Perovskite photovoltaic devices, their passivation methods, and applications

Abstract

This invention provides perovskite photovoltaic devices, their passivation methods, and applications, belonging to the field of optoelectronic device technology. The passivation method of this invention involves applying a treatment solution or atmosphere containing a precursor component of a passivation material with the same core chemical structure as the transport layer used on the surface of a perovskite thin film. Simultaneously, the applied material also contains functionalized passivation groups, allowing it to form a film on the perovskite surface and undergo penetration and interaction, thus forming an isomorphic passivation layer in situ. This invention resolves the "passivation-transport" contradiction in traditional passivation technologies by generating a passivation layer isomorphic to the transport layer in situ, thereby improving device performance and stability.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic device technology, and in particular to perovskite photovoltaic devices, their passivation methods, and applications. Background Technology

[0002] Perovskite solar cells (PSCs) have achieved photoelectric conversion efficiencies comparable to traditional silicon cells; however, their commercialization still faces significant challenges. One of the most critical issues is the long-term stability of the devices. Numerous defects (such as halogen vacancies and uncoordinated lead ions) exist on the surface of the perovskite active layer and at the interface with the charge transport layer. These defects act as non-radiative recombination centers, significantly reducing the open-circuit voltage of the device. V OC The perovskite material's permeability and fill factor (FF) limit further improvements in power conversion efficiency (PCE). More importantly, these interface defects also act as channels for moisture and oxygen intrusion, inducing the decomposition of perovskite materials and leading to rapid degradation of device performance.

[0003] Existing surface passivation technologies (such as introducing passivation layers of insulating polymers or small organic molecules) can reduce interfacial recombination to some extent, but they often introduce new energy barriers between the perovskite and the transport layer, hindering charge extraction and transport, leading to a decrease in the fill factor, thus creating an inherent contradiction between "passivation" and "transport". Summary of the Invention

[0004] In view of this, in order to solve the technical problems of nonradiative recombination, charge transport obstruction and poor stability caused by interface defects in existing perovskite photovoltaic devices, this invention provides perovskite photovoltaic devices and their passivation methods and applications. By generating a passivation layer isomorphic to the transport layer in situ, the contradiction between "passivation and transport" in traditional passivation technology is resolved, thereby improving device performance and stability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a method for surface passivation of a perovskite photovoltaic device involves applying a treatment solution or atmosphere containing a precursor component of a passivation material with the same core chemical structure as the transport layer to the surface of a perovskite thin film. Simultaneously, the applied material also contains functionalized passivation groups, which allow it to form a film on the perovskite surface and undergo penetration and interaction, thereby forming an isomorphic passivation layer in situ.

[0006] Secondly, the present invention provides the application of the perovskite photovoltaic device surface passivation method in perovskite photovoltaic devices.

[0007] Thirdly, a perovskite photovoltaic device includes a substrate, a perovskite thin film, and a charge transport layer. An isomorphic passivation layer prepared by the above-described method is disposed between the perovskite light absorption layer and the charge transport layer of the perovskite photovoltaic device. The conduction band bottom or valence band top energy level of the isomorphic passivation layer is located between the corresponding energy levels of the perovskite light absorption layer and the charge transport layer, forming a gradient energy level structure.

[0008] Fourthly, the present invention also provides a photovoltaic module or solar cell, including the perovskite photovoltaic device described above.

[0009] Compared with the prior art, the present invention has the following beneficial effects: (1) Synergistic optimization of passivation and transport: The "isomorphic passivation layer" created in this invention achieves efficient chemical passivation by chemically interacting (such as coordination bonding) between the functional groups in the passivation molecule and the defects on the perovskite surface, significantly reducing the interface defect density and suppressing nonradiative recombination. At the same time, since the core functional chemical structure of this layer is the same as that of the charge transport layer above, there is no significant interface barrier between the two, forming an ideal ohmic contact and a continuous charge transport channel, ensuring the efficient extraction and transport of photogenerated carriers, and fundamentally resolving the conflict between "passivation" and "transport" in traditional passivation technology.

[0010] (2) Improved device performance: Based on the above synergistic effect, the present invention significantly improves the performance of perovskite solar cells. V OC This technology, along with FF (Flash Filter), achieves higher photoelectric conversion efficiency. Experiments have shown that devices using this technology exhibit higher photoelectric conversion efficiency. V OC Both FF and FF have seen significant improvements.

