Perovskite / crystalline silicon tandem solar cell and preparation method thereof

Abstract

The application belongs to the field of photovoltaic devices, and relates to a preparation method of a perovskite / crystalline silicon laminated solar cell. The preparation method comprises the following steps: (1) depositing an intermediate composite layer on a crystalline silicon cell, and depositing a hole transport layer on the intermediate composite layer; wherein the crystalline silicon cell is full-textured, and the roughness is between 0.1 and 10 microns; the intermediate composite layer and the hole transport layer are conformal with the crystalline silicon cell; (2) preparing a perovskite absorption layer on the hole transport layer; wherein the perovskite absorption layer is formed by depositing perovskite precursor materials through multi-source co-evaporation, and the perovskite absorption layer is conformal with the crystalline silicon cell; and (3) sequentially depositing an electron transport layer and a conductive electrode on the perovskite absorption layer. The application is based on the method of multi-source co-evaporation, and a uniform, highly conformal perovskite layer is prepared on a cell with micron-level roughness. The preparation process of the application is excellent in controllability and repeatability, the device structure is simple, and the application is suitable for the industrialized development of laminated solar cells.

Description

Technical Field

[0001] This invention belongs to the technical field of photovoltaic devices, and more specifically, relates to a perovskite / crystalline silicon tandem solar cell and its preparation method. Background Technology

[0002] To efficiently develop and utilize solar energy, tandem photovoltaics have attracted much attention. Crystalline silicon cells, the mainstream material in the market, have already achieved a performance of 26.8%, and are about to reach the theoretical upper limit of 29.4%. Perovskite materials, with their tunable bandgap and excellent photovoltaic performance, are one of the preferred choices for tandem with crystalline silicon. Currently, the performance of perovskite / crystalline silicon tandem solar cells has reached 33.7%, and the key to further breakthroughs lies in the development of tandem processes based on textured silicon, as textured silicon can improve light absorption and carrier extraction efficiency. However, preparing a uniformly covered perovskite absorber layer on commercially available textured silicon with a micron-level roughness (1-5 μm) remains a challenge.

[0003] Thermal evaporation, with its high conformability, can solve this problem. Currently, a widely used method is to thermally evaporate and deposit an inorganic layer of the precursor, followed by treatment with an organic amine salt solution to generate an organic-inorganic hybrid perovskite absorber layer through a solution permeation reaction. While the first step, thermal evaporation, ensures a conformal film with textured silicon, the second step, solution processing, still leaves solution residues at the tips and valleys of the textured surface. This results in uneven film thickness, failing to achieve high conformability with the textured silicon and affecting carrier transport and the performance of stacked devices. Furthermore, the use of toxic organic solvents is detrimental to environmental protection. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a perovskite / crystalline silicon tandem solar cell and its fabrication method. This perovskite / crystalline silicon tandem solar cell uses a crystalline silicon cell with a roughness between 0.1 and 10 μm as the substrate. A multi-source co-evaporation process is used to simultaneously deposit the perovskite precursor material, enabling the fabrication of a uniformly covered, highly conformal perovskite layer. The fabrication process exhibits excellent controllability and repeatability, and the device structure is simple, making it suitable for the industrialization of tandem solar cells.

[0005] To achieve the above objectives, a method for fabricating a perovskite / crystalline silicon tandem solar cell is provided in a first aspect of the present invention, comprising the following steps:

[0006] (1) An intermediate composite layer is deposited on a crystalline silicon solar cell, and a hole transport layer is deposited on the intermediate composite layer; wherein the crystalline silicon solar cell is fully textured and has a roughness between 0.1 and 10 μm; the intermediate composite layer and the hole transport layer are conformally consistent with the crystalline silicon solar cell;

[0007] (2) A perovskite absorber layer is prepared on the hole transport layer; wherein the perovskite absorber layer is formed by multi-source co-evaporation deposition of perovskite precursor material, and the perovskite absorber layer is conformally consistent with the crystalline silicon cell;

[0008] (3) An electron transport layer and a conductive electrode are sequentially deposited on the perovskite absorption layer.

