Metal oxide doped layers, solar cells and their fabrication methods

Abstract

This application discloses a metal oxide doped layer, wherein the work function of the metal oxide doped layer gradually changes from its first surface to its second surface. This application also provides a method for preparing the metal oxide doped layer, a solar cell, and the same method. The metal oxide doped layer and solar cell described in this application have a gradually changing work function, which can be matched with the upper and lower layers of the solar cell, thereby improving the conversion efficiency of the solar cell.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, specifically to a metal oxide doped layer, a solar cell, and a method for fabricating the same. Background Technology

[0002] Organic-inorganic hybrid perovskite solar cells have garnered widespread attention worldwide as a novel type of high-efficiency, low-cost solar cell. In just a few years, the photoelectric conversion efficiency (PCE) of single-junction small-area perovskite cells has rapidly increased from 3.8% in 2009 to over 25%, while the PCE of perovskite / silicon heterojunction tandem cells has reached over 29%. This rapid improvement in efficiency has made them a key focus for photovoltaic research institutions and companies.

[0003] Compared to traditional thin-film solar cells (such as copper indium gallium selenide and cadmium telluride), perovskite solar cells offer advantages such as high conversion efficiency, simple fabrication processes, and low-cost potential, making them the most promising thin-film solar cell technology for industrialization. By adjusting the composition ratio of the precursor solution, the cutoff wavelength of the solar cell's spectral response can be tuned, making it the ideal material for the top-cell absorber layer.

[0004] Silicon heterojunction solar cell technology boasts advantages such as simple processing (texturing and cleaning → amorphous silicon deposition → TCO deposition → silver electrode printing), low fabrication temperature (<220℃), high conversion efficiency (>25%), and symmetrical structure (bifacial possible), and is considered the third-generation cell technology after PERC cells. The high infrared absorption, strong low-light effect, and pin-matching structural advantages of silicon heterojunction cells make them one of the best choices for bottom cells. Forming a "perovskite / silicon heterojunction" tandem cell structure by combining a perovskite cell (top cell) and a silicon-based heterojunction cell (bottom cell) can achieve distributed absorption of the solar spectrum, potentially achieving conversion efficiencies exceeding 30%. However, while the composite layer connecting the hole transport layer of the perovskite cell and the emitter of the silicon-based heterojunction cell has a simple process and is suitable for commercial production, its conduction band cannot simultaneously match the conduction band of the emitter of the silicon-based heterojunction cell and the HOMO energy level of the hole transport layer of the perovskite cell, limiting the improvement of the cell's electrical performance.

[0005] Perovskite solar cells can also form a "perovskite / PERC" tandem cell structure with PERC cells to achieve distributed absorption of the solar spectrum. For P-type PERC cells, the composite layer connecting the hole transport layer of the perovskite cell and the emitter of the P-type PERC cell is similar to the "perovskite / silicon heterojunction" tandem cell structure. Its conduction band cannot simultaneously match the conduction band of the emitter of the P-type PERC cell and the HOMO level of the hole transport layer of the perovskite cell. For N-type PERT cells, the composite layer connecting the electron transport layer of the perovskite cell and the emitter of the N-type PERT cell cannot simultaneously match the valence band of the emitter of the N-type PERT cell and the LUMO level of the electron transport layer of the perovskite cell, limiting the improvement of the cell's electrical performance. Summary of the Invention

[0006] To address the aforementioned issues, this application proposes a metal oxide doped layer and a tandem solar cell using the metal oxide doped layer as a composite layer. The metal oxide doped layer has a gradually changing work function, which can be matched with the upper and lower cells of the tandem solar cell, thereby improving the conversion efficiency of the solar cell.

[0007] This application provides a metal oxide doped layer, wherein the work function of the metal oxide doped layer gradually changes from a first surface on one side to a second surface on the other side.

[0008] Furthermore, the metal oxide doped layer includes at least one metal oxide layer and at least one doped layer stacked together.

[0009] Furthermore, the metal oxide doped layer comprises n metal oxide layers and m doped layers stacked together, wherein n and m are integers greater than 1;

[0010] The metal oxide layer and the doped layer are cross-stacked, and at the junction of the metal oxide layer and the doped layer, a portion of the material of the doped layer diffuses into the metal oxide layer.

