Preparation method of subcell for four-terminal stacked perovskite solar cell and subcell

Abstract

The present invention relates to the technical field of solar cells, and in particular to a preparation method and sub-cell for a four-terminal stacked perovskite solar cell. The preparation steps include: ultrasonically cleaning etched transparent conductive glass with a preset solution, drying it in a forced air drying oven, and treating it with ultraviolet ozone to obtain a transparent conductive oxide substrate; preparing a nickel oxide hole transport layer and then a cuprous thiocyanate hole transport layer in a glove box with a nitrogen atmosphere; adding a certain amount of self-assembled monolayer material to a perovskite precursor solution to prepare a perovskite light absorption thin film layer, an electron transport layer, and a metal electrode layer; the method not only passivates halogen vacancy defects at the grain boundaries and interfaces of the perovskite film, thereby improving the crystallinity of the perovskite film, but also improves the band matching of the interface between the perovskite layer and the NiOx hole transport layer, while passivating defects in the NiOx hole transport layer, thereby ultimately improving the performance of the perovskite solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a method for preparing a sub-cell used in a four-terminal stacked perovskite solar cell and the sub-cell. Background Art

[0002] Solar energy is a safe, environmentally friendly renewable energy source. In recent years, solar cells based on organic-inorganic hybrid perovskite materials have seen rapid development. Currently, the highest photoelectric conversion efficiency of a single-junction perovskite solar cell is 26.7%, very close to the optimal performance level of silicon-based solar cells. To further improve the performance of perovskite solar cells and overcome the SQ efficiency limit of single-junction cells, tandem perovskite solar cells can be prepared. Based on their structure, perovskite tandem solar cells can be primarily divided into two-terminal tandem and four-terminal tandem. Four-terminal tandem cells are achieved by mechanically stacking two individual cells. The upper and lower sub-cells can be prepared under optimal conditions, with a total efficiency equal to the sum of the efficiencies of each sub-cell. Four-terminal tandem cells only need to consider optical coupling, not electrical coupling. At the same time, due to their structural characteristics, four-terminal tandem cells are conducive to reducing parasitic absorption. Moreover, the two sub-cells of a four-terminal tandem cell are manufactured independently, connected only optically, and the circuits are independent of each other, making the four-terminal tandem cell easier to implement in terms of process. During operation, even if a sub-cell does not work, the entire tandem cell can be restored to normal operation by replacing it. Currently, four-terminal perovskite-crystalline silicon tandem cells are highly anticipated by industry and academia. The performance of wide-bandgap perovskite bottom cells has become a key factor restricting the performance of perovskite-crystalline silicon tandem cells. To match the bandgap of crystalline silicon, the bandgap of wide-bandgap perovskite bottom cells is generally around 1.67 eV. Currently prepared perovskite solar cells of this type generally have large turn-on voltage losses (>0.4 V). The main reasons are energy level mismatch at the interface, surface / interface defects of the perovskite film, and bulk defects of the perovskite film, which seriously restrict the efficiency and stability of the prepared perovskite-crystalline silicon tandem cells. Summary of the Invention

[0003] The present invention provides a method for preparing a sub-cell and a sub-cell for a four-terminal stacked perovskite solar cell, aiming to solve the above-mentioned technical problems.

[0004] The present invention adopts the following technical solutions:

[0005] A method for preparing a sub-cell for a four-terminal stacked perovskite solar cell comprises the following steps:

[0006] S1: Preparation of transparent conductive oxide substrate:

[0007] The etched transparent conductive glass is ultrasonically cleaned with deionized water, acetone, glass detergent, deionized water, and isopropyl alcohol in sequence, with the cleaning time set to 10-30 minutes; it is placed in a blast drying oven for drying; the dried transparent conductive glass is treated with ultraviolet ozone to obtain a transparent conductive oxide substrate.

