A method for preparing perovskite film on silicon substrate

Abstract

The invention discloses a method for preparing a perovskite film on a silicon substrate, the method comprising: preparing a perovskite precursor ink; using inkjet printing to print the perovskite precursor ink on a silicon substrate to obtain a perovskite wet film; using a vacuum flash evaporation process to assist the perovskite wet film to form a pre-crystallized dry film; and annealing the perovskite pre-crystallized dry film to obtain a perovskite film. This process uses high-precision inkjet printing on a silicon wafer to prepare a perovskite film, with higher resolution, finer and smoother details, so that the perovskite forms a dense, shrinkage-free film on the silicon substrate, forms good contact with the underlying silicon wafer, and realizes rapid and stable deposition of the perovskite film on a large-area silicon substrate.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite technology, and specifically relates to a method of preparing a perovskite film on a silicon substrate using inkjet printing, and combining the perovskite film with a perovskite-based cell in a series / multi-junction arrangement to improve the performance of a conventional silicon-based solar cell. Background Art

[0002] Perovskite solar cells are solar cells that use perovskite-type organic metal halide semiconductors in the form of thin films as light-absorbing materials. They have the characteristics of high carrier mobility, adjustable band gap, simple preparation and synthesis process, and low cost.

[0003] Some research on the application of perovskites in photovoltaic devices has focused on the potential of these materials to improve the performance of conventional silicon-based solar cells by combining them with perovskite-based cells in a tandem / multi-junction arrangement. In this regard, a multi-junction photovoltaic device includes multiple individual sub-cells (i.e., each sub-cell has its own photosensitive area), which are "stacked" on top of each other and together convert more of the solar spectrum into electricity, thereby increasing the overall efficiency of the device. Conventional commercial crystalline silicon solar cells have anti-reflection layer surfaces, and these surface textures are usually composed of pyramids made by surface etching along the crystal plane. Therefore, these textured surfaces pose a great problem for the processing of monolithic integrated silicon-based perovskite photovoltaic devices. For example, the surface roughness of conventional crystalline silicon solar cells is usually in the range of 500nm to 10μm, while the thickness of perovskite films is usually less than 1μm. Therefore, perovskite films prepared by traditional spin coating, slit coating and other processes will produce many shrinkage holes on the silicon substrate, as well as uneven textures, which seriously affect the interface between the perovskite sub-cell and the adjacent crystalline silicon bottom sub-cell. Mechanical polishing of crystalline silicon solar cells to form a flat surface increases processing costs and reduces the efficiency of silicon cells. Therefore, it is necessary to develop a technology that can efficiently and stably prepare high-quality perovskite films on silicon substrates. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a method for efficiently and stably preparing high-quality perovskite films on silicon substrates. The perovskite film is prepared on the silicon wafer by high-precision inkjet printing. The inkjet printing allows the nozzle to absorb the probe reagent from the microplate and move it to the treated support. The perovskite ink droplets are sprayed onto the surface of the support by the power of the thermal or acoustically controlled ejector. The inkjet ejects tiny perovskite ink droplets onto the paper surface. It has higher resolution, finer and smoother details. It realizes the rapid and stable deposition of large-area perovskite films on silicon substrates.

[0005] The present invention provides a method for preparing a perovskite film on a silicon wafer, the steps of which are as follows:

[0006] preparing perovskite precursor ink;

[0007] The perovskite precursor ink is printed on a silicon substrate by inkjet printing to obtain a perovskite wet film;

[0008] A vacuum flash evaporation process is used to quickly remove most of the solvent in the perovskite precursor wet film to obtain the perovskite pre-crystallization film;

[0009] The perovskite pre-crystallized dry film is annealed to obtain a perovskite film.

[0010] Optionally, the general formula of the perovskite precursor in the perovskite precursor ink is ABX3, wherein A is a monovalent cation: including but not limited to one or more cations of cesium (Cs), methylamine (MA) or formamidine (FA), phenylethylamine halide (PEA-), B is a divalent metal cation: including but not limited to one or more cations of lead (Pb) and tin (Sn), and X is a monovalent anion: including but not limited to one or more anions of iodine (I), bromine (Br), chlorine (Cl) or halogen-like (SCN-);

[0011] Optionally, the carrier solvent in the perovskite precursor ink generally includes one or more of ethylene glycol monomethyl ether (2-ME), N,N-dimethylformamide (DMF), γ-butyrolactone (GBL), ethanol, and isopropanol, and the perovskite precursor ink concentration is preferably in the range of 20wt% to 80wt%;

[0012] Optionally, the ligand in the perovskite precursor ink includes at least one of diphenyl sulfoxide (DPSO), dimethyl sulfone (DMSO), and N-methylpyrrolidone (NMP);

[0013] Optionally, when printing perovskite precursor ink, ensure that the silicon wafer is cooled to room temperature. The perovskite ink printing resolution ranges from 100×100dpi to 3000dpi×3000dpi, the print nozzle droplet volume ranges from 1 to 50pl, and the jetting frequency is 50 to 100000Hz.