[0009] As a preferred embodiment of the present invention, the total thickness of the intermediate composite layer and the hole transport layer is 50-100 nm; the thickness of the perovskite absorber layer is 300-800 nm; and the band gap of the perovskite layer is 1.6-1.8 eV.

[0010] Preferably, in step (2), the number of evaporation sources in the multi-source co-evaporation is 2-4; wherein the evaporation rate of each evaporation source is... The substrate temperature is 40-100℃.

[0011] As a preferred embodiment of the present invention, in step (2), the perovskite precursor material includes at least one of the first raw materials PbI2, PbBr2, and PbCl2, and at least one of the second raw materials CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI.

[0012] Furthermore, the perovskite absorber layer compound is a compound with the general formula ABX3, wherein A originates from CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI in the second raw material. + C2H6N + CH5N2 + CH6N + C8H 12 N + CH6N3 + At least one of the following, B is derived from PbI2, PbBr2, and PbCl2 in the first raw material. 2+ X comes from the Cl in CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI in the second raw material. - ,Br - I - At least one of them.

[0013] As a preferred embodiment of the present invention, the intermediate composite layer is tin oxide or tin oxide; when the intermediate composite layer is tin oxide, the intermediate composite layer is prepared by magnetron sputtering or reactive plasma deposition; when the intermediate composite layer is tin oxide, the intermediate composite layer is prepared by atomic layer deposition.

[0014] The hole transport layer is nickel oxide, Spiro-TTB, MeO-2PACz, or P3CT; when the hole transport layer is nickel oxide, the hole transport layer is prepared by magnetron sputtering or reactive plasma deposition; when the hole transport layer is Spiro-TTB, MeO-2PACz, or P3CT, the hole transport layer is prepared by thermal evaporation.

[0015] As a preferred embodiment of the present invention, the crystalline silicon cell is one of PERC, TOPCon, or HJT.

[0016] As a preferred embodiment of the present invention, the method further includes: sequentially depositing a thin metal electrode and an antireflection film on the conductive electrode.

[0017] As a preferred embodiment of the present invention, the method further includes: in step (2), after preparing a perovskite absorption layer on the hole transport layer, annealing is performed; the annealing temperature is 70-120℃ and the annealing time is 5-40min.

[0018] In another aspect of the invention, a perovskite / crystalline silicon solar cell is obtained by means of the first aspect of the invention.

[0019] As a preferred embodiment of the present invention, the perovskite solar cell layer comprises an intermediate composite layer, a hole transport layer, a perovskite layer, an electron transport layer, a conductive electrode, a metal electrode layer, and an antireflection film sequentially stacked on the crystalline silicon solar cell, and all of them are conformally aligned with the crystalline silicon solar cell.

[0020] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0021] The invention provides a method for fabricating perovskite / crystalline silicon tandem solar cells. This method employs a one-step multi-source co-evaporation process to obtain a uniformly covered and highly conformal perovskite layer, effectively solving the problem of non-uniform conformation when perovskite is stacked with high-roughness textured silicon. It not only eliminates the use of toxic organic solvents but also avoids the adverse effects of ambient humidity and oxygen on the perovskite layer during fabrication, thus reducing environmental constraints. Furthermore, it is compatible with existing organic light-emitting diode (OLED) production lines, facilitating the industrialization and commercialization of perovskite / silicon-based tandem solar cells.

[0022] Existing two-step processes involve thermally evaporating an inorganic layer of the precursor, followed by treatment with an organic amine salt solution to generate an organic-inorganic hybrid perovskite absorber layer through a solution permeation reaction. For example, when PbI2 and MAI react to form MAPbI3 perovskite, the two-step process involves first evaporating PbI2, then spin-coating with an MAI solution, and finally annealing to generate the perovskite absorber layer. While thermal evaporation ensures a conformal film with textured silicon, solution treatment still leaves solution residues at the tips and valleys of the textured surface, resulting in uneven film thickness and failure to achieve high conformability with the textured silicon, thus affecting carrier transport and the performance of stacked devices. This invention, however, simultaneously evaporates PbI2 and MAI to obtain this perovskite. This is because the multi-source co-evaporation process allows for precise control of process parameters to directly obtain a perovskite layer with accurate stoichiometry and complete reaction in one step, thereby achieving high conformability with the substrate.