[0008] S2: Preparation of hole transport layer:

[0009] Step 1: Prepare a concentration of 15 mg mL -1 The nickel oxide nanoparticle solution was prepared by mixing isopropyl alcohol and deionized water. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. The prepared nickel oxide nanoparticle solution was dropped onto the transparent conductive substrate using a pipette. After the spin coating was completed, the sample was placed at a temperature of 150 o Annealing on a hot plate at C for 30 min;

[0010] Step 2: Place the transparent conductive oxide substrate with a nickel oxide hole transport layer in a nitrogen atmosphere glove box with a concentration of 1-15 mg mL -1 The cuprous thiocyanate solution is prepared using diethyl sulfide as the solvent. The spin coater speed is set to 1000 to 5000 rpm and the spin coating time is 10-60 s. A pipette is used to transfer the prepared cuprous thiocyanate solution and dynamically spin-coat it onto the nickel oxide hole transport layer. After the spin coating is completed, the sample is placed on a hot plate at 100°C for annealing for 10 minutes.

[0011] S3: Preparation of a perovskite light absorbing thin film layer: adding a perovskite precursor material to a corresponding solvent in a predetermined ratio, followed by stirring and oscillation to obtain a perovskite precursor solution;

[0012] Add 0.5 mg mL into the perovskite precursor solution. -1 The MeO-2PACz self-assembled monolayer is mixed evenly, and the perovskite mixed solution is spin-coated onto the hole transport layer using a spin coater. Anti-solvent is added dropwise during the spin coating. After the spin coating is completed, the obtained perovskite light absorption film layer is placed on a hot stage for annealing at a temperature of 100° C. to 300° C. for a time of 5 min to 2 h.

[0013] S4: Preparation of electron transport layer:

[0014] The perovskite light absorbing film layer is transferred to an organic material evaporation chamber, and an electron transport layer C60 is evaporated to a thickness of 10-50 nm, followed by evaporation of bathocuproin to a thickness of 2-10 nm at an evaporation rate of 0.1-5 Å s -1 .

[0015] S5: Preparation of metal electrode layer:

[0016] Metal electrodes are deposited in a metal evaporation chamber. The material of the deposited metal electrode is selected from one of gold, silver, and copper. The thickness is 60-200 nm and the deposition rate is 0.1-10 Å s -1 .

[0017] In some embodiments, in S1, the ultrasonic cleaning time with deionized water, acetone, glass cleaner, deionized water, and isopropyl alcohol is 15 minutes respectively; the glass is placed in a 60°C forced air drying oven for drying; and the dried transparent conductive glass is treated with ultraviolet ozone for 15 minutes.

[0018] In some embodiments, in S1, the transparent conductive glass is selected from FTO or ITO conductive glass.

[0019] In some embodiments, in S2, the first step is to prepare a concentration of 15 mg mL -1 The nickel oxide nanoparticle solution was prepared by mixing isopropyl alcohol and deionized water. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. The prepared nickel oxide nanoparticle solution was dropped onto the transparent conductive substrate using a pipette. After the spin coating was completed, the sample was placed at a temperature of 150 o Annealing on a hot plate at C for 30 min;

[0020] Step 2: Place the transparent conductive oxide substrate prepared with a nickel oxide hole transport layer in a nitrogen atmosphere glove box with a concentration of 5 mg mL -1 The cuprous thiocyanate solution was prepared using diethyl sulfide as the solvent. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. A pipette was used to transfer the prepared cuprous thiocyanate solution and dynamically spin-coat it onto the nickel oxide hole transport layer. After the spin coating was completed, the sample was placed on a hot plate at 100°C for annealing for 10 min.

[0021] In some embodiments, in S3, the perovskite precursor material is selected from at least two of lead iodide, lead chloride, lead bromide, iodomethane, methylammonium chloride, methylammonium bromide, methylamine iodide, methylamine chloride, methylamine bromide, cesium iodide, cesium chloride, cesium bromide, rubidium iodide, rubidium chloride, and rubidium bromide, and the mixture is mixed in a preset ratio; the solvent is selected from at least two of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and the mixture is mixed in a preset ratio.

