Decoupling type flexible GaAs / perovskite two-end laminated solar cell and preparation method thereof

Abstract

The invention belongs to the technical field of flexible two-end laminated solar cells, and discloses a decoupling type flexible GaAs / perovskite two-end laminated solar cell and a preparation method thereof. The cell comprises a flexible substrate, a middle interconnection conducting layer arranged on the flexible substrate, a GaAs sub-cell and a perovskite sub-cell, wherein the GaAs sub-cell and the perovskite sub-cell are arranged on the middle interconnection conducting layer; the GaAs sub-cell and the perovskite sub-cell are independently arranged on the middle interconnection conductive layer; the GaAs sub-cell sequentially comprises a hole transport layer, a GaAs absorption layer and an electrode from bottom to top; the perovskite sub-cell sequentially comprises an electron transport layer, a perovskite absorption layer, a hole transport layer and an electrode from bottom to top. The invention also discloses a preparation method of the battery. The sub-cells are prepared independently, defects caused by a complex process are avoided, the optical performance is regulated and controlled independently, the two sub-cells work independently, and the reliability of the system is improved. According to the invention, the photovoltaic conversion efficiency of the cell is obviously improved.

Description

Technical Field

[0001] The present invention belongs to the field of flexible GaAs / perovskite tandem solar cells, and particularly relates to a decoupled flexible GaAs / perovskite two-terminal tandem solar cell and a preparation method thereof. Background Art

[0002] In order to improve the performance of single-junction solar cells and meet the development needs of future lightweight, high-efficiency, and wearable flexible electronic technologies, flexible GaAs / perovskite tandem cells have received extensive attention. Perovskite solar cells have the advantages of simple preparation process and low cost. GaAs solar cells have a direct bandgap structure and a bandgap width that matches that of perovskite solar cells. Application No. 202210675836.6 discloses a perovskite / GaAs two-terminal mechanical tandem solar cell with a metal grid interconnection layer. In this application, the perovskite sub-cell is prepared on the GaAs sub-cell, and the complex perovskite preparation process will inevitably cause defects in the GaAs sub-cell, resulting in low photovoltaic efficiency. The two sub-cells are of an integrated structure, and the damage of a single sub-cell will cause the paralysis of the entire system, with low reliability and inability to independently regulate optical performance. Moreover, it has a rigid structure and cannot meet the requirements of flexible wearable devices, with low application flexibility. Summary of the Invention

[0003] In order to overcome the problems of low photovoltaic conversion efficiency, low reliability, poor application flexibility, and inability to independently regulate optical performance, the present invention provides a decoupled flexible GaAs / perovskite two-terminal tandem solar cell and a preparation method thereof. By independently preparing the two sub-cells on a flexible substrate and using an intermediate interconnection conductive layer to connect the two sub-cells in series, the present invention can improve the photovoltaic conversion efficiency, reliability, and optimize the cell structure.

[0004] To solve the above technical problems, the technical solution of the present invention is as follows: A decoupled flexible GaAs / perovskite two-terminal tandem solar cell includes a flexible substrate, an intermediate interconnection conductive layer provided on the flexible substrate, a GaAs sub-cell and a perovskite sub-cell provided on the intermediate interconnection conductive layer; the GaAs sub-cell and the perovskite sub-cell are independently provided on the intermediate interconnection conductive layer; the GaAs sub-cell includes a hole transport layer, a GaAs absorption layer, and an electrode from bottom to top; the perovskite sub-cell includes an electron transport layer, a perovskite absorption layer, a hole transport layer, and an electrode from bottom to top; the hole transport layer in the GaAs sub-cell is provided on the intermediate interconnection conductive layer, and the electron transport layer in the perovskite sub-cell is provided on the intermediate interconnection conductive layer.

[0005] The GaAs sub-cell is disposed at one end of the intermediate interconnecting conductive layer, and the perovskite sub-cell is disposed at the other end of the intermediate interconnecting conductive layer. The GaAs sub-cell and the perovskite sub-cell do not contact each other.

[0006] The intermediate interconnecting conductive layer is one or more of ITO, Mxene material, and two-dimensional transition metal chalcogenide, preferably ITO.

