Perovskite solar cell based on composite hole barrier layer and preparation method thereof

Abstract

The invention relates to a perovskite solar cell based on a composite hole barrier layer and a preparation method thereof, and the structure of the perovskite solar cell comprises a transparent substrate, a transparent conductive layer, a hole transmission layer, a perovskite light absorption layer, an electron transmission layer and a back electrode layer from the bottom to the top. A composite hole blocking layer is arranged between the electron transmission layer and the back electrode layer, the composite hole blocking layer comprises an organic hole blocking layer and a concentration gradient inorganic hole blocking layer, the preparation material of the organic hole blocking layer is at least one of BCP, Bphen and TPBI, and the concentration gradient inorganic hole blocking layer is a concentration gradient film from In2O3 to In through gradual oxygen loss. The organic-inorganic composite film composed of BCP and InOx is introduced between the electron transmission layer and the back electrode layer to serve as the composite hole blocking layer, and the electron hole recombination process is effectively inhibited. In addition, the InOx thin film can effectively block the reaction between halide ions in the perovskite and the back electrode, so that the photoelectric conversion efficiency and stability of the perovskite solar cell are improved.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell fabrication technology, and specifically relates to a perovskite solar cell based on a composite hole-blocking layer and its fabrication method. Background Technology

[0002] Perovskite solar cells are a type of solar cell that uses compounds with an ABX3 structure as light-absorbing materials, where A = MA, FA, Cs, etc., B = Pb, Sn, etc., and X = I, Br, Cl, etc. Taking the inverse structure as an example, the basic structure of a perovskite solar cell includes a transparent substrate, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a hole blocking layer, and a back electrode.

[0003] In existing technologies, hole-blocking layers are composed of organic thin-film materials to block hole transport and suppress carrier recombination. However, traditional single-layer organic hole-blocking layer materials have poor conductivity, requiring them to be as thin as possible to avoid affecting carrier transport; but if they are too thin, they cannot completely cover the surface of the electron transport layer. Simultaneously, the bonding force between the metal back electrode layer and the organic hole-blocking layer is weak, leading to difficulties in charge transport. Furthermore, organic hole-blocking layers are ineffective at preventing the reaction between halide ions in perovskites and the metal back electrode, resulting in poor stability of perovskite solar cells. Therefore, there is a need to develop new hole-blocking layer thin films and their fabrication processes. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a perovskite solar cell based on a composite hole blocking layer and a method for its preparation. By introducing an organic-inorganic composite hole blocking layer between the electron transport layer and the back electrode, hole transport is suppressed, thereby suppressing electron-hole recombination, improving the hole blocking effect of the positive electrode of the perovskite solar cell, and further suppressing the reaction between perovskite halide ions and the back electrode, thereby improving the photoelectric conversion efficiency and stability of the perovskite device.

[0005] This invention is implemented as follows: a perovskite solar cell based on a composite hole-blocking layer is provided. The structure of the perovskite solar cell includes, from bottom to top, a transparent substrate, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a back electrode layer. A composite hole-blocking layer is disposed between the electron transport layer and the back electrode layer. The composite hole-blocking layer includes an organic hole-blocking layer and a concentration gradient inorganic hole-blocking layer. The organic hole-blocking layer is prepared by at least one of BCP, Bphen, and TPBI. The concentration gradient inorganic hole-blocking layer is a concentration gradient film that gradually loses oxygen from In2O3 to In.

[0006] The concentration gradient inorganic hole blocking layer of the present invention adopts a concentration gradient film from In2O3 to In, mainly because, on the one hand, it can promote electron transport, and on the other hand, In has a low melting point of only 156.6°C, which is beneficial for atomic recombination to repair defects during the service of perovskite solar cells.

[0007] Furthermore, the thickness of the composite hole blocking layer is 5nm~50nm.

[0008] Furthermore, the transparent conductive layer is prepared from one of IZO, ITO, AZO, and FTO.

[0009] Furthermore, the perovskite light-absorbing layer is prepared from an organic-inorganic hybrid perovskite material or an all-inorganic perovskite material, with a band gap of 1.4 eV to 2.0 eV; the thickness of the perovskite light-absorbing layer is 200 nm to 1500 nm.

