An inverted perovskite solar cell and its fabrication method

Abstract

The application discloses a kind of trans perovskite solar cells and preparation method thereof, it is related to perovskite solar cell technical field.The application is by being set between hole transport layer and perovskite layer first metal oxide layer, being set between perovskite layer and electron transport layer second metal oxide layer, and process optimization improvement is carried out to the atomic layer deposition technology of being set first and second metal oxide layer, interface carrier concentration distribution is regulated, interface non-radiation recombination rate is reduced, while also improving device stability, the photoelectric conversion efficiency of trans perovskite solar cell is promoted.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, and particularly to inverted perovskite solar cells and their fabrication methods. Background Technology

[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, tunable bandgap, and high photoluminescence quantum yield. Metal oxides, due to their appropriate band alignment with perovskites, wide bandgap, high transmittance, high carrier mobility, excellent material stability, and low cost, are widely used in PSCs as carrier transport layers.

[0003] The presence of uncoordinated atoms and dangling bonds on the surface of metal oxides leads to severe interfacial reactions and numerous interfacial defects at the heterojunction interface between metal oxides and perovskites. This results in a significant increase in nonradiative recombination and energy loss, thereby reducing device performance. To address this issue, the art typically employs organic molecules with specific functional groups, such as dye molecules and self-assembled molecules, to passivate the surface of metal oxides. However, these methods have limitations: most of the aforementioned interfacial treatment processes are based on spin coating, making them unsuitable for fabrication processes like blade coating or physical vapor deposition, which are applicable to large-area photovoltaic cells, thus hindering large-scale industrial production; organic materials also exhibit poor stability, particularly thermal stability, making it difficult to meet the 25-year design life requirement of photovoltaic modules.

[0004] In existing technologies, some perovskite solar cells disclose the use of methods such as atomic layer deposition, evaporation, magnetron sputtering, and plasma-enhanced chemical vapor deposition to set interfacial passivation layers (alumina, silicon oxide, and magnesium oxide) 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 suffers from the inability to freely control the carrier distribution at the interface, resulting in a high nonradiative recombination rate at the interface, which affects the photoelectric conversion efficiency of the inverted perovskite solar cell. Furthermore, the preparation methods for the passivation layer between the perovskite layer and the electron transport layer generally require high-temperature processing steps, which negatively impacts the stability of the perovskite solar cell device. Summary of the Invention

[0005] This invention provides an inverted perovskite solar cell and its fabrication method. A metal oxide thin film with a fixed charge is prepared using atomic layer deposition (ALD) technology to modify the upper and lower surfaces of the perovskite layer, thereby controlling the carrier concentration distribution, reducing the interfacial nonradiative recombination rate, and improving the photoelectric conversion efficiency of the inverted perovskite solar cell. The metal oxide film has stable physicochemical properties, preventing reactions between the perovskite layer and other structural components, as well as water and oxygen in the air, thus improving the stability of the inverted perovskite solar cell. This is specifically achieved through the following techniques.

[0006] A method for fabricating an inverted perovskite solar cell includes the following steps:

[0007] A hole transport layer is prepared on a substrate, and a first metal oxide layer is prepared by a first cyclic deposition process on the hole transport layer.

[0008] A perovskite layer is formed on the surface of the first metal oxide layer, and a second cyclic deposition process is performed on the surface of the perovskite layer to prepare a second metal oxide layer.

[0009] An electron transport layer is disposed on the surface of the second metal oxide layer, and an electrode layer is disposed 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 one or more of hafnium oxide, zirconium oxide, yttrium oxide, tantalum oxide, aluminum oxide, and magnesium oxide.

[0011] Furthermore, the methods for performing the first and second cycle deposition processes by atomic layer deposition are as follows: at 25-150°C, pulse spraying of metal source for 0.01-1 s, purging with protective gas for 1-100 s, pulse spraying of water for 0.01-1 s, purging with protective gas for 1-100 s, and cycle processing 1-50 times.

