Method for preparing metal top electrode of organic photoelectric device by utilizing high-boiling-point solvent to assist in film transfer printing

Abstract

The invention discloses a method for preparing a metal top electrode of an organic photoelectric device by utilizing a high-boiling-point solvent to assist film transfer printing, and relates to the technical field of organic photoelectric devices. The method comprises the following steps: firstly, carrying out plasma treatment and silanization grafting on a PDMS film, compounding with nano SiO2 to prepare a functionalized PDMS transfer printing medium, then synthesizing Ag-coated DA-Chi core-shell nanoparticles, spin-coating the surface of the transfer printing medium with the Ag-coated DA-Chi core-shell nanoparticles as an Ag core layer, forming a PEDOT: PSS / SWCNT conductive composite layer on the surface of the Ag core layer through in-situ polymerization, and finally, carrying out in-situ polymerization on the surface of the Ag-coated DA-Chi core-shell nanoparticles so as to obtain the composite conductive film. The preparation method comprises the following steps of: performing pre-crosslinking treatment to obtain a pre-crosslinked metal composite film, finally, fitting a metal surface of the pre-crosslinked metal composite film on an ITO (Indium Tin Oxide) substrate spin-coated with a semi-solid active layer, and performing heat preservation and PDMS (Polydimethylsiloxane) transfer printing medium stripping under the assistance of a high-boiling-point solvent, so that the core-shell structure metal composite film is subjected to complete transfer printing and a metal top electrode is formed.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic device technology, specifically to a method for preparing metal top electrodes for organic optoelectronic devices using high-boiling-point solvent-assisted thin film transfer. Background Technology

[0002] Organic optoelectronic devices (such as organic photodetectors (OPD) and organic photovoltaic cells (OPV)) have become a core research direction in fields such as flexible electronics, portable optoelectronic detection devices, wearable energy devices, and environmental monitoring sensors due to their outstanding advantages such as flexibility, low manufacturing cost, and large-area printing fabrication. They have shown irreplaceable application prospects in industries such as consumer electronics, new energy, and the Internet of Things. As the market demand for flexible, lightweight, and long-life devices continues to upgrade, the performance optimization of the core components of the devices has become the key to promoting industrialization. Among them, the metal top electrode, as the core carrier for charge collection and transport, directly determines the conductivity, interface charge transport efficiency, long-term stability, and large-scale production yield of the device due to its fabrication quality. Incomplete electrode transfer will lead to a drop in the open-circuit voltage of the device, and weak interface bonding will easily cause charge transport obstruction and environmental moisture intrusion, ultimately resulting in excessively rapid performance degradation of the device, which seriously restricts the transition of organic optoelectronic devices from laboratory research and development to industrial applications.

[0003] In the fabrication technology of metal top electrodes, high-boiling-point solvent-assisted thin-film transfer technology effectively reduces equipment investment and costs for large-scale production due to its compatibility with all-solution fabrication processes and the absence of vacuum equipment. Furthermore, the capillary action of residual high-boiling-point solvents in the active layer promotes close adhesion between the metal film and the organic active layer, successfully avoiding key problems such as increased dark current and decreased device stability caused by metal particle diffusion into the organic active layer in traditional vacuum evaporation processes. This has made it one of the mainstream research directions in recent years. The core logic of this technology lies in utilizing the low volatility of high-boiling-point solvents (such as o-dichlorobenzene and chlorobenzene) to retain a certain amount of residual solvent after the active layer is formed. Capillary adsorption forces achieve interfacial adhesion between the metal film and the active layer. Compared to vacuum evaporation processes, it has significant advantages in reducing fabrication costs and improving process compatibility.

[0004] However, existing high-boiling-point solvent-assisted thin-film transfer technology still faces significant technical bottlenecks in practical applications, limiting its industrial application: First, the surface energy characteristics of the transfer medium (represented by PDMS, polydimethylsiloxane) are limited, and the adhesion force with the metal film lacks precise control. PDMS itself has a low surface energy (approximately 20-30 mN / m). If it is not modified, weak adhesion to the metal film will lead to localized film detachment during the transfer process, while excessive adhesion will result in metal film residue remaining on the PDMS surface after transfer. Both situations result in an electrode transfer integrity rate of less than 95%, failing to meet the yield requirements for large-scale production. Second, traditional metal films used for transfer are mostly pure metal materials (such as Ag and Al). The metal film has poor flexibility and insufficient interfacial compatibility with the organic active layer. After transfer, the metal film and the active layer only rely on physical adhesion to form a bond. In actual use scenarios such as device bending and temperature and humidity changes, interface peeling is prone to occur, resulting in an interfacial shear strength that is generally lower than 1.5MPa, which seriously affects the mechanical stability and long-term service life of the device. Thirdly, existing modification schemes are mostly limited to single-dimensional optimization, or only adjust the surface energy of the transfer medium, or only improve the conductivity of the metal film. They lack a synergistic design mechanism between the transfer medium and the metal film. Single modification cannot simultaneously solve the dual requirements of complete peeling during transfer and firm bonding after transfer, which leads to a bottleneck in device performance improvement and makes it difficult to adapt to the high requirements of high-end organic optoelectronic devices for electrodes. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing metal top electrodes for organic optoelectronic devices using high-boiling-point solvent-assisted thin film transfer, so as to solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing metal top electrodes for organic optoelectronic devices using high-boiling-point solvent-assisted thin-film transfer includes the following steps: S1. Mix polydimethylsiloxane material with curing agent, degas and cure to obtain original polydimethylsiloxane film, then perform plasma treatment, then immerse in ethanol solution of perfluorooctyltriethoxysilane, rinse and dry to obtain perfluorooctyltriethoxysilane grafted PDMS film. S2. The PDMS film grafted with perfluorooctyltriethoxysilane was immersed in a tetraethoxysilane ethanol solution containing nano-SiO2 particles and hydrochloric acid, and the reaction was carried out at a certain temperature. After being taken out, it was annealed and cooled to obtain the functionalized PDMS transfer medium. S3. Mix Ag nanoparticles, chitosan acetate solution and dopamine hydrochloride, adjust pH to alkaline, and centrifuge and wash after reaction to obtain Ag@DA-Chi nanoparticles. S4. Disperse Ag@DA-Chi nanoparticles in deionized water to obtain a dispersion. Spin-coat the dispersion onto the surface of a functionalized PDMS transfer medium to form an Ag core layer, thus obtaining Ag core layer coated PDMS. S5. Mix 3,4-ethylenedioxythiophene monomer, sodium polystyrene sulfonate and FeCl3 oxidant solution, add sodium dodecyl sulfate and single-walled carbon nanotubes, disperse to obtain a mixed solution, immerse Ag core-coated PDMS in the mixed solution for in-situ polymerization reaction, and obtain a composite film after rinsing and drying. S6. Spray pentaerythritol triacrylate crosslinking agent containing photoinitiator onto the surface of the composite film, cure under ultraviolet light and then heat anneal to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film. S7. Dissolve P3HT and PCBM in o-dichlorobenzene solvent, add 1,8-diiodooctane additive, stir to obtain active layer solution, spin-coat PFN-Br solution on ITO substrate to form PFN-Br layer, spin-coat active layer solution again to form semi-solid active layer; attach pre-crosslinked metal composite film to the surface of semi-solid active layer with metal film side down, roll and press and keep warm; after keeping warm, peel off PDMS transfer medium to leave core-shell structured metal composite film on the surface of active layer to obtain metal top electrode.