[0011] Furthermore, the work function of the metal oxide doped layer is adjusted by modifying its structure and material to gradually change from the first surface to the second surface.

[0012] Furthermore, adjusting the structure and material of the metal oxide doped layer includes adjusting any one or more of the following: the thickness of the metal oxide layer, the thickness of the doped layer, the material of the metal oxide layer, the material of the doped layer, and the arrangement order of the metal oxide layer and the doped layer.

[0013] Furthermore, the thickness of the metal oxide layer in the nth layer gradually changes; the thickness of the doped layer in the mth layer is the same.

[0014] Furthermore, the thickness of the metal oxide layer gradually increases or decreases, and the work function of the metal oxide doped layer also gradually increases or decreases.

[0015] This application also provides a solar cell, including an upper cell and a lower cell stacked together, wherein the upper cell and the lower cell have the aforementioned metal oxide doped layer.

[0016] Furthermore, the upper battery has a first carrier transport layer, the lower battery has an N-type silicon layer or a P-type silicon layer, the first surface of the metal oxide doped layer is stacked with the first carrier transport layer, and the second surface of the metal oxide doped layer is stacked with the N-type silicon layer or the P-type silicon layer.

[0017] Furthermore, the lower battery layer has an N-type silicon layer, and the first carrier transport layer is a hole transport layer.

[0018] The work function of the first surface of the metal oxide doped layer is consistent with the HOMO level of the hole transport layer.

[0019] The work function of the second surface of the metal oxide doped layer is consistent with the conduction band of the N-type silicon layer.

[0020] The work function of the metal oxide doped layer gradually increases from the first surface to the second surface.

[0021] Furthermore, the lower battery layer has a P-type silicon layer, and the first carrier transport layer is an electron transport layer.

[0022] The work function of the first surface of the metal oxide doped layer is consistent with the LUMO energy level of the electron transport layer.

[0023] The work function of the second surface of the metal oxide doped layer is consistent with the valence band of the p-type silicon layer.

[0024] The work function of the metal oxide doped layer gradually decreases from the first surface to the second surface.

[0025] This application also provides a method for preparing a metal oxide doped layer, comprising the following steps:

[0026] The metal oxide layer and the doped layer are stacked in a cross manner to form a metal oxide doped layer;

[0027] The work function of the metal oxide doped layer gradually changes from a first surface on one side to a second surface on the other side.

[0028] Furthermore, the metal oxide doped layer comprises n metal oxide layers and m doped layers stacked together, where n and m are integers greater than 1.

[0029] Furthermore, the thickness of the n-layer metal oxide layer gradually changes;

[0030] The thickness of the doped layers in the m-layer is the same.

[0031] Furthermore, the thickness of the metal oxide layer gradually increases or decreases, and the work function of the metal oxide doped layer gradually increases or decreases.

[0032] Furthermore, the metal oxide layers are all selected from one of zinc oxide, indium oxide, or titanium oxide.

[0033] The doped layers are all selected from one of the following: aluminum oxide layer, boron oxide layer, or tin oxide layer.

[0034] This application also provides a method for preparing a solar cell, comprising the following steps:

[0035] Provides a lower-level battery;

[0036] Preparation of metal oxide doped layers;

[0037] Provide upper-layer batteries;

[0038] The work function of the metal oxide doped layer gradually changes from a first surface on one side to a second surface on the other side.

[0039] Furthermore, the metal oxide doped layer is the aforementioned metal oxide doped layer or a metal oxide doped layer prepared by the aforementioned preparation method.

[0040] The metal oxide doped layer provided in this application has a work function that gradually increases or decreases from the first surface to the second surface, so that the metal oxide doped layer can serve as an intermediate composite layer for different batteries, and the work function of the two sides of the metal oxide doped layer can be matched with different batteries.

