] Furthermore, in step S2, the acid anhydride includes, but is not limited to, acetic anhydride, propionic anhydride, butyric anhydride, benzoic anhydride, and maleic anhydride.

[0026] Furthermore, an appropriate electrolyte may be added to the electrolyte to improve its conductivity. The electrolyte may include, but is not limited to, non-alkaline electrolytes such as tetrabutylammonium hexafluorophosphonate, sodium chloride, and lithium bis(trifluoromethanesulfonyl)imide.

[0027] Furthermore, in step S3, in the three-electrode system, the conductive thin film substrate obtained in S1 is used as the working electrode, the platinum wire as the counter electrode, and the saturated calomel electrode as the reference electrode.

[0028] Further, in step S3, the electrochemical polymerization is performed using a constant current method, a constant voltage method, or a cyclic voltammetry method, with an oxidation potential relative to the reference electrode of -1.5 to 3.0 V or a current density of 0.001 to 500 mA / cm². 2 The polymerization time is 20-200 min or 20-2000 cycles.

[0029] Furthermore, the cyclic voltammetry method can simultaneously perform electrochemical polymerization and reduction doping treatment.

[0030] Further, in step S4, the reduction doping is performed using a constant current method or a constant voltage method, with the reduction potential relative to the reference electrode being -1.5 to 0.5V or the reduction current density being 0.001-100 mA / cm². 2 The time is 1 to 10 minutes.

[0031] Furthermore, in step S4, in the three-electrode system, the electrochemically polymerized thin film I is used as the working electrode, the platinum wire as the counter electrode, and the saturated calomel electrode as the reference electrode.

[0032] Another object of the present invention is to provide the application of the above-described high-density electron transport electrode thin film prepared by electrochemistry on a non-conductive substrate in organic electronic devices.

[0033] Furthermore, the organic electronic devices include flexible electronics, organic solar cells, organic photodetectors, organic light-emitting devices, etc.

[0034] The present invention has the following beneficial effects:

[0035] (1) This invention utilizes an electrochemical polymerization method to prepare and modify conductive films in a low-cost, non-toxic, and low-pollution manner without introducing other impurities. The electrochemical polymerization method can fill the porous PBFDO films previously obtained by chemical polymerization or deposition, making them more flat and dense. Furthermore, through further electrochemical reduction, the electrochemically polymerized PBFDO films are further doped, and the conductivity is further improved, ultimately resulting in an n-type conductive polymer film with high density, high stability, and high conductivity.

[0036] (2) This invention uses a self-designed and prepared electrolyte for electrochemical polymerization and reduction doping, which is a novel technology in the field. Different electrolyte systems can be customized according to different application scenarios. It can meet the customization of various parameters such as BFDO monomer concentration, electrolyte type, solvent type, electrochemical method, polymerization / reduction doping voltage, and polymerization / reduction doping time during the electrochemical polymerization process, thus being applicable to different scenarios and having wide practicality.

[0037] (3) Due to its ability to significantly improve the density and stability of thin films, the method involved in this invention has remarkable effects in the application of organic electronic devices, including organic solar cells, organic photodetectors, and organic light-emitting devices. The prepared thin film, as the cathode of organic electronic devices, has a dense and smooth surface morphology and good electron transport capability, and is simple to process and prepare, making it suitable for flexible devices. Attached Figure Description

[0038] Figure 1 SEM images of the films prepared in Examples 1, 3, and 5 are shown.

[0039] Figure 2 SEM images of the thin films M1-1, M3-1, M5-1, M7-1, and M9-1 prepared in Examples 1 to 9 are shown.

[0040] Figure 3 JV curves of organic solar cells based on the thin films prepared in Examples 1-6 are shown;

[0041] in,

[0042] Figure 3 (a) JV curves of organic solar cells based on the thin films prepared in Examples 1-3.

[0043] Figure 3 (b) JV curves of organic solar cells based on the thin films prepared in Examples 4 to 6.

[0044] Figure 4 The JV curves of organic solar cells based on the doped thin films prepared in Examples 1-9 are shown.

[0045] in,

[0046] Figure 4 (a) JV curves of organic solar cells based on the doped thin films prepared in Examples 1-3

[0047] Figure 4 (b) JV curves of organic solar cells based on the doped thin films prepared in Examples 4-6.

[0048] Figure 4 (c) JV curves of organic solar cells based on the doped thin films prepared in Examples 7-9.

