Passivation method of hole transport layer and organic solar cell formed by hole transport layer

Abstract

The invention discloses a passivation method of a hole transport layer and an organic solar cell formed by the hole transport layer. The metal oxide hole transport layer passivation method comprises the following steps: S1, preparing a passivation solution from a metal oxygen cluster compound and a solvent; s2, coating the passivation solution on a metal oxide hole transport layer to form a double-layer composite hole transport layer; s3, carrying out drying and annealing treatment on the composite hole transport layer; and the annealing treatment is that the composite hole transport layer is heated for 8-30 minutes under the condition of 80-150 DEG C. Through the passivation effect of the metal oxygen cluster compound, the defects of the hole transport layer can be effectively reduced, charge recombination and photocatalytic activity can be inhibited, and the carrier transport efficiency can be improved, so that the energy conversion efficiency and stability of the organic solar cell can be remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic device technology, specifically relating to a metal oxide hole transport layer with high energy conversion efficiency and its passivation method, and organic solar cells. By passivating the defects of the metal oxide hole transport layer with metal oxide cluster compounds, the energy conversion efficiency and stability of organic solar cells are improved. Background Technology

[0002] Organic solar cells, with their outstanding advantages such as low cost, solution-processability, light weight, and large-area fabrication, have become a highly promising new energy technology. In the structural system of organic solar cells, the hole transport layer is one of the core components determining the cell's performance.

[0003] Metal oxides are ideal materials for preparing hole transport layers. They possess excellent chemical inertness, are not prone to chemical reactions with organic active layers, and exhibit good hydrophobicity, effectively blocking external moisture and oxygen from penetrating the device and delaying the degradation of the active layer. Furthermore, metal oxides can be prepared using various low-cost solution methods, such as sol-gel, hydrothermal, and spray pyrolysis, and are compatible with the low-temperature processing requirements of flexible substrates (such as PET and PI). In addition, metal oxide films exhibit stable film quality with minimal batch-to-batch performance variation, achieving a relative standard deviation of <5%, making them suitable for roll-to-roll mass production and laying the foundation for the industrial application of organic solar cells.

[0004] However, metal oxide films prepared by solution methods are prone to surface defects such as oxygen vacancies and hydroxyl groups. These defects can form deep-level traps, capturing holes during transport, leading to decreased carrier mobility and increased charge recombination probability. Furthermore, the work function of pure metal oxides does not match the HOMO level of the active layer, resulting in an increased hole injection barrier and reduced device Vo. o c decreases significantly, possibly dropping below 0.7 V. Summary of the Invention

[0005] This application further improves the preparation method of the hole transport layer in order to solve the above-mentioned technical problems. One objective of this invention is to provide a passivation method for a metal oxide hole transport layer; another objective is to provide a corresponding hole transport layer; and a third objective is to provide an organic solar cell using the hole transport layer.

[0006] The specific technical solution is explained below:

[0007] The passivation method for metal oxide hole transport layers includes the following steps:

[0008] S1: The step of preparing a passivation solution by combining the metal-oxygen cluster compound and the solvent;

[0009] S2: The step of coating the passivation solution onto the metal oxide hole transport layer to form a double-layer composite hole transport layer;

[0010] S3: The step of drying and annealing the composite hole transport layer;

[0011] The annealing process involves heating the composite hole transport layer at 80-150°C for 8-30 minutes.

[0012] In a further embodiment, in step S1, the passivation solution is stirred.

[0013] In a preferred embodiment, in step S1, the concentration of the metal-oxygen cluster compound in the passivation solution is 0.1~8 mg / mL.

[0014] In a preferred embodiment, in step S1, the solvent is selected from water and / or alcohol, such as methanol, ethanol, propanol, isopropanol, etc.

[0015] In a preferred embodiment, in step S1, the metal-oxygen cluster compound is a metal-oxygen cluster compound containing any one or more of molybdenum, tungsten, and vanadium.