[0010] Furthermore, the electron transport layer is prepared using TiO2 as the material. x NbO x SnO x Any one of ZnO, PCBM, and C60.

[0011] Furthermore, the material used to fabricate the hole transport layer includes NiO. x Any one of PEDOT:PSS, Spiro-OMeTAD, or CuSCN.

[0012] Furthermore, the back electrode layer is a metal electrode layer or a transparent electrode layer. The metal electrode layer is prepared from any one of Cu, Ag, Au, Mo, and Al or an alloy thereof, and the transparent electrode layer is prepared from any one of IZO, AZO, FTO, and ITO.

[0013] This invention is achieved by providing a method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described above, comprising the following steps: Step 1: Sequentially prepare a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a transparent substrate. First, deposit an organic hole-blocking layer on the surface of the electron transport layer using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer as the evaporation source, at a depth of 1*10. -3 Pa~1*10 -5 Evaporation was carried out under a vacuum of Pa, with an evaporation rate of 0.01~10 Å / s; Step 2: Then, a thermal evaporation process is used, with In as the evaporation source and oxygen as the reactant gas, at a temperature of 1*10... -1 Pa~1*10 -5Evaporation was performed under a vacuum of Pa, with the oxygen flow rate gradually decreasing from 20 sccm to 0 sccm, so that InO x The thin film gradually transitions from In2O3 to pure metallic In, with a deposition rate ranging from 0.01 to 10 Å / s, to prepare a concentration gradient inorganic hole-blocking layer. Step 3: Prepare the back electrode layer on the surface of the concentration gradient inorganic hole blocking layer using thermal evaporation or magnetron sputtering vacuum coating process to complete the fabrication of the perovskite solar cell.

[0014] This invention is achieved by providing a method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described above, comprising the following steps: Step 1: Sequentially prepare a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a transparent substrate. First, deposit an organic hole-blocking layer on the surface of the electron transport layer using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer as the evaporation source, at a depth of 1*10. -3 Pa~1*10 -5 Evaporation was carried out under a vacuum of Pa, with an evaporation rate of 0.01~10 Å / s; Step 2: Employ electron beam evaporation, using In as the evaporation source and oxygen as the reactant gas, at a density of 1*10... -1 Pa~1*10 -5 Evaporation was performed under a vacuum of Pa, with the oxygen flow rate gradually decreasing from 20 sccm to 0 sccm, so that InO x The thin film gradually transitions from In2O3 to pure metallic In, with a deposition rate ranging from 0.01 to 10 Å / s, to prepare a concentration gradient inorganic hole-blocking layer. Step 3: Prepare the back electrode layer on the surface of the concentration gradient inorganic hole blocking layer using thermal evaporation or magnetron sputtering vacuum coating process to complete the fabrication of the perovskite solar cell.

[0015] This invention is achieved by providing a method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described above, comprising the following steps: Step A, Step 1: Sequentially prepare a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a transparent substrate. First, deposit an organic hole-blocking layer on the surface of the electron transport layer using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer as the evaporation source, at a depth of 1*10. -3 Pa~1*10 -5 Evaporation was carried out under a vacuum of Pa, with an evaporation rate of 0.01~10 Å / s; Step B: Using DC or RF magnetron sputtering, with In as the sputtering target and an argon-oxygen mixture or pure oxygen as the process gas, magnetron sputtering is performed under a vacuum between 0.01 Pa and 10 Pa. The oxygen flow rate is gradually reduced from 20 sccm to 0 sccm, so that InO x The film gradually transitions from In2O3 to pure metallic In, and the sputtering rate is 0.01~10 Å / s to prepare a concentration gradient inorganic hole blocking layer. Step C: Prepare the back electrode layer on the surface of the concentration gradient inorganic hole blocking layer using thermal evaporation or magnetron sputtering vacuum coating process to complete the fabrication of the perovskite solar cell.