[0049] Figure 5 The dark current density (J / L) of organic photodetectors based on the thin films prepared in Examples 1-6 is shown. d ) and external quantum efficiency (EQE) curves;

[0050] in,

[0051] Figure 5 (a) Dark current density (J) of organic photodetectors based on the thin films prepared in Examples 1-3. d )curve,

[0052] Figure 5 (b) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the thin films prepared in Examples 1-3.

[0053] Figure 5 (c) Dark current density (J) of organic photodetectors based on the thin films prepared in Examples 4-6. d )curve,

[0054] Figure 5 (d) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the thin films prepared in Examples 4 to 6.

[0055] Figure 6 The dark current density (J / L) of organic photodetectors based on the doped thin films prepared in Examples 1-9 is shown. d ) and external quantum efficiency (EQE) curves;

[0056] in,

[0057] Figure 6 (a) Dark current density (J) of the organic photodetector based on the doped thin films prepared in Examples 1-3 d )curve,

[0058] Figure 6 (b) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the doped thin films prepared in Examples 1-3.

[0059] Figure 6 (c) Dark current density (J) of the organic photodetector based on the doped thin films prepared in Examples 4-6. d )curve,

[0060] Figure 6 (d) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the doped thin films prepared in Examples 4-6.

[0061] Figure 6 (e) is the dark current density (J) of the organic photodetector based on the doped thin films prepared in Examples 7-9. d )curve,

[0062] Figure 6 (f) shows the external quantum efficiency (EQE) curves of the organic photodetector based on the doped thin films prepared in Examples 7-9. Detailed Implementation

[0063] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0064] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0065] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0066] Reference for the synthesis of PBFDO: Tang Haoran, et al. A solution-processed n-type conducting polymer with ultrahigh conductivity. Nature, 2022, 611, 271-277.

[0067] Preparation Example 1

[0068] A method for obtaining a conductive thin film substrate layer by chemical polymerization includes the following steps:

[0069] S1. 20 μL of PBFDO solution with a concentration of 2 mg / mL is uniformly coated onto a 1.0 cm × 1.0 cm glass slide and dried under vacuum at 80 °C for 30 min to obtain PBFDO film D1, which is the deposited conductive film substrate layer D1.

[0070] Preparation Example 2

[0071] A method for obtaining a conductive thin film substrate layer by in-situ chemical polymerization includes the following steps:

[0072] S1. Dissolve 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione monomer (BFDO) in dimethyl sulfoxide (DMSO) to obtain a BFDO monomer concentration of 10 mg / mL; dissolve selenium dioxide in isopropanol to obtain an oxidant solution with a concentration of 2 mg / mL; uniformly coat 20 μL of the oxidant solution onto a 1.0 cm × 1.0 cm glass slide and dry at 80 °C for 15 min; then uniformly coat 20 μL of the BFDO monomer solution onto the glass slide and dry under vacuum at 80 °C for 15 min. After two cycles of coating, a conductive thin film substrate layer D2 is obtained.

[0073] Preparation Example 3

[0074] A method for obtaining a conductive thin film substrate layer by in-situ chemical polymerization includes the following steps:

[0075] S1. Dissolve BFDO monomer in DMSO to obtain a solution with a BFDO monomer concentration of 10 mg / mL; dissolve copper acetate in ethanol to obtain an oxidant solution with a concentration of 5 mg / mL; immerse a 1.0 cm × 1.0 cm glass slide in the oxidant solution and the BFDO monomer solution in sequence, dry under vacuum at 80 °C for 20 min, and repeat the immersion process 4 times to obtain the conductive thin film substrate layer D3.

[0076] Preparation Example 4

[0077] A method for obtaining a conductive thin film substrate layer on a flexible substrate by in-situ chemical polymerization includes the following steps:

[0078] S1. Dissolve BFDO monomer in DMSO to obtain a solution with a BFDO monomer concentration of 10 mg / mL; dissolve selenium dioxide in isopropanol to obtain an oxidant solution with a concentration of 2 mg / mL; immerse a 1.0 cm × 1.0 cm flexible PI substrate sequentially in the oxidant solution and the BFDO monomer solution, and dry it under vacuum at 80 °C for 20 min after each immersion. After 4 cycles of immersion, the conductive thin film substrate layer D4 is obtained.