[0007] In this invention, a uniform and defect-free original substrate is first obtained through a process of mixing polydimethylsiloxane (PDMS) material with a curing agent, followed by degassing and curing. Then, plasma treatment introduces high-density hydroxyl active sites and forms a micro-roughened surface, providing conditions for subsequent functional molecule grafting and structural cross-linking. Next, PFOTS grafting with controlled concentration and temperature creates a continuous and uniform surface energy gradient, allowing the metal film to peel off gradually and orderly from the edge to the center during transfer, avoiding film tearing caused by localized stress concentration. Finally, the construction of a micro-nano cross-linked layer maintains the surface energy gradient characteristics while forming a physically interlocking structure, enhancing the temporary bonding force between PDMS and the metal film and preventing film detachment before transfer. This entire process solves the problems of metal film residue and transfer damage from the transfer medium perspective, directly improving the integrity rate of the metal top electrode transfer and providing structural assurance for the subsequent performance of the electrode.

[0008] Furthermore, Ag nanoparticles are coated with a dopamine-chitosan composite layer to optimize their dispersibility and avoid conductive defects caused by particle agglomeration during film formation. A dense and uniform Ag core layer is then formed through spin coating, providing basic conductive support for the electrode. Next, an Ag@DA-Chi / PEDOT:PSS / SWCNTs core-shell structure is constructed through in-situ polymerization. The three-dimensional conductive network formed by PEDOT:PSS and SWCNTs reduces the sheet resistance of the electrode, while the synergistic effect of the composite system enhances electrode flexibility, preventing breakage due to brittleness during transfer and device use. Finally, UV-thermal synergistic pre-crosslinking enhances the structural stability of the film and optimizes the electrode surface roughness, ensuring good interfacial contact with the organic active layer. π-π stacking further strengthens the interfacial bonding. This results in a metal top electrode that combines high conductivity, breakage resistance, and strong bonding, ensuring structural integrity after transfer and improving the interfacial bonding strength with the active layer, thereby improving the long-term stability and photoelectric performance of the device.

[0009] Preferably, in step S1, the curing agent is methyl hydrogen polysiloxane (methyl hydrogen silicone oil).

[0010] Preferably, the mass ratio of the polydimethylsiloxane material to the curing agent is 10:(0.8-1.5).

[0011] Preferably, in step S1, 3-isocyanate-propyltriethoxysilane is added to the ethanol solution of perfluorooctyltriethoxysilane.

[0012] In the technical solution of this invention, the research and development team found through in-depth research that PDMS grafted with perfluorooctyltriethoxysilane has a low surface energy. Although it can ensure the integrity of peeling during transfer, the low surface energy characteristic makes it difficult to form a stable adhesion when the core-shell composite film is spin-coated on the PDMS surface by relying solely on the physical interlocking of the micro-nano crosslinking layer. This easily leads to defects such as local peeling of the core layer and uneven growth of the shell layer. At the same time, the surface rigidity of the core-shell film is increased after pre-crosslinking, which forms an interface stress concentration with the micro-nano protrusions of PDMS. This may cause micro-cracks at the edge of the film during transfer and peeling, resulting in fluctuations in the transfer integrity rate. Furthermore, the subsequent interfacial bonding force with the active layer is difficult to further improve due to film formation defects. To further address this problem, this invention adds 3-isocyanate-propyltriethoxysilane to an ethanol solution of perfluorooctyltriethoxysilane. 3-isocyanate-propyltriethoxysilane possesses both isocyanate and ethoxy bifunctional groups. The ethoxy group can undergo a hydrolysis-condensation reaction with the hydroxyl groups on the PDMS surface to achieve chemical grafting, while the isocyanate group can form covalent bonds with the amino and hydroxyl groups of Ag@DA-Chi in the core-shell film, thereby constructing a PDMS-IPTS-core-shell film molecular bridge. Simultaneously, the IPTS grafting does not disrupt the low surface energy gradient formed by perfluorooctyltriethoxysilane; instead, it embeds anchoring sites within the gradient layer, thus perfectly balancing the peeling requirements during transfer and the adhesion requirements during film formation.

[0013] Preferably, in step S2, the mass ratio of tetraethoxysilane to nano-SiO2 particles is 5:(0.5-1.5).

[0014] Preferably, in step S3, the mass ratio of Ag nanoparticles, chitosan, and dopamine hydrochloride is 36:(2-3):(5-6).

[0015] Preferably, in step S4, the thickness of the Ag core layer is controlled at 100 nm.