[0016] Compared with existing technologies, the present invention provides a perovskite solar cell based on a composite hole-blocking layer and its fabrication method. The perovskite solar cell structure includes, from bottom to top, a transparent substrate, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a back electrode layer. A composite hole-blocking layer is disposed between the electron transport layer and the back electrode layer. The composite hole-blocking layer includes an organic hole-blocking layer and a concentration gradient inorganic hole-blocking layer. The organic hole-blocking layer is prepared from at least one of BCP, Bphen, and TPBI. The concentration gradient inorganic hole-blocking layer is a concentration gradient film from In₂O₃ gradually losing oxygen to In. The present invention introduces a layer composed of BCP and InO₂ between the electron transport layer and the back electrode layer. x The organic-inorganic composite thin film, acting as a recombination hole blocking layer, effectively suppresses the electron-hole recombination process. Meanwhile, InO... x The thin film can also effectively block the reaction between halide ions in the perovskite and the back electrode. Furthermore, when the back electrode is fabricated using magnetron sputtering, InO... x Inorganic thin films can also effectively eliminate sputtering damage, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a preferred embodiment of the perovskite solar cell based on a composite hole blocking layer of the present invention; Figure 2 This is a schematic diagram showing the light efficiency test of the perovskite solar cells prepared in Example 1 and the comparative example of the present invention. Figure 3 This is a schematic diagram of the aging stability test of the perovskite solar cells prepared in Example 1 and the comparative example of the present invention. Detailed Implementation

[0018] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0019] Please refer to Figure 1 As shown, a preferred embodiment of the perovskite solar cell based on a composite hole blocking layer of the present invention is described. The structure of the perovskite solar cell includes, from bottom to top, a transparent substrate 1, a transparent conductive layer 2, a hole transport layer 3, a perovskite light-absorbing layer 4, an electron transport layer 5, and a back electrode layer 9. A composite hole blocking layer 6 is disposed between the electron transport layer 5 and the back electrode layer 9. The composite hole blocking layer 6 includes an organic hole blocking layer 7 and a concentration gradient inorganic hole blocking layer 8.

[0020] The organic hole blocking layer 7 is prepared from at least one of BCP, Bphen, and TPBI, and the concentration gradient inorganic hole blocking layer 8 is a concentration gradient film that gradually loses oxygen from In2O3 to In.

[0021] The thickness of the composite hole blocking layer 6 is 5nm~50nm.

[0022] The transparent conductive layer 2 is made of one of IZO, ITO, AZO, or FTO.

[0023] The perovskite light-absorbing layer 4 is made of organic-inorganic hybrid perovskite material or all-inorganic perovskite material, with a band gap of 1.4 eV to 2.0 eV; the thickness of the perovskite light-absorbing layer 4 is 200 nm to 1500 nm.

[0024] The electron transport layer 5 is prepared using TiO2 as the material. x NbO x SnO x Any one of ZnO, PCBM, and C60.

[0025] The hole transport layer 3 is prepared using NiO as the material. x Any one of PEDOT:PSS, Spiro-OMeTAD, or CuSCN.

[0026] The back electrode layer 9 is a metal electrode layer or a transparent electrode layer. The metal electrode layer is made of any one of Cu, Ag, Au, Mo, Al or an alloy thereof, and the transparent electrode layer is made of any one of IZO, AZO, FTO or ITO.

[0027] This invention also discloses a method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described above, comprising the following steps: Step 1: Sequentially prepare a transparent conductive layer 2, a hole transport layer 3, a perovskite light-absorbing layer 4, and an electron transport layer 5 on a transparent substrate 1. First, deposit an organic hole-blocking layer 7 on the surface of the electron transport layer 5 using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer 7 as the evaporation source, at a depth of 1*10 mm. -3 Pa~1*10 -5 Evaporation was performed under a vacuum of 0.01 to 10 Å / s.

[0028] Step 2: Then, a thermal evaporation process is used, with In as the evaporation source and oxygen as the reactant gas, at a temperature of 1*10... -1 Pa~1*10 -5 Evaporation was performed under a vacuum of Pa, with the oxygen flow rate gradually decreasing from 20 sccm to 0 sccm, so that InO x The thin film gradually transitions from In2O3 to pure metallic In, with a deposition rate ranging from 0.01 to 10 Å / s, to prepare a concentration gradient inorganic hole blocking layer 8.

