Trans-perovskite solar cell and preparation method thereof

Abstract

The invention discloses a trans-perovskite solar cell and a preparation method thereof, and relates to the technical field of perovskite solar cells. The first metal oxide layer is arranged between the hole transport layer and the perovskite layer, the second metal oxide layer is arranged between the perovskite layer and the electron transport layer, and the atomic layer deposition technology of the first metal oxide layer and the second metal oxide layer is optimized and improved, so that the concentration distribution of interface carriers is regulated and controlled; the non-radiative recombination rate of the interface is reduced, the photoelectric conversion efficiency of the trans-perovskite solar cell is improved, and the stability of the device is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to an inverted perovskite solar cell and a preparation method thereof. Background Art

[0002] With the continuous development of perovskite solar cell technology, metal halide perovskites have been widely used due to their advantages such as long charge carrier lifetime, adjustable band gap, and high photoluminescence quantum yield. Metal oxides are widely used as carrier transport layers in PSCs due to their proper band alignment with perovskites, high transmittance with wide band gaps, high carrier mobility, excellent material stability, and low cost.

[0003] Due to the presence of uncoordinated atoms and dangling bonds on the surface of metal oxides, there are serious interfacial reactions at the heterojunction interface between metal oxides and perovskites, and many interfacial defects appear, which leads to a significant increase in non-radiative recombination and energy loss at the interface, thereby reducing device performance. In order to solve this problem, organic molecules with special functional groups such as dye molecules and self-assembly molecules are usually used in the field to passivate the surface of metal oxides. However, the above methods have certain limitations: most of the above interface treatment processes are based on spin coating, which is difficult to use for preparation processes such as scraping or physical vapor deposition that are suitable for large-area photovoltaic cells, resulting in the inability to achieve industrial large-scale and large-scale production; organic materials have poor stability, especially thermal stability, and it is difficult to meet the 25-year design service life requirements of photovoltaic modules.

[0004] In the prior art, some perovskite solar cells disclose methods such as atomic layer deposition, evaporation, magnetron sputtering and plasma chemical vapor deposition, and interfacial passivation layers (aluminum oxide, silicon oxide and magnesium oxide) are set between the hole transport layer and the perovskite layer, and between the perovskite layer and the electron transport layer. However, this type of solar cell has the problem of being unable to freely regulate the carrier distribution at the interface of the perovskite solar cell, resulting in a high non-radiative recombination rate at the interface, which affects the photoelectric conversion efficiency of the inverse perovskite solar cell. In addition, the preparation method of the passivation layer between the perovskite and the electron transport layer generally requires a high-temperature treatment step, which has a certain adverse effect on the stability of the perovskite solar cell device. Summary of the invention

[0005] The present invention provides an inverted perovskite solar cell and a preparation method thereof. A metal oxide film with a fixed charge is prepared by atomic layer deposition (ALD) technology to modify the upper and lower surfaces of the perovskite layer to regulate the carrier concentration distribution, thereby reducing the interface non-radiative recombination rate and improving the photoelectric conversion efficiency of the inverted perovskite solar cell. The metal oxide has stable physical and chemical properties, which can prevent the perovskite layer from reacting with other parts of the structure and water and oxygen in the air, thereby improving the stability of the inverted perovskite solar cell. This is specifically achieved through the following technologies.

[0006] A method for preparing an inverse perovskite solar cell comprises the following steps:

[0007] A hole transport layer is prepared on a substrate, and a first cyclic deposition process is performed on the hole transport layer to prepare a first metal oxide layer;

[0008] Disposing a perovskite layer on the surface of the first metal oxide layer, and performing a second cyclic deposition treatment on the surface of the perovskite layer to prepare a second metal oxide layer;

[0009] Disposing an electron transport layer on the surface of the second metal oxide layer, and disposing an electrode layer on the surface of the electron transport layer;

[0010] The method for preparing the first metal oxide layer and the second metal oxide layer is any one of atomic layer deposition, magnetron sputtering, reactive plasma deposition, ion beam assisted deposition, electron beam physical vapor deposition, chemical vapor deposition, and plasma enhanced chemical vapor deposition; the materials of the first metal oxide layer and the second metal oxide layer are respectively one or more of hafnium oxide, zirconium oxide, yttrium oxide, tantalum oxide, aluminum oxide and magnesium oxide.