[0016] Preferably, in step S5, the in-situ polymerization reaction temperature is 0–5°C and the reaction time is 60–80 min.

[0017] Preferably, in step S6, the photoinitiator is Irgacure184.

[0018] Preferably, in step S7, the mass ratio of P3HT to PCBM is 1:(1~1.5).

[0019] Compared with the prior art, the beneficial effects of the present invention are: By functionalizing PDMS and constructing IPTS molecular bridges, the low surface energy peeling requirement of the transfer medium and the adhesion of the core-shell film were balanced, avoiding film residue, damage or edge cracks, and significantly improving the transfer integrity rate.

[0020] The core-shell structure design, combined with a three-dimensional conductive network, enables the electrodes to have both low sheet resistance and high flexibility, resisting the risk of damage during transfer and use.

[0021] By optimizing the surface roughness of the electrode through UV-thermal synergistic pre-crosslinking and π-π stacking, the interfacial bonding force with the organic active layer is strengthened, thereby improving the long-term stability and photoelectric performance of the device. Attached Figure Description

[0022] Figure 1 This is a SEM image of the surface of the metal top electrode prepared in Example 1 of the present invention. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: A method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin film transfer, comprising the following steps: Step 1: S1. Weigh 10.0g of polydimethylsiloxane (PDMS) substrate and mix with 1.3g of methylhydropolysiloxane curing agent for 5min until uniform. After degassing at room temperature and vacuum degree -0.09MPa for 30min, pour into a mold and cure at 80℃ for 2h. After cooling, take out to obtain the original PDMS film. The thin film was cut into 5cm×5cm squares and placed in a plasma cleaner. An Ar / O2 mixed gas (volume ratio 3:1) was introduced, and the system was operated at a power of 110W and a vacuum degree of 5×10⁻⁶. -2 The plasma-treated film was treated for 18 min under Pa conditions. 0.05 mol / L, 0.1 mol / L, and 0.15 mol / L perfluorooctyltriethoxysilane (PFOTS) ethanol solutions (50 mL each) were prepared sequentially. 2% (by mass) of 3-isocyanate-propyltriethoxysilane was added to each solution. The plasma-treated film was then immersed in these solutions sequentially, and soaked for 30 min at 25 °C, 35 °C, and 60 °C respectively. After each soaking, the film was rinsed three times with anhydrous ethanol and dried with nitrogen to obtain the PFOTS-grafted PDMS film.

[0025] S2. Dissolve 5g of ethoxysilane in 100mL of ethanol solution, then add 1.3g of nano-SiO2 particles and 0.1mL of 0.1% (v / v) 37% hydrochloric acid solution, and sonicate at 100W for 30min. Immerse the PFOTS-grafted PDMS film in the mixed solution, keep it in a constant temperature water bath at 40℃ for 2h, take it out and put it in an oven at 100℃ for annealing for 1h, and cool it naturally to obtain the functionalized PDMS transfer medium.

[0026] S3. Take 0.36g of Ag nanoparticles with a particle size of 30nm and add 30mL of deionized water to prepare an aqueous solution of 12mg / mL; separately take 0.028g of chitosan and dissolve it in 10mL of 1% acetic acid aqueous solution. After mixing the two solutions, add 0.057g of dopamine hydrochloride and adjust the pH of the system to 8.5 with 0.1mol / L NaOH solution. Stir the reaction magnetically in a 30℃ constant temperature water bath for 6h. After the reaction is completed, centrifuge the solution at 8000r / min for 15min, discard the supernatant, and wash the precipitate 3 times with deionized water to obtain Ag@DA-Chi nanoparticles.

[0027] S4. Ag@DA-Chi nanoparticles were dispersed in deionized water to prepare a dispersion with a concentration of 12 mg / mL. The functionalized PDMS transfer medium was fixed on the sample stage of a spin coater, and 5 mL of the above dispersion was dropped onto it. The spin speed was set to 3000 rpm and the time to 30 s. After spin coating, the medium was dried with a nitrogen gun to form an Ag core layer with a thickness of 100 nm on the surface of the medium, thus obtaining Ag core layer coated PDMS.

[0028] S5. Prepare a 0.1 mol / L 3,4-ethylenedioxythiophene (EDOT) ethanol / water mixed solution (ethanol:water = 1:1, volume ratio, 50 mL), 50 mL of 0.05 mol / L sodium polystyrene sulfonate (PSS) aqueous solution, and 100 mL of 0.1 mol / L FeCl3 oxidant aqueous solution, and mix them evenly at a volume ratio of 1:1:2. Add 0.2 g sodium dodecyl sulfate (SDS) and 1.0 g single-walled carbon nanotubes (SWCNTs) to the mixed solution, and sonicate at 100 W for 30 min to obtain a mixed solution. Completely immerse the Ag core-coated PDMS in this solution, and allow it to polymerize in situ under ice bath conditions at 3 °C for 75 min. After the reaction is complete, remove it, rinse the surface twice with deionized water, and blow dry with nitrogen to obtain the Ag@DA-Chi / PEDOT:PSS / SWCNTs composite film.

[0029] S6. Spray 1 mL of 5% (w / w) pentaerythritol triacrylate (PETA) crosslinking agent (containing 0.001 g photoinitiator Irgacure 184) evenly onto the surface of the composite film, place it in an ultraviolet curing chamber, and cure it at a wavelength of 365 nm and a power of 50 mW / cm². 2Irradiated under the specified conditions for 20 minutes, then transferred to an 80℃ oven for heat annealing for 30 minutes to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film.

