Perovskite solar cell based on composite hole blocking layer and preparation method therefor

Abstract

The present invention relates to a perovskite solar cell based on a composite hole blocking layer and a preparation method therefor. The structure of the perovskite solar cell comprises, 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 arranged between the electron transport 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. A preparation material of the organic hole blocking layer is at least one of BCP, Bphen, and TPBI. The concentration-gradient inorganic hole blocking layer is a thin film with a concentration gradient from In2O3 to In formed by gradual oxygen loss. In the present invention, an organic-inorganic composite thin film composed of BCP and InOx is introduced between the electron transport layer and the back electrode layer to serve as the composite hole blocking layer, thereby effectively suppressing the electron-hole recombination process. The InOx film can further effectively block reactions between the halide ions in the perovskite and the back electrode, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

Description

Perovskite solar cell based on composite hole blocking layer and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of perovskite solar cell preparation, and particularly relates to a perovskite solar cell based on a composite hole blocking layer and a preparation method thereof. BACKGROUND

[0002] The perovskite solar cell is a solar cell using a compound with an ABX3 structure as a light-absorbing material, wherein A=MA, FA, Cs, etc., B=Pb, Sn, etc., and X=I, Br, Cl, etc. Taking a trans structure as an example, the basic structure of the 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 the prior art, the hole blocking layer is composed of an organic thin film material to block the hole transport and inhibit the carrier recombination. However, the conventional single-layer organic hole blocking layer material has poor conductivity, and can only be thinned as much as possible without affecting the carrier transport; but it cannot completely cover the surface of the electron transport layer when it is too thin. Meanwhile, the bonding force between the metal back electrode layer and the organic hole blocking layer is weak, resulting in difficult charge transport. In addition, the organic hole blocking layer is difficult to block the reaction between the halogen ions in the perovskite and the metal back electrode, resulting in poor stability of the perovskite solar cell. Therefore, it is necessary to develop a new hole blocking layer film and its preparation process. TECHNICAL PROBLEM

[0004] The technical problem to be solved by the present application is to provide a perovskite solar cell based on a composite hole blocking layer and a preparation method thereof. By introducing an organic-inorganic composite hole blocking layer between the electron transport layer and the back electrode, the hole transport is inhibited, the electron-hole recombination is inhibited, the hole blocking effect of the anode of the perovskite solar cell is improved, and the reaction between the perovskite halogen ions and the back electrode is further inhibited, thereby improving the photoelectric conversion efficiency and stability of the perovskite device. TECHNICAL SOLUTION

[0005] The present application is implemented in the following manner. 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 arranged 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 preparation material of the organic hole blocking layer is at least one of BCP, Bphen, and TPBI. The concentration gradient inorganic hole blocking layer is a concentration gradient thin film gradually losing oxygen from In2O3 to In.

[0006] The concentration gradient inorganic hole blocking layer of the application adopts a concentration gradient thin film of In2O3 to In, mainly because on the one hand, it can promote electron transmission, and on the other hand, the melting point of In is relatively low, only 156.6℃, which is beneficial to atomic recombination to repair defects in the service process of the perovskite solar cell.

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

[0008] Further, the preparation material of the transparent conductive layer is one of IZO, ITO, AZO and FTO.

[0009] Further, the preparation material of the perovskite light-absorbing layer is organic-inorganic hybrid perovskite material or all-inorganic perovskite material, and the band gap is 1.4eV~2.0eV; the thickness of the perovskite light-absorbing layer is 200nm~1500nm.

[0010] Further, the preparation material of the electron transport layer includes any one of TiO x , NbO x , SnO x , ZnO, PCBM and C60.

[0011] Further, the preparation material of the hole transport layer includes any one of NiO x , PEDOT:PSS, Spiro-OMeTAD and CuSCN.

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

[0013] The application is realized by providing a preparation method of the perovskite solar cell based on the composite hole blocking layer as described above, which comprises the following steps:

[0014] Step one, sequentially preparing a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer and an electron transport layer on a transparent substrate, and first depositing an organic hole blocking layer on the surface of the electron transport layer, using a thermal evaporation process, taking the preparation material of the organic hole blocking layer as an evaporation source, and performing evaporation under a vacuum degree of 1*10 -3 Pa~1*10 -5 Pa, and an evaporation rate of 0.01~10Å / s.