[0079] Preparation Example 5

[0080] A method for chemically immersing a conductive thin film substrate includes the following steps:

[0081] The conductive film substrate D1 obtained in Preparation Example 1 was immersed in a DMSO solution of 10 mg / mL BFDO monomer, and 2% of the total volume of acetic anhydride was added. After immersion at room temperature for 60 min, the chemically immersed conductive film substrate D5 was obtained.

[0082] Preparation Example 6

[0083] A method for chemically immersing a conductive thin film substrate includes the following steps:

[0084] The conductive film substrate D2 obtained in Preparation Example 2 was immersed in a DMSO solution of 10 mg / mL BFDO monomer, and 2% of acetic anhydride was added by total volume. After immersion for 60 min, the chemically immersed conductive film substrate D6 was obtained.

[0085] Example 1

[0086] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0087] S2. Dissolve BFDO monomer in a mixed solvent of DMSO and acetic anhydride (DMSO and acetic anhydride in a volume ratio of 95:5) to obtain a solution with a BFDO monomer concentration of 10 mg / mL. Add 0.1 mol / L of tetrabutylhexafluorophosphonate to obtain an electrolyte.

[0088] S3. The conductive film substrate layer D1 is added to the electrolyte. D1 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 1.4V and the time is 60min. After the polymerization reaction, the working electrode is removed and dried in a vacuum at 80℃ for 20min to obtain the electrochemically polymerized film M1.

[0089] S4. Add the electrochemically polymerized film M1 to the electrolyte. Use M1 as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Use a three-electrode system and constant voltage method for reduction doping treatment. The potential relative to the reference electrode is -0.5V, and the time is 2min. After the reaction, remove the working electrode and dry it in vacuum at 80℃ for 20min to obtain the final conductive film M1-1.

[0090] Example 2

[0091] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0092] S2. Dissolve BFDO monomer in a mixed solvent of DMSO and propionic anhydride (DMSO and propionic anhydride in a volume ratio of 95:5) to obtain a solution with a BFDO monomer concentration of 10 mg / mL. Add 0.1 mol / L of tetrabutylhexafluorophosphonate to obtain an electrolyte.

[0093] S3. The conductive film substrate layer D4 is added to the electrolyte. D4 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 2.0V and the time is 60min. After the polymerization reaction, the working electrode is removed and dried in vacuum at 80℃ for 30min to obtain the electrochemically polymerized film M2.

[0094] S4. Add the electrochemically polymerized film M2 to the electrolyte. Use M2 as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Use a three-electrode system and constant voltage method for reduction doping treatment. The potential relative to the reference electrode is -0.5V, and the time is 3min. After the reaction, remove the working electrode and dry it in vacuum at 80℃ for 20min to obtain the final conductive film M2-1.

[0095] Example 3

[0096] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0097] S2. Dissolve BFDO monomer in a mixed solvent of DMSO and butyric anhydride (the volume ratio of DMSO to butyric anhydride is 95:5) to obtain an electrolyte with a BFDO monomer concentration of 10 mg / mL.

[0098] S3. The conductive film substrate layer D2 is added to the electrolyte. D2 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 2.0V and the time is 60min. After the polymerization reaction, the working electrode is removed and dried in vacuum at 80℃ for 60min to obtain the electrochemically polymerized film M3.

[0099] S4. Add the electrochemically polymerized film M3 to the electrolyte. Use M3 as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Use a three-electrode system and constant voltage method for reduction doping treatment. The potential relative to the reference electrode is -0.4V, and the time is 2min. After the reaction, remove the working electrode and dry it in vacuum at 80℃ for 20min to obtain the final conductive film M3-1.

[0100] Example 4

[0101] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0102] S2. Dissolve BFDO monomer in a mixed solution of acetonitrile, DMSO and propionic anhydride (the volume ratio of acetonitrile, DMSO and propionic anhydride is 90:5:5) to obtain an electrolyte with a BFDO monomer concentration of 10 mg / mL.

[0103] S3. The conductive film substrate layer D2 is added to the electrolyte. D2 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 2.5V and the time is 50min. After the polymerization reaction, the working electrode is removed and dried in vacuum at 80℃ for 20min to obtain the electrochemically polymerized film M4.