[0007] The flexible substrate is PI, PET, PDMS, or a metal foil flexible substrate, preferably PI.

[0008] In the GaAs sub-cell, the hole transport layer is one or more of graphene, carbon nanotubes, PEDOT, and Mxene material, preferably graphene and carbon nanotubes.

[0009] In the perovskite sub-cell, the electron transport layer is one or more of TiO2, SnO2, C60, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), or PCBM (benzothieno[3,2-b]thiophene-2,6-dicarboxylic acid bis-(2-ethylhexyl)ester).

[0010] In the perovskite sub-cell, the perovskite absorption layer is one or more of MAPbI3, FAPbI3, and MAPbBr3.

[0011] In the perovskite sub-cell, the hole transport layer is one or more of PEDOT, Spiro-OMeTAD, P3HT, and 2PACz.

[0012] In the GaAs sub-cell, the electrode is one or more of Au, Ag, Ti, Cu, Ni, and Pt electrodes.

[0013] In the perovskite sub-cell, the electrode is one or more of Ag, Au, Ti, Cu, Ni, and Pt electrodes.

[0014] The GaAs absorption layer is N-type Si doped, and the doping concentration is 1 × 10 17 / cm 3 ~1 × 10 18 / cm 3 。

[0015] The preparation of the GaAs sub-cell and the perovskite sub-cell is independent of each other, and the two sub-cells are connected in series through the intermediate interconnecting conductive layer.

[0016] A preparation method of a decoupled flexible GaAs / perovskite tandem solar cell includes the following steps: 1) A GaAs buffer layer is grown on a GaAs substrate by MBE (molecular beam) epitaxy, and then an AlAs layer and a GaAs absorption layer are grown. A hole transport layer of a GaAs sub-cell is prepared on the surface of the GaAs absorption layer; 2) The AlAs layer is removed by wet etching to obtain a GaAs absorption layer / hole transport layer; the GaAs absorption layer / hole transport layer is transferred to one end of an intermediate interconnection conductive layer on a flexible substrate, and the hole transport layer is in contact with the intermediate interconnection conductive layer; an electrode is evaporated on the surface of the GaAs absorption layer and annealed to form an ohmic contact to obtain a GaAs sub-cell; 3) The GaAs sub-cell is covered, and an electron transport layer of a perovskite sub-cell is prepared at the other end of the intermediate interconnection conductive layer on the flexible substrate; 4) A perovskite precursor is formulated into a solution, which is spin-coated on the surface of the electron transport layer, and the anti-solvent method is used and annealed to obtain a perovskite absorption layer of the perovskite sub-cell; 5) A hole transport layer of the perovskite sub-cell is prepared on the surface of the perovskite absorption layer; an electrode is evaporated on the hole transport layer to obtain a decoupled flexible GaAs / perovskite tandem solar cell.

[0017] In step 1), the GaAs substrate is of (100) crystal plane, the thickness of the GaAs buffer layer is 1 - 5 nm, the thickness of the AlAs is 20 - 50 nm, the GaAs absorption layer is doped with N-type Si, and the doping concentration is 1 × 10 17 / cm 3 ~1 × 10 18 / cm 3 , and the thickness is 200 - 800 nm.

[0018] The growth temperature of the AlAs layer is 580 °C - 620 °C, the temperature of the Al source is 1000 °C - 1200 °C, and the temperature of the As source is 900 °C - 950 °C.

[0019] The growth temperature of the GaAs absorption layer is 550 °C - 600 °C, the temperature of the Ga source is 850 °C - 900 °C, the temperature of the As source is 900 °C - 950 °C, and the temperature of the Si doping source is 950 - 1000 °C.

[0020] The hole transport layer of the GaAs sub-cell is prepared into a thin film by a suction filtration method or a wet transfer method, and then transferred to the surface of the GaAs absorption layer; the thickness of the hole transport layer of the GaAs sub-cell is 100 - 200 nm.

[0021] In step 2), the solution for wet etching is one or more of HF acid, phosphoric acid, and hydrochloric acid, the mass concentration of the solution is 5% - 10%, and the etching time is 10 - 15 min.