[0011] (3) Enhance device stability: The dense isomorphic passivation layer effectively blocks the direct contact between moisture and oxygen and the underlying perovskite material, while stabilizing the interface structure, significantly improving the long-term thermal and optical stability of the device from both physical and chemical dimensions.

[0012] (4) Simple process and strong compatibility: This preparation method does not require complex equipment or harsh process conditions, is easy to operate, and is highly compatible with the solution preparation process of existing mainstream perovskite devices, making it easy to promote large-scale production. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the surface passivation technology for perovskite photovoltaic devices based on transport layer isomorphism in this invention.

[0014] Figure 2Examples of molecular chemical structure diagrams illustrating isomorphism strategies employed in different transport layer material systems in formal and inverse devices. Here, a represents the structure of a perovskite solar photovoltaic device with a formal structure, and b represents the chemical structure of the hole transport material spiro-OMeTAD and the passivation material. 4,4',4''- Chemical structure diagrams of triphenylamine triformate and fluorene-9-acetic acid, c is the structure diagram of a perovskite solar photovoltaic device with a trans structure, and d is the chemical structure diagram of the battery transport material PCBM and the passivation material PCBA.

[0015] Figure 3 This is a mechanism diagram for the passivation of perovskite thin films using the isomorphism strategy in Example 1.

[0016] Figure 4 This is a schematic diagram illustrating the mechanism of perovskite thin film passivation using the isomorphism strategy in Example 2.

[0017] Figure 5 This is a schematic diagram illustrating the mechanism of perovskite thin film passivation using an isomorphism strategy in Example 3.

[0018] Figure 6 The image shows the current-voltage curve of the perovskite solar cell device obtained in Example 1 under standard sunlight irradiation. The device that did not undergo step 4 is referred to as the unpassivated perovskite photovoltaic device and serves as the control group for Example 1.

[0019] Figure 7 The image shows the current-voltage curve of the perovskite solar cell device obtained in Example 2 under standard sunlight irradiation. The device that did not undergo step 4 is referred to as the unpassivated perovskite photovoltaic device and serves as the control group for Example 2.

[0020] Figure 8 The image shows the current-voltage curve of the perovskite solar cell device obtained in Example 3 under standard sunlight irradiation. The device that did not undergo step 4 is referred to as the unpassivated perovskite photovoltaic device and serves as the control group for Example 3. Detailed Implementation

[0021] like Figure 1 As shown, this invention provides a method for surface passivation of perovskite photovoltaic devices. A treatment solution or atmosphere containing a passivation material precursor component with the same core chemical structure as the transport layer is applied to the surface of the perovskite thin film, causing it to form a film on the perovskite surface and undergo penetration and interaction, thus forming an isomorphic passivation layer in situ. The passivation material has the same or similar chemical composition as the transport layer, wherein the transport layer can be an electron transport layer or a hole transport layer. Electron transport layer materials include PCBM, C60, or fullerene derivatives; hole transport layer materials include spiro-OMeTAD, PTAA, triphenylamine derivatives (such as...). 4,4',4''- Triphenylamine triformate or fluorene derivatives (such as fluoreneacetic acid), etc. The concentration of the treatment solution ranges from 0.1 mg / mL to 10 mg / mL. The interaction is achieved by annealing at 150 °C for 0 to 30 minutes. The thickness of the isomorphic passivation layer is 1 to 20 nm, and it is applied by one of spin coating, blade coating, spray coating, or vapor deposition.

[0022] The surface passivation method for perovskite photovoltaic devices specifically includes the following steps: (1) Substrate and perovskite layer preparation: A perovskite light-absorbing layer was prepared on an FTO / ITO glass substrate. The chemical formula of this perovskite layer is ABX3, where A is methylammonium ion (MA). + ), formamidinium ion (FA) + ) or cesium ions (Cs + B represents lead ions (Pb). 2 + ) and / or tin ions (Sn 2+ X represents iodide ions (I); - ), bromide ions (Br) - ), chloride ions (Cl) - One or two of the following. The thickness of the perovskite layer is preferably 100-1000 nm.

[0023] (2) Preparation of isomorphic passivation layer: A treatment solution or atmosphere containing an isomorphic passivating agent is applied to the surface of the perovskite light-absorbing layer. This can be done during or after the preparation of the perovskite thin film. The passivating agent can be in solution form (such as a chlorobenzene / isopropanol solution of PCBM or its derivatives, a chlorobenzene / isopropanol solution of Spiro-OMeTAD or a triphenylamine derivative) or in gas phase form.