[0022] In some embodiments, in S3, the perovskite precursor solution is spin-coated onto the hole transport layer using a spin coater, and the process of adding an anti-solvent during the spin coating comprises:

[0023] First, add an appropriate amount of perovskite precursor solution to the hole transport layer, and then turn on the spin coater for spin coating. Step 1: The speed range is 300-1000 rpm, and the speed increase rate is 200 rpm s -1 , time is 10 s; Step 2: Select the speed range of 2000-8000 rpm, and the speed increase rate is 2000 rpm s -1 The total spin coating time range of the first and second steps is set to 30-90s. 150 μL of anti-solvent chlorobenzene is added 10 s before the end of spin coating. The amount of anti-solvent is 100 microliters to 5 milliliters. After the spin coating is completed, the film is placed on a hot plate at a temperature of 100°C and heated for 30 minutes.

[0024] In some embodiments, in S3, the spin coater is turned on for spin coating. In the first step, the rotation speed is set to 1000 rpm, and the speed is increased at a rate of 200 rpm s -1 , time is 10 s; Step 2: Select the speed to be 5000 rpm, and the speed increase rate is 2000 rpms -1 The total spin coating time of the first step and the second step was 35 s, and 150 μL of anti-solvent chlorobenzene was added dropwise 10 s before the end of spin coating.

[0025] In some embodiments, in S4, the perovskite light absorbing thin film layer is transferred to an organic material evaporation chamber, and an electron transport layer C60 is evaporated to a thickness of 30 nm, followed by evaporation of bathocuproin to a thickness of 7 nm at an evaporation rate of 0.3 Å s -1 .

[0026] In some embodiments, in S5, a metal electrode is evaporated in a metal evaporation chamber, wherein the evaporated metal electrode material is silver, with a thickness of 100 nm and an evaporation rate of 0.1-10 Å s -1 , using step-by-step rate control, when the thickness of the evaporated metal is 0-10 nm, the rate is 0.1 Å s -1 ; When the thickness is 10-20 nm, the rate is 0.2 Å s -1 ; When the thickness is 20-30 nm, the rate is 0.3 Å s -1 ; When the thickness is 30-40 nm, the rate is 0.3 Å s -1 ; When the thickness is 40-50 nm, the rate is 0.4 Å s -1 ; When the thickness is 50-60 nm, the rate is 0.5 Å s -1 ; When the thickness is 60-70 nm, the rate is 0.6 Å s -1 ; When the thickness is 70-100 nm, the rate is 1-10 Å s -1 .

[0027] The present invention also discloses a sub-cell applied to a four-terminal tandem perovskite solar cell, which is prepared using the above-mentioned method for preparing a sub-cell applied to a four-terminal tandem perovskite solar cell. Beneficial effects

[0028] The present invention discloses a method for preparing a sub-cell for a four-terminal stacked perovskite solar cell and the sub-cell. Compared with the prior art, the present invention has the following advantages:

[0029] The present invention is mainly used in the preparation process of the sub-cell of the four-terminal stacked perovskite solar cell, which is mainly aimed at the preparation of the inverted structure perovskite solar cell. A layer of cuprous thiocyanate (CuSCN) hole transport layer is prepared on the nickel oxide (NiOx) hole transport layer, and then a certain amount of self-assembled monolayer material (MeO-2PACz) is added to the perovskite precursor solution. Since the solvent of the cuprous thiocyanate (CuSCN) hole transport layer is diethyl sulfite with strong polarity, most of the CuSCN will be dissolved and ionized after the perovskite solution is coated, and Cu+ tends to be enriched at the bottom interface of the perovskite. The Cu+ doping improves the carrier transport performance of the NiOx hole transport layer. Secondly, the pseudo-halogen SCN- ions can passivate the halogen vacancy defects at the grain boundaries and interfaces of the perovskite film, and also improve the crystallinity of the perovskite film. Due to the "molecular extrusion" effect, the self-assembled monolayer material doped into the perovskite film will spontaneously enrich at the bottom interface of the perovskite film during the preparation of the perovskite film, thereby improving the band matching between the perovskite layer and the NiOx hole transport layer interface, and passivating the defects of the NiOx hole transport layer, thereby ultimately improving the performance of the perovskite solar cell.