[0012] After the first cycle deposition treatment is completed, an annealing treatment at 100-500℃ is performed.

[0013] Furthermore, the first cyclic deposition process is as follows: at 100°C, a metal source is pulse-sprayed for 0.2 seconds, purged with protective gas for 20 seconds, pulse-sprayed with water for 0.02 seconds, purged with protective gas for 25 seconds, and the process is repeated twice; after the first cyclic deposition process, a pre-annealing at 180°C for 10 minutes is performed, followed by 400-row annealing for 45 minutes to obtain the first metal oxide layer.

[0014] Furthermore, the second cyclic deposition process is as follows: at 100°C, pulse spraying of the metal source for 0.2 s, purging with protective gas for 20 s, pulse spraying of water for 0.02 s, purging with protective gas for 25 s, and repeating the process twice.

[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 It consists of a thin film layer and a BCP layer, wherein the C 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 inverted perovskite solar cell prepared by any of the above preparation methods.

[0019] The excessively high nonradiative recombination rates at various interfaces in solar cells have long been a significant reason for their low photoelectric conversion efficiency. According to classical recombination theory in semiconductor physics, the interfacial recombination rate is expressed by the following formula: ,in For the thermal velocity of electrons, , These are the capture sections for electrons and holes, respectively. , These represent the concentrations of electrons and holes at the interface, respectively. This term is called the recombination pre-factor, which occurs when the ratio of hole to electron concentration at the interface equals the ratio of the trapping cross-sections. The obtained value is the largest.

[0020] The inverted perovskite solar cell provided by this invention inserts metal oxide layers prepared by atomic layer deposition between the hole transport layer and the perovskite layer, and between the perovskite layer and the electron transport layer. This invention optimizes the above-mentioned cell structure and simultaneously controls and optimizes the process parameters (adjusting temperature, cycle number) and post-processing methods (annealing, etc.) of the atomic layer deposition method. This allows the metal oxide layer to carry a fixed charge, and by controlling the type and quantity of fixed charges in the metal oxide film, the carrier distribution in the perovskite solar cell can be controlled, thereby reducing non-radiative recombination at the interface and ultimately improving the performance of the inverted perovskite solar cell.

[0021] Specifically, this invention deposits a first metal oxide layer with a fixed negative charge at the interface between the hole transport layer and the perovskite layer, thereby achieving targeted control of the carrier concentration at the interface and reducing the interface recombination rate. Because the hole concentration on this side is greater than the electron concentration (…),… Furthermore, the fixed negative charge of the first metal oxide layer introduced in this invention can attract holes and repel electrons, thus increasing the hole / electron concentration ratio and making it more prone to shifting the trapping cross-section, reducing the recombination pre-recombination factor, and ultimately achieving the effect of reducing the nonradiative recombination rate at the interface. This invention also deposits a second metal oxide layer with a fixed positive charge at the interface between the electron transport layer and the perovskite layer. Since the hole concentration on this side is less than the electron concentration (…),… Furthermore, the fixed negative charge of the second metal oxide layer introduced in this invention can attract electrons and repel holes, thus reducing the hole / electron concentration ratio and making it more likely to deviate from the trapping cross section. This also reduces the recombination pre-factor, thereby reducing the nonradiative recombination rate at the interface.

[0022] A standard perovskite solar cell, from bottom to top, mainly consists of a conductive substrate (e.g., FTO conductive glass), an electron transport layer (e.g., TiO2, ZnO), a perovskite layer, a hole transport layer (e.g., Spiro-OMeTAD, PTAA), and a metal counter electrode. In contrast, an inverted perovskite solar cell swaps the positions of the electron and hole transport layers and uses significantly different materials. The electron transport layer of an inverted perovskite solar cell can be made of PCBM, C... 60 For materials such as PEDOT:PSS and NiO, the hole transport layer can be selected. x Materials, etc.

