A bottom passivated perovskite solar cell

Abstract

The application discloses a perovskite solar cell with bottom passivation, which comprises, from a light-receiving front surface to a light-receiving back surface, a transparent conductive substrate, a hole transport layer, a nanocrystal mixed passivation layer, a perovskite light absorption layer, an electron transport layer and a back electrode; the nanocrystal mixed passivation layer is made of an insulating oxide and an organic passivation molecule. The bottom nanocrystal passivation method combining nanometer oxide particles and organic passivation molecules can enhance the bottom passivation adsorption, increase the passivation area, provide more binding sites, effectively relieve the internal stress of the bottom, enhance the mechanical adhesion, avoid the peeling phenomenon, and improve the photoelectric conversion efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cells, and particularly relates to a bottom passivated perovskite solar cell. BACKGROUND

[0002] As a kind of renewable energy, solar energy is inexhaustible, environmentally friendly and ideal energy, and its potential annual power generation capacity is as high as 23000 TW. Solar cells use photovoltaic effect to directly convert solar energy into electrical energy, which has attracted high attention in the energy field to meet the growing demand for sustainable green and clean energy. The widely used solar cells in the market are crystalline silicon solar cells, but after decades of technical research and industrial development, their performance has been continuously improved and basically reached the peak, and there is little room for improvement. The purity of the crystalline silicon solar cells must reach more than 99.9999% to be used in solar cell manufacturing, which is costly. The record-breaking power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased from 3.8% in the past to more than 26% at present, which is comparable to commercial silicon solar cells. Most importantly, PSCs have great advantages in easy manufacturing and solution-based processing cost. Therefore, it is of great significance to further study perovskite solar cells and promote their industrial application.

[0003] However, in the process of industrial application of perovskite solar cells, in order to improve the production efficiency and reduce the production cost per unit area, it is necessary to prepare PSCs in a large area. However, in the process of preparing perovskite materials in a large area, due to insufficient interfacial adhesion, accumulation of internal stress, mechanical damage, and a large number of defects in thin film materials, the peeling phenomenon of the perovskite layer from the substrate is a common problem, which may seriously affect the performance and stability of the device. In response to these challenges, it is necessary to optimize the substrate surface treatment process, enhance the interfacial adhesion, reduce the accumulation of internal stress, and improve the mechanical strength of the bottom layer. In addition, although the passivation technology of the surface of the perovskite thin film has been mature, the directional passivation of the bottom of the perovskite thin film still faces many process problems in actual operation. For example, when the passivation molecules are simply coated on the substrate, these molecules are easily dissolved in the process of preparing perovskite solution, and cannot be effectively anchored to the lower interface. Further problems include that due to weak interfacial adhesion, insufficient chemical bonding force, and mismatched interface roughness, the passivation molecules may fall off from the interface and mix into the perovskite layer, which destroys the internal structure of the perovskite layer and further reduces the overall performance of the PSC assembly.

[0004] In view of these problems, it is the key to enhance the passivation effect and improve the mechanical strength of the interface to develop new interface engineering technology and materials to improve the performance and stability of large-area PSCs. SUMMARY

[0005] The purpose of this invention is to provide a bottom-passivated perovskite solar cell, which includes, from the light-receiving front side to the light-receiving back side, a transparent conductive substrate, a hole transport layer, a nanocrystalline hybrid passivation layer, a perovskite light-absorbing layer, an electron transport layer, and a back electrode.

[0006] The bottom nanocrystalline hybrid passivation layer is made of insulating oxide and organic passivation molecules, with a mass ratio of insulating oxide to organic passivation molecules of 3:1 to 1:3.

[0007] Furthermore, the insulating oxide is silicon oxide, aluminum oxide, or zirconium oxide, and the particle size of the insulating oxide is 5-100 nm.