[0014] Optionally, when a vacuum flash evaporation process is used to assist the perovskite wet film formation process, the air pressure of the vacuum box needs to be maintained at 100 Pa for 5 to 300 s.

[0015] Optionally, when the perovskite pre-crystallized dry film is annealed, the annealing temperature is 40 to 250° C., and the annealing time is 1 to 60 minutes.

[0016] According to the present invention, the perovskite film prepared by inkjet printing on a silicon substrate still has good uniformity and density and no shrinkage holes at a thickness of 300 to 1000 nm, and the preparation time of the perovskite film is greatly shortened compared with other coating methods.

[0017] The perovskite layer in the perovskite module prepared by the present invention has good contact with the adjacent crystalline silicon bottom cell, which greatly increases the photoelectric conversion efficiency and stability of the device. The use of inkjet printing technology greatly shortens the preparation cycle of the perovskite film, which has great potential value in the industrial application of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the process of preparing perovskite film by inkjet printing in the present invention;

[0020] Figure 2 The process of preparing a perovskite film by inkjet printing on a semi-finished heterojunction silicon solar cell in the present invention;

[0021] Figure 3 Schematic diagram of the structure of the perovskite / heterojunction stacked battery prepared by this process in Example 2 of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0023] The following will be combined with the drawings in the embodiments of the patent of the present invention to clearly and completely describe the technical solutions in the embodiments of the patent of the present invention. Obviously, the described embodiments are only part of the embodiments of the patent of the present invention, not all of them. Based on the embodiments in the patent 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 patent of the present invention.

[0024] The specific implementation of the present invention is described in detail below.

[0025] Figure 1 The schematic diagram of the process of preparing the perovskite film by inkjet printing in the present invention is as follows:

[0026] S11, preparing perovskite precursor ink;

[0027] S13, printing the perovskite precursor ink on the silicon substrate by inkjet printing to obtain a perovskite wet film;

[0028] S14, using a vacuum flash evaporation process to assist the formation of a perovskite wet film to obtain a perovskite pre-crystallized dry film;

[0029] S15, annealing the perovskite pre-crystallized dry film to obtain a perovskite thin film.

[0030] Optionally, the general formula of the perovskite precursor in the perovskite precursor ink is ABX3, wherein A is a monovalent cation: including but not limited to one or more cations of cesium (Cs), methylamine (MA) or formamidine (FA), phenylethylamine halide (PEA-), B is a divalent metal cation: including but not limited to one or more cations of lead (Pb) and tin (Sn), and X is a monovalent anion: including but not limited to one or more anions of iodine (I), bromine (Br), chlorine (Cl) or halogen-like (SCN-);

[0031] Optionally, the carrier solvent in the perovskite precursor ink generally includes one or more of ethylene glycol monomethyl ether (2-ME), N,N-dimethylformamide (DMF), γ-butyrolactone (GBL), ethanol, and isopropanol, and the perovskite precursor ink concentration is preferably in the range of 20wt% to 80wt%;

[0032] Optionally, the ligand in the perovskite precursor ink includes at least one of diphenyl sulfoxide (DPSO), dimethyl sulfone (DMSO), and N-methylpyrrolidone (NMP);

[0033] Optionally, when printing perovskite precursor ink, ensure that the silicon wafer is cooled to room temperature. The perovskite ink printing resolution ranges from 100×100dpi to 3000dpi×3000dpi, the print nozzle droplet volume ranges from 1 to 50pl, and the jetting frequency is 50 to 100000Hz.

[0034] Optionally, when a vacuum flash evaporation process is used to assist the perovskite wet film formation process, the air pressure of the vacuum box needs to be maintained at 100 Pa for 5 to 300 s.

[0035] Optionally, when the perovskite pre-crystallized dry film is annealed, the annealing temperature is 40 to 250° C., and the annealing time is 1 to 60 minutes.