[0016] In a preferred embodiment, the metal-oxygen cluster compound is phosphotungstic acid (H6O8P2W). 24 ) or phosphomolybdic acid (H3Mo) 12 O 40 P).

[0017] In a preferred embodiment, the metal oxide in the metal oxide hole transport layer is selected from any one or a combination of two or more of the following: molybdenum oxide, vanadium oxide, tungsten oxide, nickel oxide, zinc oxide, and titanium oxide.

[0018] In a further embodiment, the metal oxide can be deposited by a variety of common methods, such as wet preparation (spin coating, blade coating, inkjet printing, etc.) or dry preparation (PVD, vapor deposition, etc.).

[0019] In a preferred embodiment, in step S2, the passivation solution can be applied to the metal oxide hole transport layer by any one of spin coating, doctor blade coating, slot coating, or inkjet printing.

[0020] The composite hole transport layer is made by the passivation method described in any of the above technical solutions, and the composite hole transport layer includes a bilayer structure composed of metal oxygen cluster compounds and metal oxides.

[0021] Organic solar cells include the aforementioned passivated composite hole transport layer.

[0022] In a further embodiment, the organic solar cell includes a top electrode, an electron transport layer, an active layer, the aforementioned composite hole transport layer, a substrate, and a bottom electrode arranged sequentially.

[0023] In summary, the technical solution described in this invention has the following main beneficial effects:

[0024] Compared with the prior art, the technical solution of the present invention forms a double-layer structure of metal-oxygen cluster compound and metal oxide, so that the metal-oxygen cluster salt covers the surface of the metal oxide and acts on the defects such as oxygen vacancies and hydroxyl groups on the surface of the metal oxide, thereby effectively reducing the defects on the surface of the hole transport layer, suppressing charge recombination, improving the carrier transport efficiency, and significantly improving the energy conversion efficiency of organic solar cells.

[0025] Meanwhile, the passivated hole transport layer exhibits superior stability compared to the unpassivated layer.

[0026] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Attached Figure Description

[0027] Figure 1 This is a comparison of the stability performance of the batteries prepared in Example 1 and Comparative Example 1 under LED white light irradiation in an air atmosphere (temperature 25°C, humidity 40%~50%). The vertical axis represents the normalized power conversion efficiency (PCE), and the horizontal axis represents time. Detailed Implementation

[0028] The present invention will be further explained in conjunction with the embodiments:

[0029] The core technical problem faced by the technical solution of this application embodiment stems from the inventor's accurate understanding of the prior art. Therefore, how to improve the energy conversion efficiency and stability of the hole transport layer in organic solar cells is a technical problem that the inventor urgently needs to solve.

[0030] It should be noted that the embodiments do not constitute a limitation on the scope of protection of the claims of this invention. All technical solutions that can be reasonably expected by those skilled in the art based on the technical concepts provided / proved by the embodiments should be covered within the scope of protection of the claims of this invention.

[0031] In the following specific embodiments, the annealing process after coating the hole transport layer surface with a passivation solution enables the metal ions in the metal-oxygen cluster salt to interact with the defect sites on the surface of the hole transport layer, forming chemical bonds or coordination bonds, thereby filling the defects and achieving passivation of the hole transport layer.

[0032] Because the hole transport layer undergoes passivation treatment with metal-oxygen cluster salts, the number of defects is significantly reduced, charge recombination is effectively suppressed, and holes can be transported to the electrodes more efficiently. This improves the open-circuit voltage, short-circuit current, and fill factor of the battery, ultimately enhancing its energy conversion efficiency. Simultaneously, the presence of metal-oxygen cluster salts enhances the stability of the hole transport layer, reduces the impact of environmental factors on its performance, and extends the battery's lifespan.

[0033] The specific implementation of the organic photovoltaic device, from bottom to top, consists of a transparent substrate, a bottom electrode layer, a hole transport layer, an organic active layer, an electron transport layer, and a top electrode layer.