[0022] The thickness of the electrode described in step 2) is 100 - 120 nm. For example, when the electrode is Au, the annealing temperature is 300 - 330 °C and the annealing time is 15 - 30 s; the thickness of the intermediate interconnection conductive layer is 100 - 120 nm.

[0023] The electron transport layer described in step 3) is prepared by magnetron sputtering. The preparation conditions are as follows: the power is 60 - 120 W, the vacuum degree is 0.4 - 0.7 Pa, and the sputtering time is 10 - 30 min.

[0024] The perovskite precursor described in step 4) is MAI, FAI, MABr, PbI2 and / or PbBr2. After the precursor is formulated into a solution, the solvent in the solution is DMF and DMSO, and the volume ratio of DMF to DMSO is (3 - 5):1.

[0025] When the perovskite is MAPbI3, the perovskite precursor is MAI and PbI2; When the perovskite is FAPbI3, the perovskite precursor is FAI and PbI2; When the perovskite is MAPbBr3, the perovskite precursor is MABr and PbBr2.

[0026] The concentration of the precursor solution is 0.5 - 1.2 M, and the concentration here is calculated based on the perovskite.

[0027] The rotation speed of spin coating described in step 4) is 2000 - 4000 rpm, and the spin coating time is 20 - 60 s; in the anti-solvent method, the time for dropping the anti-solvent is 10 - 15 s before the rotation ends.

[0028] The annealing temperature described in step 4) is 80 - 120 °C, and the annealing time is 10 - 30 min.

[0029] The anti-solvent used in the anti-solvent method is one or more of chlorobenzene, toluene, and ethyl acetate.

[0030] The hole transport layer of the perovskite sub-cell described in step 5) is obtained by formulating the hole transport layer material into a solution for spin coating and then annealing; the rotation speed is 4000 - 6000 rpm, the spin coating time is 30 - 60 s, the annealing temperature is 100 - 150 °C, and the annealing time is 10 - 20 min.

[0031] The solvent used for formulating the hole transport layer material into a solution is one of isopropanol, ethanol, and chlorobenzene, and the concentration of the solution is 0.5 - 1.5 mg / mL; the thickness of the hole transport layer is 50 - 150 nm.

[0032] The thickness of the electrode described in step 5) is 100 - 120 nm.

[0033] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows: In the battery of the present invention, two sub-batteries are independently prepared on a flexible substrate, and the two sub-batteries are connected in series using an intermediate interconnection conductive layer, effectively avoiding the problem of damage to the sub-batteries caused by complex manufacturing processes and improving the photovoltaic conversion efficiency. The optical performance of the battery of the present invention can be independently regulated, and the sub-batteries can work independently, with high reliability and application flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the decoupled flexible GaAs / perovskite two-terminal tandem solar cell of the present invention; 1 - flexible substrate, 2 - intermediate interconnection conductive layer, 3 - hole transport layer of the GaAs sub-battery, 4 - GaAs absorption layer of the GaAs sub-battery, 5 - electrode of the GaAs sub-battery, 6 - electron transport layer of the perovskite sub-battery, 7 - perovskite absorption layer, 8 - hole transport layer of the perovskite sub-battery, 9 - electrode of the perovskite sub-battery, 10 - GaAs sub-battery, 11 - perovskite sub-battery; Figure 2 Flow chart for the preparation of the decoupled flexible GaAs / perovskite two-terminal tandem solar cell of Example 1; Figure 3 I-V curve diagram of the solar cells prepared in Example 1 and Comparative Example 1 after 100 bending cycles. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention will be further described below with reference to the accompanying drawings of the specification and specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the following embodiments are commercially available.

