All-wet inversion organic solar cell based on sputtering electrode and preparation method of all-wet inversion organic solar cell

Abstract

The invention relates to the technical field of organic solar cells, and discloses a sputtering electrode-based all-wet inversion organic solar cell and a preparation method thereof, and the preparation method comprises the steps: carrying out the pretreatment of a substrate and a transparent conductive electrode composite layer; preparing an electron transport layer dispersion liquid, coating the transparent conductive electrode layer with the electron transport layer dispersion liquid by a wet method, and annealing to obtain a wet electron transport layer; preparing an active layer solution, coating the wet electron transport layer with the active layer solution, and annealing to obtain a wet active layer; preparing a hole transport layer solution which comprises a metal oxygen cluster and a silane coupling agent, coating the hole transport layer solution on the wet active layer through a wet coating method, and annealing to obtain a wet hole transport layer; and preparing a conductive electrode layer on the wet hole transport layer through magnetron sputtering. According to the wet hole transport layer in the scheme, through interaction of the metal oxygen cluster and the silane coupling agent, the formed interface layer can effectively resist high-energy ion bombardment in the electrode sputtering process, the functional layer below is protected from being damaged, and the efficiency and stability of the battery are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of organic solar cell technology, and more particularly to a fully wet inverted organic solar cell based on sputtered electrodes and its fabrication method. Background Technology

[0002] Organic solar cells have attracted much attention in the photovoltaic field due to their advantages such as low cost, flexible fabrication, and light weight. Inverted organic solar cells have become one of the research hotspots because of their better stability. Their structure usually consists of a substrate, a transparent conductive electrode, an electron transport layer, an active layer, a hole transport layer, and electrodes. Under illumination, the active layer generates excitons, which separate electrons and holes at the donor-acceptor interface. Electrons are collected by the bottom transparent cathode through the electron transport layer, while holes are collected by the top anode through the hole transport layer, thereby forming a current in the external circuit.

[0003] In inverted organic solar cells, the hole transport layer is a key functional layer. Its main function is to efficiently extract and transport holes while blocking electrons, thereby improving charge collection efficiency, reducing recombination loss, and enhancing the overall performance and stability of the device. However, in the industrial fabrication of inverted organic solar cells, traditional high-performance hole transport layers (such as MoO3) rely on high-cost and low-efficiency vacuum evaporation processes, making it difficult to achieve large-area continuous production. Although some studies have used solution methods to prepare hole transport layers to reduce costs, these wet-process materials generally have low mechanical strength and poor resistance to sputtering damage, and cannot withstand the bombardment of high-energy ions during subsequent electrode sputtering, which seriously restricts the industrialization process of preparing high-efficiency and stable inverted organic solar cells using all-wet methods. Summary of the Invention

[0004] The purpose of this invention is to design a special wet hole transport layer that can resist high-energy ion bombardment from sputtering electrodes, replacing the traditional vapor-deposited molybdenum oxide hole transport layer. At the same time, it enables continuous wet coating of all functional layers except for the sputtering electrodes, thereby improving the performance, stability, and production efficiency of inverted organic solar cells, reducing production costs, and promoting their industrial application.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for fabricating a fully wet inverted organic solar cell based on sputtered electrodes includes: pretreating a substrate and a transparent conductive electrode composite layer; preparing an electron transport layer dispersion, coating it onto the transparent conductive electrode layer using a wet coating method, and annealing it to obtain a wet electron transport layer; preparing an active layer solution, coating it onto the wet electron transport layer using a wet coating method, and annealing it to obtain a wet active layer; preparing a hole transport layer solution, the hole transport layer solution comprising a metal oxide cluster and a silane coupling agent, coating it onto the wet active layer using a wet coating method, and annealing it to obtain a wet hole transport layer; and fabricating a conductive electrode layer substrate on the wet hole transport layer using magnetron sputtering.

[0007] As a preferred embodiment of the present invention, the preparation of the hole transport layer solution includes: dissolving a metal oxide cluster in an organic solvent to prepare a metal oxide cluster solution at room temperature; adding a silane coupling agent to the metal oxide cluster solution and stirring at room temperature to obtain the hole transport layer solution.

[0008] As a preferred embodiment of the present invention, in the hole transport layer solution: the metal oxo cluster is a polyoxometalate, including phosphotungstic acid and phosphomolybdic acid; the organic solvent includes methanol and ethanol.