[0023] In this invention, the roughness of the crystalline silicon solar cell is between 0.1-10 μm, compared to the existing 1-5 μm. The multi-source co-evaporation process enables accurate fabrication of the perovskite layer while maintaining high conformality with the crystalline silicon substrate, resulting in better performance of the perovskite / crystalline silicon solar cell. Furthermore, the better roughness uniformity of the crystalline silicon solar cell leads to even better roughness uniformity of the perovskite layer, resulting in improved light absorption and carrier collection in the perovskite / crystalline silicon solar cell.

[0024] In this invention, the perovskite has a band gap of 1.6-1.8 eV and the perovskite absorber layer has a thickness of 300-800 nm, which helps to ensure that the perovskite solar cell can absorb enough sunlight.

[0025] In this invention, the preferred total thickness of the intermediate composite layer and hole transport layer is 50-100 nm, and the thickness of the perovskite absorber layer is 300-800 nm. Between the crystalline silicon solar cell and the perovskite absorber layer, there are also an intermediate composite layer and a hole transport layer. By controlling the thickness of both to be relatively small, and ensuring that both the intermediate composite layer and the hole transport layer are consistent with the crystalline silicon solar cell, the impact on the surface roughness of the crystalline silicon solar cell is minimal. Furthermore, the perovskite absorber layer is prepared by deposition using this multi-source co-evaporation method. Thanks to the precise metering of the multi-source co-evaporation process, a high degree of conformity with the textured crystalline silicon solar cell can be achieved.

[0026] In this invention, the intermediate composite layer, hole transport layer, perovskite layer, electron transport layer, conductive electrode, metal electrode layer, and antireflective film in the perovskite solar cell layer are all conformally aligned with the crystalline silicon solar cell. This conformal alignment ensures uniform thickness and further guarantees that carrier transport remains unaffected. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the fully textured perovskite / crystalline silicon heterojunction tandem solar cell structure shown in this invention;

[0028] Figure 2 This is a scanning electron microscope cross-sectional image of the perovskite absorber layer prepared by dual-source co-evaporation as shown in Example 1 of the present invention;

[0029] Figure 3 This is a scanning electron microscope cross-sectional view of the perovskite absorber layer prepared by dual-source co-evaporation as shown in Example 2 of the present invention.

[0030] Figure labeling: 1: Crystalline silicon solar cell, 2: Intermediate composite layer, 3: Hole transport layer, 4: Perovskite layer, 5: Electron transport layer, 6: Conductive electrode, 7: Metal electrode layer, 8: Anti-reflection coating. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0032] In this embodiment of the invention, the method for fabricating a perovskite / crystalline silicon tandem solar cell includes the following steps:

[0033] An intermediate composite layer is deposited on a crystalline silicon solar cell; the intermediate composite layer is either tin oxide (ITO) or tin oxide (SnO2). ITO is prepared by magnetron sputtering or reactive plasma deposition, and SnO2 is prepared by atomic layer deposition.

[0034] A hole transport layer is deposited on the intermediate composite layer. The hole transport layer includes inorganic oxides such as nickel oxide, Spiro-TTB, MeO-2PACz, and P3CT. When the hole transport layer is nickel oxide, it is prepared by magnetron sputtering or reactive plasma deposition; other materials are prepared by thermal evaporation.

[0035] Furthermore, the total thickness of the aforementioned intermediate composite layer and hole transport layer is 50-100 nm.

[0036] A perovskite absorber layer is fabricated on the hole transport layer;

[0037] Deposit an electron transport layer on the perovskite absorber layer;

[0038] Deposit conductive electrodes on the electron transport layer;

[0039] A thin metal electrode and an antireflection film are sequentially deposited on a conductive electrode to obtain the perovskite / crystalline silicon tandem solar cell.

[0040] The multi-source thermal evaporation process mentioned above is specifically as follows:

[0041] The number of evaporation sources in the vacuum multi-source co-evaporation process is 2-4, varying depending on the composition of the target perovskite material (band gap width of 1.6-1.8 eV). The evaporation rate of each evaporation source is... The evaporation rate varies slightly for each evaporation source, depending on the composition of the target perovskite material. The substrate temperature is 40-100℃.