[0011] Further, the methods of performing the first cycle deposition treatment and the second cycle deposition treatment by atomic layer deposition are respectively: at 25-150° C., pulse spraying the metal source for 0.01-1 s, using a protective gas purge for 1-100 s, pulse spraying water for 0.01-1 s, using a protective gas purge for 1-100 s, and cyclic treatment for 1-50 times;

[0012] After the first cycle deposition process is completed, an annealing process at 100-500° C. is performed.

[0013] Furthermore, the first cycle deposition treatment is performed as follows: at 100°C, pulse spraying of the metal source for 0.2s, purging with a protective gas for 20s, pulse spraying of water for 0.02s, purging with a protective gas for 25s, and cyclic treatment for 2 times; after the first cycle deposition treatment is completed, a pre-annealing at 180°C for 10 min is performed, followed by an annealing at 400°C for 45 min to obtain the first metal oxide layer.

[0014] Furthermore, the second cycle deposition treatment is performed as follows: at 100° C., pulse spraying of the metal source for 0.2 s, purging with a protective gas for 20 s, pulse spraying of water for 0.02 s, purging with a protective gas for 25 s, and cyclic treatment for 2 times.

[0015] Furthermore, the thickness of the first metal oxide layer is 0.1-5 nm.

[0016] Furthermore, the thickness of the second metal oxide layer is 0.1-5 nm.

[0017] Furthermore, the electron transport layer is composed of C 60 The film layer and the BCP layer are composed of 60 The thickness of the thin film layer is 20 nm, and the thickness of the BCP layer is 7 nm.

[0018] The present invention also provides an inverse perovskite solar cell prepared by any of the above preparation methods.

[0019] The high non-radiative recombination rate at each interface in solar cells has always been one of the important reasons for its low photoelectric conversion efficiency. According to the classical recombination theory in semiconductor physics, the interface recombination rate is expressed by the following formula: ,in is the thermal velocity of electrons, , are the capture cross sections for electrons and holes, respectively, , are the concentrations of electrons and holes at the interface, This term is called the composite prefactor, which is equal to the ratio of the hole and electron concentrations at the interface when the ratio of the capture cross sections is equal to the ratio of the capture cross sections. , the obtained value is the largest.

[0020] In the inverted perovskite solar cell provided by the present invention, a metal oxide layer prepared by atomic layer deposition is inserted between the hole transport layer and the perovskite layer, and between the perovskite layer and the electron transport layer. The present invention optimizes and innovates the above-mentioned battery structure, and at the same time regulates and optimizes the process parameters (adjusting temperature, number of cycles) and post-processing methods (annealing treatment, etc.) of the atomic layer deposition method, so that the metal oxide layer has a fixed charge, and regulates the type and amount of fixed charges of the metal oxide film, so that the carrier distribution can be regulated in the perovskite solar cell, thereby reducing non-radiative recombination at the interface, and ultimately improving the performance of the inverted perovskite solar cell.

[0021] Specifically, the present invention deposits a first metal oxide layer with a fixed negative charge at the contact interface between the hole transport layer and the perovskite layer, thereby achieving targeted regulation of the carrier concentration at the interface and thereby reducing the interface recombination rate. ), and the fixed negative charge of the first metal oxide layer introduced by the present invention can attract holes and repel electrons, thereby increasing the hole / electron concentration ratio, making it more offset to a greater extent than the capture cross-section ratio, reducing the recombination prefactor, and ultimately achieving the effect of reducing the interface non-radiative recombination rate. The present invention also deposits a second metal oxide layer with a fixed positive charge at the contact interface between the electron transport layer and the perovskite layer. Since the hole concentration on this side is less than the electron concentration ( ), and the fixed negative charge of the second metal oxide layer introduced in the present invention can attract electrons and repel holes, thereby reducing the hole / electron concentration ratio, making the ratio of the offset capture cross section greater, and also reducing the recombination prefactor, thereby achieving the effect of reducing the interface non-radiative recombination rate.