[0030] Based on this process, an inverted perovskite solar cell with an efficiency of 23.31% was obtained, with an open-circuit voltage of 1.25 V and a short-circuit current density of 22.2 mA cm -2 , the fill factor is 0.84, while the highest photoelectric conversion efficiency of the cell without this process is 20.14%, the open circuit voltage is 1.18 V, and the short circuit current density is 21.6 mA cm -2 , the filling factor is 0.79, and the present invention greatly improves the photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0032] Figure 1 A flow chart of a method for preparing a sub-cell for a four-terminal tandem perovskite solar cell according to an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the technical structure formed by the preparation process of sub-cells applied to a four-terminal tandem perovskite solar cell provided by an embodiment of the present invention;

[0034] Figure 3 This is a JV curve diagram of a sub-battery provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following description of exemplary embodiments of the present invention is made in conjunction with the accompanying drawings, in which various details of the embodiments of the present invention are included to facilitate understanding. These details should be considered as merely exemplary. Therefore, it should be appreciated by those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0036] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0037] like Figure 1 - Figure 3 As shown, the technical solution of the present invention:

[0038] A method for preparing a sub-cell for a four-terminal stacked perovskite solar cell comprises the following steps:

[0039] S1: Preparation of transparent conductive oxide substrate:

[0040] The etched transparent conductive glass is ultrasonically cleaned with deionized water, acetone, glass detergent, deionized water, and isopropyl alcohol in sequence, with the cleaning time set to 10-30 minutes; the glass is dried in a forced air drying oven; the dried transparent conductive glass is treated with ultraviolet ozone to obtain a transparent conductive oxide substrate;

[0041] S2: Preparation of hole transport layer:

[0042] Step 1: Prepare a concentration of 15 mg mL -1The nickel oxide (NiOx) nanoparticle solution was prepared by mixing isopropyl alcohol (IPA) and deionized water. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. The prepared nickel oxide (NiOx) nanoparticle solution was dropped onto the transparent conductive substrate using a pipette. After the spin coating was completed, the sample was placed at a temperature of 150 o Annealing on a hot plate at C for 30 min;

[0043] Step 2: Place the transparent conductive oxide substrate with a nickel oxide (NiOx) hole transport layer in a nitrogen atmosphere glove box with a concentration of 1-15 mg mL -1 Prepare a cuprous thiocyanate (CuSCN) solution using diethyl sulfide as the solvent. Set the spin coater speed to 1000 to 5000 rpm and the spin coating time to 10-60 s. Use a pipette to transfer the prepared cuprous thiocyanate (CuSCN) solution onto the nickel oxide (NiOx) hole transport layer by dynamic spin coating. After the spin coating is completed, place the sample on a hot plate at 100°C for annealing for 10 min.

[0044] S3: Preparation of a perovskite light absorbing thin film layer: adding a perovskite precursor material to a corresponding solvent in a predetermined ratio, followed by stirring and oscillation to obtain a perovskite precursor solution;

[0045] Add 0.5 mg mL into the perovskite precursor solution. -1 The MeO-2PACz self-assembled monolayer is mixed evenly, and the perovskite mixed solution is spin-coated onto the hole transport layer using a spin coater. Anti-solvent is added dropwise during the spin coating. After the spin coating is completed, the obtained perovskite light absorption film layer is placed on a hot stage for annealing at a temperature of 100° C. to 300° C. for a time of 5 min to 2 h.