[0034] The transparent substrate includes glass and an organic film, wherein the organic film is made of any one of thermoplastic polyurethane elastomer (TPU), polyimide (PI), polyethylene terephthalate (PET), or polyethylene naphthalate (PEN).

[0035] The material of the bottom electrode layer includes any one of indium tin oxide thin film, silver nanowire thin film, and semi-transparent silver thin film.

[0036] The electron transport layer is made of either a metal oxide or an organic compound. Metal oxides include tin oxide and zinc oxide, while organic compounds include poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) dibromide (PFN-Br) and poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) (PFN). Examples include 2,9-bis(3-((3-(dimethylamino)propyl)amino)propyl)-3,3'-(1,3,8,10-tetraanthrone[2,1,9-DEF:6,5,10-D'E'F']diisoquinoline (PDINN) and N,N'-bis[3-(dimethylamino)propyl]perylene-3,4,9,10-tetracarboxylic acid diimide (PDIN).

[0037] The materials of the organic active layer are divided into donors and acceptors, which can be any one of oligothiophene materials, triphenylamine materials, benzodithiophene materials or pyrrolopyrrole dione materials, such as PM6, Y6, L8-BO, etc.

[0038] The hole transport layer is made of passivated metal oxides, including molybdenum oxide, vanadium oxide, and nickel oxide.

[0039] The material of the top electrode layer is at least one of a metal, a conductive nanomaterial, or a material with a multilayer structure, wherein the metal material includes Ag, Al, Cu, and Au; and the conductive nanomaterial includes metal nanowires and nanoparticle pastes.

[0040] The specific implementation examples are described below.

[0041] Example 1:

[0042] This embodiment relates to the application of a nickel oxide hole transport layer prepared by PTA (phosphotungstic acid) passivation dry method in organic photovoltaic devices.

[0043] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0044] Preparation process of PTA solution:

[0045] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0046] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 100℃ for 10 min.

[0047] Preparation of the active layer thin film:

[0048] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0049] (2) The ink is spin-coated onto the passivated hole transport layer, and then dried and annealed to form the thin film. The spin-coating conditions are: 3000 rpm for 30 s. The annealing conditions are: annealing at 100°C for 15 min.

[0050] The organic photovoltaic device in this embodiment has the following structure in sequence: ITO cathode layer, dry nickel oxide hole transport layer, PTA passivation layer, active layer, PDINN electron transport layer, and Ag anode layer.

[0051] Example 2:

[0052] This embodiment relates to the application of a nickel oxide hole transport layer prepared by PMA (phosphomolybdic acid) passivation dry method in organic photovoltaic devices.

[0053] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0054] Preparation process of PMA solution:

[0055] (1) Preparation of ink: PMA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0056] (2) Preparation of PMA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed after drying and annealing. The spin coating process was performed at a speed of 3000 rpm for 30 s. The annealing process was performed at 100°C for 10 min.

[0057] Preparation of the active layer thin film:

[0058] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0059] (2) The ink is coated onto the passivated hole transport layer by spin coating, and the thin film is formed after drying, annealing and other post-treatments. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0060] The organic photovoltaic device in this embodiment has the following structure in sequence: ITO cathode layer, nickel oxide hole transport layer, PMA passivation layer, active layer, PDINN electron transport layer, and Ag anode layer.

[0061] Example 3:

[0062] This embodiment relates to the application of a nickel oxide hole transport layer prepared by a PTA (phosphotungstic acid) passivation wet process in organic photovoltaic devices.

[0063] Fabrication process of wet nickel oxide hole transport layer:

[0064] (1) Preparation of ink: Nickel acetate tetrahydrate was dissolved in ethylene glycol monomethyl ether at a concentration of 10 mg / mL, and aged overnight with stirring at room temperature. Then, acetylacetone at a volume ratio of 10% was added and stirred for 30 min. The ink was filtered through a 0.45 μm PES water filter before coating.