[0022] The structure of a formal perovskite solar cell is mainly composed of a conductive substrate (such as FTO conductive glass), an electron transport layer (such as TiO2, ZnO, etc.), a perovskite layer, a hole transport layer (such as Spiro-OMeTAD, PTAA, etc.) and a metal counter electrode. Compared with the inverse perovskite solar cell, the electron transport layer and the hole transport layer are swapped, and the materials used are also significantly different. The electron transport layer of the inverse perovskite solar cell can be made of PCBM, C 60 Materials such as PEDOT:PSS and NiO can be used for the hole transport layer. x And other materials.

[0023] When depositing the first metal oxide layer and the second metal oxide layer, the present invention uses metal oxides to be directly deposited on the corresponding hole transport layer and the perovskite layer. Compared with the method of first depositing metal particles and then oxidizing them, it has the effect of simplifying the process. At the same time, the thin film is prepared by atomic layer deposition. The coverage and shape retention of the thin film will be better, and the film thickness can also be precisely controlled, which is more suitable for large-scale commercial production.

[0024] Compared with the prior art, the present invention is beneficial in that: the present invention optimizes and improves the atomic layer deposition technology, regulates the carrier concentration distribution, reduces the interface non-radiative recombination rate, and improves the photoelectric conversion efficiency of the inverse perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a cross-sectional view of the device structure of the inverted perovskite solar cell prepared in Example 1.

[0026] Figure 2 The best device current-voltage curve (JV curve) of the inverse perovskite solar cell of Example 1 and Comparative Examples 1-3.

[0027] Figure 3 Photoluminescence spectra (PL) of semi-devices prepared based on the structures of hole transport layer (HTL) / perovskite film (PVK) / electron transport layer (ETL) and hole transport layer (HTL) / first metal oxide layer (MO1) / perovskite film (PVK) / second metal oxide layer (MO2) / electron transport layer (ETL).

[0028] Figure 4 Kelvin probe atomic force microscopy (KPFM) images of hole transport layer film (HTL) and hole transport layer / first metal oxide layer (MO1) samples.

[0029] Figure 5 Kelvin probe atomic force microscopy (KPFM) images of perovskite (PVK) and perovskite (PVK) / second metal oxide layer (MO2) samples. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Figure 1 The cross-sectional view of the structure of the inverted perovskite solar cell provided by the present invention is shown, and its structure includes, from bottom to top, a substrate, a hole transport layer, a first metal oxide layer, a perovskite layer, a second metal oxide layer, an electron transport layer and an electrode layer.

[0032] In existing perovskite solar cells, the non-radiative recombination rate at each interface of the structure is relatively high, which has a significant adverse effect on the photoelectric conversion efficiency. In order to solve this problem, the present invention inserts a metal oxide layer with a fixed charge property between the perovskite layer and the hole transport layer, and between the perovskite layer and the electron transport layer. Among them, a first metal oxide layer with a fixed negative charge is inserted between the perovskite film and the hole transport layer, which has the effect of attracting holes and repelling electrons at the interface; a second metal oxide layer with a fixed positive charge is inserted between the perovskite film and the electron transport layer, which has the effect of attracting electrons and repelling holes at the interface. Taken together, this method can effectively reduce the non-radiative recombination rate at the two interfaces, thereby improving the photoelectric conversion efficiency of the device.