[0029] Step 3: Prepare the back electrode layer 9 on the surface of the concentration gradient inorganic hole blocking layer 8 using thermal evaporation or magnetron sputtering vacuum deposition process to complete the fabrication of the perovskite solar cell. Alternatively, the fabricated perovskite solar cell can be further annealed. The annealing method is as follows: anneal the transparent substrate 1 on which the back electrode layer 9 has been prepared, with an annealing temperature range of 80℃~160℃ and an annealing time of 20s~600s.

[0030] This invention also discloses a method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described above, comprising the following steps: Step 1: Sequentially prepare a transparent conductive layer 2, a hole transport layer 3, a perovskite light-absorbing layer 4, and an electron transport layer 5 on a transparent substrate 1. First, deposit an organic hole-blocking layer 7 on the surface of the electron transport layer 5 using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer 7 as the evaporation source, at a depth of 1*10 -3 Pa~1*10 -5 Evaporation was performed under a vacuum of 0.01 to 10 Å / s.

[0031] Step 2: Employ electron beam evaporation, using In as the evaporation source and oxygen as the reactant gas, at a density of 1*10... -1 Pa~1*10 -5 Evaporation was performed under a vacuum of Pa, with the oxygen flow rate gradually decreasing from 20 sccm to 0 sccm, so that InO x The thin film gradually transitions from In2O3 to pure metallic In, with a deposition rate ranging from 0.01 to 10 Å / s, thus preparing a concentration gradient inorganic hole-blocking layer.

[0032] Step 3: Prepare the back electrode layer 9 on the surface of the concentration gradient inorganic hole blocking layer 8 using thermal evaporation or magnetron sputtering vacuum deposition process to complete the fabrication of the perovskite solar cell. Alternatively, the fabricated perovskite solar cell can be further annealed. The annealing method is as follows: anneal the transparent substrate 1 on which the back electrode layer 9 has been prepared, with an annealing temperature range of 80℃~160℃ and an annealing time of 20s~600s.

[0033] This invention also discloses a method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described above, comprising the following steps: Step A: Sequentially prepare a transparent conductive layer 2, a hole transport layer 3, a perovskite light-absorbing layer 4, and an electron transport layer 5 on a transparent substrate 1. First, deposit an organic hole-blocking layer 7 on the surface of the electron transport layer 5 using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer 7 as the evaporation source, at a depth of 1*10 -3 Pa~1*10 -5 Evaporation was performed under a vacuum of 0.01 to 10 Å / s.

[0034] Step B: Using DC or RF magnetron sputtering, with In as the sputtering target and an argon-oxygen mixture or pure oxygen as the process gas, magnetron sputtering is performed under a vacuum between 0.01 Pa and 10 Pa. The oxygen flow rate is gradually reduced from 20 sccm to 0 sccm, so that InO x The film gradually transitions from In2O3 to pure metallic In, with a sputtering rate of 0.01~10 Å / s, to prepare a concentration gradient inorganic hole blocking layer.

[0035] Step C: Prepare the back electrode layer 9 on the surface of the concentration gradient inorganic hole blocking layer 8 using thermal evaporation or magnetron sputtering vacuum deposition process to complete the fabrication of the perovskite solar cell. Alternatively, the fabricated perovskite solar cell can be further annealed. The annealing method is as follows: anneal the transparent substrate 1 on which the back electrode layer 9 has been prepared, with an annealing temperature range of 80℃~160℃ and an annealing time of 20s~600s.

[0036] The InO involved in this invention x The preparation process of concentration gradient inorganic hole-blocking layers includes vacuum deposition processes such as thermal evaporation, electron beam evaporation, and magnetron sputtering. Its main characteristic is oxygen-assisted reactive deposition, utilizing metallic In as the evaporation raw material or target. An oxygen-assisted reaction occurs during deposition, and the oxygen flux is gradually reduced, resulting in deposited InO... x The thin film achieves a concentration gradient transition from In2O3 to In.