[0030] S7. Weigh 0.275g P3HT and 0.352g PCBM, add 10mL of o-dichlorobenzene (ODCB) solvent, add 0.011g 1,8-diiodooctane, and stir at 500r / min for 10h at 70℃ to obtain the active layer solution; cut the ITO substrate into a 1cm×1.5cm rectangle, and ultrasonically clean it for 20min each with 50mL acetone, ethanol, and deionized water (power 100W). After drying with nitrogen, place it in a glove box and spin-coat with 5mg / mL... A PFN-Br solution (2000 rpm, 30 s) is used to form a PFN-Br layer, followed by spin coating of an active layer solution (800 rpm, 30 s) to form an active layer. The layer is then placed in a glove box for 20 min to achieve a semi-solid state. A pre-crosslinked metal composite film is then attached to the surface of the semi-solid active layer with the metal film side down. The film is rolled and pressed three times with a rubber roller at a pressure of 0.1 MPa and a speed of 5 mm / s. The film is then kept at 80°C for 15 min. After cooling to room temperature, the PDMS transfer medium is peeled off at a rate of 5 mm / min, leaving the core-shell structured metal composite film on the surface of the active layer, thus obtaining the metal top electrode.

[0031] Example 2: A method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin film transfer, comprising the following steps: Step 1: S1. Weigh 10.0g of polydimethylsiloxane (PDMS) substrate and mix with 0.9g of methylhydropolysiloxane curing agent for 5min until uniform. After degassing at room temperature and vacuum degree -0.09MPa for 30min, pour into a mold and cure at 80℃ for 2h. After cooling, take out to obtain the original PDMS film. The thin film was cut into 5cm×5cm squares and placed in a plasma cleaner. An Ar / O2 mixed gas (volume ratio 3:1) was introduced, and the system was operated at a power of 110W and a vacuum degree of 5×10⁻⁶. -2 The plasma-treated film was treated for 18 min under Pa conditions. 0.05 mol / L, 0.1 mol / L, and 0.15 mol / L perfluorooctyltriethoxysilane (PFOTS) ethanol solutions (50 mL each) were prepared sequentially. 2% (by mass) of 3-isocyanate-propyltriethoxysilane was added to each solution. The plasma-treated film was then immersed in these solutions sequentially, and soaked for 30 min at 25 °C, 35 °C, and 60 °C respectively. After each soaking, the film was rinsed three times with anhydrous ethanol and dried with nitrogen to obtain the PFOTS-grafted PDMS film.

[0032] S2. Dissolve 5g of ethoxysilane in 100mL of ethanol solution, then add 0.8g of nano-SiO2 particles and 0.1mL of 0.1% (v / v) 37% hydrochloric acid solution, and sonicate at 100W for 30min. Immerse the PFOTS-grafted PDMS film in the mixed solution, keep it in a constant temperature water bath at 40℃ for 2h, take it out and put it in an oven at 100℃ for annealing for 1h, and cool it naturally to obtain the functionalized PDMS transfer medium.

[0033] S3. Take 0.36 g of Ag nanoparticles with a particle size of 30 nm and add 30 mL of deionized water to prepare an aqueous solution with a concentration of 12 mg / mL. Separately, take 0.022 g of chitosan and dissolve it in 10 mL of 1% acetic acid aqueous solution. After mixing the two solutions, add 0.053 g of dopamine hydrochloride and adjust the pH of the system to 8.5 with 0.1 mol / L NaOH solution. Stir the reaction in a 30℃ constant temperature water bath for 6 h. After the reaction is completed, centrifuge the solution at 8000 r / min for 15 min, discard the supernatant, and wash the precipitate three times with deionized water to obtain Ag@DA-Chi nanoparticles.

[0034] S4. Ag@DA-Chi nanoparticles were dispersed in deionized water to prepare a dispersion with a concentration of 12 mg / mL. The functionalized PDMS transfer medium was fixed on the sample stage of a spin coater, and 5 mL of the above dispersion was dropped onto it. The spin speed was set to 3000 rpm and the time to 30 s. After spin coating, the medium was dried with a nitrogen gun to form an Ag core layer with a thickness of 100 nm on the surface of the medium, thus obtaining Ag core layer coated PDMS.

[0035] S5. Prepare a 0.1 mol / L 3,4-ethylenedioxythiophene (EDOT) ethanol / water mixed solution (ethanol:water = 1:1, volume ratio, 50 mL), 50 mL of 0.05 mol / L sodium polystyrene sulfonate (PSS) aqueous solution, and 100 mL of 0.1 mol / L FeCl3 oxidant aqueous solution, and mix them evenly at a volume ratio of 1:1:2. Add 0.2 g sodium dodecyl sulfate (SDS) and 1.0 g single-walled carbon nanotubes (SWCNTs) to the mixed solution, and sonicate at 100 W for 30 min to obtain a mixed solution. Completely immerse the Ag core-coated PDMS in this solution, and allow it to polymerize in situ under ice bath conditions at 3 °C for 65 min. After the reaction is complete, remove it, rinse the surface twice with deionized water, and blow dry with nitrogen to obtain the Ag@DA-Chi / PEDOT:PSS / SWCNTs composite film.

[0036] S6. Spray 1 mL of 5% (w / w) pentaerythritol triacrylate (PETA) crosslinking agent (containing 0.001 g photoinitiator Irgacure 184) evenly onto the surface of the composite film, place it in an ultraviolet curing chamber, and cure it at a wavelength of 365 nm and a power of 50 mW / cm². 2Irradiated under the specified conditions for 20 minutes, then transferred to an 80℃ oven for heat annealing for 30 minutes to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film.

[0037] S7. Weigh 0.275g P3HT and 0.296g PCBM, add 10mL of o-dichlorobenzene (ODCB) solvent, add 0.011g 1,8-diiodooctane, and stir at 500r / min for 10h at 70℃ to obtain the active layer solution; cut the ITO substrate into a 1cm×1.5cm rectangle, and ultrasonically clean it for 20min each with 50mL acetone, ethanol, and deionized water (power 100W). After drying with nitrogen, place it in a glove box and spin-coat with 5mg / mL... A PFN-Br solution (2000 rpm, 30 s) is used to form a PFN-Br layer, followed by spin coating of an active layer solution (800 rpm, 30 s) to form an active layer. The layer is then placed in a glove box for 20 min to achieve a semi-solid state. A pre-crosslinked metal composite film is then attached to the surface of the semi-solid active layer with the metal film side down. The film is rolled and pressed three times with a rubber roller at a pressure of 0.1 MPa and a speed of 5 mm / s. The film is then kept at 80°C for 15 min. After cooling to room temperature, the PDMS transfer medium is peeled off at a rate of 5 mm / min, leaving the core-shell structured metal composite film on the surface of the active layer, thus obtaining the metal top electrode.