[0009] As a preferred embodiment of the present invention, the silane coupling agent contains double bonds and hydrolyzable silicon groups, and the silane coupling agent includes vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

[0010] As a preferred embodiment of the present invention, the hole transport layer solution is prepared in such a way that the silane coupling agent accounts for 50-150% of the volume of the organic solvent, and the concentration of the metal oxide cluster in the overall hole transport layer solution is between 0.5-10 mg / ml.

[0011] As a preferred embodiment of the present invention, in the preparation step of the wet hole transport layer, the annealing temperature of the annealing treatment is 60-100℃, the annealing time is 5-20min, and the film thickness of the wet hole transport layer is between 10-50nm.

[0012] As a preferred technical solution of the present invention, the pretreatment includes: cleaning: the substrate and the transparent conductive electrode composite layer are sequentially ultrasonically cleaned with detergent, deionized water, acetone and isopropanol. After cleaning, the surface of the composite layer is dried with nitrogen gas; surface activation treatment: the dried composite layer is cleaned with ozone.

[0013] As a preferred embodiment of the present invention, in the wet electron transport layer preparation step: the preparation of the electron transport layer dispersion includes: mixing SnO2 or ZnO metal oxide with an organic solvent to obtain an electron transport layer dispersion with a concentration of 3-15 mg / ml; the annealing temperature is 60–150℃ and the annealing time is 5–20 min.

[0014] As a preferred embodiment of the present invention, in the wet active layer preparation step: the preparation of the active layer solution includes: dissolving organic donor material and organic acceptor material in a non-halogen solvent at a ratio of 0.5-1.5:0.5-1.5 in an inert atmosphere; the annealing temperature is 60-150℃ and the annealing time is 5-20 min.

[0015] The wet-process inverting organic solar cell based on sputtered electrodes is prepared by the above-described method for preparing a wet-process inverting organic solar cell based on sputtered electrodes. It includes a substrate, a transparent conductive electrode layer, a wet electron transport layer, a wet active layer, a wet hole transport layer, and a sputtered electrode layer arranged in layers from bottom to top.

[0016] The present invention has the following beneficial effects:

[0017] 1. The wet hole transport layer of this invention has extremely strong resistance to high-energy ion bombardment, effectively protecting the internal functional layers of the device from damage during magnetron sputtering. Traditional wet hole transport materials have a loose structure and low mechanical strength, making them highly susceptible to bombardment by high-energy argon ions during sputtering of metal electrodes. This can lead to perforation, cracking, chemical degradation, or interlayer delamination of the film, severely damaging hole transport performance and causing leakage current. This invention constructs a three-dimensional network interface layer by combining metal oxygen clusters with silane coupling agents to form a stable metal-oxygen-silicon bond structure during annealing. This structure significantly improves the mechanical strength and impact resistance of the film, effectively resisting ion bombardment during sputtering and completely protecting the underlying active layer and electron transport layer. This maintains efficient charge extraction and transport, significantly improving the photoelectric conversion efficiency and long-term stability of the device.

[0018] 2. The wet hole transport layer provided by this invention can completely replace the molybdenum oxide hole transport layer that must be prepared by vacuum evaporation in traditional inverted organic solar cells. This breaks through the dependence of high-performance devices on high-cost dry processes. The preparation equipment for traditional hole layers requires large investment, is complex to operate and maintain, has low material utilization, and low production efficiency. Moreover, it is difficult to achieve process compatibility with other functional layers prepared by solution methods, which seriously restricts the large-area preparation and industrialization of devices. The metal oxide cluster material used in this invention can achieve efficient hole extraction and can be film-formed by solution methods without the need for evaporation equipment. This fundamentally avoids the high-cost and low-efficiency dry process and provides a practical and feasible technical path for the low-cost and scalable manufacturing of high-performance organic solar cells.

[0019] 3. This invention achieves continuous wet coating of the electron transport layer, active layer, and hole transport layer, significantly improving preparation efficiency and process compatibility, which is conducive to large-scale industrial production. Compared with the traditional process that relies on vapor deposition, this solution has a simple process flow, is easy to operate, and has a high material utilization rate, greatly reducing equipment investment and energy consumption. This all-wet integration strategy not only simplifies the process flow but also improves production flexibility and scalability, laying a solid technical foundation for organic solar cells to move from laboratory research to commercial application. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the all-wet inverted organic solar cell based on sputtered electrodes proposed in this invention;

[0021] Figure 2 This is a flowchart of the all-wet inversion organic solar cell fabrication method based on sputtering electrodes proposed in this invention;

[0022] Figure 3 This is a physical image of the all-wet inverted organic solar cell based on sputtered electrodes proposed in this invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this specification.