[0036] A decoupled flexible GaAs / perovskite two-terminal tandem solar cell, the schematic structural diagram of which is as Figure 1As shown in the figure, it includes a flexible substrate, an intermediate interconnection conductive layer 2 disposed on the flexible substrate 1, a GaAs sub-cell 10 and a perovskite sub-cell 11 disposed on the intermediate interconnection conductive layer 2; the GaAs sub-cell 10 and the perovskite sub-cell 11 are independently disposed on the intermediate interconnection conductive layer 2; the GaAs sub-cell 10 sequentially includes a hole transport layer 3 of the GaAs sub-cell, a GaAs absorption layer 4 of the GaAs sub-cell, and an electrode 5 of the GaAs sub-cell from bottom to top; the perovskite sub-cell 11 sequentially includes an electron transport layer 6 of the perovskite sub-cell, a perovskite absorption layer 7, a hole transport layer 8 of the perovskite sub-cell, and an electrode 9 of the perovskite sub-cell from bottom to top; the hole transport layer 3 of the GaAs sub-cell in the GaAs sub-cell 10 is disposed on the intermediate interconnection conductive layer 2, and the electron transport layer 6 of the perovskite sub-cell in the perovskite sub-cell 11 is disposed on the intermediate interconnection conductive layer 2.

[0037] The GaAs sub-cell 10 is disposed at one end of the intermediate interconnection conductive layer 2, and the perovskite sub-cell 11 is disposed at the other end of the intermediate interconnection conductive layer 2. The GaAs sub-cell 10 and the perovskite sub-cell 11 do not contact.

[0038] The intermediate interconnection conductive layer is one or more of ITO, Mxene material, and two-dimensional transition metal chalcogenide, preferably ITO.

[0039] The flexible substrate is PI, PET, PDMS, or a metal foil flexible substrate, preferably PI.

[0040] In the GaAs sub-cell, the hole transport layer is one or more of graphene, carbon nanotubes, PEDOT, and Mxene material, preferably graphene and carbon nanotubes.

[0041] In the perovskite sub-cell, the electron transport layer is one or more of TiO2, SnO2, C60, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), and PCBM (benzo[c][1,2,5]thiadiazole-4,7-dicarboximide).

[0042] In the perovskite sub-cell, the perovskite absorption layer is one or more of MAPbI3, FAPbI3, and MAPbBr3.

[0043] In the perovskite sub-cell, the hole transport layer is one or more of PEDOT, Spiro-OMeTAD, P3HT, and 2PACz.

[0044] In the GaAs sub-cell, the electrode (such as Au) is divided into two parts and is respectively disposed at both ends of the GaAs absorption layer of the GaAs sub-cell.

[0045] In the perovskite sub-cell, the electrode (e.g., Ag) is divided into two parts and is respectively arranged at both ends of the hole transport layer of the perovskite sub-cell.

[0046] The preparation of the GaAs sub-cell and the perovskite sub-cell is independent of each other, and the two sub-cells are connected in series through an intermediate interconnecting conductive layer.

[0047] Example 1 A preparation method of a decoupled flexible GaAs / perovskite two-terminal tandem solar cell includes the following steps: 1) First, grow a GaAs buffer layer on a GaAs substrate by MBE. The GaAs substrate is a (100) crystal plane, the thickness of the GaAs buffer layer is 5 nm, and then grow an AlAs and a GaAs absorption layer. The thickness of the AlAs is 20 nm, the GaAs absorption layer is doped with N-type Si, and the doping concentration is 1 × 10 17 / cm 3 , and the thickness is 500 nm. Prepare a carbon nanotube film with a thickness of 100 nm on the surface of the GaAs absorption layer by suction filtration, that is, prepare the hole transport layer of the GaAs sub-cell on the GaAs absorption layer.

[0048] The growth temperature of AlAs is 600 °C, the temperature of the Al source is 1200 °C, and the temperature of the As source is 950 °C; the growth temperature of the GaAs absorption layer is 600 °C, the temperature of the Ga source is 900 °C, and the temperature of the As source is 950 °C; the temperature of the Si doping source is 1000 °C.

[0049] 2) Remove the AlAs layer by wet etching. The etching solution is HF acid with a mass concentration of 10%, and the etching time is 10 min to obtain the GaAs absorption layer / hole transport layer; transfer the GaAs absorption layer / hole transport layer to one end of the conductive layer ITO on the flexible substrate PI, and the hole transport layer of the GaAs sub-cell is in contact with the conductive layer; evaporate an Au electrode on the surface of the GaAs absorption layer and anneal to form an ohmic contact to obtain the GaAs sub-cell; the thickness of the Au electrode is 120 nm, the annealing temperature is 330 °C, and the annealing time is 30 s; the thickness of the ITO on the flexible substrate PI film is 100 nm.