[0033] In some implementation cases of the present invention, the inverted perovskite solar cell provided is prepared by a method of sequentially preparing a hole transport layer, a first metal oxide layer, a perovskite layer, a second metal oxide layer, an electron transport layer and an electrode layer on a substrate.

[0034] Optionally, the material used for the substrate is a FTO conductive glass substrate.

[0035] Optionally, the material used for the hole transport layer is nickel oxide (NiOx).

[0036] Optionally, the materials used for the first metal oxide layer and the second metal oxide layer are one or more of hafnium oxide, zirconium oxide, yttrium oxide, tantalum oxide, aluminum oxide and magnesium oxide.

[0037] Optionally, the material used for the electron transport layer is C 60 (Fullerene) films and BCP materials.

[0038] Optionally, the material used for the electrode layer is metal Cu.

[0039] Further optionally, the thickness of the first metal oxide layer is 0.1-5 nm.

[0040] Further optionally, the thickness of the second metal oxide layer is 0.1-5 nm.

[0041] Further optionally, the total electron transport layer, C 60 The thickness of the (fullerene) film is 20 nm; the thickness of the BCP material is 7 nm.

[0042] Further optionally, the thickness of the copper electrode layer is 100 nm.

[0043] When the first metal oxide layer and the second metal oxide are subjected to atomic layer deposition, the cyclic treatment is performed in the following manner: at 25-150° C., pulse spraying of the metal source for 0.01-1 s, purging with a protective gas for 1-100 s, pulse spraying of water for 0.01-1 s, purging with a protective gas for 1-100 s, cyclic treatment for 1-50 times, and annealing at 100-500° C. after the treatment.

[0044] Example 1

[0045] The inverse perovskite solar cell provided in this embodiment is prepared by the following preparation method:

[0046] (1) Preparation of hole transport layer. Prepare FTO transparent conductive glass with a thickness of 200 nm as a substrate; and prepare the hole transport layer by spin coating on the substrate.

[0047] The specific method is: dissolve 32.11 mg of Ni(acac)2 in 1 ml of ethanol, add 17 μl of hydrochloric acid, stir overnight, spin coat on the substrate, and anneal on a hot plate at 150°C for 10 min.

[0048] (2) Preparing the first metal oxide layer. Using atomic layer deposition technology, hafnium oxide material is selected to perform a first cycle deposition process on the hole transport layer to prepare the first metal oxide layer.

[0049] The specific method is: in an atomic layer deposition system, at 100°C, pulse spray the metal source for 0.2 s, purge with protective gas for 20 s, pulse spray water for 0.02 s, purge with protective gas for 25 s, and cycle the treatment twice; after the treatment, transfer to a high-temperature hot stage at 180°C for pre-annealing for 10 min, then raise the high-temperature hot stage to 400°C for annealing for 45 min to obtain the first metal oxide layer.

[0050] (3) Preparation of perovskite layer. Spin-coat 1.67 M Cs on the first metal oxide layer. 0.05 MA 0.1 FA 0.85 PbI3 perovskite solution was annealed at 100°C for 30 min.

[0051] (4) Preparing a second metal oxide layer. Using atomic layer deposition technology, hafnium oxide material is selected to perform a second cycle deposition process on the perovskite layer to prepare a second metal oxide layer.

[0052] The specific method is: in an atomic layer deposition system, at 100°C, pulse spray a metal source for 0.2 s, purge with a protective gas for 20 s, pulse spray water for 0.02 s, purge with a protective gas for 25 s, and cycle the process twice to obtain a second metal oxide layer.

[0053] (5) Preparation of electron transport layer. 20 nm of C 60 Thin film (fullerene) and 7nm BCP material to obtain the electron transport layer.

[0054] The specific method is to transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 C was deposited at a rate of 0.02 nm / s in a Pa evaporator. 60 After that, the BCP film was deposited at a rate of 0.02 nm / s.

[0055] (6) Preparation of electrode layer: Deposit a 100 nm thick copper layer on the surface of the electron transport layer.