[0024] The terms "first," "second," "third," etc., in the description, claims, and accompanying drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0025] In the following description, terms such as “inner,” “outer,” “upper,” “lower,” “left,” and “right” are used only to facilitate the description of the embodiments and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0026] Before introducing the technical solutions described in this manual, the application scenarios and related technologies of the technical solutions will be introduced.

[0027] Currently, high-performance inverted organic solar cells widely use MoO3 as the hole transport layer. MoO3 has a deep work function, which allows it to match well with the HOMO energy levels of most organic donor materials, enabling efficient hole extraction. Simultaneously, its chemical stability helps improve device lifetime. This layer is typically deposited in a vacuum chamber via vapor deposition, yielding a dense and uniform thin film. However, vapor deposition requires a minimum operating temperature of 10 °C. -4 The process is carried out in a high vacuum environment above Pa, which requires large equipment investment and complex maintenance. The evaporation rate is slow, making it difficult to achieve continuous roll-to-roll production. The evaporation source sprays material in all directions, with only a small amount deposited on the substrate, resulting in serious material waste and further increasing costs. Evaporation is a dry process, which is incompatible with wet processes such as solution processing for active layers and electron transport layers, thus limiting the realization of the all-solution preparation process.

[0028] In addition, to overcome the limitations of vapor deposition processes, researchers have developed a variety of solution-processable hole transport materials. These materials can be prepared by wet processes such as spin coating, blade coating, and inkjet printing, which are easy to achieve large-area, low-cost, and continuous production. However, most wet-process thin films, especially polymers such as PEDOT:PSS, are relatively soft and have a loose structure, lacking sufficient density and mechanical stability. When metal electrodes are subsequently prepared by magnetron sputtering, high-energy argon ions with energies of tens to hundreds of electron volts will violently bombard the film surface, causing surface roughening or even perforation of the wet hole transport layer, chemical structure damage such as PSS chain breakage, film peeling or delamination, etc. After the hole transport layer structure is damaged, the hole extraction efficiency decreases significantly, resulting in a reduction in the device open-circuit voltage and fill factor. It may also cause the active layer to be exposed or short-circuited, leading to increased leakage current, accelerated efficiency decay, and deterioration of the overall device performance and repeatability, failing to meet the consistency and reliability requirements of industrial production.

[0029] In summary, current inverted organic solar cells face a dilemma where performance and process cannot be simultaneously achieved: if high performance is pursued, MoO3 evaporation must be used, sacrificing cost and scalability; if low-cost wet processes are pursued, it is difficult to withstand the damage of subsequent sputtered electrodes, leading to performance degradation.

[0030] Therefore, this invention provides a fully wet inverted organic solar cell based on sputtered electrodes. The cell, from bottom to top, comprises a substrate, a transparent conductive electrode layer, a wet electron transport layer, a wet active layer, a wet hole transport layer, and a sputtered electrode layer. The materials used to fabricate each layer are as follows:

[0031] When used for rigid devices, glass, such as soda-lime glass or borosilicate glass, is selected as the substrate. When used for flexible devices, flexible polymers, such as PEN (polyethylene naphthalate) and PET (polyethylene terephthalate), are used. The substrate is used to provide mechanical support and allow light to pass through efficiently.

[0032] The transparent conductive electrode layer uses transparent conductive materials such as ITO (indium tin oxide) nanoparticle dispersion or AZO (aluminum-doped zinc oxide) nanocolloid dispersion to collect electrons and conduct current while ensuring high light transmittance.

[0033] The wet electron transport layer uses solution-processable materials such as ZnO (zinc oxide) and SnO2 (tin oxide) to extract electrons from the active layer, block hole recombination, and improve device efficiency.

[0034] The active layer uses conventional organic donor and acceptor materials, namely a bulk heterojunction (BHJ) structure of a wide-bandgap polymer donor and a narrow-bandgap non-fullerene acceptor (NFA), such as PM6:Y6 and its derivatives. This layer is used to absorb photons, generate excitons, and separate them into free electrons and holes.