[0050] 3) Cover the GaAs sub-cell with tape, and prepare an electron transport layer on the other end of the conductive layer of the flexible substrate. The electron transport layer is TiO2, and the electron transport layer is prepared by magnetron sputtering. The preparation conditions are: power is 80 W, vacuum degree is 0.57 Pa, and sputtering time is 20 min.

[0051] 4) Prepare a solution of the perovskite precursor. The perovskite is MAPbI3, and the perovskite precursor is MAI and PbI2 (molar ratio 1:1). The volume ratio of DMF to DMSO is 4:1, and the concentration of the precursor solution is 0.6 M. Spin-coat and anneal the precursor solution on the electron transport layer to prepare the perovskite absorption layer. During the preparation of the perovskite absorption layer, the spinning speed of the precursor is 4000 rpm for 30 s, and chlorobenzene is used as an anti-solvent and is added 10 s before the end of rotation. The annealing temperature is 100 °C for 10 min.

[0052] 5) Prepare the PEDOT hole transport layer on the surface of the perovskite absorption layer by spin-coating. After spin-coating, anneal at a rotation speed of 5000 rpm for 30 s, an annealing temperature of 120 °C, and an annealing time of 10 min. The solvent used to prepare the PEDOT solution is isopropanol, and the concentration of the solution is 1 mg / mL. The thickness of the hole transport layer is 100 nm. Finally, evaporate an Ag electrode with a thickness of 100 nm on the hole transport layer to obtain a decoupled flexible GaAs / perovskite tandem solar cell.

[0053] Figure 2 It is a flowchart for the preparation of the decoupled flexible GaAs / perovskite tandem solar cell of Example 1.

[0054] Example 2 A method for preparing a decoupled flexible GaAs / perovskite tandem solar cell, comprising the following steps: 1) First, epitaxially grow a GaAs buffer layer on the GaAs substrate by MBE. The GaAs substrate is a (100) crystal plane, and the thickness of the GaAs buffer layer is 5 nm. Then grow an AlAs and a GaAs absorption layer. The thickness of AlAs is 50 nm, and the GaAs absorption layer is doped with N-type Si with a doping concentration of 1 × 10 17 / cm 3 and a thickness of 800 nm. Prepare a graphene film with a thickness of 100 nm on the surface of the GaAs epitaxial layer by spin-coating, that is, prepare the hole transport layer of the GaAs sub-cell on the GaAs absorption layer.

[0055] The growth temperature of AlAs is 620 °C, the Al source temperature is 1000 °C, and the As source temperature is 950 °C; the growth temperature of GaAs is 580 °C, the Ga source temperature is 900 °C, and the As source temperature is 950 °C; the Si doping source temperature is 1000 °C.

[0056] 2) By wet etching, the AlAs layer was removed. The etching solution was phosphoric acid with a mass concentration of 10%, and the etching time was 10 min to obtain the GaAs absorption layer / hole transport layer. The GaAs absorption layer / hole transport layer was transferred to one end of the conductive layer ITO on the flexible substrate PI, and the hole transport layer of the GaAs sub-cell was in contact with the conductive layer. An Au electrode was evaporated on the surface of the GaAs absorption layer and annealed to form an ohmic contact to obtain the GaAs sub-cell. The thickness of the Au electrode was 120 nm, the annealing temperature was 330 °C, and the annealing time was 30 s. The thickness of ITO on the flexible substrate PI film was 100 nm.

[0057] 3) The GaAs sub-cell was covered with tape, and an electron transport layer was prepared at the other end of the conductive layer on the flexible substrate. The electron transport layer was SnO2, and the electron transport layer was prepared by magnetron sputtering. The preparation conditions were: power of 120 W, vacuum degree of 0.57 Pa, and sputtering time of 20 min.