[0065] (2) Preparation of wet nickel oxide thin film: The ink was coated onto the ITO substrate by a common method such as spin coating, and the film was formed after drying and annealing. The spin coating process conditions were: 3000 rpm and 30 s. The annealing process conditions were: first heating at 120℃ for 5 min, then heating at 320℃ for 1 h, then cooling to 120℃ and then transferring to a glove box to cool to room temperature.

[0066] Preparation process of PTA solution:

[0067] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0068] (2) Preparation of PTA film: The ink was spin-coated onto the above-mentioned nickel oxide hole transport layer, and after drying and annealing, a passivated hole transport layer was formed. The spin-coating conditions were: 3000 rpm and 30 s. The annealing conditions were: annealing at 100℃ for 10 min.

[0069] Preparation of the active layer thin film:

[0070] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0071] (2) The ink is spin-coated onto the passivated hole transport layer, and then dried and annealed to form an active layer film. The spin-coating conditions are: 3000 rpm and 30 s. The annealing conditions are: 100℃ for 15 min.

[0072] The organic photovoltaic device in this embodiment has the following structure in sequence: ITO cathode layer, wet nickel oxide hole transport layer, PTA passivation layer, active layer, PDINN electron transport layer, and Ag anode layer.

[0073] Example 4:

[0074] This embodiment relates to the application of a nickel oxide hole transport layer prepared by a wet passivation process using PMA (phosphomolybdic acid) in organic photovoltaic devices.

[0075] The wet-process preparation process for nickel oxide thin films is the same as in Example 1.

[0076] Preparation process of PMA solution:

[0077] (1) Preparation of ink: PMA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0078] (2) Preparation of PMA film: The ink was coated onto the above-mentioned nickel oxide hole transport layer by spin coating, and the film was formed after drying and annealing. The spin coating process conditions were: 3000 rpm and 30 s. The annealing process conditions were: annealing at 100℃ for 10 min.

[0079] Preparation of the active layer thin film:

[0080] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0081] (2) The ink is spin-coated onto the passivated hole transport layer, and then dried and annealed to form an active layer film. The spin-coating conditions are: 3000 rpm for 30 s. The annealing conditions are: 100℃ for 15 min.

[0082] The organic photovoltaic device in this embodiment has the following structure in sequence: ITO cathode layer, wet nickel oxide hole transport layer, PMA passivation layer, active layer, PDINN electron transport layer, and Ag anode layer.

[0083] Example 5:

[0084] This embodiment demonstrates the application of PTA passivated molybdenum oxide hole transport layer in organic photovoltaic devices.

[0085] Preparation process of PTA solution:

[0086] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0087] (2) Preparation of PTA film: The ink was coated onto a molybdenum oxide film by spin coating, followed by drying, annealing and other post-treatments to form the film. The spin coating process conditions were: 3000 rpm and 30 s. The annealing process conditions were: annealing at 100℃ for 10 min.

[0088] Preparation of the active layer thin film:

[0089] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0090] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0091] The structure of the organic photovoltaic device corresponding to this comparative example is, in order, an ITO cathode layer, a nickel oxide hole transport layer, a PTA passivation layer, an active layer, a PDINN electron transport layer, and an Ag anode layer.

[0092] Example 6:

[0093] This embodiment demonstrates the application of PMA passivated molybdenum oxide hole transport layer in organic photovoltaic devices.

[0094] Preparation process of PMA solution:

[0095] (1) Preparation of ink: PMA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0096] (2) Preparation of PMA film: The ink was coated onto a molybdenum oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 100℃ for 10 min.

[0097] Preparation of the active layer thin film:

[0098] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0099] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0100] The structure of the organic photovoltaic device corresponding to this comparative example is, in order, an ITO cathode layer, a molybdenum oxide hole transport layer, a PMA passivation layer, an active layer, a PDINN electron transport layer, and an Ag anode layer.