[0024] (3) After preparation by spin coating, spraying, or vapor deposition, anneal at room temperature to 150°C for 0 to 20 minutes. The passivation layer functional groups and uncoordinated ions (such as Pb) on the perovskite surface... 2+ Coordination occurs, forming a dense isomorphic passivation layer with a thickness controlled between 1 nm and 20 nm.

[0025] (4) Charge transport layer preparation: Prepare charge transport layers with the same or similar chemical composition (such as electron transport layer PCBM, or hole transport layer Spiro-OMeTAD, PTAA) on the isomorphic passivation layer. The passivation layer and the transport layer have similar chemical structures, and the two form a near-perfect interface fusion and band alignment.

[0026] The working principle of this invention is as follows: An ultrathin passivation layer is generated on the surface of the perovskite light-absorbing layer using a passivation material with a structure similar to that of the transport layer. This isomorphic passivation material partially penetrates to the grain boundaries of the perovskite film, forming a concentration gradient distribution from the surface inwards. This interface layer, with a chemical composition identical or similar to the upper electron transport layer (ETL) or hole transport layer (HTL), significantly improves charge extraction efficiency. Simultaneously, the Lewis acid-base functional groups of the passivation layer effectively passivate surface defects in the perovskite film, reducing non-radiative recombination energy loss in the device. This interface layer combines energy level buffering and defect passivation functions, achieving efficient suppression of interface defects and efficient charge extraction.

[0027] The technical solution of the present invention will be clearly and thoroughly described below with reference to specific embodiments.

[0028] Example 1 use 4,4',4'' - Triphenylamine tricarboxylate molecules are used as isomorphic passivation molecules on the surface of perovskite thin films in Spiro-OMeTAD hole transport layers. nip Taking a perovskite solar cell as an example, the fabrication method includes the following steps: Step 1: Cleaning ITO glass: Clean the ITO conductive glass sequentially with dish soap water, deionized water, acetone, ethanol and isopropanol ultrasonically for 10 minutes, then dry the cleaned ITO conductive glass with an air gun, and treat it with a UV ozone cleaner for 30 minutes.

[0029] Step 2: Preparation of Transport Layer 1 (SnO2): The SnO2 hydrocolloid dispersion was diluted 1:3 with ultrapure water in ambient air and then spin-coated onto the ITO substrate at 3000 rpm for 30 s. Finally, the spin-coated film was annealed at 150 °C for 30 min on a heating stage. After annealing, it was stored in a nitrogen glove box for later use.

[0030] Step 3: Preparation of the perovskite layer: The perovskite layer was prepared in ambient air using a two-step deposition method. The perovskite composition was FA. 0.95 Cs 0.05PbI3. The PbI2 precursor solution was prepared by dissolving 360 mg PbI2 and 10.2 mg CsI in 600 μL of a mixed solution (DMF:DMSO (v / v=95:5)). The FAI precursor solution was prepared by adding 78 mg FAI and 15.2 mg MACl to 1300 μL of IPA. All solutions were completely dissolved and set aside for use. Before spin-coating the perovskite solution, the prepared ITO glass containing transport layer 1 (SnO2) was treated with a UV ozone cleaner for 30 min. First, 20 μL of PbI2 solution was spin-coated onto the SnO2 substrate at 2000 rpm for 60 s. When the spin-coating time reached 50 s, 40 μL of FAI precursor solution was added dropwise. After spin-coating, the spin-coated perovskite film was immediately transferred to a hot plate at 150 °C for annealing for 11 min.

[0031] Step 4: Preparation of the isomorphic passivation layer: Select 4,4',4'' - Triphenylamine triformate was used as an isomorphic passivation material, and triphenylamine triformate (whose molecular structure is as follows) was used as an isomorphic passivation material. Figure 2 (As shown in a) The powder was dissolved in IPA. After the solution was completely dissolved, 40 μL of triphenylamine triformate solution was spin-coated onto the perovskite film surface at 3500 rpm for 30 s.

[0032] Step 5: Preparation of Transport Layer 2 (Spiro-OMeTAD): 36.15 mg of spiro-OMeTAD was dissolved in 500 μL CCB, and 14.4 μL of TBP and 8.8 μL of Li-TFSI (520 mg of Li-TFSI dissolved in 1 mL CAN) were added to form a mixed solution. The resulting spiro-OMeTAD mixed solution was spin-coated onto the perovskite film surface at 3500 rpm. The spin-coating time of the spiro-OMeTAD mixed solution was 30 s.