[0058] 4) The perovskite precursor was formulated into a solution. The perovskite was MAPbI3, the perovskite precursor was MAI and PbI2 (molar ratio of 1:1), the volume ratio of DMF and DMSO was 4:1, and the concentration of the precursor solution was 0.6 M. The precursor solution was spin-coated and annealed on the electron transport layer to prepare the perovskite absorption layer. During the preparation of the perovskite absorption layer, the rotation speed of spin-coating the precursor was 4000 rpm, the time was 30 s, and chlorobenzene was used as an anti-solvent and added dropwise 10 s before the end of rotation. The annealing temperature was 100 °C and the time was 10 min.

[0059] 5) A 2PACz hole transport layer was prepared on the surface of the perovskite absorption layer by spin-coating. After spin-coating, it was annealed. The rotation speed was 5000 rpm, the time was 30 s, the annealing temperature was 100 °C, and the annealing time was 10 min. The solvent used to formulate the 2PACz solution was isopropanol, and the concentration was 1 mg / mL. The thickness was 100 nm. Finally, an Ag electrode with a thickness of 100 nm was evaporated on the hole transport layer to obtain a decoupled flexible GaAs / perovskite two-terminal stacked solar cell.

[0060] Comparative Example 1 The difference between Comparative Example 1 and Examples 1 and 2 was that the prepared cell was a flexible GaAs / perovskite two-terminal stacked cell, and the perovskite sub-cell was directly prepared on top of the GaAs sub-cell without independently preparing the two sub-cells.

[0061] Specific steps: 1) First, a GaAs buffer layer is epitaxially grown on a GaAs substrate by MBE. The GaAs substrate has a (100) crystal plane, and the thickness of the GaAs buffer layer is 2 nm. Then, AlAs and GaAs layers are grown. The thickness of AlAs is 20 nm, and the GaAs layer is doped with N-type Si with a doping concentration of 1 × 10 17 / cm 3 , and the thickness is 500 nm. A carbon nanotube film with a thickness of 100 nm is prepared on the surface of the GaA layer by suction filtration.

[0062] The growth temperature of AlAs is 600 °C, the temperature of the Al source is 1200 °C, and the temperature of the As source is 950 °C; the growth temperature of the GaAs layer is 600 °C, the temperature of the Ga source is 900 °C, and the temperature of the As source is 950 °C; the temperature of the Si doping source is 1000 °C.

[0063] 2) The AlAs layer is removed by wet etching. The etching solution is HF acid with a mass concentration of 10%, and the etching time is 10 min to obtain the GaAs layer / hole transport layer; the GaAs layer / hole transport layer is transferred to the surface of the conductive layer ITO on the flexible substrate PI, and the GaAs layer is in contact with the conductive layer; the thickness of ITO on the flexible substrate PI film is 100 nm.

[0064] 3) An intermediate interconnection conductive layer and an electron transport layer of a perovskite sub-cell are sequentially prepared on the surface of the hole transport layer of the GaAs sub-cell. The intermediate interconnection layer is ITO, and the electron transport layer is TiO2. Both are prepared by magnetron sputtering. The preparation conditions are: power is 80 W, the vacuum degree is 0.57 Pa, and the sputtering times are 20 min respectively.

[0065] 4) The perovskite precursor is formulated into a solution. The perovskite is MAPbI3, the perovskite precursor is MAI and PbI2 (molar ratio 1:1), the volume ratio of DMF and DMSO is 4:1, and the concentration of the precursor solution is 0.6 M; the precursor solution is spin-coated and annealed on the electron transport layer of the perovskite sub-cell to prepare a perovskite absorption layer; during the preparation of the perovskite absorption layer, the rotation speed of the spin-coated precursor is 4000 rpm, the time is 30 s, and chlorobenzene is used as an anti-solvent and is added 10 s before the end of rotation; the annealing temperature is 100 °C, and the time is 10 min.

[0066] 5) A PEDOT hole transport layer was prepared by spin coating on the surface of the perovskite absorption layer. After spin coating, annealing was carried out at a rotation speed of 5000 rpm for 30 s, the annealing temperature was 120 °C, and the annealing time was 10 min. The solvent used to prepare the PEDOT solution was isopropanol, and the concentration was 1 mg / mL. The thickness of the PEDOT hole transport layer was 100 nm. Finally, an Ag electrode with a thickness of 100 nm was evaporated on the PEDOT hole transport layer to obtain a solar cell.