[0046] S4: Preparation of electron transport layer:

[0047] The perovskite light absorbing film layer is transferred to an organic material evaporation chamber, and an electron transport layer C60 is evaporated to a thickness of 10-50 nm, followed by evaporation of bathocuproin to a thickness of 2-10 nm at an evaporation rate of 0.1-5 Å s -1 ;

[0048] S5: Preparation of metal electrode layer:

[0049] Metal electrodes are deposited in a metal evaporation chamber. The material of the deposited metal electrode is selected from one of gold, silver, and copper. The thickness is 60-200 nm and the deposition rate is 0.1-10 Å s -1 .

[0050] The preferred embodiment disclosed by the present invention is as follows Figure 1-Figure 3 As shown:

[0051] A method for preparing a sub-cell for a four-terminal stacked perovskite solar cell comprises the following steps:

[0052] S1: Preparation of transparent conductive oxide substrate:

[0053] The etched transparent conductive glass is ultrasonically cleaned in sequence with deionized water, acetone, glass cleaner, deionized water, and isopropyl alcohol. FTO or ITO conductive glass is usually selected. In this embodiment, ITO transparent conductive glass is selected. The cleaning time is set to 10-30 minutes. The present invention sets the ultrasonic cleaning time for each of the cleaning steps to 15 minutes. The glass is then placed in a 60°C forced air drying oven for drying. The dried transparent conductive glass is treated with ultraviolet ozone for 15 minutes to obtain a transparent conductive oxide substrate.

[0054] S2: Preparation of hole transport layer:

[0055] The hole transport layer is prepared using a multi-step spin coating process, which includes:

[0056] Step 1: Prepare a concentration of 15 mg mL -1 The nickel oxide (NiOx) nanoparticle solution was prepared using a mixture of isopropyl alcohol (IPA) and deionized water as the solvent. In this example, 15 mg mL -1 The nickel oxide; the speed of the glue machine is set to 3000 rpm, the spin coating time is 30 s, and the speed of the glue machine is selected to be 3000 rpm, and the spin coating time is 30 s; the prepared nickel oxide (NiOx) nanoparticle solution is dropped on the transparent conductive oxide substrate with a pipette, and the sample is placed at a temperature of 150 o Annealing on a hot plate at C for 30 min;

[0057] Step 2: Prepare a CuSCN (cuprous thiocyanate) hole transport layer on the nickel oxide (NiOx) hole transport layer: Place the transparent conductive oxide substrate with the nickel oxide (NiOx) hole transport layer in a nitrogen atmosphere glove box with a water and oxygen content of less than 0.01 ppm and a concentration of 1-15 mg mL -1 Cuprous thiocyanate (CuSCN) solution, the solvent is diethyl sulfide, in this example, 5 mg mL -1 The cuprous thiocyanate (CuSCN) solution is prepared, and the spin coater speed is set to 1000 to 5000 rpm, and the spin coating time is 10-60 s. In this embodiment, the spin coater speed is set to 3000 rpm, and the spin coating time is 30 s. The prepared cuprous thiocyanate (CuSCN) solution is transferred with a pipette and dynamically spin-coated onto the nickel oxide (NiOx) hole transport layer. After the spin coating is completed, the sample is placed on a hot plate at a temperature of 100°C for annealing for 10 min.

[0058] S3: Preparation of perovskite light absorbing thin film layer:

[0059] First, the perovskite precursor materials include at least two of lead iodide (PbI2), lead chloride (PbCl2), lead bromide (PbBr2), iodomethanesulfonate (FAI), methylammonium chloride (FACl), methylammonium bromide (FABr), methylamine iodide (MAI), methylamine chloride (MACl), methylamine bromide (MABr), cesium iodide (CsI), cesium chloride (CsCl), cesium bromide (CsBr), rubidium iodide (RbI), rubidium chloride (RbCl), and rubidium bromide (RbBr), which are mixed in a preset ratio; the corresponding solvent is added, and the solvent is selected from at least two of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP), and mixed in a preset ratio; the two mixed solutions are mixed in a preset ratio, stirred and shaken to obtain a perovskite precursor solution.