[0056] The specific method is to transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 In the Pa evaporator, 10 nm Cu was first deposited at a rate of 0.01 nm / s, followed by 90 nm copper at a rate of 0.1 nm / s.

[0057] Example 2

[0058] The inverted perovskite solar cell provided in this embodiment has a preparation method different from that in embodiment 1 in that: the method of step (2) is specifically as follows: in an atomic layer deposition system, at 100° C., pulse spraying a metal source for 0.2 s, using a protective gas to purge for 20 s, pulse spraying water for 0.02 s, using a protective gas to purge for 25 s, and cyclic treatment for 5 times; after the treatment, transferring to a high-temperature hot stage at 180° C. for pre-annealing for 10 min, and then raising the high-temperature hot stage to 400° C. for annealing for 45 min to obtain a first metal oxide layer.

[0059] The method of step (4) is specifically as follows: in an atomic layer deposition system, at 100° C., pulse spraying a metal source for 0.2 s, purging with a protective gas for 20 s, pulse spraying water for 0.02 s, purging with a protective gas for 25 s, and performing a cycle of treatment 5 times to obtain a second metal oxide layer.

[0060] Comparative Example 1

[0061] The inverse perovskite solar cell provided in this comparative example has a preparation method that does not include a second metal oxide layer between the perovskite layer and the electron transport layer, as compared to Example 1. The specific preparation method is as follows.

[0062] (1) Preparation of hole transport layer. Prepare FTO transparent conductive glass with a thickness of 200 nm as a substrate; and prepare the hole transport layer by spin coating on the substrate.

[0063] The specific method is: dissolve 32.11 mg of Ni(acac)2 in 1 ml of ethanol, add 17 μl of hydrochloric acid, stir overnight, spin coat on the substrate, and anneal on a hot plate at 150°C for 10 min.

[0064] (2) Preparing the first metal oxide layer. Using atomic layer deposition technology, hafnium oxide material is selected to perform a first cycle deposition process on the hole transport layer to prepare the first metal oxide layer.

[0065] The specific method is: in an atomic layer deposition system, at 100°C, pulse spray the metal source for 0.2 s, purge with protective gas for 20 s, pulse spray water for 0.02 s, purge with protective gas for 25 s, and cycle the treatment twice; after the treatment, transfer to a high-temperature hot stage at 180°C for pre-annealing for 10 min, then raise the high-temperature hot stage to 400°C for annealing for 45 min to obtain the first metal oxide layer.

[0066] (3) Preparation of perovskite layer. Spin-coat 1.67 M Cs on the first metal oxide layer. 0.05 MA 0.1 FA 0.85 PbI3 perovskite solution, annealed at 100℃ for 30min. ..

[0067] (4) Preparation of electron transport layer. 20 nm of C 60 Thin film (fullerene) and 7nm BCP material to obtain the electron transport layer.

[0068] The specific method is to transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 C was deposited at a rate of 0.02 nm / s in a Pa evaporator. 60 After that, the BCP film was deposited at a rate of 0.02 nm / s.

[0069] (5) Preparation of electrode layer. Deposit a 100 nm copper layer on the surface of the electron transport layer. The specific method is: transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 A 10 nm thick copper layer was deposited at a rate of 0.01 nm / s in a vapor deposition apparatus at 1000 Pa. A 90 nm thick copper layer was then deposited at a rate of 0.1 nm / s.

[0070] Comparative Example 2

[0071] The inverse perovskite solar cell provided in this comparative example has a preparation method that does not include a first metal oxide layer between the hole transport layer and the perovskite layer, as compared to Example 1. The specific preparation method is as follows.

[0072] (1) Preparation of hole transport layer. Prepare FTO transparent conductive glass with a thickness of 200 nm as a substrate; and prepare the hole transport layer by spin coating on the substrate.

[0073] The specific method is: dissolve 32.11 mg of Ni(acac)2 in 1 ml of ethanol, add 17 μl of hydrochloric acid, stir overnight, spin coat on the substrate, and anneal on a hot plate at 150°C for 10 min.