[0008] Furthermore, the organic passivating molecule is phenylethyl ammonium iodide (PEAI), 4-fluorophenylethyl ammonium iodide (4F-PEAI), 4-fluorophenylethyl ammonium chloride (4F-PEACl), phenylethyl ammonium chloride (PEACl), 4-trifluoromethylphenyl ammonium chloride (CF3-PACl), ethylenediamine iodide (EDADI), trioctylphosphine oxide (TOPO), 1-octadecyl mercaptan (ODT), or triphenylphosphine (PPh3).

[0009] In one embodiment of the present invention, the bottom nanocrystalline mixed passivation layer is made of nano-silica and 4-fluorophenylethyl ammonium chloride (4F-PEACl), with a mass ratio of nano-silica to 4-fluorophenylethyl ammonium chloride (4F-PEACl) of 1:1.

[0010] Furthermore, the transparent conductive substrate is an indium tin oxide (ITO) substrate, an indium tungsten oxide (IWO) substrate, a fluorine-doped tin oxide (FTO) substrate, an indium zinc oxide (IZO) substrate, or an aluminum-doped zinc oxide (AZO) substrate.

[0011] Furthermore, the hole transport layer is made of a p-type semiconductor material, selected from nickel oxide (NiO). x Molybdenum oxide (MoO3), cuprous oxide (Cu2O), cuprous iodide (CuI), copper phthalocyanine (CuPc), cuprous thiocyanate (CuSCN), redox graphene, poly(triaryl amine) (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), poly(4-phenyl)(4-butylphenyl)amine (Ploy-TPD), monolayers, and one or more of the following.

[0012] Furthermore, the perovskite light-absorbing layer is made of perovskite material ABX3, wherein: A is selected from formamidinium ions (FA). + ), Methylamine ion (MA + ), cesium ions (Cs) + B is selected from lead ions (Pb). 2+ ), tin ions (Sn) 2+ germanium ions (Ge) 2+ X is selected from iodide ions (I); - ), bromide ions (Br) - ), chloride ions (Cl) - ).

[0013] Furthermore, the electron transport layer is made of an n-type semiconductor material, selected from fullerenes (C2). 60 ), graphene, fullerene derivatives [6,6]-phenyl-C 61 - Methyl butyrate (PCBM), carbon nanotubes, or one or more of these.

[0014] Furthermore, the back electrode can be a metal electrode or a metal grid electrode. The metal grid electrode can be made of one or more of the following metals: gold, palladium, silver, titanium, chromium, nickel, aluminum, copper, etc. The preparation method of the grid electrode can be vacuum evaporation, sputtering, atomic layer deposition, 3D printing, screen printing, inkjet printing, etc.

[0015] A second objective of this invention is to provide a method for fabricating the aforementioned bottom-passivated perovskite solar cell.

[0016] Provide a transparent conductive substrate;

[0017] A hole transport layer is formed on the upper surface of a transparent conductive substrate;

[0018] A nanocrystalline hybrid passivation layer is formed on the upper surface of the hole transport layer;

[0019] A perovskite light-absorbing layer is formed on the upper surface of the bottom nanocrystalline hybrid passivation layer;

[0020] An electron transport layer is formed on the upper surface of the perovskite light-absorbing layer;

[0021] A back electrode is formed on the upper surface of the electron transport layer.

[0022] Furthermore, the formation of the nanocrystalline hybrid passivation layer on the upper surface of the hole transport layer involves dissolving insulating oxides and organic passivation molecules in a solvent and then coating them onto the hole transport layer using a blade coating method.

[0023] A third objective of this invention is to provide a photovoltaic module comprising at least one cell string, wherein the cell string comprises at least two of the aforementioned perovskite solar cells.