[0060] The perovskite precursor materials selected in this embodiment are PbI2, PbBr2, MABr, CsI, and FAI, and the solution concentration is 1.5 M. If 1 mL of perovskite solution is needed, 0.075 mmol of CsI, 1.2 mmol of FAI, 0.225 mmol of MABr, 0.075 mmol of CsI, 1.125 mmol of PbI2, and 0.375 mmol of PbBr2 need to be mixed together; DMF and DMSO are selected as the added solvents, and the ratio of DMF:DMSO=4:1. After stirring and shaking, the perovskite precursor solution CsI is obtained. 0.05 FA 0.8 MA 0.15 PbI 0.75 Br 0.25 .

[0061] The perovskite precursor solution Cs 0.05 FA 0.8 MA 0.15 PbI 0.75 Br 0.25 Add 0.5 mg mL -1 The MeO-2PACz self-assembled monolayer was mixed evenly.

[0062] The perovskite mixed solution is spin-coated onto the hole transport layer using a spin coater, using a multi-step spin coating process, with an anti-solvent added dropwise during the spin coating process. The process includes:

[0063] Step 1: First, add an appropriate amount of perovskite mixed solution onto the hole transport layer, then turn on the spin coater for spin coating. The spin coating speed range is 300-1000 rpm, and the speed increase rate is 200 rpm s -1 , In this embodiment, 1000 rpm, time 10s;

[0064] Step 2: Select the speed range from 2000-8000 rpm, and the speed increase rate is 2000 rpm s -1 , in this embodiment, the speed is 5000 rpm; the total spin coating time range of the first and second steps is set to 30-90 seconds, and the total spin coating time in this embodiment is 35 seconds; 10 seconds before the end of spin coating, the anti-solvent chlorobenzene is added dropwise, and the amount of the anti-solvent is 100 microliters to 5 milliliters. In this embodiment, 150 μL of chlorobenzene is used. After the spin coating is completed, the film is placed on a hot plate at a temperature of 100°C and heated for 30 minutes.

[0065] The present invention adopts a two-step spin coating method and adopts different speed increase rates, which can better regulate the volatilization rate of the perovskite precursor solvent and regulate the thickness of the perovskite film.

[0066] After the spin coating is completed, the obtained perovskite light absorbing thin film layer is placed on a hot plate for annealing at a temperature of 100° C. to 300° C. for a time of 5 min to 2 h. In this embodiment, the perovskite light absorbing thin film layer is placed on a hot plate at a temperature of 100° C. and heated for 30 min.

[0067] S4: Preparation of electron transport layer:

[0068] The perovskite light absorbing film layer is transferred to an organic material evaporation chamber, and an electron transport layer C60 is evaporated to a thickness of 10-50 nm. In this embodiment, the thickness is 30 nm. Then, bathocuproin (BCP) is evaporated to a thickness of 2-10 nm. In this embodiment, the thickness is 7 nm. The evaporation rate is 0.1-5 Å s -1 In this embodiment, the evaporation rate is selected as 0.3 Å s -1 .

[0069] S5: Preparation of metal electrode layer:

[0070] The metal electrode is evaporated in the metal evaporation chamber. The evaporation metal electrode material is silver, and the evaporation rate is 0.1-10 Ås -1 , using step-by-step rate control, when the thickness of the evaporated metal is 0-10 nm, the rate is 0.1 Å s -1 ; When the thickness is 10-20 nm, the rate is 0.2 Å s -1 ; When the thickness is 20-30 nm, the rate is 0.3 Å s -1; When the thickness is 30-40 nm, the rate is 0.3 Å s -1 ; When the thickness is 40-50 nm, the rate is 0.4 Å s -1 ; When the thickness is 50-60 nm, the rate is 0.5 Å s -1 ; When the thickness is 60-70 nm, the rate is 0.6 Å s -1 ; When the thickness is 70-100 nm, the rate is 1-10 Å s -1 , deposited on the electron transport layer 100 nm to complete the preparation of the sub-battery, such as Figure 1 、 Figure 2 shown.