[0038] Example 3: A method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin film transfer, comprising the following steps: Step 1: S1, Weigh 10.0g of polydimethylsiloxane (PDMS) substrate and mix with 1.1g of methylhydropolysiloxane curing agent for 5min until uniform. After degassing at room temperature and vacuum degree -0.09MPa for 30min, pour into a mold and cure at 80℃ for 2h. After cooling, take out to obtain the original PDMS film. The thin film was cut into 5cm×5cm squares and placed in a plasma cleaner. An Ar / O2 mixed gas (volume ratio 3:1) was introduced, and the system was operated at a power of 110W and a vacuum degree of 5×10⁻⁶. -2 The plasma-treated film was treated for 18 min under Pa conditions. 0.05 mol / L, 0.1 mol / L, and 0.15 mol / L perfluorooctyltriethoxysilane (PFOTS) ethanol solutions (50 mL each) were prepared sequentially. 2% (by mass) of 3-isocyanate-propyltriethoxysilane was added to each solution. The plasma-treated film was then immersed in these solutions sequentially, and soaked for 30 min at 25 °C, 35 °C, and 60 °C respectively. After each soaking, the film was rinsed three times with anhydrous ethanol and dried with nitrogen to obtain the PFOTS-grafted PDMS film.

[0039] S2. Dissolve 5g of ethoxysilane in 100mL of ethanol solution, then add 1.0g of nano-SiO2 particles and 0.1mL of 0.1% (v / v) 37% hydrochloric acid solution, and sonicate at 100W for 30min. Immerse the PFOTS-grafted PDMS film in the mixed solution, keep it in a constant temperature water bath at 40℃ for 2h, take it out and put it in an oven at 100℃ for annealing for 1h, and cool it naturally to obtain the functionalized PDMS transfer medium.

[0040] S3. Take 0.36 g of Ag nanoparticles with a particle size of 30 nm and add 30 mL of deionized water to prepare an aqueous solution with a concentration of 12 mg / mL. Separately, take 0.025 g of chitosan and dissolve it in 10 mL of 1% acetic acid aqueous solution. Mix the two solutions and add 0.055 g of dopamine hydrochloride. Adjust the pH of the system to 8.5 with 0.1 mol / L NaOH solution and react with magnetic stirring in a 30℃ constant temperature water bath for 6 h. After the reaction is completed, centrifuge the solution at 8000 r / min for 15 min, discard the supernatant, and wash the precipitate three times with deionized water to obtain Ag@DA-Chi nanoparticles.

[0041] S4. Ag@DA-Chi nanoparticles were dispersed in deionized water to prepare a dispersion with a concentration of 12 mg / mL. The functionalized PDMS transfer medium was fixed on the sample stage of a spin coater, and 5 mL of the above dispersion was dropped onto it. The spin speed was set to 3000 rpm and the time to 30 s. After spin coating, the medium was dried with a nitrogen gun to form an Ag core layer with a thickness of 100 nm on the surface of the medium, thus obtaining Ag core layer coated PDMS.

[0042] S5. Prepare a 0.1 mol / L 3,4-ethylenedioxythiophene (EDOT) ethanol / water mixed solution (ethanol:water = 1:1, volume ratio, 50 mL), 50 mL of 0.05 mol / L sodium polystyrene sulfonate (PSS) aqueous solution, and 100 mL of 0.1 mol / L FeCl3 oxidant aqueous solution, and mix them evenly at a volume ratio of 1:1:2. Add 0.2 g sodium dodecyl sulfate (SDS) and 1.0 g single-walled carbon nanotubes (SWCNTs) to the mixed solution, and sonicate at 100 W for 30 min to obtain a mixed solution. Completely immerse the Ag core-coated PDMS in this solution, and polymerize in situ under ice bath conditions at 3 °C for 70 min. After the reaction is completed, remove the film, rinse the surface twice with deionized water, and dry it with nitrogen to obtain the Ag@DA-Chi / PEDOT:PSS / SWCNTs composite film.

[0043] S6. Spray 1 mL of 5% (w / w) pentaerythritol triacrylate (PETA) crosslinking agent (containing 0.001 g photoinitiator Irgacure 184) evenly onto the surface of the composite film, place it in an ultraviolet curing chamber, and cure it at a wavelength of 365 nm and a power of 50 mW / cm². 2Irradiated under the specified conditions for 20 minutes, then transferred to an 80℃ oven for heat annealing for 30 minutes to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film.

[0044] S7. Weigh 0.275g P3HT and 0.321g PCBM, add 10mL of o-dichlorobenzene (ODCB) solvent, add 0.011g 1,8-diiodooctane, and stir at 500r / min for 10h at 70℃ to obtain the active layer solution; cut the ITO substrate into a 1cm×1.5cm rectangle, and ultrasonically clean it for 20min each with 50mL acetone, ethanol, and deionized water (power 100W). After drying with nitrogen, place it in a glove box and spin-coat with 5mg / mL... A PFN-Br solution (2000 rpm, 30 s) is used to form a PFN-Br layer, followed by spin coating of an active layer solution (800 rpm, 30 s) to form an active layer. The layer is then placed in a glove box for 20 min to achieve a semi-solid state. A pre-crosslinked metal composite film is then attached to the surface of the semi-solid active layer with the metal film side down. The film is rolled and pressed three times with a rubber roller at a pressure of 0.1 MPa and a speed of 5 mm / s. The film is then kept at 80°C for 15 min. After cooling to room temperature, the PDMS transfer medium is peeled off at a rate of 5 mm / min, leaving the core-shell structured metal composite film on the surface of the active layer, thus obtaining the metal top electrode.