[0074] (2) Preparation of perovskite layer. Spin-coat 1.67M Cs on the hole transport layer. 0.05 MA 0.1 FA 0.85 PbI3 perovskite solution was annealed at 100°C for 30 min.

[0075] (3) Preparing a second metal oxide layer. Using atomic layer deposition technology, hafnium oxide material is selected to perform a second cycle deposition process on the perovskite layer to prepare a second metal oxide layer.

[0076] The specific method is as follows: in an atomic layer deposition system, at 100°C, pulse spray the metal source for 0.2 s, purge with protective gas for 20 s, pulse spray water for 0.2 s, purge with protective gas for 25 s, and cycle the process twice.

[0077] (4) Preparation of electron transport layer. 20 nm of C 60 Thin film (fullerene) and 7nm BCP material to obtain the electron transport layer.

[0078] The specific method is to transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 C was deposited at a rate of 0.02 nm / s in a Pa evaporator. 60 After that, the BCP film was deposited at a rate of 0.02 nm / s.

[0079] (5) Preparation of electrode layer. Deposit a 100 nm copper layer on the surface of the electron transport layer. The specific method is: transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 In the Pa evaporator, 10 nm Cu was first deposited at a rate of 0.01 nm / s, followed by 90 nm copper at a rate of 0.1 nm / s.

[0080] Comparative Example 3

[0081] The inverse perovskite solar cell provided in this comparative example has a preparation method that does not provide a first metal oxide layer between the hole transport layer and the perovskite layer, nor does it provide a second metal oxide layer between the perovskite layer and the hole transport layer, compared to Example 1. The specific preparation method is as follows.

[0082] (1) Preparation of hole transport layer. Prepare FTO transparent conductive glass with a thickness of 200 nm as a substrate; and prepare the hole transport layer by spin coating on the substrate.

[0083] The specific method is: dissolve 32.11 mg of Ni(acac)2 in 1 ml of ethanol, add 17 μl of hydrochloric acid, stir overnight, spin coat on the substrate, and anneal on a hot plate at 150°C for 10 min.

[0084] (2) Preparation of perovskite layer. Spin-coat 1.67M Cs on the hole transport layer. 0.05 MA 0.1 FA 0.85 PbI3 perovskite solution was annealed at 100°C for 30 min.

[0085] (3) Preparation of electron transport layer. 20 nm of C 60 Thin film (fullerene) and 7nm BCP material to obtain the electron transport layer.

[0086] The specific method is to transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 C was deposited at a rate of 0.02 nm / s in a Pa evaporator. 60 After that, the BCP film was deposited at a rate of 0.02 nm / s.

[0087] (4) Preparation of electrode layer. Deposit a 100 nm copper layer on the surface of the electron transport layer. The specific method is: transfer the previously prepared semi-device to a vacuum chamber with a vacuum degree of less than 1×10 -4 In the Pa evaporator, 10 nm Cu was first deposited at a rate of 0.01 nm / s, followed by 90 nm copper at a rate of 0.1 nm / s.

[0088] Comparative Example 4

[0089] The inverse perovskite solar cell provided in this comparative example is prepared in a method different from that in Example 1 in that the method in step (2) is as follows: in an atomic layer deposition system, at 100° C., pulse spraying a metal source for 0.2 s, purging with a protective gas for 20 s, pulse spraying water for 0.02 s, purging with a protective gas for 25 s, and cyclically treating twice to obtain a first metal oxide layer. That is, in this comparative example, no pre-annealing and annealing process is performed when the first metal oxide layer is obtained.

[0090] Test Example 1: Performance test of inverse perovskite solar cells

[0091] This test example uses the inverted perovskite solar cells prepared in the above embodiments and comparative examples to perform J-V curve tests. The test results are shown in Figure 2 And as shown in Table 1.