[0037] The following specific embodiments further illustrate the perovskite solar cell based on a composite hole-blocking layer and its fabrication method of the present invention. Example 1

[0038] The first embodiment of the method for fabricating a perovskite solar cell based on a composite hole-blocking layer of the present invention includes the following steps: S11: Cleaning the conductive glass transparent substrate 1: Clean the conductive glass transparent substrate 1 on which the FTO transparent conductive layer 2 has been prepared, dry it with high-purity nitrogen, and treat it with ultraviolet ozone for 15 minutes.

[0039] S12: Deposit hole transport layer 3: Deposit NiO on the surface of FTO transparent conductive layer 2 x The thin film serves as the hole transport layer 3.

[0040] S13: Preparation of the perovskite absorber layer 4: Weigh 172 mg of formamidinium iodide, 507.1 mg of lead iodide, 22.4 mg of methylamine bromide, and 73.4 mg of lead bromide, and dissolve them in 800 μL of N,N-dimethylformamide and 200 μL of dimethyl sulfoxide solution. Use a pipette to take an appropriate amount of the mixed solution and add it dropwise to NiO. x The film was spin-coated at 5000 rpm for 30 seconds, then 150 μL of the anti-solvent chlorobenzene was quickly added, and the spin-coating was continued for another 10 seconds. The substrate sample was then placed on a hot plate at 100°C and annealed for 45 minutes to obtain the perovskite light-absorbing layer 4.

[0041] S14: Fabrication of electron transport layer 5: A PCBM electron transport layer 5 with a thickness of 10nm~30nm is deposited on the surface of the perovskite light-absorbing layer 4.

[0042] S15: Preparation of organic hole blocking layer 7: A BCP organic hole blocking layer 7 is deposited on the surface of electron transport layer 5 by thermal evaporation process, with a film thickness of about 5nm.

[0043] S16: Thermal Evaporation Preparation of Inorganic InO x Concentration gradient inorganic hole blocking layer 8: An InO layer is deposited on the surface of the BCP organic hole blocking layer 7 using high-purity metallic In particles as raw material through a thermal evaporation process. x Thin films were deposited using pure oxygen as the reaction process gas. The oxygen flow rate was gradually decreased from 20 sccm to 0 sccm, and the deposition rate was 0.2 A / s, ultimately resulting in the deposition of InO. x Concentration gradient inorganic hole blocking layer 8, with a film thickness of 20 nm.

[0044] S17: Preparation of back electrode layer 9: A layer of metallic silver electrode is prepared on the surface of the concentration gradient inorganic hole blocking layer 8 as the back electrode layer 9 by thermal evaporation process, with a film thickness of about 120nm.

[0045] S18: Annealing: Place the prepared component on a hot plate and anneal at 150°C for 50 seconds to complete the preparation of the perovskite solar cell. Example 2

[0046] The second embodiment of the method for fabricating a perovskite solar cell based on a composite hole-blocking layer of the present invention includes the following steps: S21: Cleaning the conductive glass transparent substrate 1: Clean the conductive glass transparent substrate 1 on which the ITO transparent conductive layer 2 has been prepared, dry it with high-purity nitrogen, and treat it with ultraviolet ozone for 15 minutes.

[0047] S22: Deposit hole transport layer 3: Deposit NiO on the surface of ITO transparent conductive layer 2 x The thin film serves as the hole transport layer 3.

[0048] S23: Preparation of the perovskite absorber layer 4: Weigh 172 mg of formamidinium iodide, 507.1 mg of lead iodide, 22.4 mg of methylamine bromide, and 73.4 mg of lead bromide, and dissolve them in 800 μL of N,N-dimethylformamide and 200 μL of dimethyl sulfoxide solution. Use a pipette to take an appropriate amount of the mixed solution and add it dropwise to NiO. x The film was spin-coated at 5000 rpm for 30 seconds, then 150 μL of the anti-solvent chlorobenzene was quickly added, and the spin-coating was continued for another 10 seconds. The substrate sample was then placed on a hot plate at 100°C and annealed for 45 minutes to obtain the perovskite light-absorbing layer 4.