[0045] Example 4: A method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin film transfer, comprising the following steps: Step 1: S1. Weigh 10.0g of polydimethylsiloxane (PDMS) substrate and mix with 1.5g of methylhydropolysiloxane curing agent for 5 minutes until uniform. After degassing at room temperature and vacuum degree -0.09MPa for 30 minutes, pour into a mold and cure at 80℃ for 2 hours. After cooling, take out to obtain the original PDMS film. The thin film was cut into 5cm×5cm squares and placed in a plasma cleaner. An Ar / O2 mixed gas (volume ratio 3:1) was introduced, and the system was operated at a power of 110W and a vacuum degree of 5×10⁻⁶. -2 The plasma-treated film was treated for 18 min under Pa conditions. 0.05 mol / L, 0.1 mol / L, and 0.15 mol / L perfluorooctyltriethoxysilane (PFOTS) ethanol solutions (50 mL each) were prepared sequentially. 2% (by mass) of 3-isocyanate-propyltriethoxysilane was added to each solution. The plasma-treated film was then immersed in these solutions sequentially, and soaked for 30 min at 25 °C, 35 °C, and 60 °C respectively. After each soaking, the film was rinsed three times with anhydrous ethanol and dried with nitrogen to obtain the PFOTS-grafted PDMS film.

[0046] S2. Dissolve 5g of ethoxysilane in 100mL of ethanol solution, then add 1.5g of nano-SiO2 particles and 0.1mL of 0.1% (v / v) 37% hydrochloric acid solution, and sonicate at 100W for 30min. Immerse the PFOTS-grafted PDMS film in the mixed solution, keep it in a constant temperature water bath at 40℃ for 2h, take it out and put it in an oven at 100℃ for annealing for 1h, and cool it naturally to obtain the functionalized PDMS transfer medium.

[0047] S3. Take 0.36 g of Ag nanoparticles with a particle size of 30 nm and add 30 mL of deionized water to prepare an aqueous solution with a concentration of 12 mg / mL. Separately, take 0.03 g of chitosan and dissolve it in 10 mL of 1% acetic acid aqueous solution. Mix the two solutions and add 0.06 g of dopamine hydrochloride. Adjust the pH of the system to 8.5 with 0.1 mol / L NaOH solution. Stir the mixture magnetically in a 30℃ constant temperature water bath for 6 h. After the reaction is completed, centrifuge the solution at 8000 r / min for 15 min, discard the supernatant, and wash the precipitate three times with deionized water to obtain Ag@DA-Chi nanoparticles.

[0048] S4. Ag@DA-Chi nanoparticles were dispersed in deionized water to prepare a dispersion with a concentration of 12 mg / mL. The functionalized PDMS transfer medium was fixed on the sample stage of a spin coater, and 5 mL of the above dispersion was dropped onto it. The spin speed was set to 3000 rpm and the time to 30 s. After spin coating, the medium was dried with a nitrogen gun to form an Ag core layer with a thickness of 100 nm on the surface of the medium, thus obtaining Ag core layer coated PDMS.

[0049] S5. Prepare a 0.1 mol / L 3,4-ethylenedioxythiophene (EDOT) ethanol / water mixed solution (ethanol:water = 1:1, volume ratio, 50 mL), 50 mL of 0.05 mol / L sodium polystyrene sulfonate (PSS) aqueous solution, and 100 mL of 0.1 mol / L FeCl3 oxidant aqueous solution, and mix them evenly at a volume ratio of 1:1:2. Add 0.2 g sodium dodecyl sulfate (SDS) and 1.0 g single-walled carbon nanotubes (SWCNTs) to the mixed solution, and sonicate at 100 W for 30 min to obtain a mixed solution. Completely immerse the Ag core-coated PDMS in this solution, and allow it to polymerize in situ under ice bath conditions at 5 °C for 80 min. After the reaction is complete, remove it, rinse the surface twice with deionized water, and blow dry with nitrogen to obtain the Ag@DA-Chi / PEDOT:PSS / SWCNTs composite film.

[0050] S6. Spray 1 mL of 5% (w / w) pentaerythritol triacrylate (PETA) crosslinking agent (containing 0.001 g photoinitiator Irgacure 184) evenly onto the surface of the composite film, place it in an ultraviolet curing chamber, and cure it at a wavelength of 365 nm and a power of 50 mW / cm². 2Irradiated under the specified conditions for 20 minutes, then transferred to an 80℃ oven for heat annealing for 30 minutes to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film.

[0051] S7. Weigh 0.275g P3HT and 0.413g PCBM, add 10mL of o-dichlorobenzene (ODCB) solvent, add 0.011g 1,8-diiodooctane, and stir at 500r / min for 10h at 70℃ to obtain the active layer solution; cut the ITO substrate into a 1cm×1.5cm rectangle, and ultrasonically clean it for 20min each with 50mL acetone, ethanol, and deionized water (power 100W). After drying with nitrogen, place it in a glove box and spin-coat with 5mg / mL... A PFN-Br solution (2000 rpm, 30 s) is used to form a PFN-Br layer, followed by spin coating of an active layer solution (800 rpm, 30 s) to form an active layer. The layer is then placed in a glove box for 20 min to achieve a semi-solid state. A pre-crosslinked metal composite film is then attached to the surface of the semi-solid active layer with the metal film side down. The film is rolled and pressed three times with a rubber roller at a pressure of 0.1 MPa and a speed of 5 mm / s. The film is then kept at 80°C for 15 min. After cooling to room temperature, the PDMS transfer medium is peeled off at a rate of 5 mm / min, leaving the core-shell structured metal composite film on the surface of the active layer, thus obtaining the metal top electrode.