[0104] S4. The electrochemically polymerized film M4 was added to the electrolyte. M4 was used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. The reduction doping treatment was carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode was -0.5V, and the time was 2min. After the reaction, the working electrode was removed and dried in vacuum at 80℃ for 20min to obtain the final conductive film M4-1.

[0105] Example 5

[0106] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0107] S2. Dissolve BFDO monomer in a mixed solution of 1,4-dioxane, DMSO and propionic anhydride (volume ratio of 1,4-dioxane, DMSO and propionic anhydride is 8:1:1) to obtain an electrolyte with a BFDO monomer concentration of 10 mg / mL.

[0108] S3. The conductive film substrate layer D2 is added to the electrolyte. D2 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 2.0V and the time is 50min. After the polymerization reaction, the working electrode is removed and dried in vacuum at 80℃ for 30min to obtain the electrochemically polymerized film M5.

[0109] S4. Add the electrochemically polymerized film M5 to the electrolyte. Use M5 as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Use a three-electrode system and constant voltage method for reduction doping treatment. The potential relative to the reference electrode is -0.5V, and the time is 2min. After the reaction, remove the working electrode and dry it in vacuum at 80℃ for 20min to obtain the final conductive film M5-1.

[0110] Example 6

[0111] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0112] S2. Dissolve BFDO monomer in a mixed solvent of DMSO and propionic anhydride (DMSO: propionic anhydride volume ratio of 95:5) to obtain a solution with BFDO monomer concentration of 10 mg / mL. Add 0.1 mol / L lithium bis(trifluoromethanesulfonyl)imide to obtain an electrolyte.

[0113] S3. The conductive film substrate layer D3 is added to the electrolyte. D3 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 2.0V and the time is 40min. After the polymerization reaction, the working electrode is removed and dried in vacuum at 80℃ for 60min to obtain the electrochemically polymerized film M6.

[0114] S4. Add the electrochemically polymerized film M6 to the electrolyte. Use M6 as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Use a three-electrode system and constant voltage method for reduction doping treatment. The potential relative to the reference electrode is -0.5V, and the time is 2min. After the reaction, remove the working electrode and dry it in vacuum at 80℃ for 20min to obtain the final conductive film M6-1.

[0115] Example 7

[0116] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0117] S2. Dissolve BFDO monomer in a mixed solvent of DMSO and propionic anhydride (DMSO and propionic anhydride in a volume ratio of 95:5) to obtain an electrolyte with a BFDO monomer concentration of 10 mg / mL.

[0118] S3. The conductive film substrate layer D3 is added to the electrolyte. D3 is used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization is carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode is 2.2V and the time is 60min. After the polymerization reaction, the working electrode is removed and dried in vacuum at 80℃ for 20min to obtain the electrochemically polymerized film M7.

[0119] S4. The electrochemically polymerized film M7 was added to the electrolyte. M7 was used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. The reduction doping treatment was carried out using a three-electrode system and constant voltage method. The potential relative to the reference electrode was -0.5V, and the time was 3min. After the reaction, the working electrode was removed and dried in vacuum at 80℃ for 20min to obtain the final conductive film M7-1.

[0120] Example 8

[0121] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0122] S2. Dissolve BFDO monomer in a mixed solution of DMSO and propionic anhydride (DMSO:propionic anhydride volume ratio of 93:7) to obtain a solution with BFDO monomer concentration of 10 mg / mL. Add 0.1 mol / L lithium bis(trifluoromethanesulfonyl)imide to obtain the electrolyte.

[0123] S3. The conductive thin film substrate D3 is added to the electrolyte. Using D3 as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, electrochemical polymerization is carried out using a three-electrode system and a constant current method at a current density of 0.50 mA / cm². 2 The time was 70 min. After the polymerization reaction, the working electrode was removed and dried under vacuum at 80 °C for 20 min to obtain the electrochemically polymerized thin film M8.

[0124] S4. The electrochemically polymerized thin film M8 is added to the electrolyte. Using M8 as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode, a three-electrode system and a constant current method are used for reduction doping treatment. The reduction current density is 0.1 mA / cm². 2The reaction time was 2 minutes. After the reaction, the working electrode was removed and dried under vacuum at 80°C for 20 minutes to obtain the final conductive film M8-1.