[0101] Example 7:

[0102] This embodiment relates to the application of a nickel oxide hole transport layer prepared by dry passivation with 1 mg / mL PTA in organic photovoltaic devices.

[0103] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0104] Preparation process of PTA solution:

[0105] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 1 mg / mL and stirred at room temperature for 1 h.

[0106] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 100℃ for 10 min.

[0107] Preparation of the active layer thin film:

[0108] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0109] (2) The ink is spin-coated onto the passivated hole transport layer, and then dried and annealed to form the thin film. The spin-coating conditions are: 3000 rpm for 30 s. The annealing conditions are: annealing at 100°C for 15 min.

[0110] The organic photovoltaic device in this embodiment has the following structure in sequence: ITO cathode layer, dry nickel oxide hole transport layer, PTA passivation layer, active layer, PDINN electron transport layer, and Ag anode layer.

[0111] Example 8:

[0112] This embodiment relates to the application of a nickel oxide hole transport layer prepared by dry PTA passivation at a post-processing temperature of 80°C in organic photovoltaic devices.

[0113] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0114] Preparation process of PTA solution:

[0115] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0116] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 80℃ for 10 min.

[0117] Preparation of the active layer thin film:

[0118] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0119] (2) The ink is spin-coated onto the passivated hole transport layer, and then dried and annealed to form the thin film. The spin-coating conditions are: 3000 rpm for 30 s. The annealing conditions are: annealing at 100°C for 15 min.

[0120] The organic photovoltaic device in this embodiment has the following structure in sequence: ITO cathode layer, dry nickel oxide hole transport layer, PTA passivation layer, active layer, PDINN electron transport layer, and Ag anode layer.

[0121] Comparative Example 1:

[0122] This comparative example demonstrates the application of a dry-prepared nickel oxide hole transport layer without passivation in organic photovoltaic devices.

[0123] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0124] Preparation of the active layer thin film:

[0125] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0126] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0127] The structure of the organic photovoltaic device corresponding to this comparative example is, in order, an ITO cathode layer, a nickel oxide hole transport layer, an active layer, a PDINN electron transport layer, and an Ag anode layer.

[0128] Comparative Example 2:

[0129] This comparative example demonstrates the application of a nickel oxide hole transport layer prepared by dry passivation with excessively low PTA concentration in organic photovoltaic devices.

[0130] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0131] Preparation process of PTA solution:

[0132] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.1 mg / mL and stirred at room temperature for 1 h.

[0133] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 100℃ for 10 min.

[0134] Preparation of the active layer thin film:

[0135] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0136] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0137] The organic photovoltaic device corresponding to this comparative example has the following structure in sequence: ITO cathode layer, nickel oxide hole transport layer, PTA passivation active layer, PDINN electron transport layer, and Ag anode layer.

[0138] Comparative Example 3:

[0139] This comparative example demonstrates the application of a nickel oxide hole transport layer prepared by dry passivation with excessively high PTA concentration in organic photovoltaic devices.

[0140] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0141] Preparation process of PTA solution:

[0142] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 8 mg / mL and stirred at room temperature for 1 h.

[0143] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 100℃ for 10 min.

[0144] Preparation of the active layer thin film:

[0145] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0146] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0147] The structure of the organic photovoltaic device corresponding to this comparative example is, in order, an ITO cathode layer, a nickel oxide hole transport layer, a PTA passivation layer, an active layer, a PDINN electron transport layer, and an Ag anode layer.

[0148] Comparative Example 4:

[0149] This comparative example demonstrates the application of a nickel oxide hole transport layer prepared by a dry PTA passivation method at a higher annealing temperature in organic photovoltaic devices.

[0150] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0151] Preparation process of PTA solution:

[0152] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0153] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed under the following conditions: 3000 rpm for 30 s. The annealing process was performed under the following conditions: annealing at 150℃ for 10 min.