[0052] Example 5: A method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin film transfer, comprising the following steps: Step 1: S1. Weigh 10.0g of polydimethylsiloxane (PDMS) substrate and mix with 0.8g of methylhydropolysiloxane curing agent for 5 minutes until uniform. After degassing at room temperature and vacuum degree -0.09MPa for 30 minutes, pour into a mold and cure at 80℃ for 2 hours. After cooling, take out to obtain the original PDMS film. The thin film was cut into 5cm×5cm squares and placed in a plasma cleaner. An Ar / O2 mixed gas (volume ratio 3:1) was introduced, and the system was operated at a power of 110W and a vacuum degree of 5×10⁻⁶. -2 The plasma-treated film was treated for 18 min under Pa conditions. 0.05 mol / L, 0.1 mol / L, and 0.15 mol / L perfluorooctyltriethoxysilane (PFOTS) ethanol solutions (50 mL each) were prepared sequentially. 2% (by mass) of 3-isocyanate-propyltriethoxysilane was added to each solution. The plasma-treated film was then immersed in these solutions sequentially, and soaked for 30 min at 25 °C, 35 °C, and 60 °C respectively. After each soaking, the film was rinsed three times with anhydrous ethanol and dried with nitrogen to obtain the PFOTS-grafted PDMS film.

[0053] S2. Dissolve 5g of ethoxysilane in 100mL of ethanol solution, then add 0.5g of nano-SiO2 particles and 0.1mL of 0.1% (v / v) 37% hydrochloric acid solution, and sonicate at 100W for 30min. Immerse the PFOTS-grafted PDMS film in the mixed solution, keep it in a constant temperature water bath at 40℃ for 2h, take it out and put it in an oven at 100℃ for annealing for 1h, and cool it naturally to obtain the functionalized PDMS transfer medium.

[0054] S3. Take 0.36 g of Ag nanoparticles with a particle size of 30 nm and add 30 mL of deionized water to prepare an aqueous solution with a concentration of 12 mg / mL. Separately, take 0.02 g of chitosan and dissolve it in 10 mL of 1% acetic acid aqueous solution. After mixing the two solutions, add 0.05 g of dopamine hydrochloride and adjust the pH of the system to 8.5 with 0.1 mol / L NaOH solution. Stir the reaction magnetically in a 30℃ constant temperature water bath for 6 h. After the reaction is completed, centrifuge the solution at 8000 r / min for 15 min, discard the supernatant, and wash the precipitate three times with deionized water to obtain Ag@DA-Chi nanoparticles.

[0055] S4. Ag@DA-Chi nanoparticles were dispersed in deionized water to prepare a dispersion with a concentration of 12 mg / mL. The functionalized PDMS transfer medium was fixed on the sample stage of a spin coater, and 5 mL of the above dispersion was dropped onto it. The spin speed was set to 3000 rpm and the time to 30 s. After spin coating, the medium was dried with a nitrogen gun to form an Ag core layer with a thickness of 100 nm on the surface of the medium, thus obtaining Ag core layer coated PDMS.

[0056] S5. Prepare a 0.1 mol / L 3,4-ethylenedioxythiophene (EDOT) ethanol / water mixed solution (ethanol:water = 1:1, volume ratio, 50 mL), 50 mL of 0.05 mol / L sodium polystyrene sulfonate (PSS) aqueous solution, and 100 mL of 0.1 mol / L FeCl3 oxidant aqueous solution, and mix them evenly at a volume ratio of 1:1:2. Add 0.2 g sodium dodecyl sulfate (SDS) and 1.0 g single-walled carbon nanotubes (SWCNTs) to the mixed solution, and sonicate at 100 W for 30 min to obtain a mixed solution. Completely immerse the Ag core-coated PDMS in this solution, and allow it to polymerize in situ under 0℃ ice bath conditions for 60 min. After the reaction is complete, remove it, rinse the surface twice with deionized water, and blow dry with nitrogen to obtain the Ag@DA-Chi / PEDOT:PSS / SWCNTs composite film.

[0057] S6. Spray 1 mL of 5% (w / w) pentaerythritol triacrylate (PETA) crosslinking agent (containing 0.001 g photoinitiator Irgacure 184) evenly onto the surface of the composite film, place it in an ultraviolet curing chamber, and cure it at a wavelength of 365 nm and a power of 50 mW / cm². 2Irradiated under the specified conditions for 20 minutes, then transferred to an 80℃ oven for heat annealing for 30 minutes to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film.

[0058] S7. Weigh 0.275g P3HT and 0.275g PCBM, add 10mL of o-dichlorobenzene (ODCB) solvent, add 0.011g 1,8-diiodooctane, and stir at 500r / min for 10h at 70℃ to obtain the active layer solution; cut the ITO substrate into a 1cm×1.5cm rectangle, and ultrasonically clean it for 20min each with 50mL acetone, ethanol, and deionized water (power 100W). After drying with nitrogen, place it in a glove box and spin-coat with 5mg / mL... A PFN-Br solution (2000 rpm, 30 s) is used to form a PFN-Br layer, followed by spin coating of an active layer solution (800 rpm, 30 s) to form an active layer. The layer is then placed in a glove box for 20 min to achieve a semi-solid state. A pre-crosslinked metal composite film is then attached to the surface of the semi-solid active layer with the metal film side down. The film is rolled and pressed three times with a rubber roller at a pressure of 0.1 MPa and a speed of 5 mm / s. The film is then kept at 80°C for 15 min. After cooling to room temperature, the PDMS transfer medium is peeled off at a rate of 5 mm / min, leaving the core-shell structured metal composite film on the surface of the active layer, thus obtaining the metal top electrode.

[0059] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the PFOTS grafting treatment in step 1 is omitted (the plasma-treated PDMS film is used directly), and the micro-nano crosslinking layer preparation in step 2 is omitted (the plasma-treated PDMS is used directly as the transfer medium).

[0060] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that step 3, preparation of Ag@DA-Chi nanoparticles, step 5, preparation of in-situ polymerized shell, and step 6, pre-crosslinking treatment are omitted. The pure Ag nanoparticle dispersion is directly spin-coated onto the surface of functionalized PDMS transfer medium (100 nm thick) as a metal film.

[0061] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the perfluorooctyltriethoxysilane (PFOTS) ethanol solution prepared in step 1 did not contain 3-isocyanate-propyltriethoxysilane (IPTS).