[0125] Example 9

[0126] A method for preparing a highly dense electron transport electrode thin film on a non-conductive substrate using electrochemistry includes the following steps:

[0127] S2. Dissolve BFDO monomer in a mixed solution of DMSO and propionic anhydride (DMSO and propionic anhydride in a volume ratio of 9:1) to obtain a solution with a BFDO monomer concentration of 10 mg / mL. Add 0.1 mol / L of tetrabutylhexafluorophosphonate to obtain an electrolyte.

[0128] S3. The conductive film substrate D4 was added to the electrolyte. D4 was used as the working electrode, platinum wire as the counter electrode, and saturated calomel electrode as the reference electrode. Electrochemical polymerization and reduction doping were carried out using a three-electrode system and cyclic voltammetry. The oxidation potential was 2.0 V, the reduction potential was -0.6 V, and the time was 80 min. After the polymerization reaction, the working electrode was removed and dried in vacuum at 80 °C for 20 min to obtain the final conductive film M9-1.

[0129] Test Example 1

[0130] The conductivity of the films prepared in Preparation Examples 1-6 and Examples 1-9 was tested; SEM images of the films M1-1, M3-1, M5-1, M7-1, and M9-1 prepared in Preparation Examples 1, 3, 5 and Examples 1-9 were obtained.

[0131] The conductivity was calculated using four-probe testing and film thickness testing.

[0132] Test Results

[0133] Figure 1 SEM images of the films prepared in Examples 1, 3, and 5 are shown. Figure 2 SEM images of the thin films M1-1, M3-1, M5-1, M7-1, and M9-1 prepared in Examples 1 to 9 are shown; Table 1 shows the conductivity of the thin films prepared in Examples 1 to 6, and Table 2 shows the conductivity of the thin films prepared in Examples 1 to 9.

[0134] Table 1. Conductivity of the thin films prepared in Examples 1-6

[0135]

[0136] Table 2. Conductivity of the thin films prepared in Examples 1-9

[0137]

[0138]

[0139] Depend on Figure 1 , Figure 2 As can be seen, compared with the conductive film obtained in the preparation example, the conductive film obtained through the example has a significantly smoother and denser morphological structure, which is beneficial to improving the compactness, stability and conductivity of the n-type conductive polymer PBFDO film or BFDO film.

[0140] As can be seen from Tables 1 and 2, the conductivity of Preparation Examples 1 and 5 is significantly higher than that of the other Preparation Examples, with Preparation Example 1 having the highest conductivity, exceeding 2000 S / cm. This is because Preparation Examples 1 and 5 use PBFDO polymer solutions, which have a large molecular weight and high degree of polymerization and doping. In Preparation Example 5, due to the secondary soaking in DMSO solution, the PBFDO film may become loose, resulting in a decrease in conductivity compared to Preparation Example 1. This also reflects that the density of the film is crucial to the conductivity. The reason why the conductivity of Example 1 is significantly higher than that of the other examples is consistent with the reason why Preparation Example 1 has the highest conductivity. The conductivity of the prepared examples is significantly improved compared to the corresponding Preparation Examples. This is because after electrochemical polymerization, the density and flatness of the film are greatly improved. In particular, after reduction doping, the doping degree of the film is further increased, and the conductivity is further improved.

[0141] Test Example 2

[0142] The doped thin films prepared in Examples 1-6 and Examples 1-9 were used as cathodes to prepare organic solar cells and organic photodetectors, and the relevant device performance curves were obtained.

[0143] Test method:

[0144] The device structure of the organic solar cell is: silver (Ag) / molybdenum trioxide (MoO3) / active layer / cathode and substrate prepared according to the preparation examples or embodiments of this invention. The active layer is a bulk heterojunction structure, including but not limited to polymer donor D18 and polymer acceptor PY-IT. The materials, preparation, and testing methods are all conventional methods well-known to practitioners in the organic solar cell industry.

[0145] The device structure of the organic photodetector is: silver (Ag) / molybdenum trioxide (MoO3) / active layer / cathode and substrate prepared according to the preparation examples or embodiments of this invention. The active layer is a bulk heterojunction structure, including polymer donor PTB7-Th and non-fullerene acceptor COTIC-4F. The materials, preparation, and testing methods are all conventional methods well-known to practitioners in the organic photodetector industry.

[0146] Test Results

[0147] Table 3 shows the performance test results of organic solar cells based on the thin films prepared in Examples 1 to 6; Table 4 shows the performance test results of organic solar cells based on the doped thin films prepared in Examples 1 to 9; Table 5 shows the performance test results of organic photodetectors based on the thin films prepared in Examples 1 to 6; and Table 6 shows the performance test results of organic photodetectors based on the doped thin films prepared in Examples 1 to 9.