[0023] In this invention, when depositing the first and second metal oxide layers, the metal oxides are directly deposited on the corresponding hole transport layer and perovskite layer. Compared with the method of first depositing metal particles and then oxidizing, this method simplifies the process. At the same time, the thin film prepared by atomic layer deposition has better coverage and shape retention, and the film thickness can be precisely controlled, making it more suitable for large-area commercial production.

[0024] Compared with the prior art, the advantages of the present invention are: by optimizing and improving the atomic layer deposition technology process, the present invention controls the carrier concentration distribution, reduces the non-radiative recombination rate at the interface, and improves the photoelectric conversion efficiency of inverted perovskite solar cells. Attached Figure Description

[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 optimal device current-voltage curves (JV curves) for the inverted perovskite solar cells of Example 1 and Comparative Examples 1-3 are shown.

[0027] Figure 3 Photoluminescence (PL) spectra of semiconductor devices fabricated based on 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 (HTL) thin film 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 Implementation

[0030] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Figure 1 The diagram shows a cross-sectional view of the structure of the inverted perovskite solar cell provided by the present invention. The structure, from bottom to top, includes 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 high nonradiative recombination rates at the interfaces of the structure significantly negatively impact photoelectric conversion efficiency. To address this issue, this invention inserts metal oxide layers with fixed charges between the perovskite layer and the hole transport layer, and between the perovskite layer and the electron transport layer. Specifically, a first metal oxide layer with a fixed negative charge is inserted between the perovskite film and the hole transport layer, attracting holes and repelling electrons at this interface; a second metal oxide layer with a fixed positive charge is inserted between the perovskite film and the electron transport layer, attracting electrons and repelling holes at this interface. Combined, this method effectively reduces the nonradiative recombination rates at the two interfaces, thereby improving the photoelectric conversion efficiency of the device.

[0033] In some embodiments of the present invention, the provided inverted perovskite solar cell is prepared by sequentially fabricating 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 substrate is made of FTO conductive glass substrate.

[0035] Optionally, the hole transport layer may be made of 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 electrode layer may be made of metallic Cu.

[0039] Alternatively, 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] Alternatively, the thickness of the copper electrode layer is 100 nm.

[0043] When performing atomic layer deposition of the first metal oxide layer and the second metal oxide layer, the cyclic treatment method is as follows: at 25-150℃, pulse spray metal source for 0.01-1 s, purge with protective gas for 1-100 s, pulse spray water for 0.01-1 s, purge with protective gas for 1-100 s, repeat the cycle 1-50 times, and then anneal at 100-500℃ after the treatment.

[0044] Example 1

[0045] The inverted perovskite solar cell provided in this embodiment is prepared using the following method:

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

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

[0048] (2) Preparation of the first metal oxide layer. The first metal oxide layer is prepared by using atomic layer deposition technology and selecting hafnium oxide material to perform the first cycle deposition process on the hole transport layer.

[0049] The specific method is as follows: In the atomic layer deposition system, at 100℃, the metal source is pulse-sprayed for 0.2 s, purged with protective gas for 20 s, pulse-sprayed with water for 0.02 s, purged with protective gas for 25 s, and the process is repeated twice; after the process, it is transferred to a high-temperature hot stage at 180℃ for pre-annealing for 10 min, and then the high-temperature hot stage is heated to 400℃ for annealing for 45 min to obtain the first metal oxide layer.

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

[0051] (4) Preparation of the 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 the second metal oxide layer.

[0052] The specific method is as follows: In an atomic layer deposition system, at 100°C, a metal source is pulse-sprayed for 0.2 s, purged with protective gas for 20 s, water is pulse-sprayed for 0.02 s, purged with protective gas for 25 s, and the process is repeated twice to obtain a second metal oxide layer.

[0053] (5) Fabrication of the electron transport layer. A 20 nm thick C layer is sequentially deposited on the surface of the second metal oxide layer. 60 An electron transport layer was obtained using a thin film (fullerene) and a 7nm BCP material.