[0154] Preparation of the active layer thin film:

[0155] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0156] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0157] The structure of the organic photovoltaic device corresponding to this comparative example is, in order, an ITO cathode layer, a nickel oxide hole transport layer, a PTA passivation layer, an active layer, a PDINN electron transport layer, and an Ag anode layer.

[0158] Comparative Example 5:

[0159] This comparative example demonstrates the application of a nickel oxide hole transport layer prepared by a PTA passivation dry method with a longer annealing time in organic photovoltaic devices.

[0160] Dry-process nickel oxide hole transport layer: A 15 nm thick nickel oxide film was prepared by magnetron sputtering (DC mode) with a sputtering power of 4.2 kW, a process gas pressure of 0.35 Pa, a deposition rate of 13 nm / min, and an oxygen flow ratio of 4%. The prepared nickel oxide film was then subjected to UV ozone treatment for 20 min.

[0161] Preparation process of PTA solution:

[0162] (1) Preparation of ink: PTA was dissolved in methanol at a concentration of 0.5 mg / mL and stirred at room temperature for 1 h.

[0163] (2) Preparation of PTA film: The ink was coated onto a nickel oxide film by spin coating, and the film was formed by post-treatment such as drying and annealing. The spin coating process was performed at a speed of 3000 rpm for 30 s. The annealing process was performed at 100℃ for 30 min.

[0164] Preparation of the active layer thin film:

[0165] (1) Preparation of ink: The active layer acceptors PM6 and L8-BO were weighed in a mass ratio of 1:1.2, and o-xylene solvent was added at a total concentration of 24 mg / mL. The mixture was heated and stirred at 80°C for 6 h.

[0166] (2) The ink is coated onto a nickel oxide film by spin coating, and the film is formed after drying and annealing. The spin coating process is performed under the following conditions: 3000 rpm for 30 s. The annealing process is performed under the following conditions: annealing at 100°C for 15 min.

[0167] The structure of the organic photovoltaic device corresponding to this comparative example is, in order, an ITO cathode layer, a nickel oxide hole transport layer, a PTA passivation layer, an active layer, a PDINN electron transport layer, and an Ag anode layer.

[0168] The battery performance of Examples 1-7 and Comparative Examples 1-5 is shown in Table 1 below:

[0169] Table 1. Performance of the batteries prepared in Example 1 and Comparative Examples 1-5 <![CDATA[V OC (V)]]> FF (%) PCE (%) <![CDATA[J SC (mA / cm 2 )]]> Example 1 0.854 77.16 18.76 28.48 Comparative Example 1 0.818 65.09 12.43 23.35 Comparative Example 2 0.844 67.15 14.70 25.94 Comparative Example 3 0.828 67.23 14.41 25.89 Comparative Example 4 0.840 74.03 17.11 27.52 Comparative Example 5 0.850 77.05 17.97 27.44 Example 2 0.850 74.54 18.64 28.77 Example 3 0.847 76.29 17.75 27.48 Example 4 0.848 74.20 17.64 28.06 Example 5 0.853 77.83 18.65 28.11 Example 6 0.852 77.87 18.62 28.07 Example 7 0.851 75.57 18.42 28.64 Example 8 0.852 76.93 18.57 28.34

[0170] In Table 1, V OC (V) is the open-circuit voltage; FF is the fill factor; PCE is the power conversion efficiency; J SC Characterizes short-circuit current.

[0171] As can be seen from Table 1, compared to Example 1:

[0172] Comparative Example 1, due to the lack of passivation treatment on the hole transport layer, showed a decrease in its open-circuit voltage, filler current, and short-circuit current, resulting in a significant reduction in energy conversion efficiency.

[0173] The low concentration of metal-oxygen cluster compounds in Comparative Example 2 (0.1 mg / mL) also negatively impacts open-circuit voltage, filler, and short-circuit current, ultimately resulting in a reduced energy conversion efficiency, though still better than Comparative Example 1.