[0148] Figure 3 JV curves of organic solar cells based on the thin films prepared in Examples 1-6 are shown;

[0149] in,

[0150] Figure 3 (a) JV curves of organic solar cells based on the thin films prepared in Examples 1-3.

[0151] Figure 3 (b) JV curves of organic solar cells based on the thin films prepared in Examples 4 to 6.

[0152] Figure 4 The JV curves of organic solar cells based on the doped thin films prepared in Examples 1-9 are shown.

[0153] in,

[0154] Figure 4 (a) JV curves of organic solar cells based on the doped thin films prepared in Examples 1-3

[0155] Figure 4 (b) JV curves of organic solar cells based on the doped thin films prepared in Examples 4-6.

[0156] Figure 4 (c) JV curves of organic solar cells based on the doped thin films prepared in Examples 7-9.

[0157] Figure 5 The dark current density (J / L) of organic photodetectors based on the thin films prepared in Examples 1-6 is shown. d ) and external quantum efficiency (EQE) curves;

[0158] in,

[0159] Figure 5 (a) Dark current density (J) of organic photodetectors based on the thin films prepared in Examples 1-3. d )curve,

[0160] Figure 5 (b) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the thin films prepared in Examples 1-3.

[0161] Figure 5 (c) Dark current density (J) of organic photodetectors based on the thin films prepared in Examples 4-6. d )curve,

[0162] Figure 5 (d) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the thin films prepared in Examples 4 to 6.

[0163] Figure 6 The dark current density (J / L) of organic photodetectors based on the doped thin films prepared in Examples 1-9 is shown. d ) and external quantum efficiency (EQE) curves;

[0164] in,

[0165] Figure 6 (a) Dark current density (J) of the organic photodetector based on the doped thin films prepared in Examples 1-3 d )curve,

[0166] Figure 6 (b) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the doped thin films prepared in Examples 1-3.

[0167] Figure 6 (c) Dark current density (J) of the organic photodetector based on the doped thin films prepared in Examples 4-6. d )curve,

[0168] Figure 6 (d) shows the external quantum efficiency (EQE) curves of the organic photodetectors based on the doped thin films prepared in Examples 4-6.

[0169] Figure 6 (e) is the dark current density (J) of the organic photodetector based on the doped thin films prepared in Examples 7-9. d )curve,

[0170] Figure 6 (f) shows the external quantum efficiency (EQE) curves of the organic photodetector based on the doped thin films prepared in Examples 7-9.

[0171] Table 3 shows the performance test results of organic solar cells based on the thin films prepared in Examples 1-6.

[0172]

[0173]

[0174] Table 4 shows the performance test results of organic solar cells based on the doped thin films prepared in Examples 1-9.

[0175]

[0176] Table 5 shows the performance test results of the organic photodetectors based on the thin films prepared in Examples 1-6.

[0177]

[0178] Table 6 shows the performance test results of the organic photodetectors based on the doped thin films prepared in Examples 1-9.

[0179]

[0180] Depend on Figure 3 , Figure 4 As can be seen from Tables 3 and 4, the organic solar cells based on the doped thin films prepared in Examples 1-6 and Examples 1-9 have good photoelectric conversion efficiency, and the photoelectric conversion efficiency is not significantly affected by the encapsulation and storage over a period of time.

[0181] Depend on Figure 5 , Figure 6 As can be seen from Tables 5 and 6, the organic photodetectors based on the doped thin films prepared in Examples 1-6 and Examples 1-9 exhibit good performance. When the voltage is -2V, the dark current density of the organic photodetectors in these examples reaches a minimum of approximately 5 × 10⁻⁶. -7 A / cm 2 The dark current density is around the same level, and the lower the dark current density, the higher the detection sensitivity, indicating that the embodiment has good sensitivity; the external quantum efficiency (EQE) of the embodiment at 1050nm can reach up to 46.5%, and the 100-day encapsulation and storage has little impact on the external quantum efficiency of the embodiment at 1050nm, indicating that the embodiment has a high efficiency in converting photons into electrical energy or light energy.

[0182] Test Example 3

[0183] The bending stability of organic solar cells and organic photodetectors based on the doped flexible thin films prepared in Example 4 and Example 9 was tested.