[0024] This invention employs a bottom nanocrystal passivation method combining nano-oxide particles and organic passivation molecules. This mixture enhances the passivation adsorption at the bottom, increases the passivation area, provides more binding sites, effectively alleviates internal stress at the bottom, strengthens mechanical adhesion, prevents peeling, and improves photoelectric conversion efficiency. This method is applied to a 0.049 cm... 2 In the fabrication of perovskite solar cells with effective area, the photoelectric conversion efficiency was increased from 23.02% to 25.48%. Furthermore, when this method was applied to the fabrication of large-area modules, a photoelectric conversion efficiency of 20.28% was also achieved on an effective area of ​​20.25 cm². Attached Figure Description

[0025] Figure 1 A schematic diagram of the device structure after introducing a bottom nanocrystalline hybrid passivation layer for a perovskite solar cell.

[0026] Figure 2 Time-of-flight secondary ion mass spectrometry was used to measure perovskite films with and without bottom nanocrystal hybrid passivation.

[0027] Figure 3 X-ray diffraction patterns of perovskite films with and without bottom nanocrystal hybrid passivation at different incident angles.

[0028] Figure 4 Fourier transform infrared spectra of the passivation layer when using only passivation molecules, only oxide nanocrystals, and a mixture of both.

[0029] Figure 5 Fluorescence spectra of perovskite films with no passivation layer, using only passivation molecules, using only oxide nanocrystals, and using a mixture of both.

[0030] Figure 6 Stress-strain curves of perovskite films with no passivation layer, using only passivation molecules, using only oxide nanocrystals, and using a mixture of both.

[0031] Figure 7 The current density-voltage curves of small-area perovskite solar cells prepared with and without the bottom nanocrystal hybrid passivation method are shown.

[0032] Figure 8 Current density-voltage curves of large-area perovskite solar modules prepared using the bottom nanocrystal hybrid passivation method. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0035] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0036] Comparative Example 1

[0037] This embodiment uses a blade coating method to prepare perovskite solar cells. The specific preparation process is as follows:

[0038] 1. A monolayer of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACZ) was prepared on a cleaned ITO substrate as a hole transport layer, approximately 20 nm in size.

[0039] 2. Preparation of Cs at approximately 800 nm using an air-blowing coating method. 0.05 FA 0.95 PbI3 perovskite light-absorbing layer.

[0040] 3. Preparation of a layer of fullerene (C1) using thermal evaporation. 60 As an electron transport layer, it is approximately 20 nm thick.

[0041] 4. Finally, a 150 nm thick Cu layer was deposited by thermal evaporation as the back metal electrode.

[0042] Comparative Example 2

[0043] This embodiment uses a blade coating method to prepare a perovskite solar cell with a bottom passivation layer. The specific preparation process is as follows:

[0044] 1. A monolayer of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACZ) was prepared on a cleaned ITO substrate as a hole transport layer, approximately 20 nm in size.

[0045] 2. A bottom passivation layer was prepared on the prepared hole transport layer using a blade coating method. The passivation molecule 4-fluorophenylethyl ammonium chloride (4F-PEACl) was dissolved in the solvent ethanol (EA) to prepare a solution with a concentration of 1 mg / mL. The bottom passivation layer was then prepared using a nitrogen gas blowing rate of about 30 psi and a blade speed of about 20 mm / s, and annealed at 100 °C for 2 min.

[0046] 3. Preparation of Cs at approximately 800 nm using an air-blowing coating method. 0.05 FA 0.95 PbI3 perovskite light-absorbing layer.

[0047] 4. Preparation of a layer of fullerene (C) using thermal evaporation. 60 As an electron transport layer, it is approximately 20 nm thick.

[0048] 5. Finally, a 150 nm thick Cu layer was deposited by thermal evaporation as the back metal electrode.

[0049] Comparative Example 3

[0050] This embodiment uses a blade coating method to prepare a perovskite solar cell with a bottom nanocrystalline passivation layer. The specific preparation process is as follows:

[0051] 1. A monolayer of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACZ) was prepared on a cleaned ITO substrate as a hole transport layer, approximately 20 nm in size.