[0015] Step two, again using a thermal evaporation process, taking In as an evaporation source and oxygen as a reaction gas, and performing evaporation under a vacuum degree of 1*10 -1 Pa~1*10-5 The evaporation is carried out under a vacuum degree of 1*10 Pa~1*10 Pa, and the oxygen flow rate is gradually reduced from 20 seem to 0 seem, so that InO x The thin film gradually transitions from In2O3 to pure metal In, the evaporation rate ranges from 0.01 to 10 Å / s, and the concentration gradient inorganic hole blocking layer is prepared.

[0016] Step three, a back electrode layer is prepared on the surface of the concentration gradient inorganic hole blocking layer by using a thermal evaporation or magnetron sputtering vacuum coating process, and the preparation of the perovskite solar cell is completed.

[0017] The application is implemented in the following manner, and provides a preparation method of a perovskite solar cell based on a composite hole blocking layer, which comprises the following steps:

[0018] Step 1, Step one, a transparent conductive layer, a hole transport layer, a perovskite light absorption layer and an electron transport layer are prepared on a transparent substrate in sequence, an organic hole blocking layer is first deposited on the surface of the electron transport layer, a thermal evaporation process is used, the preparation material of the organic hole blocking layer is used as an evaporation source, and the pressure is 1*10 -3 Pa~1*10 -5 The evaporation is carried out under a vacuum degree of 1*10 Pa~1*10 Pa, and the oxygen flow rate is gradually reduced from 20 seem to 0 seem, so that InO

[0019] Step 2, an electron beam evaporation process is used, In is used as an evaporation source, and oxygen is used as a reaction gas, the pressure is 1*10 -1 Pa~1*10 -5 The evaporation is carried out under a vacuum degree of 1*10 Pa~1*10 Pa, and the oxygen flow rate is gradually reduced from 20 seem to 0 seem, so that InO x The thin film gradually transitions from In2O3 to pure metal In, the evaporation rate ranges from 0.01 to 10 Å / s, and the concentration gradient inorganic hole blocking layer is prepared.

[0020] Step 3, a back electrode layer is prepared on the surface of the concentration gradient inorganic hole blocking layer by using a thermal evaporation or magnetron sputtering vacuum coating process, and the preparation of the perovskite solar cell is completed.

[0021] The application is implemented in the following manner, and provides a preparation method of a perovskite solar cell based on a composite hole blocking layer, which comprises the following steps:

[0022] Step A, Step one, a transparent conductive layer, a hole transport layer, a perovskite light absorption layer and an electron transport layer are prepared on a transparent substrate in sequence, an organic hole blocking layer is first deposited on the surface of the electron transport layer, a thermal evaporation process is used, the preparation material of the organic hole blocking layer is used as an evaporation source, and the pressure is 1*10 -3 Pa~1*10 -5The evaporation is performed under a vacuum degree of 0.01 Pa to 10 Pa, and the evaporation rate is 0.01-10 Å / s;

[0023] In step B, a direct current or radio frequency magnetron sputtering process is adopted, In is used as a sputtering target material, argon-oxygen mixed gas or pure oxygen is used as a process gas, and magnetron sputtering is performed under a vacuum degree of 0.01 Pa to 10 Pa, the oxygen flow rate is gradually reduced from 20 sccm to 0 sccm, and InO x The thin film gradually transitions from In2O3 to pure metal In, the sputtering rate is 0.01-10 Å / s, and a concentration gradient inorganic hole blocking layer is prepared.

[0024] In step C, a thermal evaporation or magnetron sputtering vacuum coating process is adopted to prepare a back electrode layer on the surface of the concentration gradient inorganic hole blocking layer, and the preparation of the perovskite solar cell is completed. Beneficial effects

[0025] Compared with the prior art, the perovskite solar cell based on a composite hole blocking layer and the preparation method thereof have the following beneficial effects. 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 absorption layer, an electron transport layer, and a back electrode layer. A composite hole blocking layer is arranged 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 preparation material of the organic hole blocking layer is at least one of BCP, Bphen, and TPBI. The concentration gradient inorganic hole blocking layer is a concentration gradient thin film gradually losing oxygen from In2O3 to In. The composite hole blocking layer is introduced between the electron transport layer and the back electrode layer, and the organic-inorganic composite thin film composed of BCP and InO x can effectively inhibit the electron-hole recombination process. At the same time, the InO x thin film can also effectively block the reaction between halogen ions in the perovskite and the back electrode. In addition, when the back electrode is prepared by a magnetron sputtering process, the InO x The inorganic thin film can also effectively eliminate sputtering damage, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a structural schematic diagram of a preferred embodiment of the perovskite solar cell based on a composite hole blocking layer according to the present application;

[0027] FIG. 2 is a light efficiency test schematic diagram of the perovskite solar cells prepared in Example 1 and the comparative example according to the present application;

[0028] FIG. 3 is an aging stability test schematic diagram of the perovskite solar cells prepared in Example 1 and the comparative example according to the present application. Best mode for carrying out the present application

[0029] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0030] Please refer to FIG. 1, the preferred embodiment of the present application is based on a perovskite solar cell with a composite hole blocking layer, the structure of the perovskite solar cell includes a transparent substrate 1 from bottom to top, 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 arranged 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.