[0067] The photovoltaic parameters of the solar cell prepared in Example 1 and the solar cell device prepared in Comparative Example 1 after 100 bending cycles are compared as shown in Table 1.

[0068] Table 1 Performance parameters of the batteries prepared in Example 1 and Comparative Example 1

[0069] Figure 3 I-V curve diagrams for the solar cells prepared in Example 1 and Comparative Example 1.

[0070] The present invention is not limited to the above embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and deformations of some technical features without creative labor according to the disclosed technical content, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A decoupled flexible GaAs / perovskite tandem solar cell, characterized in that: It includes a flexible substrate, an intermediate interconnecting conductive layer disposed on the flexible substrate, a GaAs sub-cell and a perovskite sub-cell disposed on the intermediate interconnecting conductive layer; the GaAs sub-cell and the perovskite sub-cell are independently disposed on the intermediate interconnecting conductive layer; the GaAs sub-cell includes a hole transport layer, a GaAs absorption layer and an electrode from bottom to top in sequence; the perovskite sub-cell includes an electron transport layer, a perovskite absorption layer, a hole transport layer and an electrode from bottom to top in sequence; the hole transport layer in the GaAs sub-cell is disposed on the intermediate interconnecting conductive layer, and the electron transport layer in the perovskite sub-cell is disposed on the intermediate interconnecting conductive layer; the GaAs sub-cell and the perovskite sub-cell do not contact. The GaAs absorption layer is doped with N-type Si, and the doping concentration is 1 × 10 17 / cm 3 ~1 × 10 18 / cm 3 .

2. The decoupled flexible GaAs / perovskite tandem solar cell according to claim 1, wherein: The GaAs sub-cell is disposed at one end of the intermediate interconnecting conductive layer, and the perovskite sub-cell is disposed at the other end of the intermediate interconnecting conductive layer. The intermediate interconnecting conductive layer is one or more of ITO, Mxene material, and two-dimensional transition metal chalcogenide. The flexible substrate is PI, PET, PDMS or a metal foil flexible substrate. In the GaAs sub-cell, the hole transport layer is one or more of graphene, carbon nanotubes, PEDOT, and MXene. In the perovskite sub-cell, the electron transport layer is TiO2, SnO2, C60, BCP or PCBM. In the perovskite sub-cell, the perovskite absorption layer is one or more of MAPbI3, FAPbI3, and MAPbBr3. In the perovskite sub-cell, the hole transport layer is one or more of PEDOT, Spiro-OMeTAD, P3HT, and 2PACz.

3. The decoupled flexible GaAs / perovskite tandem solar cell according to claim 2, wherein: The intermediate interconnecting conductive layer is ITO. The flexible substrate is PI. In the GaAs sub-cell, the hole transport layer is one or more of graphene and carbon nanotubes.

4. The decoupled flexible GaAs / perovskite tandem solar cell according to claim 1, characterized in that: The conductive layer is a transparent conductive layer. In the GaAs sub-cell, the electrode is one or more of Au, Ag, Ti, Cu, Ni, and Pt electrodes. In the perovskite sub-cell, the electrode is one or more of Ag, Au, Ti, Cu, Ni, and Pt electrodes.

5. The preparation method of the decoupled flexible GaAs / perovskite tandem solar cell according to any one of claims 1 to 4, characterized in that: It includes the following steps: 1) Grow a GaAs buffer layer on a GaAs substrate by molecular beam epitaxy, then grow an AlAs layer and a GaAs absorption layer, and prepare the hole transport layer of the GaAs sub-cell on the surface of the GaAs absorption layer. 2) Remove the AlAs layer by wet etching to obtain a GaAs absorption layer / hole transport layer; transfer the GaAs absorption layer / hole transport layer to one end of the intermediate interconnecting conductive layer on the flexible substrate, and the hole transport layer contacts the intermediate interconnecting conductive layer; evaporate an electrode on the GaAs surface and anneal to form an ohmic contact to obtain the GaAs sub-cell. 3) Cover the GaAs sub-cell, and prepare the electron transport layer of the perovskite sub-cell at the other end of the intermediate interconnecting conductive layer on the flexible substrate. 4) Prepare a solution of the perovskite precursor, spin-coat it on the surface of the electron transport layer, and use the anti-solvent method and anneal to obtain the perovskite absorption layer of the perovskite sub-cell. 5) Prepare the hole transport layer of the perovskite sub-cell on the surface of the perovskite absorption layer. An electrode is evaporated on the hole transport layer to obtain a decoupled flexible GaAs / perovskite tandem solar cell.