[0033] Step 6: Fabrication of the metal electrode: Under vacuum conditions, a metal electrode (Ag) with a thickness of 80 nm is deposited on the surface of transport layer 2 (Spiro-OMeTAD) by evaporation.

[0034] After completing the above steps, the perovskite solar cell with the nip formal structure based on Spiro-OMeTAD as the hole transport layer is obtained.

[0035] Example 1: The structure of the perovskite solar cell device is as follows Figure 2 As shown in Figure a. The corresponding passivation schematic is shown in Figure a. Figure 3 As shown.

[0036] Figure 3 for 4,4',4''- A schematic diagram illustrating the mechanism of triphenylamine tricarboxylate passivation of perovskite films. From Figure 3 It can be found 4,4', 4'' - Triphenylamine triformate possesses the same triphenylamine core structure as the spiro-OMeTAD hole transport layer. Meanwhile... 4,4', 4'' The three carboxylic acid groups of triphenylamine tricarboxylate can effectively passivate defects on the surface of perovskite thin films.

[0037] like Figure 6 As shown, the device that did not undergo step 4 is called an unpassivated perovskite photovoltaic device, which serves as the control group for Example 1.

[0038] from Figure 6 The voltage-current curve shows that 4,4',4'' The triphenylamine tricarboxylate isomorphic passivation strategy significantly improved the performance of perovskite solar cells. V OC And FF, thus improving the photoelectric conversion efficiency. This shows that by using 4,4',4'' The isomorphic passivation of triphenylamine tricarboxylate significantly reduced the defect density on the perovskite film surface and suppressed nonradiative recombination. Meanwhile, due to... 4,4',4'' The triphenylamine tricarboxylate passivation layer and the Spiro-OMeTAD hole transport layer have the same chemical structure and excellent interfacial contact, forming an ideal ohmic contact and a continuous charge transport channel, ensuring efficient extraction and transport of photogenerated carriers. Therefore, the device's... V OC Both FF and FF have been significantly improved.

[0039] Example 2 Fluorene-9-acetic acid was used as a surface isomorphic passivation molecule for perovskite thin films in the Spiro-OMeTAD hole transport layer. nip Taking a perovskite solar cell as an example, the fabrication method includes the following steps: Step 1: Cleaning ITO glass: Clean the ITO conductive glass sequentially with dish soap water, deionized water, acetone, ethanol and isopropanol ultrasonically for 10 minutes, then dry the cleaned ITO conductive glass with an air gun, and treat it with a UV ozone cleaner for 30 minutes.

[0040] Step 2: Preparation of Transport Layer 1 (SnO2): The SnO2 hydrocolloid dispersion was diluted 1:3 with ultrapure water in ambient air and then spin-coated onto an ITO substrate at 3000 rpm. Finally, the spin-coated film was annealed at 150°C for 30 min on a heating stage. Transport Layer 1 was prepared by spin-coating the diluted SnO2 hydrocolloid dispersion for 30 s. After annealing, the film was stored in a nitrogen glove box for later use.

[0041] Step 3: Preparation of the perovskite layer: The perovskite layer was prepared in ambient air using a two-step deposition method. The perovskite composition was FA. 0.95 Cs 0.05 PbI3. The PbI2 precursor solution was prepared by dissolving 360 mg PbI2 and 10.2 mg CsI in 600 μL of a mixed solution (DMF:DMSO (v / v=95:5)), and the FAI precursor solution was prepared by adding 78 mg FAI and 15.2 mg MACl to 1300 μL of IPA. All solutions were completely dissolved and set aside for use. Before spin-coating the perovskite solution, the prepared ITO glass containing transport layer 1 (SnO2) was treated with a UV ozone cleaner for 30 min. First, 20 μL of PbI2 solution was spin-coated onto the SnO2 substrate at 2000 rpm for 60 s. When the spin-coating time reached 50 s, 40 μL of FAI precursor solution was added dropwise. After spin-coating, the spin-coated perovskite film was immediately transferred to a hot plate at 150℃ and annealed for 11 min.