[0042] The perovskite precursor materials include inorganic materials such as PbI2, CsI, CsBr, PbBr2, CsCl, and PbCl2 (first type), and organic ammonium salts such as DMAI, FAI, MACl, PEABr, and GAI (second type). In actual multi-source co-evaporation, the number of evaporation sources is 2-4. The perovskite precursor materials include at least one of PbI2, PbBr2, and PbCl2, and at least one of CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI. Multiple sets of perovskite precursor materials form a compound with the general formula ABX3. The perovskite absorber layer compound is also a compound with the general formula ABX3, where A originates from CsI in the second raw material. + C2H6N + CH5N2 + CH6N + C8H 12 N + CH6N3 + At least one of which, B comes from Pb in the first raw material. 2+ X comes from Cl in the second raw material. - ,Br - I - At least one of the following. The thickness of the perovskite absorber layer is 300-800 nm.

[0043] Preferably, after deposition by vacuum co-evaporation process, annealing is performed at a temperature of 70-120℃ for a duration of 5-40 minutes.

[0044] The structure of the fully textured perovskite / crystalline silicon solar cell prepared according to the above method is as follows: Figure 1 As shown: 1 is a crystalline silicon solar cell, 2 is an intermediate composite layer, 3 is a hole transport layer, 4 is a perovskite layer, 5 is an electron transport layer, 6 is a conductive electrode, 7 is a metal electrode layer, and 8 is an antireflection coating.

[0045] The band gap between the crystalline silicon solar cell and the perovskite layer is 1.6-1.8 eV, and the thickness of the perovskite absorber layer is 300-800 nm.

[0046] The specific implementation method is as follows:

[0047] Example 1:

[0048] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0049] The method for preparing perovskite absorber layers based on vacuum co-evaporation includes the following steps:

[0050] After fabricating an intermediate composite layer and a hole transport layer conforming to the crystalline silicon solar cell on a fully textured crystalline silicon solar cell substrate with a roughness of 3-4 μm, a perovskite absorber layer was prepared by in-situ substrate heating and vacuum co-evaporation. For example... Figure 2 The image shown is a scanning electron microscope cross-sectional view of the perovskite absorber layer prepared by dual-source co-evaporation in Example 1.

[0051] The vacuum co-evaporation process uses two evaporation sources. The evaporation precursor materials are PbI₂ and CsI. The evaporation rates of these materials are respectively... and

[0052] The annealing temperature was 100℃ and the annealing time was 10 minutes.

[0053] The substrate temperature is 70°C.

[0054] The thickness of the perovskite absorber layer is 400 nm.

[0055] The perovskite / crystalline silicon tandem solar cell obtained according to the above-mentioned fabrication method.

[0056] Crystalline silicon cell 1 is a heterojunction cell.

[0057] The intermediate composite layer 2 is ITO prepared by reactive plasma deposition.

[0058] Hole transport layer 3 is made of nickel oxide. The total thickness of the intermediate composite layer 2 and hole transport layer 3 is 100 nm.

[0059] The perovskite layer 4 was prepared by co-evaporation of PbI2 and CsI from two sources, and the thickness of the perovskite absorber layer was 400 nm.

[0060] Electron transport layer 4 is C60 with a thickness of 30 nm.

[0061] The conductive electrode 5 is an ITO prepared by reactive plasma deposition with a thickness of 200 nm.

[0062] The metal electrode layer 7 is Ag with a thickness of 20 nm.

[0063] The antireflective coating 8 is made of MgF2.

[0064] Example 2:

[0065] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0066] The method for preparing perovskite absorber layers based on vacuum co-evaporation includes the following steps:

[0067] After fabricating an intermediate composite layer and a hole transport layer conforming to the crystalline silicon solar cell on a fully textured crystalline silicon solar cell substrate with a roughness of 1-2 μm, a perovskite absorber layer was prepared by in-situ substrate heating and vacuum co-evaporation, such as... Figure 3 The image shown is a scanning electron microscope cross-sectional view of the perovskite absorber layer prepared by dual-source co-evaporation in Example 2.