[0031] The preparation material of the organic hole blocking layer 7 is at least one of BCP, Bphen and TPBI, and the concentration gradient inorganic hole blocking layer 8 is a concentration gradient thin film gradually losing oxygen from In2O3 to In.

[0032] The thickness of the composite hole blocking layer 6 is 5nm-50nm.

[0033] The preparation material of the transparent conductive layer 2 is one of IZO, ITO, AZO and FTO.

[0034] The preparation material of the perovskite light absorbing layer 4 is an organic-inorganic hybrid perovskite material or a full inorganic perovskite material, and the band gap is 1.4eV-2.0eV; the thickness of the perovskite light absorbing layer 4 is 200nm-1500nm.

[0035] The preparation material of the electron transport layer 5 includes any one of TiO x , NbO x , SnO x , ZnO, PCBM and C60.

[0036] The preparation material of the hole transport layer 3 includes any one of NiO x , PEDOT:PSS, Spiro-OMeTAD and CuSCN.

[0037] The back electrode layer 9 is a metal electrode layer or a transparent electrode layer, the preparation material of the metal electrode layer is any one of Cu, Ag, Au, Mo and Al or an alloy thereof, and the preparation material of the transparent electrode layer is any one of IZO, AZO, FTO and ITO.

[0038] The present application also discloses a preparation method of the perovskite solar cell with a composite hole blocking layer as described above, including the following steps:

[0039] Step one, on the transparent substrate 1, sequentially prepare transparent conductive layer 2, hole transport layer 3, perovskite light absorption layer 4 and electron transport layer 5, first deposit organic hole blocking layer 7 on the surface of electron transport layer 5, using thermal evaporation process, with the preparation material of organic hole blocking layer 7 as the evaporation source, under the vacuum degree of 1*10 -3 Pa~1*10 -5 Pa, the evaporation rate is 0.01~10Å / s.

[0040] Step two, again using thermal evaporation process, taking In as the evaporation source, oxygen as the reaction gas, under the vacuum degree of 1*10 -1 Pa~1*10 -5 Pa, gradually reducing the oxygen flow rate from 20sccm to 0sccm, so that the InO x thin film gradually transitions from In2O3 to pure metal In, the evaporation rate ranges from 0.01~10Å / s, and a concentration gradient inorganic hole blocking layer 8 is prepared.

[0041] Step three, using thermal evaporation or magnetron sputtering vacuum coating process to prepare back electrode layer 9 on the surface of the concentration gradient inorganic hole blocking layer 8, and the preparation of perovskite solar cell is completed. Or, the prepared perovskite solar cell is further annealed, and the annealing method is as follows: annealing the transparent substrate 1 with the prepared back electrode layer 9, the annealing temperature ranges from 80℃ to 160℃, and the annealing time ranges from 20s to 600s.

[0042] The application also discloses a preparation method of the perovskite solar cell based on the composite hole blocking layer.

[0043] Step 1, on the transparent substrate 1, sequentially prepare transparent conductive layer 2, hole transport layer 3, perovskite light absorption layer 4 and electron transport layer 5, first deposit organic hole blocking layer 7 on the surface of electron transport layer 5, using thermal evaporation process, with the preparation material of organic hole blocking layer 7 as the evaporation source, under the vacuum degree of 1*10 -3 Pa~1*10 -5 Pa, the evaporation rate is 0.01~10Å / s.

[0044] Step 2, using electron beam evaporation process, taking In as the evaporation source, oxygen as the reaction gas, under the vacuum degree of 1*10 -1 Pa~1*10 -5 Pa, gradually reducing the oxygen flow rate from 20sccm to 0sccm, so that the InO x thin film gradually transitions from In2O3 to pure metal In, the evaporation rate ranges from 0.01~10Å / s, and a concentration gradient inorganic hole blocking layer is prepared.

[0045] Step 3, a back electrode layer 9 is prepared on the surface of the concentration gradient inorganic hole blocking layer 8 by a thermal evaporation or magnetron sputtering vacuum coating process, and the preparation of the perovskite solar cell is completed. Alternatively, the prepared perovskite solar cell is further annealed, and the annealing method is as follows: the transparent substrate 1 with the prepared back electrode layer 9 is annealed, the annealing temperature is in the range of 80-160 DEG C, and the annealing time is 20-600 s.