[0036] Embodiment 1: Figure 2 The process of preparing a perovskite film by inkjet printing on a semi-finished heterojunction silicon solar cell in the present invention is to prepare a perovskite film on a semi-finished heterojunction silicon solar cell of M6 size in the present invention, and lead iodide (PbI2) and formamidinium iodine (FAI), cesium iodide (CsI), and methylamine iodine (MAI) are selected as perovskite precursor raw materials, and a mixed solvent of DMF and DMSO is used as the ink solvent of the precursor raw materials, and the precursor raw materials are dissolved in the solvent to obtain a precursor ink. ;

[0037] The perovskite precursor ink was injected into the inkjet printer cartridge, the printing resolution was set to 600×1200dpi, the print nozzle droplet volume was set to 30pl, and the jet frequency was set to 3000Hz to complete the printing of the perovskite wet film.

[0038] The perovskite precursor wet film was transferred to a vacuum flash chamber, and the air pressure in the chamber was evacuated to 300 Pa and maintained for 60 seconds to obtain a pre-crystallized dry film.

[0039] The pre-crystallized dry film was annealed at 120°C for 5 min to obtain a PVK film.

[0040] Embodiment 2: Figure 3 The schematic diagram of the structure of the perovskite / heterojunction stacked cell prepared by the process in Example 2 of the present invention is shown in Figure 2. The perovskite / heterojunction stacked cell is prepared by the present invention on a finished heterojunction silicon solar cell of M6 size, specifically comprising:

[0041] The carrier transport layer-1 (CTL-1) was prepared on the semi-finished heterojunction silicon solar cell.

[0042] A certain proportion of lead iodide (PbI2), lead bromide (PbBr2), formamidinium iodide (FAI), cesium iodide (CsI) and methylamine iodine (MAI) are selected as perovskite precursor raw materials, and a certain proportion of DMF, DMSO, and NMP mixed solvent is used as the solvent of the precursor raw materials. The precursor raw materials are dissolved in the solvent and mixed evenly to obtain perovskite precursor ink.

[0043] The perovskite precursor ink was injected into the inkjet printer cartridge, the printing resolution was set to 600×600 dpi, the print nozzle droplet volume was set to 60 pl, and the jet frequency was set to 6000 Hz. The perovskite wet film was printed.

[0044] The perovskite wet film was transferred to a vacuum flash chamber, and the air pressure in the chamber was evacuated to 60 Pa and maintained for 60 seconds to obtain a perovskite pre-crystallized dry film.

[0045] The pre-crystallized dry film was annealed at 155°C for 30 min to obtain a perovskite film.

[0046] The carrier transport layer-2 (CTL-2) was prepared on the PVK film.

[0047] The TCO layer and the electrode are sequentially deposited on the carrier transport layer-2 to obtain a perovskite / heterojunction stacked cell.

[0048] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a perovskite film on a silicon substrate, characterized in that: The following steps are involved: a. Prepare perovskite precursor ink; b. Printing the perovskite precursor ink on a textured silicon substrate having an electron transport layer by inkjet printing to obtain a perovskite wet film; c. Using vacuum flash evaporation process to assist the formation of perovskite wet film to obtain perovskite pre-crystallized dry film; d. annealing the perovskite pre-crystallized dry film to obtain a perovskite film; In step b, the silicon substrate is a finished product or semi-finished product of a heterojunction solar cell or a homojunction solar cell, and the surface roughness of the silicon substrate and the pyramid velvet surface fluctuation range are 200nm-2um; In step b, the perovskite ink printing resolution ranges from 100×100dpi to 3000dpi×3000dpi, the printing nozzle droplet volume ranges from 1 to 50pl, and the jetting frequency is from 10 to 100000Hz.

2. The preparation method according to claim 1, characterized in that: In step a, the general formula of the perovskite precursor in the perovskite precursor ink is ABX3, wherein A is a monovalent cation: including one or more cations of cesium, methylamine or methylammonium, phenylethylamine halide salts, B is a divalent metal cation: including one or more cations of lead and tin, and X is a monovalent anion: including one or more anions of iodine, bromine, chlorine or halogen-like.

3. The preparation method according to claim 1, characterized in that: In step a, the carrier solvent in the perovskite precursor ink includes ethylene glycol monomethyl ether, N,N-dimethylformamide and γ-butyrolactone, and one or more alcohol solvents, and the concentration of the perovskite precursor ink ranges from 20wt% to 80wt%.

4. The preparation method according to claim 1, characterized in that: In step a, the ligand in the perovskite precursor ink includes at least one of diphenyl sulfoxide, dimethyl sulfone, and N-methylpyrrolidone.

5. The preparation method according to claim 1, characterized in that: In step c, when the vacuum flash evaporation process is used to assist the perovskite wet film formation process, it is necessary to maintain the air pressure in the range of 1-100 Pa for 5 to 300 seconds.

6. The preparation method according to claim 1, characterized in that: In step d, when the perovskite pre-crystallized dry film is annealed, the annealing temperature is 40 to 250° C., and the annealing time is 1 to 60 minutes.

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