[0042] Step 4: Preparation of the isomorphic passivation layer: Fluorene-9-acetic acid was selected as the isomorphic passivation material. Fluorene-9-acetic acid (its molecular structure is as follows) was prepared by... Figure 2 (As shown in b) The powder was dissolved in ultrapure water. After the solution was completely dissolved, 20 μL of fluorene-9-acetic acid solution was spin-coated onto the perovskite film surface at 3500 rpm for 30 s.

[0043] Step 5: Preparation of Transport Layer 2 (Spiro-OMeTAD): 36.15 mg of spiro-OMeTAD was dissolved in 500 μL of CB, and 14.4 μL of TBP and 8.8 μL of Li-TFSI (520 mg of Li-TFSI dissolved in 1 mL of CAN) were added to form a mixed solution. The resulting spiro-OMeTAD mixed solution was spin-coated onto the perovskite film surface at 3500 rpm. The spin-coating time of the spiro-OMeTAD mixed solution was 30 s.

[0044] Step 6: Fabrication of the metal electrode: Under vacuum conditions, a metal electrode (Ag) with a thickness of 80 nm is deposited on the surface of transport layer 2 (Spiro-OMeTAD) by evaporation.

[0045] After completing the above steps, the hole transport layer is obtained as Spiro-OMeTAD. nip A perovskite solar cell with a formal structure.

[0046] Example 2: The structure of the perovskite solar cell device is as follows Figure 2 As shown in Figure a. The corresponding passivation schematic is shown in Figure a. Figure 4 As shown.

[0047] Figure 4 This is a schematic diagram illustrating the mechanism of fluorene-9-acetic acid passivation of perovskite films. From... Figure 4 It can be found that fluorene-9-acetic acid shares the same fluorene group structure as the hole transport layer spiro-OMeTAD. Furthermore, the carboxylic acid group at the tail of fluorene-9-acetic acid can effectively passivate defects on the perovskite film surface.

[0048] like Figure 7 As shown, the device that did not undergo step 4 is called an unpassivated perovskite photovoltaic device, which serves as the control group for Example 2.

[0049] from Figure 7 The voltage-current curves show that the isomorphic passivation strategy of fluorene-9-acetic acid significantly improves the performance of perovskite solar cells. V OC The fluorene-9-acetic acid passivation layer and the Spiro-OMeTAD hole transport layer share the same fluorene chemical structure, resulting in excellent interfacial contact. This forms an ideal ohmic contact and a continuous charge transport channel, ensuring efficient extraction and transport of photogenerated carriers. Therefore, the device's... V OC Both FF and FF have been significantly improved.

[0050] Example 3 PCBA molecules are used as isomorphic passivation molecules on the surface of perovskite thin films in the electron transport layer of PCBM. pin Taking a perovskite solar cell as an example, the fabrication method includes the following steps: Step 1: Cleaning ITO glass: Clean the ITO conductive glass sequentially with dish soap, deionized water, acetone, ethanol and isopropanol using ultrasonic cleaning for 15 minutes each. Then, place the cleaned ITO conductive glass in a 75°C oven to dry for more than 12 hours.

[0051] Step 2: NiO X Preparation of the SAM hole transport layer: After cleaning, the ITO conductive glass was treated with UV ozone for 20 min, then spin-coated with a 10 mg / mL nickel oxide solution at 2000 rpm for 30 s, followed by annealing at 150°C for 30 min. Next, a 0.5 g / mL MeO-4PACz solution was spin-coated at 4000 rpm for 30 s, and annealed at 100°C for 10 min. The glass was then cooled to room temperature before use.

[0052] Step 3: Preparation of the perovskite layer: FAI, PbI2, and CsI are mixed in a DMF:DMSO mixed solvent (v / v=4:1), with the chemical formula CsI. 0.05 FA 0.95A 1.4 M perovskite precursor solution was prepared using PbI3. Then, excess amounts of 5% PbI2, 3% PbCl2, and 10% MACl were added to the precursor solution. Finally, 50 μL of the prepared precursor solution was spin-coated at 2000 rpm for 10 s and 5000 rpm for 50 s onto a NiO-based substrate. X On the ITO substrate of / SAM, 170 μLLCB was dropped onto the film as an antisolvent 5 seconds before the end of the last process, and finally annealed at 100 °C for 30 min.