6. The preparation method of the decoupled flexible GaAs / perovskite tandem solar cell according to claim 5, characterized in that: The GaAs substrate described in step 1) has a (100) crystal plane. The thickness of the GaAs buffer layer is 1 - 5 nm, the thickness of the AlAs layer is 20 - 50 nm, the GaAs layer is doped with N-type Si, and the doping concentration is 1 × 10 17 / cm 3 ~1 × 10 18 / cm 3 , and the thickness of the GaAs layer is 200 - 800 nm; The growth temperature of the AlAs is 580°C to 620°C, the temperature of the Al source is 1000°C to 1200°C, and the temperature of the As source is 900°C to 950°C; the growth temperature of the GaAs absorption layer is 550°C to 600°C, the temperature of the Ga source is 850°C to 900°C, the temperature of the As source is 900°C to 950°C, and the temperature of the Si doping source is 950 to 1000°C; The hole transport layer of the GaAs sub-cell is prepared into a film by suction filtration or wet transfer, and then transferred to the surface of the GaAs absorption layer; the thickness of the hole transport layer of the GaAs sub-cell is 100 to 200 nm.

7. The preparation method of the decoupled flexible GaAs / perovskite tandem solar cell according to claim 5, wherein: The solution for wet etching in step 2) is one or more of HF acid, phosphoric acid, and hydrochloric acid, with a mass concentration of 5% to 10%, and the etching time is 10 to 15 min; The thickness of the electrode in step 2) is 100 to 120 nm, the annealing temperature is 300 to 330°C, and the annealing time is 15 to 30 s; the thickness of the intermediate interconnection conductive layer is 100 to 120 nm; The electron transport layer in step 3) is prepared by magnetron sputtering, and the preparation conditions are: power is 60 to 120 W, vacuum degree is 0.4 to 0.7 Pa, and sputtering time is 10 to 30 min.

8. The preparation method of the decoupled flexible GaAs / perovskite tandem solar cell according to claim 5, characterized in that: The perovskite precursor in step 4) is MAI, FAI, MABr, PbI2, and / or PbBr2. After the precursor is made into a solution, the solvent in the solution is DMF and DMSO, and the volume ratio of DMF to DMSO is (3 to 5):1; When the perovskite is MAPbI3, the perovskite precursor is MAI and PbI2. When the perovskite is FAPbI3, the perovskite precursor is FAI and PbI2; When the perovskite is MAPbBr3, the perovskite precursor is MABr and PbBr2; The concentration of the solution after the precursor is made into a solution is 0.5 to 1.2 M, and this concentration is based on the perovskite; The rotation speed of spin coating in step 4) is 2000 to 4000 rpm, and the spin coating time is 20 to 60 s; in the anti-solvent method, the time for dropping the anti-solvent is 10 to 15 s before the end of rotation; The annealing temperature in step 4) is 80 to 120°C, and the annealing time is 10 to 30 min; In the anti-solvent method of step 4), the anti-solvent used is one or more of chlorobenzene, toluene, and ethyl acetate.

9. The preparation method of the decoupled flexible GaAs / perovskite tandem solar cell according to claim 5, wherein: The hole transport layer of the perovskite sub-cell in step 5) is obtained by spin coating the material of the hole transport layer into a solution and then annealing; the rotation speed is 4000 to 6000 rpm, the spin coating time is 30 to 60 s, the annealing temperature is 100 to 150°C, and the annealing time is 10 to 20 min; The solvent used to make the material of the hole transport layer into a solution is one of isopropanol, ethanol, and chlorobenzene, and the concentration of the solution is 0.5 to 1.5 mg / mL; the thickness of the hole transport layer is 50 to 150 nm; The thickness of the electrode in step 5) is 100 to 120 nm.

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