[0049] S24 Preparation of electron transport layer 5: A C60 electron transport layer 5 with a thickness of 10nm~30nm is deposited on the surface of the perovskite light-absorbing layer 4.

[0050] S25: Preparation of organic hole blocking layer 7: A BCP organic hole blocking layer 7 is deposited on the surface of electron transport layer 5 by thermal evaporation process, with a film thickness of about 5nm.

[0051] S26: Thermal Evaporation Preparation of Inorganic InO x Concentration gradient inorganic hole blocking layer 8: An InO layer is deposited on the surface of the BCP organic hole blocking layer 7 using high-purity metallic In particles as raw material through a thermal evaporation process. x Thin films were deposited using pure oxygen as the reaction process gas. The oxygen flow rate was gradually decreased from 20 sccm to 0 sccm, and the deposition rate was 0.2 A / s, ultimately resulting in the deposition of InO. x Concentration gradient inorganic hole blocking layer 8, with a film thickness of 18 nm.

[0052] S27: Preparation of back electrode layer 9: An ITO transparent electrode is deposited on the surface of the concentration gradient inorganic hole blocking layer 8 as the back electrode layer 9 by DC magnetron sputtering process, with an ITO thickness of 150 nm.

[0053] S28: Annealing: Place the prepared component on a hot plate and anneal at 150°C for 50 seconds to complete the preparation of the perovskite solar cell.

[0054] Comparative Example Referring to Example 1, in the comparative preparation of perovskite solar cells, steps 15 and 16 are omitted, that is, the preparation of the composite hole blocking layer is omitted, and the back electrode layer 9 is directly prepared on the surface of the electron transport layer 5. The other steps are the same as in the example.

[0055] Reference Figure 2 As shown, the perovskite solar cell prepared in Example 1 was used as the experimental group, and the perovskite solar cell prepared in the comparative example was used as the reference group. The experimental group and the reference group were placed under standard sunlight and current-voltage curve tests were performed. It can be seen that the efficiency of the perovskite solar cell with the introduction of organic-inorganic composite hole blocking layer 6 is significantly improved.

[0056] Reference Figure 3 As shown, the perovskite solar cell prepared in Example 1 was used as the experimental group, and the perovskite solar cell prepared in the comparative example was used as the reference group. The experimental group and the reference group were subjected to aging tests under the dual 85 conditions (i.e., temperature 85°C and relative humidity 85%). It can be seen that the stability of the perovskite solar cell with the introduction of organic-inorganic composite hole blocking layer 6 is significantly improved.

[0057] The composite hole blocking layer 6 of this invention has good electrical properties and effectively suppresses the electron-hole recombination process. (Inorganic InO) x The thin film can also effectively block the reaction between halide ions in the perovskite light-absorbing layer 4 and the back electrode, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A perovskite solar cell based on a composite hole-blocking layer, the perovskite solar cell comprising, from bottom to top, a transparent substrate, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a back electrode layer, characterized in that, A composite hole blocking layer is disposed between the electron transport layer and the back electrode layer. The composite hole blocking layer includes an organic hole blocking layer and a concentration gradient inorganic hole blocking layer. The organic hole blocking layer is prepared by at least one of BCP, Bphen, and TPBI. The concentration gradient inorganic hole blocking layer is a concentration gradient film that gradually loses oxygen from In2O3 to In.

2. The perovskite solar cell based on a composite hole-blocking layer as described in claim 1, characterized in that, The thickness of the composite hole-blocking layer is 5nm~50nm.

3. The perovskite solar cell based on a composite hole-blocking layer as described in claim 1, characterized in that, The transparent conductive layer is made of one of IZO, ITO, AZO, or FTO.

4. The perovskite solar cell based on a composite hole-blocking layer as described in claim 1, characterized in that, The perovskite light-absorbing layer is prepared from an organic-inorganic hybrid perovskite material or an all-inorganic perovskite material, with a band gap of 1.4 eV to 2.0 eV; the thickness of the perovskite light-absorbing layer is 200 nm to 1500 nm.