[0062] Performance testing: 1. Transfer Integrity Test: The prepared metal top electrode was observed using an optical microscope. Five fields of view (each field of view area 0.5cm × 0.5cm) were randomly selected for each sample. The proportion of electrode areas without residue, damage, or cracks to the total observed area was counted, and the average of the five samples was taken as the final transfer integrity rate. The magnification was 200x during the test, and the area of ​​damaged and residual areas was quantified using image analysis software to ensure statistical accuracy. The test results are shown in Table 1.

[0063] 2. Interfacial Shear Strength Test: The interfacial shear strength between the electrode and the active layer was tested using a nanoindenter with a scratch method. The indenter loading rate was set to 5 mN / s, the scratch length to 500 μm, and the scratch speed to 10 μm / s. The critical load (i.e., the load at which the electrode begins to peel off) during the scratching process was recorded. The interfacial shear strength was calculated using the formula τ = F / A (where τ is the shear strength, F is the critical load, and A is the scratch contact area). Three different locations were tested for each sample, and the average value was taken. The test results are shown in Table 1.

[0064] 3. Sheet resistance test: The sheet resistance of the metal top electrode was tested using a four-probe tester with a probe spacing of 1 mm and a test current of 1 mA. Eight test points were randomly selected for each sample, avoiding the edge area (≥2 mm from the edge). The maximum and minimum values ​​were removed, and the average value was taken as the final sheet resistance value. The test results are shown in Table 1.

[0065] 4. Elongation at break test: The metal top electrode was peeled off from the substrate to prepare a standard specimen of 10mm × 2mm × 0.22μm. A universal testing machine was used for tensile testing, with a tensile rate of 1mm / min and a gauge length of 5mm. The elongation at break was recorded. The elongation at break was calculated using the formula ε = ΔL / L0 (where ε is the elongation at break, ΔL is the elongation at break, and L0 is the gauge length). Five specimens were tested for each sample, and the average value was taken. The test results are shown in Table 1.

[0066] 5. Long-term stability test: The prepared organic optoelectronic device (taking OPD as an example) was placed in a constant temperature and humidity chamber with environmental conditions set at 25℃ and 60% humidity. The photoresponse current of the device under a -5V bias voltage was tested periodically (0h, 200h, 500h, 1000h) using a solar simulator (AM1.5G) and a Keithley 2450 digital source meter. The photoresponse current retention rate (η=I) after 1000h was calculated. 1000 / I0×100%, where I 1000 I0 is the initial photoresponse current (I0 is the initial photoresponse current) after 1000 hours, and the retention rate reflects the long-term stability of the device. The test results are shown in Table 1.

[0067] Table 1:

[0068] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing metal top electrodes for organic optoelectronic devices using high-boiling-point solvent-assisted thin-film transfer, characterized in that, Includes the following steps: S1. Mix polydimethylsiloxane material with curing agent, degas and cure to obtain original polydimethylsiloxane film, then perform plasma treatment, then immerse in ethanol solution of perfluorooctyltriethoxysilane, rinse and dry to obtain perfluorooctyltriethoxysilane grafted PDMS film. S2. The PDMS film grafted with perfluorooctyltriethoxysilane was immersed in a tetraethoxysilane ethanol solution containing nano-SiO2 particles and hydrochloric acid, and the reaction was carried out at a certain temperature. After being taken out, it was annealed and cooled to obtain the functionalized PDMS transfer medium. S3. Mix Ag nanoparticles, chitosan acetate solution and dopamine hydrochloride, adjust pH to alkaline, and centrifuge and wash after reaction to obtain Ag@DA-Chi nanoparticles. S4. Disperse Ag@DA-Chi nanoparticles in deionized water to obtain a dispersion. Spin-coat the dispersion onto the surface of a functionalized PDMS transfer medium to form an Ag core layer, thus obtaining Ag core layer coated PDMS. S5. Mix 3,4-ethylenedioxythiophene monomer, sodium polystyrene sulfonate and FeCl3 oxidant solution, add sodium dodecyl sulfate and single-walled carbon nanotubes, disperse to obtain a mixed solution, immerse Ag core-coated PDMS in the mixed solution for in-situ polymerization reaction, and obtain a composite film after rinsing and drying. S6. Spray pentaerythritol triacrylate crosslinking agent containing photoinitiator onto the surface of the composite film, cure under ultraviolet light and then heat anneal to complete the pre-crosslinking and obtain a pre-crosslinked metal composite film. S7. Dissolve P3HT and PCBM in o-dichlorobenzene solvent, add 1,8-diiodooctane additive, stir to obtain active layer solution, spin-coat PFN-Br solution on ITO substrate to form PFN-Br layer, and then spin-coat active layer solution to form semi-solid active layer. The pre-crosslinked metal composite film is attached to the surface of the semi-solid active layer with the metal film side down, and then rolled and pressed to keep it warm. After heat preservation, the PDMS transfer medium is peeled off, leaving the core-shell structured metal composite film on the surface of the active layer, thus obtaining the metal top electrode.

2. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S1, the curing agent is methyl hydrogen polysiloxane (methyl hydrogen silicone oil).

3. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, The mass ratio of the polydimethylsiloxane material to the curing agent is 10:(0.8-1.5).

4. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S1, 3-isocyanate-propyltriethoxysilane is added to the ethanol solution of perfluorooctyltriethoxysilane.

5. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S2, the mass ratio of tetraethoxysilane to nano-SiO2 particles is 5:(0.5-1.5).

6. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S3, the mass ratio of Ag nanoparticles, chitosan, and dopamine hydrochloride is 36:(2-3):(5-6).

7. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S4, the thickness of the Ag core layer is controlled at 100 nm.

8. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S5, the in-situ polymerization reaction temperature is 0–5°C, and the reaction time is 60–80 min.

9. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S6, the photoinitiator is Irgacure184.

10. The method for preparing a metal top electrode for an organic optoelectronic device using a high-boiling-point solvent-assisted thin-film transfer according to claim 1, characterized in that, In step S7, the mass ratio of P3HT to PCBM is 1:(1~1.5).

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