[0184] Test method:

[0185] The device structure of the organic solar cell is: silver (Ag) / molybdenum trioxide (MoO3) / active layer / cathode and substrate prepared according to the preparation examples or embodiments of this invention. The active layer is a bulk heterojunction structure, including but not limited to polymer donor D18 and polymer acceptor PY-IT. The materials, preparation, and testing methods are all conventional methods well-known to practitioners in the organic solar cell industry.

[0186] The device structure of the organic photodetector is: silver (Ag) / molybdenum trioxide (MoO3) / active layer / cathode and substrate prepared according to the preparation examples or embodiments of this invention. The active layer is a bulk heterojunction structure, including polymer donor PTB7-Th and non-fullerene acceptor COTIC-4F. The materials, preparation, and testing methods are all conventional methods well-known to practitioners in the organic photodetector industry.

[0187] Test Results

[0188] Table 7 shows the bending stability test results of the doped flexible thin films prepared in Examples 4 and 9, as well as their organic solar cells and organic photodetectors.

[0189] Table 7 shows the bending stability test results of the doped flexible thin films prepared in Examples 4 and 9, as well as their organic solar cells and organic photodetectors.

[0190]

[0191]

[0192] As can be seen from Table 7, after 500 bends, the conductivity, PCE of the organic solar cell device, and external quantum efficiency of the organic photodetector of Preparation Example 4 all decreased significantly, while those of Example M9-1 decreased only slightly, indicating that the bending stability of Example M9-1 is significantly better than that of Preparation Example 4.

[0193] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0194] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a high-density electron transport electrode thin film on a non-conductive substrate using electrochemistry, characterized in that, The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemistry includes the following steps: S1. An oxidant, 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione and / or poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) are disposed on a substrate to obtain a conductive thin film substrate layer; S2. Mix 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione, solvent, and acid anhydride to obtain an electrolyte; S3. Add the conductive thin film substrate layer described in S1 to the electrolyte and perform electrochemical polymerization using a three-electrode system to obtain electrochemically polymerized film I.

2. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemical means according to claim 1, characterized in that, The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemistry further includes the following steps: S4. Using a three-electrode system, the electrochemically polymerized thin film I is subjected to reduction doping treatment to obtain the final conductive thin film II.

3. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate using electrochemistry according to claim 1, characterized in that, In step S1, the step of setting the oxidant, 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione and / or poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) on the substrate is as follows: An oxidant and 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione were placed on the substrate surface, heated and dried, and the process was repeated n times to obtain a conductive thin film substrate layer. or Poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) was deposited on the surface of a substrate and dried by heating to obtain a conductive thin film substrate layer. The value of n is 1 to 20.

4. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemical fabrication according to claim 3, characterized in that, The substrate is applied to the surface using either an immersion method or a coating method.

5. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate using electrochemistry according to claim 1, characterized in that, In step S2, the solvent is selected from one or more polar aprotic solvents.

6. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemical fabrication according to claim 1, characterized in that, In step S3, in the three-electrode system, the conductive thin film substrate obtained in S1 is used as the working electrode, the platinum wire as the counter electrode, and the saturated calomel electrode as the reference electrode.

7. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemical fabrication according to claim 1, characterized in that, In step S3, the electrochemical polymerization is performed using a constant current method, a constant voltage method, or a cyclic voltammetry method, with a potential relative to the reference electrode of -1.5 to 3.0 V or a current density of 0.001 to 500 mA / cm². 2 The polymerization time is 20~200min or 20~2000 cycles.

8. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemical fabrication according to claim 7, characterized in that, The cyclic voltammetry method can simultaneously perform electrochemical polymerization and reduction doping treatment.

9. The method for preparing a high-density electron transport electrode thin film on a non-conductive substrate by electrochemical fabrication according to claim 2, characterized in that, In step S4, the reduction doping is performed using a constant current method or a constant voltage method, with the reduction potential relative to the reference electrode being -1.5 to 0.5 V or the reduction current density being 0.001 to 100 mA / cm². 2 The time is 1 to 10 minutes.

10. An application of a high-density electron transport electrode film in organic electronic devices, wherein the high-density electron transport electrode film is prepared by the preparation method of the high-density electron transport electrode film prepared by electrochemical preparation on a non-conductive substrate as described in any one of claims 1-9.

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