[0092] Table 1

[0093] Voc (V) <![CDATA[Jsc (mA·cm -2 )]]> FF (%) PCE (%) Example 1 1.184 25.48 84.16 25.39 Example 2 1.181 24.82 81.67 23.94 Comparative Example 1 1.152 25.33 79.68 23.25 Comparative Example 2 1.154 25.26 80.07 23.34 Comparative Example 3 1.139 25.27 77.13 22.20 Comparative Example 4 1.145 24.97 78.24 22.37

[0094] Table 1 and Figure 2 It can be seen that the open circuit voltage (V oc ) is 1.184V, the short-circuit current (J sc ) is 25.48 mA·cm -2 , the fill factor (FF) is 84.16%, and the final photoelectric conversion efficiency (PCE) is 25.39%.

[0095] The inverted perovskite solar cell prepared in Example 2 has an open circuit voltage (V oc ) is 1.181V, the short-circuit current (J sc ) is 24.82 mA·cm -2 , the fill factor (FF) is 81.67%, and the final photoelectric conversion efficiency (PCE) is 23.94%.

[0096] The inverse perovskite solar cell prepared in Comparative Example 1 has an open circuit voltage (V oc ) is 1.152 V, the short-circuit current (J sc ) is 25.33 mA·cm -2 , fill factor (FF) is 79.68%, and the final photoelectric conversion efficiency (PCE) is 23.25%.

[0097] The inverse perovskite solar cell prepared in Comparative Example 2 has an open circuit voltage (V oc ) is 1.154 V, the short-circuit current (J sc ) is 25.26 mA·cm -2 , the fill factor (FF) is 80.07%, and the final photoelectric conversion efficiency (PCE) is 23.34%.

[0098] The inverse perovskite solar cell prepared in Comparative Example 3 has an open circuit voltage (V oc ) is 1.139 V, the short-circuit current (J sc ) is 25.27 mA·cm -2 , the fill factor (FF) is 77.13%, and the final photoelectric conversion efficiency (PCE) is 22.20%.

[0099] The inverse perovskite solar cell prepared in Comparative Example 4 has an open circuit voltage (V oc ) is 1.145V, the short circuit current (J sc ) is 24.97 mA·cm -2 , the fill factor (FF) is 78.24%, and the final photoelectric conversion efficiency (PCE) is 22.37%.

[0100] It can be seen from the photoelectric conversion efficiency of the devices in Example 1 and Comparative Examples 1, 2, and 3 that after the first metal oxide layer and the second metal oxide layer are added at the same time, the photoelectric conversion efficiency of the device is the highest; after the first metal oxide layer or the second metal oxide layer is added separately, the efficiency is improved compared with the device without the metal oxide layer, but not as good as the device with both added at the same time.

[0101] It can be seen from the photoelectric conversion efficiency of the devices in Examples 1, 2 and Comparative Example 4 that the number of cycles and the deposition temperature in the preparation process of the first metal oxide layer and the second metal oxide layer are also the key to achieving the optimal efficiency.

[0102] Experimental Example 2: Testing of non-radiative recombination rate and fixed charge of thin films

[0103] like Figure 3 As shown in the figure, we prepared a semi-device based on the structure of hole transport layer (HTL) / perovskite film (PVK) / electron transport layer (ETL) and hole transport layer (HTL) / first metal oxide layer (MO1) / perovskite film (PVK) / second metal oxide layer (MO2) / electron transport layer (ETL) and conducted photoluminescence (PL) tests. We found that after inserting the first metal oxide layer and the second metal oxide layer, the luminescence intensity became significantly stronger. It can be seen that the non-radiative recombination between the perovskite and the transport layer is significantly suppressed.