[0046] The application further discloses a preparation method of the perovskite solar cell based on the composite hole blocking layer.

[0047] Step A, a transparent conductive layer 2, a hole transport layer 3, a perovskite light absorption layer 4 and an electron transport layer 5 are prepared on the transparent substrate 1 in sequence, and an organic hole blocking layer 7 is first deposited on the surface of the electron transport layer 5, a thermal evaporation process is adopted, the material for preparing the organic hole blocking layer 7 is used as an evaporation source, and the vacuum degree is in the range of 1*10 -3 Pa~1*10 -5 Pa, and the evaporation rate is 0.01-10 Å / s.

[0048] Step B, a direct current or radio frequency magnetron sputtering process is adopted, In is used as a sputtering target material, argon-oxygen mixed gas or pure oxygen is used as a process gas, the vacuum degree is in the range of 0.01 Pa-10 Pa, the oxygen flow rate is gradually reduced from 20 sccm to 0 sccm, the InO x thin film gradually transits from In2O3 to pure metal In, the sputtering rate is 0.01-10 Å / s, and the concentration gradient inorganic hole blocking layer is prepared.

[0049] Step C, a back electrode layer 9 is prepared on the surface of the concentration gradient inorganic hole blocking layer 8 by a thermal evaporation or magnetron sputtering vacuum coating process, and the preparation of the perovskite solar cell is completed. Alternatively, the prepared perovskite solar cell is further annealed, and the annealing method is as follows: the transparent substrate 1 with the prepared back electrode layer 9 is annealed, the annealing temperature is in the range of 80-160 DEG C, and the annealing time is 20-600 s.

[0050] The InO x The preparation process of the concentration gradient inorganic hole blocking layer includes a thermal evaporation process, an electron beam evaporation process, a magnetron sputtering process and the like, and the main feature is a oxygen-permeation reaction deposition, the metal In is used as an evaporation raw material or a target material, the oxygen-permeation reaction is carried out in the deposition process, and the oxygen-permeation amount is gradually reduced, so that the deposited InO x thin film gradually transits from In2O3 to In. Embodiments of the application

[0051] The perovskite solar cell based on the composite hole blocking layer and the preparation method thereof will be further illustrated by specific examples.

[0052] Example 1

[0053] The first embodiment of the preparation method of the perovskite solar cell based on the composite hole blocking layer of the present application comprises the following steps:

[0054] S11: cleaning the conductive glass transparent substrate 1: clean the conductive glass transparent substrate 1 with the prepared FTO transparent conductive layer 2, and dry it with high-purity nitrogen, and treat it with ultraviolet ozone for 15 minutes.

[0055] S12: depositing a hole transport layer 3: depositing NiO x thin film as the hole transport layer 3.

[0056] S13: preparing a perovskite light-absorbing layer 4: weighing 172 milligrams of formamidinium iodide, 507.1 milligrams of lead iodide, 22.4 milligrams of methylamine bromide, and 73.4 milligrams of lead bromide respectively, and dissolving them in 800 microliters of N, N-dimethylformamide and 200 microliters of dimethyl sulfoxide solution. Take an appropriate amount of mixed solution with a pipette, and drop it on the NiO x thin film, and spin it at a speed of 5000 revolutions per minute for 30 seconds, then quickly drop 150 microliters of anti-solvent chlorobenzene, continue to spin for 10 seconds, and then place the substrate sample on a hot plate at 100°C for annealing for 45 minutes to obtain the perovskite light-absorbing layer 4.

[0057] S14: preparing an electron transport layer 5: depositing a PCBM electron transport layer 5 on the surface of the perovskite light-absorbing layer 4, with a thickness of 10nm~30nm.

[0058] S15: preparing an organic hole blocking layer 7: depositing a BCP organic hole blocking layer 7 on the surface of the electron transport layer 5 by a thermal evaporation process, with a film thickness of about 5nm.

[0059] S16: preparing an inorganic InO x concentration gradient inorganic hole blocking layer 8: taking high-purity metal In particles as raw materials, depositing an InO x thin film on the surface of the BCP organic hole blocking layer 7 by a thermal evaporation process, and using pure oxygen as the reaction process gas. Among them, the oxygen flow is gradually reduced from 20sccm to 0sccm, the evaporation rate is 0.2A / s, and finally an InO x concentration gradient inorganic hole blocking layer 8 with a film thickness of 20nm is deposited.