[0054] The specific method is as follows: transfer the previously prepared semiconductor device to a vacuum level below 1×10⁻⁶. -4 C was deposited at a rate of 0.02 nm / s in a Pa vapor deposition apparatus. 60 Thin film. Then, BCP thin films were deposited at a rate of 0.02 nm / s.

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

[0056] The specific method is as follows: transfer the previously prepared semiconductor device to a vacuum level below 1×10⁻⁶. -4 In the Pa vapor deposition apparatus, 10 nm of Cu was first deposited at a rate of 0.01 nm / s, followed by 90 nm of copper at a rate of 0.1 nm / s.

[0057] Example 2

[0058] The inverted perovskite solar cell provided in this embodiment differs from that in Example 1 in that the method of step (2) is as follows: In the atomic layer deposition system, at 100°C, the metal source is pulse-sprayed for 0.2 s, purged with protective gas for 20 s, pulse-sprayed with water for 0.02 s, purged with protective gas for 25 s, and the process is repeated 5 times; after the process is completed, it is transferred to a high-temperature hot stage at 180°C for pre-annealing for 10 min, and then the high-temperature hot stage is heated to 400°C for annealing for 45 min to obtain the first metal oxide layer.

[0059] The specific method of step (4) is as follows: In the atomic layer deposition system, at 100°C, the metal source is pulse-sprayed for 0.2 s, purged with protective gas for 20 s, water is pulse-sprayed for 0.02 s, purged with protective gas for 25 s, and the process is repeated 5 times to obtain the second metal oxide layer.

[0060] Comparative Example 1

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

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

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

[0064] (2) Preparation of the first metal oxide layer. The first metal oxide layer is prepared by using atomic layer deposition technology and selecting hafnium oxide material to perform the first cycle deposition process on the hole transport layer.

[0065] The specific method is as follows: In the atomic layer deposition system, at 100℃, the metal source is pulse-sprayed for 0.2 s, purged with protective gas for 20 s, pulse-sprayed with water for 0.02 s, purged with protective gas for 25 s, and the process is repeated twice; after the process, it is transferred to a high-temperature hot stage at 180℃ for pre-annealing for 10 min, and then the high-temperature hot stage is heated to 400℃ for annealing for 45 min to obtain the first metal oxide layer.

[0066] (3) Preparation of the perovskite layer. A 1.67M Cs oxide layer was spin-coated onto the first metal oxide layer. 0.05 MA 0.1 FA 0.85 A perovskite solution of PbI3 was annealed at 100°C for 30 min.

[0067] (4) Fabrication of the electron transport layer. A 20 nm thick C layer is sequentially deposited on the surface of the perovskite layer. 60 An electron transport layer was obtained using a thin film (fullerene) and a 7nm BCP material.

[0068] The specific method is as follows: transfer the previously prepared semiconductor device to a vacuum level below 1×10⁻⁶. -4 C was deposited at a rate of 0.02 nm / s in a Pa vapor deposition apparatus. 60 Thin film. Then, BCP thin films were deposited at a rate of 0.02 nm / s.

[0069] (5) Fabrication of the electrode layer. A 100 nm copper layer is deposited on the surface of the electron transport layer. Specifically, the previously fabricated semiconductor device is transferred to a vacuum level below 1×10⁻⁶. -4 A 10 nm thick elemental copper layer was deposited in a Pa vapor deposition apparatus at a rate of 0.01 nm / s. A 90 nm thick elemental copper layer was then deposited at a rate of 0.1 nm / s.

[0070] Comparative Example 2

[0071] The inverted perovskite solar cell provided in this comparative example, compared with Example 1, does not have a first metal oxide layer between the hole transport layer and the perovskite layer. The specific fabrication method is as follows.

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

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

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

[0075] (3) Preparation of the second metal oxide layer. The second metal oxide layer is prepared by using atomic layer deposition technology and selecting hafnium oxide material to perform a second cycle deposition process on the perovskite layer.