[0174] The ink concentration of the metal oxygen cluster compound in Comparative Example 3 was relatively high, at 8 mg / mL, which resulted in a significant decrease in energy conversion efficiency, which was better than that of Comparative Example 1 and also better than that of Comparative Example 2.

[0175] The annealing temperature of the metal oxide cluster compound film in Comparative Example 4 was 150°C, which was much higher than that of Example 1 (100°C), resulting in a slight decrease in energy conversion efficiency compared to Example 1, but still better than Comparative Example 1.

[0176] The annealing time of the metal oxide cluster compound film in Comparative Example 5 was 30 minutes, which was much longer than the 10 minutes in Example 1. This also resulted in a slight decrease in energy conversion efficiency compared to Example 1, but it was still better than Comparative Example 1.

[0177] As can be seen, the metal-oxygen cluster compound / metal oxide bilayer structure formed in Example 1 effectively overcomes the adverse effects of defects such as oxygen vacancies and hydroxyl groups on the surface of metal oxides, and can suppress charge recombination, improve carrier transport efficiency and energy conversion efficiency of organic solar cells.

[0178] Examples 2-8 also demonstrate that the above-mentioned technical effects and relatively ideal battery performance can be obtained in different types of hole transport layers, with metal-oxygen cluster compound concentrations of 0.5-1 mg / mL and annealing temperatures of 80-100°C.

[0179] Appendix Figure 1 The comparison of the stability performance of the batteries prepared in Example 1 and Comparative Example 1 demonstrates that the bilayer structure of metal-oxygen cluster compound and metal oxide formed by the passivation method of the present invention can also reduce the impact of environmental factors on performance and extend the battery's service life.

[0180] In the description of this specification, the references to terms such as "embodiment," "basic embodiment," "preferred embodiment," "other embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0181] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0182] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for passivating a metal oxide hole transport layer, characterized by: Includes the following steps: S1: The step of preparing a passivation solution by combining the metal-oxygen cluster compound and the solvent; S2: The step of coating the passivation solution onto the metal oxide hole transport layer to form a double-layer composite hole transport layer; S3: The step of drying and annealing the composite hole transport layer; The annealing process involves heating the composite hole transport layer at 80-150°C for 8-30 minutes.

2. The passivation method according to claim 1, characterized in that: In step S1, the concentration of the metal-oxygen cluster compound in the passivation solution is 0.1~8 mg / mL.

3. The passivation method according to claim 2, characterized in that: In step S1, the solvent is selected from water and / or alcohol.

4. The passivation method of claim 2, wherein: In step S1, the metal-oxygen cluster compound is a metal-oxygen cluster compound containing any one or more of molybdenum, tungsten, and vanadium.

5. The passivation method according to claim 4, characterized in that: The metal-oxygen cluster compound is phosphotungstic acid or phosphotomolybdic acid.

6. The passivation method of claim 1, wherein: The metal oxide in the metal oxide hole transport layer is selected from any one or a combination of two or more of the following: molybdenum oxide, vanadium oxide, tungsten oxide, nickel oxide, zinc oxide, and titanium oxide.

7. The passivation method of claim 1, wherein: In step S2, the passivation solution can be applied to the metal oxide hole transport layer by any one of spin coating, doctor blade coating, slot coating, or inkjet printing.

8. A composite hole transport layer characterized by: Made by the passivation method according to any one of claims 1 to 7, the composite hole transport layer comprises a bilayer structure composed of a metal-oxygen cluster compound and a metal oxide.

9. Organic solar cell, characterized in that: It includes the composite hole transport layer as described in claim 8.

10. The organic solar cell according to claim 9, characterized in that: It includes a top electrode, an electron transport layer, an active layer, the aforementioned composite hole transport layer, a substrate, and a bottom electrode arranged sequentially.

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