[0060] S17: Preparing the back electrode layer 9: a layer of metal silver electrode is prepared as the back electrode layer 9 on the surface of the concentration gradient inorganic hole blocking layer 8 by a thermal evaporation process, and the film thickness is about 120 nm.

[0061] S18: Annealing: the prepared assembly is placed on a hot plate, and annealing is performed at 150℃ for 50 s, thereby completing the preparation of the perovskite solar cell.

[0062] Example 2

[0063] The second embodiment of the preparation method of the perovskite solar cell based on the composite hole blocking layer comprises the following steps:

[0064] S21: Cleaning the conductive glass transparent substrate 1: the conductive glass transparent substrate 1 on which the ITO transparent conductive layer 2 has been prepared is cleaned, and then dried by blowing high-purity nitrogen and treated by ultraviolet ozone for 15 minutes.

[0065] S22: Depositing the hole transport layer 3: the NiO x thin film is deposited as the hole transport layer 3 on the surface of the ITO transparent conductive layer 2.

[0066] S23: Preparing the perovskite light-absorbing layer 4: 172 mg of formamidinium iodide, 507.1 mg of lead iodide, 22.4 mg of methylamine bromide and 73.4 mg of lead bromide are weighed respectively, and then dissolved in 800 μL of N, N-dimethylformamide and 200 μL of dimethyl sulfoxide solution. An appropriate amount of mixed solution is taken by a pipette, and then dropped on the NiO x thin film, and then spin-coated at a speed of 5000 rpm for 30 seconds. Then, 150 μL of anti-solvent chlorobenzene is quickly dropped, and then spin-coated for another 10 seconds. Then, the substrate sample is placed on a hot plate at 100℃ for annealing for 45 minutes, thereby obtaining the perovskite light-absorbing layer 4.

[0067] S24: Preparing the electron transport layer 5: a layer of C60 electron transport layer 5 is deposited on the surface of the perovskite light-absorbing layer 4, and the thickness is 10 nm~30 nm.

[0068] S25: Preparing the organic hole blocking layer 7: a layer of BCP organic hole blocking layer 7 is deposited on the surface of the electron transport layer 5 by a thermal evaporation process, and the film thickness is about 5 nm.

[0069] S26: Preparing the inorganic InO x concentration gradient inorganic hole blocking layer 8: a layer of InO x thin film is deposited on the surface of the BCP organic hole blocking layer 7 by a thermal evaporation process, and pure oxygen is used as the reaction process gas. The oxygen flow is gradually reduced from 20 sccm to 0 sccm, and the evaporation rate is 0.2 A / s. Finally, the InO xThe concentration gradient inorganic hole blocking layer 8 has a film thickness of 18 nm.

[0070] S27: Preparing a back electrode layer 9: depositing an ITO transparent electrode as the back electrode layer 9 on the surface of the concentration gradient inorganic hole blocking layer 8 by a direct current magnetron sputtering process, and the ITO has a thickness of 150 nm.

[0071] S28: Annealing: placing the prepared component on a hot plate, and annealing at 150 DEG C for 50 s, thereby completing the preparation of the perovskite solar cell.

[0072] Comparative Example

[0073] Referring to the steps of preparing the perovskite solar cell in the comparative example, steps 15 and 16 are cancelled, i.e., the preparation of the composite hole blocking layer is cancelled, and the back electrode layer 9 is directly prepared on the surface of the electron transport layer 5, and the other steps are the same as those of the example.

[0074] Referring to FIG. 2, the perovskite solar cell prepared in the example 1 is taken as an experimental group, and the perovskite solar cell prepared in the comparative example is taken as a reference group, and the experimental group and the reference group are simultaneously placed under standard sunlight, and a current-voltage curve test is performed, and it can be known that the efficiency of the perovskite solar cell with the introduction of the organic-inorganic composite hole blocking layer 6 is obviously improved.

[0075] Referring to FIG. 3, the perovskite solar cell prepared in the example 1 is taken as an experimental group, and the perovskite solar cell prepared in the comparative example is taken as a reference group, and the experimental group and the reference group are simultaneously placed under a double 85 condition (i.e., a temperature of 85 DEG C and a relative humidity of 85%), and an aging test is performed, and it can be seen that the stability of the perovskite solar cell with the introduction of the organic-inorganic composite hole blocking layer 6 is obviously improved.

[0076] The composite hole blocking layer 6 has good electrical properties, effectively inhibits the electron-hole recombination process, and the inorganic InO x The film can also effectively block the reaction between the halogen 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.

[0077] The above only describes the preferred embodiments of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

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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