[0035] The wet hole transport layer is composed of a metal oxide cluster and a silane coupling agent. The metal oxide cluster is selected from polyoxometalates with good hole transport performance, such as H3PW. 12 O 40 (phosphotungstic acid), H3PMo 12 O 40 Phosphomolybdic acid, etc., with a deep HOMO energy level of approximately 5.4 eV, can provide excellent hole transport capabilities and can replace MoO3. Silane coupling agents are selected from compounds containing double bonds and hydrolyzable silicon groups, such as VTMS (vinyltrimethoxysilane) and KH570 (γ-methacryloyloxypropyltrimethoxysilane). The surface of the metal-oxygen cluster has a large number of hydroxyl groups (-OH). Under certain conditions, the hydrolyzable silicon groups in the silane coupling agent molecule, such as methoxy and ethoxy groups, will react with the hydroxyl groups on the surface of the metal-oxygen cluster to form a stable metal-oxygen-silicon (MO-S) group. i) Bonding connects the metal-oxygen clusters, enhancing the interfacial bonding force. At the same time, the double bonds in the silane coupling agent molecule will undergo cross-linking under appropriate conditions such as heating or ultraviolet irradiation to form a three-dimensional network structure. Through these two actions, the metal-oxygen clusters and silane coupling agent are combined to form a hard interfacial layer. This interfacial layer has high mechanical strength and impact resistance, which can effectively resist high-energy ion bombardment during the sputtering electrode preparation process and protect the underlying active layer and other functional layers from damage. In addition, the metal-oxygen clusters themselves have good hole transport capabilities, which can ensure the effective transport of holes.

[0036] The sputtered electrode layer is used to collect holes. It is made of metal materials such as Ag (silver) and ITO (transparent conductive oxide) and is prepared by magnetron sputtering. This step can obtain metal or transparent conductive films with excellent conductivity, strong adhesion and uniform density, which is beneficial to achieving efficient charge collection and device stability. It is especially suitable for large-area and industrial production.

[0037] Based on the aforementioned inverted organic solar cell, this invention provides a method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode, the fabrication steps of which include:

[0038] Step 1: Pretreatment of the substrate and transparent conductive electrode: The conductive substrate undergoes cleaning and surface activation treatment. The conductive substrate is a composite layer formed by the integrated molding of the transparent conductive electrode layer and the substrate layer using an industrial sputtering process. This conductive substrate is a commercially available standard material and can be directly purchased and used. The treatment of the conductive substrate includes:

[0039] Cleaning: Use diluted detergent for ultrasonic cleaning for 10-20 minutes to remove oil and particulate matter. Rinse three times with deionized water for 5-10 minutes each time to thoroughly remove residual detergent. Then perform ultrasonic cleaning with acetone for 10-20 minutes to dissolve organic contaminants. Finally, perform ultrasonic cleaning with isopropanol for 10-20 minutes to further clean and improve surface energy. After cleaning, use high-purity nitrogen to dry the conductive substrate surface to avoid water stains.

[0040] Surface activation treatment: Use a UV-Ozone cleaner for ozone cleaning, with a cleaning time of 15-20 minutes and a power of 150-200W. The purpose is to remove residual organic matter and improve the surface work function and hydrophilicity of ITO. It should be noted that if it is used for flexible substrates such as PEN, the ozone treatment time can be shortened to 5-10 minutes to avoid polymer oxidation.

[0041] Step 2, Preparation of the wet electron transport layer: A solution-processable metal oxide such as SnO2 or ZnO is mixed with an organic solvent such as methanol or ethanol to obtain an electron transport layer dispersion with a concentration of 3-15 mg / ml. The dispersion is filtered through a 0.45 μm filter membrane and then coated onto a transparent conductive electrode layer using wet coating methods such as spin coating, blade coating, and slot coating. When using spin coating, a spin coater is used with a rotation speed of 2000–4000 rpm, a spin coating time of 20–40 s, and a drop volume of 20–40 μL. After coating, the layer is annealed at a temperature of 60–150℃ for 5–20 min to form a wet electron transport layer with a thickness of 10–50 nm.

[0042] Step 3: Preparation of the wet active layer: In an inert atmosphere, organic donor materials such as PM6 and D18 and acceptor materials such as Y6 and L8-BO are dissolved in an organic solvent such as toluene or o-xylene at a ratio of 0.5-1.5:0.5-1.5. The dissolution temperature is between 60-120℃ to prepare an active layer solution with a concentration of 5-25 mg / ml. The active layer solution is coated onto the wet electron transport layer by a wet coating method. After annealing, the annealing temperature is between 60-150℃ and the annealing time is 5-20 min, finally forming a wet active layer with a film thickness between 60-150 nm.