[0068] The vacuum co-evaporation process uses two evaporation sources. The evaporation precursor materials are PbI₂ and CsI. The evaporation rates of these materials are respectively... and

[0069] The substrate temperature is 70℃.

[0070] The annealing process was carried out at a temperature of 70℃ for 30 minutes.

[0071] The thickness of the perovskite absorber layer is 400 nm.

[0072] The perovskite / crystalline silicon tandem solar cell obtained according to the above-mentioned fabrication method.

[0073] Crystalline silicon cell 1 is a heterojunction cell.

[0074] The intermediate composite layer 2 is ITO prepared by reactive plasma deposition.

[0075] Hole transport layer 3 is made of nickel oxide. The total thickness of the intermediate composite layer 2 and hole transport layer 3 is 100 nm.

[0076] The perovskite layer 4 was prepared by co-evaporation of PbI2 and CsI from two sources, and the thickness of the perovskite layer was 400 nm.

[0077] Electron transport layer 4 is C60 with a thickness of 30 nm.

[0078] The conductive electrode 5 is an ITO prepared by reactive plasma deposition with a thickness of 200 nm.

[0079] The metal electrode layer 7 is Ag with a thickness of 20 nm.

[0080] The antireflective coating 8 is made of MgF2.

[0081] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a perovskite / crystalline silicon tandem solar cell, characterized in that, Includes the following steps: (1) An intermediate composite layer is deposited on a crystalline silicon solar cell, and a hole transport layer is deposited on the intermediate composite layer; wherein, the crystalline silicon solar cell is fully textured and has a roughness between 0.1-10 μm; the intermediate composite layer and the hole transport layer are conformally conformal to the crystalline silicon solar cell; the intermediate composite layer is tin oxide or tin oxide; when the intermediate composite layer is tin oxide; the intermediate composite layer is prepared by magnetron sputtering or reactive plasma deposition; when the intermediate composite layer is tin oxide, the intermediate composite layer is prepared by atomic layer deposition; the hole transport layer is nickel oxide, Spiro-TTB, MeO-2PACz or P3CT; when the hole transport layer is nickel oxide, the hole transport layer is prepared by magnetron sputtering or reactive plasma deposition; when the hole transport layer is Spiro-TTB, MeO-2PACz or P3CT, the hole transport layer is prepared by thermal evaporation; the total thickness of the intermediate composite layer and the hole transport layer is 50-100 nm. (2) A perovskite absorber layer is prepared on the hole transport layer; wherein the perovskite absorber layer is formed by multi-source co-evaporation deposition of perovskite precursor material, and the perovskite absorber layer is conformally consistent with the crystalline silicon solar cell; the thickness of the perovskite absorber layer is 300-800 nm; the band gap of the perovskite absorber layer is 1.6-1.8 eV; the number of evaporation sources in the multi-source co-evaporation is 2-4; wherein the evaporation rate of each evaporation source is 0.2-1.0 Å / s, and the substrate temperature is 40-100 °C; the perovskite precursor material includes at least one of the first raw material PbI2, PbBr2, and PbCl2, and at least one of the second raw material CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI; (3) An electron transport layer and a conductive electrode are sequentially deposited on the perovskite absorption layer.

2. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, In step (2), the perovskite absorber layer is a compound with the general formula ABX3, wherein A comes from CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI in the second raw material. + C2H6N + CH5N2 + CH6N + C8H 12 N + CH6N3 + At least one of the following, B is derived from PbI2, PbBr2, and PbCl2 in the first raw material. 2+ X comes from at least one of Cl-, Br-, and I- from CsI, CsBr, CsCl, DMAI, FAI, MACl, PEABr, and GAI in the second raw material.

3. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The crystalline silicon solar cell is one of PERC, TOPCon, or HJT.

4. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The method further includes: sequentially depositing a thin metal electrode and an antireflection film on the conductive electrode.

5. The method for fabricating a perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The method further includes: in step (2), after preparing a perovskite absorption layer on the hole transport layer, annealing is performed; the annealing temperature is 70-120℃ and the annealing time is 5-40min.

6. A perovskite / crystalline silicon tandem solar cell prepared by the method according to any one of claims 1-5.

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