[0076] The specific method is as follows: In the atomic layer deposition system, at 100°C, the metal source is pulse-sprayed for 0.2 s, purged with protective gas for 20 s, water is pulse-sprayed for 0.2 s, purged with protective gas for 25 s, and the process is repeated twice.

[0077] (4) Fabrication of the electron transport layer. A 20 nm thick C layer is sequentially deposited on the surface of the second metal oxide layer. 60 An electron transport layer was obtained using a thin film (fullerene) and a 7nm BCP material.

[0078] The specific method is as follows: transfer the previously prepared semiconductor device to a vacuum level below 1×10⁻⁶. -4 C was deposited at a rate of 0.02 nm / s in a Pa vapor deposition apparatus. 60 Thin film. Then, BCP thin films were deposited at a rate of 0.02 nm / s.

[0079] (5) Fabrication of the electrode layer. A 100 nm copper layer is deposited on the surface of the electron transport layer. Specifically, the previously fabricated semiconductor device is transferred to a vacuum level below 1×10⁻⁶. -4 In the Pa vapor deposition apparatus, 10 nm of Cu was first deposited at a rate of 0.01 nm / s, followed by 90 nm of copper at a rate of 0.1 nm / s.

[0080] Comparative Example 3

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

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

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

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

[0085] (3) Fabrication of the electron transport layer. A 20 nm thick C layer is sequentially deposited on the surface of the second metal oxide layer. 60 An electron transport layer was obtained using a thin film (fullerene) and a 7nm BCP material.

[0086] The specific method is as follows: transfer the previously prepared semiconductor device to a vacuum level below 1×10⁻⁶. -4 C was deposited at a rate of 0.02 nm / s in a Pa vapor deposition apparatus. 60 Thin film. Then, BCP thin films were deposited at a rate of 0.02 nm / s.

[0087] (4) Fabrication of the electrode layer. A 100 nm copper layer is deposited on the surface of the electron transport layer. Specifically, the previously fabricated semiconductor device is transferred to a vacuum level below 1×10⁻⁶. -4 In the Pa vapor deposition apparatus, 10 nm of Cu was first deposited at a rate of 0.01 nm / s, followed by 90 nm of copper at a rate of 0.1 nm / s.

[0088] Comparative Example 4

[0089] The inverted perovskite solar cell provided in this comparative example differs from that in Example 1 in that step (2) is specifically performed as follows: In an atomic layer deposition system, at 100°C, a metal source is pulse-sprayed for 0.2 s, purged with a protective gas for 20 s, followed by pulse-spraying with water for 0.02 s, and then purged with a protective gas for 25 s. This process is repeated twice to obtain the first metal oxide layer. That is, in this comparative example, no pre-annealing or annealing process is performed when the first metal oxide layer is obtained.

[0090] Experimental Example 1: Performance Testing of Inverted Perovskite Solar Cells

[0091] This experimental example uses the inverted perovskite solar cells prepared in the above-described embodiments and comparative examples, and performs J-V curve tests. The test results are as follows: Figure 2 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 As can be seen, the open-circuit voltage (V) of the inverted perovskite solar cell prepared in Example 1 is... oc The voltage is 1.184V, and the short-circuit current (J) is... sc The value 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 The voltage is 1.181V, and the short-circuit current (J) is... sc The value 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 inverted perovskite solar cell prepared in Comparative Example 1 has an open-circuit voltage (V). oc The voltage is 1.152 V, and the short-circuit current (J) is 1.152 V. sc The value is 25.33 mA·cm. -2 The fill factor (FF) is 79.68%, and the final photoelectric conversion efficiency (PCE) is 23.25%.