[0053] Step 4: Preparation of the isomorphic passivation layer: PCBA molecules are selected as the isomorphic passivation material, and PCBA (whose molecular structure is as follows) is applied to the surface. Figure 2 (As shown in d) The powder was dissolved in CB. After the solution was completely dissolved, 20 μL of PCBA solution was spin-coated onto the perovskite film surface at 5000 rpm for 30 s, and then annealed at 100°C for 10 min.

[0054] Step 5: Preparation of the electron transport layer PCBM: Dissolve 20 mg of PCBM in 1000 μL of CB. After the solution is fully dissolved, spin-coat the PCBM solution onto the perovskite film surface at 1800 rpm. The spin-coating time for the PCBM solution is 30 s. The PCBM solution needs to be filtered before spin-coating.

[0055] Step 6: Fabrication of metal electrode: Under vacuum conditions, a metal electrode (Ag) with a thickness of 100 nm is deposited on the surface of transport layer 2 (PCBM) by evaporation.

[0056] After completing the above steps, the hole transport layer is obtained as PCBM. pin Inverted perovskite solar cells.

[0057] Example 3: The structure of the perovskite solar cell device is as follows Figure 2 As shown in Figure c. The corresponding passivation diagram is shown below. Figure 5 As shown.

[0058] Figure 5 This is a schematic diagram illustrating the mechanism of PCBA passivation of perovskite thin films. From... Figure 5 It can be observed that the PCBA and the electron transport layer PCBM share the same C60 core structure. Furthermore, the carboxylic acid groups at the tail of the PCBA can effectively passivate defects on the perovskite film surface.

[0059] like Figure 8 As shown, the device that did not undergo step 4 is called an unpassivated perovskite photovoltaic device, which serves as the control group for Example 3.

[0060] from Figure 8 The voltage-current curves show that the isomorphic passivation strategy of the PCBA significantly improves the performance of perovskite solar cells. V OC The use of PCBA and FF (fullerene ionization) improves photoelectric conversion efficiency. This indicates that isomorphic passivation using PCBA significantly reduces the defect density on the perovskite film surface and suppresses nonradiative recombination. Simultaneously, because the PCBA layer and the PCBM electron transport layer share the same fullerene chemical structure, they have excellent interfacial contact, forming an ideal ohmic contact and a continuous charge transport channel, ensuring efficient extraction and transport of photogenerated carriers. Therefore, the device's... V OC Both FF and FF have been significantly improved.

[0061] The above description is merely a preferred embodiment of the present invention. However, 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 should be covered within the scope of protection of the present invention.

Claims

1. A method for surface passivation of perovskite photovoltaic devices, characterized in that, A treatment solution containing a precursor component of a passivation material with the same core chemical structure as the transport layer is applied to the surface of a perovskite film. The applied material also contains functionalized passivation groups, which allows it to form a film on the perovskite surface and undergo penetration and interaction, thus forming an isomorphic passivation layer in situ. passivation material is 4,4',4'' -Triphenylamine triformate molecule or PCBA molecule; The interaction method is annealing, the annealing temperature is 150℃, and the treatment time is 0~30 minutes; The transport layer is an electron transport layer or a hole transport layer. The electron transport layer is made of materials including PCBM, C60, or fullerene derivatives, and the hole transport layer is made of materials including spiro-OMeTAD, PTAA, triphenylamine derivatives, or fluorene derivatives.

2. The perovskite photovoltaic device surface passivation method according to claim 1, characterized in that, The concentration of the treatment solution is from 0.1 mg / mL to 10 mg / mL.

3. The perovskite photovoltaic device surface passivation method according to claim 1, characterized in that, The thickness of the isomorphic passivation layer is 1~20 nm.

4. A method for surface passivation of a perovskite photovoltaic device according to any one of claims 1-3, characterized in that, The application method is one of spin coating, blade coating, spray coating or vapor deposition.

5. The application of the perovskite photovoltaic device surface passivation method according to any one of claims 1-4 in perovskite photovoltaic devices.

6. A perovskite photovoltaic device, comprising a substrate, a perovskite thin film, and a charge transport layer, characterized in that, An isomorphic passivation layer prepared by any one of claims 1-4 is disposed between the perovskite light absorption layer and the charge transport layer of the perovskite photovoltaic device, wherein the conduction band bottom or valence band top energy level of the isomorphic passivation layer is located between the corresponding energy levels of the perovskite light absorption layer and the charge transport layer, forming a gradient energy level structure.

7. A photovoltaic module or solar cell, characterized in that, Including the perovskite photovoltaic device as described in claim 6.

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