[0071] The experiment found that the sub-cell used in the four-terminal stacked perovskite solar cell had a photoelectric conversion efficiency of 23.31%, an open circuit voltage of 1.25 V, and a short-circuit current density of 22.2 mA cm -2 , the filling factor is 0.84, e.g. Figure 3 As shown, Figure 3 This is a graph showing the photoelectric conversion efficiency jv curve of the sub-cell provided in an embodiment of the present invention.

[0072] The sub-cells are manufactured according to conventional methods and applied to four-terminal stacked perovskite solar cells.

[0073] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for preparing a subcell for a four-terminal tandem perovskite solar cell, characterized in that: The steps include: S1: Preparation of transparent conductive oxide substrate: The etched transparent conductive glass is ultrasonically cleaned with deionized water, acetone, glass detergent, deionized water, and isopropyl alcohol in sequence, with the cleaning time set to 10-30 minutes; the glass is dried in a forced air drying oven; the dried transparent conductive glass is treated with ultraviolet ozone to obtain a transparent conductive oxide substrate; S2: Preparation of hole transport layer: Step 1: Prepare a concentration of 15 mg mL -1 The nickel oxide nanoparticle solution was prepared by mixing isopropyl alcohol and deionized water. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. The prepared nickel oxide nanoparticle solution was dropped onto the transparent conductive substrate using a pipette. After the spin coating was completed, the sample was placed at a temperature of 150 o Annealing on a hot plate at C for 30 min; Step 2: Place the transparent conductive oxide substrate with a nickel oxide hole transport layer in a nitrogen atmosphere glove box with a concentration of 1-15 mg mL -1 The cuprous thiocyanate solution is prepared using diethyl sulfide as the solvent. The spin coater speed is set to 1000 to 5000 rpm and the spin coating time is 10-60 s. The prepared cuprous thiocyanate solution is transferred to the nickel oxide hole transport layer by a pipette and dynamically spin-coated. After the spin coating is completed, the sample is annealed on a hot plate at 100°C for 10 min. S3: Preparation of a perovskite light absorbing thin film layer: adding a perovskite precursor material to a corresponding solvent in a predetermined ratio, followed by stirring and oscillation to obtain a perovskite precursor solution; Add 0.5 mg mL into the perovskite precursor solution. -1 After the MeO-2PACz self-assembled monolayer is formed, the mixture is mixed evenly, and the perovskite mixed solution is spin-coated on the hole transport layer using a spin coater. An anti-solvent is added dropwise during the spin coating. After the spin coating is completed, the obtained perovskite light absorption film layer is placed on a hot plate for annealing at a temperature of 100° C. to 300° C. for a time of 5 min to 2 h. S4: Preparation of electron transport layer: The perovskite light absorbing film layer is transferred to an organic material evaporation chamber, and an electron transport layer C60 is evaporated to a thickness of 10-50 nm, followed by evaporation of bathocuproin to a thickness of 2-10 nm at an evaporation rate of 0.1-5 Å s -1 ; S5: Preparation of metal electrode layer: Metal electrodes are deposited in a metal evaporation chamber. The material of the deposited metal electrode is selected from one of gold, silver, and copper. The thickness is 60-200 nm and the deposition rate is 0.1-10 Å s -1 .

2. The method for preparing a sub-battery according to claim 1, wherein: In S1, the ultrasonic cleaning time of deionized water, acetone, glass cleaning agent, deionized water, and isopropyl alcohol was 15 minutes respectively; the glass was placed in a 60°C forced air drying oven for drying; and the dried transparent conductive glass was treated with ultraviolet ozone for 15 minutes.

3. The method for preparing a sub-battery according to claim 1, wherein: In S1, the transparent conductive glass is selected from FTO or ITO conductive glass.