[0104] like Figure 4 As shown in the figure, we prepared samples of hole transport layer film (HTL) and hole transport layer / first metal oxide layer (MO1) and tested them with Kelvin probe atomic force microscopy (KPFM). We found that after adding MO1, the potential value increased by about 0.2 V. Since Kelvin probe atomic force microscopy (KPFM) is very sensitive to changes in surface electrostatic potential, which is easily affected by fixed charges, we can infer that the surface has introduced fixed negative charges due to the insertion of MO1.

[0105] like Figure 5 As shown in the figure, we prepared samples of perovskite (PVK) and perovskite (PVK) / second metal oxide layer (MO2) and performed Kelvin probe atomic force microscopy (KPFM) tests on them. We found that after the addition of MO2, the potential value decreased by about 0.6 V. Since Kelvin probe atomic force microscopy (KPFM) is very sensitive to changes in surface electrostatic potential, which is easily affected by fixed charges, we can infer that the surface has introduced fixed positive charges due to the insertion of MO2.

[0106] The above specific embodiments describe the implementation of the present invention in detail, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, the technical solution of the present invention can be modified and changed in many simple ways, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A method for preparing an inverse perovskite solar cell, characterized in that: The following steps are involved: A hole transport layer is prepared on a substrate, and a first cyclic deposition process is performed on the hole transport layer to prepare a first metal oxide layer; Disposing a perovskite layer on the surface of the first metal oxide layer, and performing a second cyclic deposition treatment on the surface of the perovskite layer to prepare a second metal oxide layer; Disposing an electron transport layer on the surface of the second metal oxide layer, and disposing an electrode layer on the surface of the electron transport layer; The method for preparing the first metal oxide layer and the second metal oxide layer is any one of atomic layer deposition, magnetron sputtering, reactive plasma deposition, ion beam assisted deposition, electron beam physical vapor deposition, chemical vapor deposition, and plasma enhanced chemical vapor deposition; the materials of the first metal oxide layer and the second metal oxide layer are respectively one or more of hafnium oxide, zirconium oxide, yttrium oxide, tantalum oxide, aluminum oxide and magnesium oxide.

2. The method for preparing an inverse perovskite solar cell according to claim 1, characterized in that: The methods of performing the first cycle deposition treatment and the second cycle deposition treatment by atomic layer deposition are respectively: at 25-150° C., pulse spraying the metal source for 0.01-1 s, using a protective gas purge for 1-100 s, pulse spraying water for 0.01-1 s, using a protective gas purge for 1-100 s, and cyclic treatment for 1-50 times; After the first cycle deposition process is completed, an annealing process at 100-500° C. is performed.

3. The method for preparing an inverse perovskite solar cell according to claim 2, characterized in that: The first cycle deposition treatment is performed as follows: at 100°C, pulse spraying of a metal source for 0.2 s, purging with a protective gas for 20 s, pulse spraying of water for 0.02 s, purging with a protective gas for 25 s, and cyclic treatment twice; after the first cycle deposition treatment is completed, a pre-annealing at 180°C for 10 min is performed, followed by an annealing at 400m for 45 min to obtain the first metal oxide layer.

4. The method for preparing an inverse perovskite solar cell according to claim 2, characterized in that: The second cycle deposition treatment is performed as follows: at 100° C., pulse spraying of the metal source for 0.2 s, purging with a protective gas for 20 s, pulse spraying of water for 0.02 s, purging with a protective gas for 25 s, and the cycle treatment is repeated twice.

5. The method for preparing an inverse perovskite solar cell according to claim 1, characterized in that: The thickness of the first metal oxide layer is 0.1-5 nm.

6. The method for preparing an inverse perovskite solar cell according to claim 1, characterized in that: The thickness of the second metal oxide layer is 0.1-5 nm.

7. The method for preparing an inverse perovskite solar cell according to claim 1, characterized in that: The electron transport layer is composed of C 60 The film layer and the BCP layer are composed of 60 The thickness of the thin film layer is 20 nm, and the thickness of the BCP layer is 7 nm.

8. An inverse perovskite solar cell prepared by the preparation method according to any one of claims 1 to 7.

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