[0043] Step 4: Preparation of the wet hole transport layer: Dissolve the metal oxide cluster in an organic solvent, preferably a polar alcohol solvent such as methanol or ethanol, to prepare a metal oxide cluster solution at room temperature; add a silane coupling agent to the metal oxide cluster solution in a certain proportion, with the silane coupling agent accounting for 50-150% of the organic solvent volume, and the total concentration of the metal oxide cluster is between 0.5-10 mg / ml (this concentration is calculated as the mass of the metal oxide cluster / (volume of silane coupling agent + volume of methanol)). After stirring evenly at room temperature, the desired solution is obtained. The hole transport layer solution is coated onto the wet active layer using a wet coating method, followed by annealing at a temperature of 60-100℃ for 5-20 minutes. During annealing, the silane coupling agent reacts and crosslinks with the metal oxide clusters to form a three-dimensional network structure, ultimately yielding a wet hole transport layer that combines hole transport and sputter protection. This step enhances the mechanical strength and sputter resistance of the hole transport layer, with a film thickness between 10-50 nm.

[0044] Step 5: Fabrication of the conductive electrode layer: A conductive electrode layer is fabricated on the wet hole transport layer using magnetron sputtering. The sputtering process is maintained in a high-purity argon atmosphere with a vacuum degree ≤ 5 × 10⁻⁶. -3 The sputtering process is carried out at a pressure between 0.5 and 1.0 Pa, a sputtering power of 50–100 W, and a sputtering time of 60–120 s to form a sputtered electrode layer with a film thickness of 80–150 nm, ultimately resulting in an inverted organic solar cell.

[0045] Example

[0046] Using the above-described preparation steps, this invention spin-coates a 1.5cm × 1.5cm inverted organic solar cell:

[0047] All required materials can be commercially available or prepared using conventional methods in the field as disclosed in the literature. PM6 can be prepared using the method provided in the literature "Adv. Mater. 2015, 27, 4655–4660", and L8-BO can be prepared using the method provided in the literature "Nat. Energy 2021, 6, 605". Phosphomolybdic acid (PMA), VTMS, ITO / glass, etc. can all be purchased from the exploration platform.

[0048] Specifically, ITO glass, as a transparent conductive substrate, was ultrasonically cleaned for 15 minutes each with detergent, deionized water, acetone, and isopropanol, and then dried with high-purity nitrogen. Subsequently, ozone cleaning was performed at a power of 180 W for 15 minutes, which increased the surface work function of ITO to approximately 4.9 eV.

[0049] A SnO2 nano-dispersion with a concentration of 10 mg / mL was prepared, filtered through a 0.45 μm filter membrane, spin-coated in air onto a prepared ITO glass, and annealed to obtain an electron transport layer with a thickness of about 25 nm. The annealing temperature was 80℃ and the annealing time was 10 min.

[0050] In a glove box under a nitrogen atmosphere, 5 mg of PM6 and 5 mg of L8-BO were dissolved in 0.5 mL of o-xylene to obtain an active layer solution with a concentration of 20 mg / mL. This solution was then spin-coated onto the electron transport layer and annealed to obtain an active layer film with a thickness of approximately 100 nm. The annealing temperature was 100 °C and the time was 15 min.

[0051] 5 mg of PMA was dissolved in a mixture of 600 μL methanol and 400 μL VTMS, stirred, and then spin-coated onto the active layer. After annealing, a hole transport layer with a thickness of about 20 nm was obtained. The annealing temperature was 100 °C and the time was 5 min.

[0052] Subsequently, a conductive electrode layer Ag was prepared on the wet hole transport layer using magnetron sputtering to form a 100 nm thick sputtered electrode layer.

[0053] Comparative Example

[0054] Unlike the previous example, in the preparation step of the hole transport layer, 5 mg of PMA was dissolved in 1 ml of methanol, spin-coated onto the active layer to obtain the hole transport layer, and then annealed at 100°C for 5 min. All other steps were the same as in the previous example.