4. The method for preparing a sub-battery according to claim 1, wherein: In S2, Step 1: Prepare a concentration of 15 mg mL -1 The nickel oxide nanoparticle solution was prepared by mixing isopropyl alcohol and deionized water. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. The prepared nickel oxide nanoparticle solution was dropped onto the transparent conductive substrate using a pipette. After the spin coating was completed, the sample was placed at a temperature of 150 o Annealing on a hot plate at C for 30 min; Step 2: Place the transparent conductive oxide substrate prepared with a nickel oxide hole transport layer in a nitrogen atmosphere glove box with a concentration of 5 mg mL -1 The cuprous thiocyanate solution was prepared using diethyl sulfide as the solvent. The spin coater speed was set to 3000 rpm and the spin coating time was 30 s. A pipette was used to transfer the prepared cuprous thiocyanate solution and dynamically spin-coat it onto the nickel oxide hole transport layer. After the spin coating was completed, the sample was placed on a hot plate at 100°C for annealing for 10 min.

5. The method for preparing a sub-battery according to claim 1, wherein: In S3, the perovskite precursor materials are selected from at least two of lead iodide, lead chloride, lead bromide, iodomethane, formamidine chloride, formamidine bromide, methylamine iodide, methylamine chloride, methylamine bromide, cesium iodide, cesium chloride, cesium bromide, rubidium iodide, rubidium chloride, and rubidium bromide, and are mixed in a preset ratio; the solvent is selected from at least two of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and are mixed in a preset ratio.

6. The method for preparing a sub-battery according to claim 1, wherein: In S3, the perovskite precursor solution is spin-coated onto the hole transport layer using a spin coater, and the process of adding an anti-solvent during the spin coating includes: First, add an appropriate amount of perovskite precursor solution to the hole transport layer, and then turn on the spin coater for spin coating. Step 1: The speed range is 300-1000 rpm, and the speed increase rate is 200 rpm s -1 , time is 10 s; Step 2: Select the speed range of 2000-8000 rpm, and the speed increase rate is 2000 rpm s -1 The total spin coating time range of the first and second steps is set to 30-90s. 150 μL of anti-solvent chlorobenzene is added 10 s before the end of spin coating. The amount of anti-solvent is 100 microliters to 5 milliliters. After the spin coating is completed, the film is placed on a hot plate at a temperature of 100°C and heated for 30 minutes.

7. The method for preparing a sub-battery according to claim 6, wherein: In S3, the spin coater is turned on. Step 1: the speed is set to 1000 rpm and the speed increase rate is 200 rpm s -1 , time is 10 s; Step 2: Select the speed to be 5000 rpm, and the speed increase rate is 2000 rpm s -1 The total spin coating time of the first step and the second step was 35 s, and 150 μL of anti-solvent chlorobenzene was added dropwise 10 s before the end of spin coating.

8. The method for preparing a sub-battery according to claim 1, wherein: In S4, the perovskite light absorbing film layer is transferred to an organic material evaporation chamber, and an electron transport layer C60 is evaporated to a thickness of 30 nm, followed by evaporation of bathocuproin to a thickness of 7 nm at an evaporation rate of 0.3 Å s -1 .

9. The method for preparing a sub-battery according to claim 1, wherein: In S5, a metal electrode is deposited in a metal evaporation chamber. Silver is selected as the material for the deposited metal electrode with a thickness of 100 nm and a deposition rate of 0.1-10 Å s -1 , using step-by-step rate control, when the thickness of the evaporated metal is 0-10 nm, the rate is 0.1 Å s -1 ; When the thickness is 10-20 nm, the rate is 0.2 Å s -1 ; When the thickness is 20-30 nm, the rate is 0.3 Å s -1 ; When the thickness is 30-40 nm, the rate is 0.3 Å s -1 ; When the thickness is 40-50 nm, the rate is 0.4 Å s -1 ; When the thickness is 50-60 nm, the rate is 0.5 Å s -1 ; When the thickness is 60-70 nm, the rate is 0.6 Å s -1 ; When the thickness is 70-100 nm, the rate is 1-10 Å s -1 .

10. A subcell for a four-terminal tandem perovskite solar cell, characterized by: It is prepared using the method for preparing a sub-cell applied to a four-terminal stacked perovskite solar cell according to any one of claims 1 to 9.

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