5. The perovskite solar cell based on a composite hole-blocking layer as described in claim 1, characterized in that, The electron transport layer is prepared using TiO2. x NbO x SnO x Any one of ZnO, PCBM, and C60.

6. The perovskite solar cell based on a composite hole-blocking layer as described in claim 1, characterized in that, The hole transport layer is prepared using NiO. x Any one of PEDOT:PSS, Spiro-OMeTAD, or CuSCN.

7. The perovskite solar cell based on a composite hole-blocking layer as described in claim 1, characterized in that, The back electrode layer is a metal electrode layer or a transparent electrode layer. The metal electrode layer is made of any one of Cu, Ag, Au, Mo, and Al or an alloy thereof, and the transparent electrode layer is made of any one of IZO, AZO, FTO, and ITO.

8. A method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Sequentially prepare a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a transparent substrate. First, deposit an organic hole-blocking layer on the surface of the electron transport layer using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer as the evaporation source, at a depth of 1*10. -3 Pa~1*10 -5 Evaporation was carried out under a vacuum of Pa, with an evaporation rate of 0.01~10 Å / s; Step 2: Then, a thermal evaporation process is used, with In as the evaporation source and oxygen as the reactant gas, at a temperature of 1*10... -1 Pa~1*10 -5 Evaporation was performed under a vacuum of Pa, with the oxygen flow rate gradually decreasing from 20 sccm to 0 sccm, so that InO x The thin film gradually transitions from In2O3 to pure metallic In, with a deposition rate ranging from 0.01 to 10 Å / s, to prepare a concentration gradient inorganic hole-blocking layer. Step 3: Prepare the back electrode layer on the surface of the concentration gradient inorganic hole blocking layer using thermal evaporation or magnetron sputtering vacuum coating process to complete the fabrication of the perovskite solar cell.

9. A method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Sequentially prepare a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a transparent substrate. First, deposit an organic hole-blocking layer on the surface of the electron transport layer using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer as the evaporation source, at a depth of 1*10. -3 Pa~1*10 -5 Evaporation was carried out under a vacuum of Pa, with an evaporation rate of 0.01~10 Å / s; Step 2: Employ electron beam evaporation, using In as the evaporation source and oxygen as the reactant gas, at a density of 1*10... -1 Pa~1*10 - 5 Evaporation was performed under a vacuum of Pa, with the oxygen flow rate gradually decreasing from 20 sccm to 0 sccm, so that InO x The thin film gradually transitions from In2O3 to pure metallic In, with a deposition rate ranging from 0.01 to 10 Å / s, to prepare a concentration gradient inorganic hole-blocking layer. Step 3: Prepare the back electrode layer on the surface of the concentration gradient inorganic hole blocking layer using thermal evaporation or magnetron sputtering vacuum coating process to complete the fabrication of the perovskite solar cell.

10. A method for fabricating a perovskite solar cell based on a composite hole-blocking layer as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step A, Step 1: Sequentially prepare a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, and an electron transport layer on a transparent substrate. First, deposit an organic hole-blocking layer on the surface of the electron transport layer using a thermal evaporation process, with the material used to prepare the organic hole-blocking layer as the evaporation source, at a depth of 1*10. -3 Pa~1*10 -5 Evaporation was carried out under a vacuum of Pa, with an evaporation rate of 0.01~10 Å / s; Step B: Using DC or RF magnetron sputtering, with In as the sputtering target and an argon-oxygen mixture or pure oxygen as the process gas, magnetron sputtering is performed under a vacuum between 0.01 Pa and 10 Pa. The oxygen flow rate is gradually reduced from 20 sccm to 0 sccm, so that InO x The film gradually transitions from In2O3 to pure metallic In, and the sputtering rate is 0.01~10 Å / s to prepare a concentration gradient inorganic hole blocking layer. Step C: Prepare the back electrode layer on the surface of the concentration gradient inorganic hole blocking layer using thermal evaporation or magnetron sputtering vacuum coating process to complete the fabrication of the perovskite solar cell.

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