[0097] The inverted perovskite solar cell prepared in Comparative Example 2 has an open-circuit voltage (V). oc The voltage is 1.154 V, and the short-circuit current (J) is 1.154 V. sc The value 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 The voltage is 1.139 V, and the short-circuit current (J) is 1.139 V. sc The value is 25.27 mA·cm. -2 The fill factor (FF) is 77.13%, and the final power conversion efficiency (PCE) is 22.20%.

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

[0100] As can be seen from the photoelectric conversion efficiency of the devices in Example 1 and Comparative Examples 1, 2, and 3, the device has the highest photoelectric conversion efficiency after adding the first metal oxide layer and the second metal oxide layer at the same time. After adding the first metal oxide layer or the second metal oxide layer respectively, the photoelectric conversion efficiency is improved compared with the device without the metal oxide layer, but it is not as good as the device with both layers added at the same time.

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

[0102] Experimental Example 2: Testing of Nonradiative Recombination Rate and Fixed Charge in Thin Films

[0103] like Figure 3 As shown, we fabricated semiconductor devices based on 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) structures and performed photoluminescence (PL) spectroscopy tests. We found that the luminescence intensity significantly increased after inserting the first and second metal oxide layers. This indicates that the nonradiative recombination between the perovskite and the transport layer is significantly suppressed.

[0104] like Figure 4 As shown, we prepared samples of the hole transport layer (HTL) and the hole transport layer / first metal oxide layer (MO1) and performed Kelvin probe atomic force microscopy (KPFM) tests on them. We found that the potential increased by approximately 0.2 V after the addition of MO1. Since KPFM is very sensitive to changes in surface electrostatic potential, which is easily affected by fixed charges, we can infer that a fixed negative charge was introduced into the surface due to the insertion of MO1.

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

[0106] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a trans-perovskite solar cell, characterized by, The method comprises the following steps: a hole transport layer is prepared on a substrate, a first metal oxide layer is prepared by a first cyclic deposition process on the hole transport layer; a perovskite layer is arranged on the surface of the first metal oxide layer, and a second metal oxide layer is prepared by a second cyclic deposition process on the surface of the perovskite layer; an electron transport layer is arranged on the surface of the second metal oxide layer, and an electrode layer is arranged on the surface of the electron transport layer; the material of the first metal oxide layer and the second metal oxide layer is one or more of hafnium oxide, zirconium oxide, yttrium oxide, tantalum oxide, aluminum oxide and magnesium oxide; the first cyclic deposition process and the second cyclic deposition process are performed by an atomic layer deposition method, which comprises the following steps: at 25-150 DEG C, pulse spraying a metal source for 0.01-1 s, using a protective gas to purge for 1-100 s, pulse spraying water for 0.01-1 s, using a protective gas to purge for 1-100 s, and repeating the process for 1-50 times; after the first cyclic deposition process, an annealing process at 100-500 DEG C is further performed.

2. The method for preparing an inverted perovskite solar cell according to claim 1, characterized in that, the first cyclic deposition process is performed by the following method: at 100 DEG 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 repeating the process for 2 times; after the first cyclic deposition process, a pre-annealing process at 180 DEG C for 10 min and an annealing process at 400 DEG C for 45 min are further performed to obtain the first metal oxide layer.

3. The method for preparing an inverted perovskite solar cell according to claim 1, characterized in that, the second cyclic deposition process is performed by the following method: at 100 DEG 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 repeating the process for 2 times.

4. The method of claim 1, wherein the trans -perovskite solar cell is prepared by the steps of: the thickness of the first metal oxide layer is 0.1-5 nm.

5. The method of claim 1, wherein the trans -perovskite solar cell is prepared by the steps of: the thickness of the second metal oxide layer is 0.1-5 nm.

6. The method of claim 1, wherein the trans -perovskite solar cell is prepared by the steps of: The electron transport layer is composed of C 60 a thin film layer and a BCP layer, the C 60 The thickness of the thin film layer is 20 nm, and the thickness of the BCP layer is 7 nm.

7. A transversal perovskite solar cell prepared by the method of any one of claims 1-6.

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