[0052] 2. A bottom passivation layer was prepared on the prepared hole transport layer using a blade coating method. Nano-silica was dissolved in ethanol (EA) to prepare a solution with a concentration of 1 mg / mL. The bottom passivation layer was then prepared using a nitrogen gas blowing rate of approximately 30 psi and a blade speed of approximately 20 mm / s, and annealed at 100 °C for 2 min.

[0053] 3. Preparation of Cs at approximately 800 nm using an air-blowing coating method. 0.05 FA 0.95 PbI3 perovskite light-absorbing layer.

[0054] 4. Preparation of a layer of fullerene (C) using thermal evaporation. 60 As an electron transport layer, it is approximately 20 nm thick.

[0055] 5. Finally, a 150 nm thick Cu layer was deposited by thermal evaporation as the back metal electrode. Example 1

[0056] This embodiment uses a blade coating method to prepare a perovskite solar cell with a bottom nanocrystalline hybrid passivation layer (effective area 0.049 cm²). 2 The specific preparation process is as follows:

[0057] 1. A monolayer of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACZ) was prepared on a cleaned ITO substrate as a hole transport layer, approximately 20 nm in size.

[0058] 2. A bottom nanocrystalline hybrid passivation layer was prepared on the prepared hole transport layer using a blade coating method. Nanocrystalline silica and the passivation molecule 4-fluorophenylethyl ammonium chloride (4F-PEACl) were mixed and dissolved in ethanol (EA) at a mass ratio of 1:1 to prepare a solution with a concentration of 1 mg / mL. The bottom nanocrystalline hybrid passivation layer was then prepared using a nitrogen gas blowing rate of approximately 30 psi and a blade speed of approximately 20 mm / s, and annealed at 100 °C for 2 min.

[0059] 3. Preparation of Cs at approximately 800 nm using an air-blowing coating method. 0.05 FA 0.95 PbI3 perovskite light-absorbing layer.

[0060] 4. Preparation of a layer of fullerene (C) using thermal evaporation. 60 As an electron transport layer, it is approximately 20 nm thick.

[0061] 5. Finally, a 150 nm thick Cu layer was deposited by thermal evaporation as the back metal electrode.

[0062] The perovskite films prepared under the conditions of Comparative Example 1 and Example 1 were tested. Figure 2 It can be seen that introducing nanocrystalline mixed passivation molecules can allow more organic passivation molecules to remain at the bottom interface; from Figure 3 It can be seen that the peak shift at different incident angles is reduced after bottom nanocrystal mixing passivation, indicating that the longitudinal tensile stress of the perovskite layer is relieved.

[0063] The passivation layers prepared under the conditions of Comparative Example 2, Comparative Example 3, and Example 1 were tested. Figure 4 It can be seen that the surface of oxide nanocrystals is rich in -OH groups, which form hydrogen bonds with passivation molecules, causing the -OH bond vibration to shift to lower wavenumbers, indicating strong bonding and interaction between nanocrystals and passivation molecules.

[0064] The perovskite films prepared under the conditions of Comparative Examples 1-3 and Example 1 were tested. Figure 5 It can be seen that introducing nanocrystalline hybrid passivation at the bottom can further reduce perovskite defects.

[0065] The perovskite films prepared under the conditions of Comparative Examples 1-3 and Example 1 were tested. Figure 6 It can be seen that introducing nanocrystalline hybrid passivation at the bottom can significantly improve interfacial adhesion.

[0066] The titanium dioxide solar cells prepared in Comparative Example 1 and Example 1 were tested by... Figure 7 It can be seen that the photoelectric conversion efficiency of the solar cell with nanocrystalline hybrid passivation at the bottom increased from 23.02% to 25.48%. Example 2

[0067] This embodiment uses a blade coating method to prepare a large-area perovskite solar cell module (effective area 20.25 cm²) with a bottom nanocrystalline hybrid passivation layer. 2 The specific preparation process is as follows:

[0068] 1. Laser edge cleaning and p1 cutting were performed on a cleaned ITO substrate, and then a monolayer of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACZ) was prepared on it as a hole transport layer, about 20 nm thick.