[0055] Using a solar simulator and an AM1.5G solar spectral filter, at 100mW / cm²... –2 Photovoltaic performance tests were performed on the device under varying light intensity, calibrated using a standard polycrystalline silicon solar cell. The tests yielded short-circuit current, open-circuit voltage, fill factor, and photoelectric conversion efficiency, as shown in the table below:

[0056]

[0057] Therefore, in the device testing of this invention, the wet hole transport layer prepared by combining PMA and VTMS exhibits significant advantages: this layer not only has excellent hole transport capability, but can also replace traditionally vapor-deposited MoO3, achieving an open-circuit voltage of up to 0.846V and a short-circuit current density of 27.97 mA / cm². More importantly, the M–O–Si bonding and three-dimensional cross-linked network structure formed during the annealing process endows the film with excellent mechanical strength, effectively resisting high-energy ion bombardment during magnetron sputtering electrodes. Comparative experiments show that the performance of traditional wet hole transport layers drops sharply after sputtering, while the hole transport layer in this scheme allows the device to maintain complete functionality, ultimately achieving a high photoelectric conversion efficiency of 18.08%. This fully demonstrates that it achieves full wet process compatibility while possessing both high performance and high stability, solving the core problem that wet devices cannot withstand sputtering processes.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for fabricating an all-wet inverted organic solar cell based on a sputtered electrode, characterized in that, Includes the following steps: Step 1: Clean and perform surface activation pretreatment on the substrate and transparent conductive electrode composite layer; Step 2: Mix the solution-processable metal oxide with an organic solvent to prepare an electron transport layer dispersion, coat it onto a transparent conductive electrode layer by a wet coating method, and then anneal it to obtain a wet electron transport layer. Step 3: Dissolve the organic donor material and the organic acceptor material in an organic solvent to prepare an active layer solution. Coat the solution onto the wet electron transport layer using a wet coating method. After annealing, obtain the wet active layer. Step 4: Prepare a hole transport layer solution, which includes metal oxide clusters and silane coupling agents. The solution is coated onto a wet active layer by a wet coating method and then annealed to obtain a wet hole transport layer. The metal oxide clusters and silane coupling agents are combined to form a stable metal-oxygen-silicon bond structure during the annealing process. Step 5: Prepare a conductive electrode layer on the wet hole transport layer using magnetron sputtering.

2. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 1, characterized in that, The hole transport layer solution is prepared as follows: Metal-oxygen clusters were dissolved in an organic solvent to prepare a metal-oxygen cluster solution at room temperature. A silane coupling agent was added to the metal-oxygen cluster solution and stirred at room temperature to obtain a hole transport layer solution.

3. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 2, characterized in that, In the hole transport layer solution: The metal oxo clusters are polyoxoacid salts, including phosphotungstic acid and phosphomolybdic acid; The organic solvents include methanol and ethanol.

4. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 3, characterized in that, The silane coupling agent contains double bonds and hydrolyzable silicon groups, and the silane coupling agent includes vinyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane.

5. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 4, characterized in that, The hole transport layer solution is prepared as follows: The silane coupling agent accounts for 50-150% of the volume of the organic solvent, and the concentration of metal oxide clusters in the overall hole transport layer solution is between 0.5-10 mg / ml.

6. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 5, characterized in that, In step 4, the annealing temperature is 60-100℃, the annealing time is 5-20 min, and the thickness of the wet hole transport layer is between 10-50 nm.

7. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 6, characterized in that, In step 1, the preprocessing includes: Cleaning: The substrate and the transparent conductive electrode composite layer are sequentially ultrasonically cleaned with detergent, deionized water, acetone and isopropanol. After cleaning, the surface of the composite layer is dried with nitrogen. Surface activation treatment: The dried composite layer is cleaned with ozone.

8. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 7, characterized in that, In step 2: The preparation of the electron transport layer dispersion includes: mixing SnO2 or ZnO metal oxide with an organic solvent to obtain an electron transport layer dispersion with a concentration of 3-15 mg / ml. The annealing temperature is 60–150°C, and the annealing time is 5–20 min.

9. The method for fabricating a fully wet inverted organic solar cell based on a sputtered electrode according to claim 8, characterized in that, In step 3: The preparation of the active layer solution includes: dissolving an organic donor material and an organic acceptor material in a non-halogen solvent at a ratio of 0.5-1.5:0.5-1.5 in an inert atmosphere; The annealing temperature is 60-150℃, and the annealing time is 5-20min.

10. A fully wet inverting organic solar cell based on a sputtered electrode, comprising the method for fabricating a fully wet inverting organic solar cell based on a sputtered electrode according to any one of claims 1-9, characterized in that, It includes, from bottom to top, a substrate, a transparent conductive electrode layer, a wet electron transport layer, a wet active layer, a wet hole transport layer, and a sputtered electrode layer arranged in layers.

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