[0069] 2. A bottom nanocrystalline hybrid passivation layer was prepared on the prepared hole transport layer using a blade coating method. Nanocrystalline silica and the passivation molecule 4-fluorophenylethyl ammonium chloride (4F-PEACl) were mixed and dissolved in ethanol (EA) at a mass ratio of 1:1 to prepare a solution with a concentration of 1 mg / ml. The bottom nanocrystalline hybrid passivation layer was then prepared using a nitrogen gas blowing rate of approximately 30 psi and a blade speed of approximately 20 mm / s, and annealed at 100 °C for 2 min.

[0070] 3. Preparation of Cs at approximately 800 nm using an air-blowing coating method. 0.05 FA 0.95 PbI3 perovskite light-absorbing layer.

[0071] 4. Preparation of a layer of fullerene (C) using thermal evaporation. 60 As an electron transport layer, it is approximately 20 nm thick.

[0072] 5. Use laser cutting for p2.

[0073] 6. A 180 nm thick Cu layer was deposited by thermal evaporation as the back metal electrode.

[0074] 7. Finally, p3 is cut using a laser.

[0075] The titanium dioxide solar cell of Example 2 was tested by... Figure 8 It can be seen that the solar cell with nanocrystalline hybrid passivation at the bottom achieved a photoelectric conversion efficiency of 20.28% on an effective area of ​​20.25 cm².

Claims

1. A perovskite solar cell, characterized by, From the light receiving front surface to the light receiving back surface, successively comprises: a transparent conductive substrate, a hole transport layer, a nanocrystal mixed passivation layer, a perovskite light absorption layer, an electron transport layer and a back electrode; The nanocrystal mixed passivation layer is made of an insulating oxide and an organic passivation molecule, and the mass ratio of the insulating oxide and the organic passivation molecule is 3:1-1:3; The insulating oxide is silicon oxide, aluminum oxide or zirconium oxide. The organic passivation molecule is PEAI, 4F-PEAI, 4F-PEACl, PEACl, CF3-PACl, EDADI, TOPO, ODT or PPh3.

2. The perovskite solar cell according to claim 1, characterized in that, The particle size of the insulating oxide is 5-100 nm. 3.The perovskite solar cell of claim 1, wherein, The transparent conductive substrate is an indium tin oxide substrate, an indium tungsten oxide substrate, a fluorine-doped tin oxide substrate, an indium zinc oxide substrate or an aluminum-doped zinc oxide substrate. 4.The perovskite solar cell of claim 1, wherein, The hole transport layer is made of a p-type semiconductor material. 5.The perovskite solar cell of claim 1, wherein, The perovskite light absorption layer is made of a perovskite material ABX3, wherein: A is selected from formamidinium ion, methylamine ion and cesium ion; B is selected from lead ion, tin ion and germanium ion; X is selected from iodine ion, bromine ion and chlorine ion. 6.The perovskite solar cell of claim 1, wherein, The electron transport layer is made of an n-type semiconductor material.

7. The method of producing a perovskite solar cell according to any one of claims 1 to 6, characterized by, The method comprises the following steps: providing a transparent conductive substrate; forming a hole transport layer on the upper surface of the transparent conductive substrate; forming a nanocrystal mixed passivation layer on the upper surface of the hole transport layer; forming a perovskite light absorption layer on the upper surface of the bottom nanocrystal mixed passivation layer; forming an electron transport layer on the upper surface of the perovskite light absorption layer; forming a back electrode on the upper surface of the electron transport layer.

8. The preparation method according to claim 7, characterized in that, The nanocrystal mixed passivation layer is formed on the upper surface of the hole transport layer by dissolving the insulating oxide and the organic passivation molecule in a solvent and then coating them on the hole transport layer by using a doctor blade method.

9. A photovoltaic module, characterized by The method comprises: at least one battery string, the battery string comprising at least two perovskite solar cells according to claim 1.

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