[0041] The solar cell provided in this application, when the lower cell uses a silicon heterojunction cell or a P-type PERC cell, has a work function on the first surface of the metal oxide doped layer that matches the HOMO level of the first carrier transport layer (hole transport layer) of the upper cell, and a work function on the second surface of the metal oxide doped layer that matches the conduction band of the N-type silicon layer of the lower cell. This ensures smooth charge transport between the upper and lower cells, resulting in good performance of the solar cell. When the lower cell uses an N-type PERT cell, the work function on the first surface of the metal oxide doped layer matches the LUMO level of the first carrier transport layer (electron transport layer) of the upper cell, and a work function on the second surface of the metal oxide doped layer that matches the valence band of the P-type silicon layer of the lower cell. This also ensures smooth charge transport between the upper and lower cells, resulting in good performance of the solar cell. Attached Figure Description

[0042] The accompanying drawings are provided to better understand this application and do not constitute an undue limitation thereof. Wherein:

[0043] Figure 1 This is a schematic diagram of the structure of the "perovskite / silicon-based heterojunction" tandem solar cell provided in this application.

[0044] Figure 2 This is a schematic diagram of the structure of the "perovskite / P-type PERC" tandem solar cell provided in this application.

[0045] Figure 3 This is a schematic diagram of the structure of the "perovskite / N-type PERT" tandem solar cell provided in this application.

[0046] Figure 4 This is a schematic diagram of the structure of the metal oxide doped layer provided in this application.

[0047] Explanation of reference numerals in the attached figures

[0048] 111-Back transparent conductive layer, 112-P-type silicon layer, 113-First intrinsic amorphous silicon layer, 114-N-type crystalline silicon substrate layer, 115-Second intrinsic amorphous silicon layer, 116-N-type silicon layer, 117-Metal oxide doped layer, 1171-First surface; 1172-Second surface, 1173-Metal oxide layer, 1174-Doped layer, 121-First carrier transport layer, 122-Perovskite absorber layer, 123-Second carrier transport layer, 124-Front transparent conductive layer, 131-Metal electrode.

[0049] 211-Al back surface, 212-silicon nitride layer, 213-alumina layer, 214-P-type crystalline silicon substrate, 215-N-type emitter, 217-metal oxide doped layer; 221-first carrier transport layer, 222-perovskite absorber layer, 223-second carrier transport layer, 224-front transparent conductive layer, 231-metal electrode, 2171-first surface, 2172-second surface.

[0050] 311-Silicon nitride layer, 312-Aluminum oxide layer, 313-Phosphorus diffused back field layer, 314-N-type silicon substrate, 315-Boron diffused P-type silicon layer, 317-Metal oxide doped layer; 321-First carrier transport layer, 322-Perovskite absorber layer, 323-Second carrier transport layer, 324-Front transparent conductive layer, 331-Metal electrode, 3171-First surface, 3172-Second surface. Detailed Implementation

[0051] The following description illustrates exemplary embodiments of this application, including various details to aid understanding; these should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description. In this application, the vertical position is determined according to the direction of light incidence, with the point of light incidence being vertical.

[0052] like Figure 4 As shown, this application provides a metal oxide doped layer 117, the work function of which gradually changes from a first surface 1171 on one side to a second surface 1172 on the other side. That is, the work function of the metal oxide doped layer 117 gradually increases or decreases from its first surface 1171 to its second surface 1172.

[0053] In one specific embodiment, on the metal oxide doped layer 117, the work function gradually increases from the first surface 1171 to the second surface 1172.

[0054] In another specific embodiment, on the metal oxide doped layer 117, the work function gradually decreases from the first surface 1171 to the second surface 1172.

[0055] In this application, the metal oxide doped layer 117 includes at least one metal oxide layer 1173 and at least one doped layer 1174 stacked together.

[0056] Specifically, the metal oxide doped layer 117 includes n metal oxide layers 1173 and m doped layers 1174 stacked together, where n and m are integers greater than 1; m and n can be equal or unequal, and when m and n are unequal, the difference between m and n is 1, i.e., m = n ± 1.

[0057] The thickness of the n-layer metal oxide layer 1173 gradually changes;

[0058] The thickness of the doped layer 1174 in the m layer is the same.

[0059] Specifically, the metal oxide layer 1173 and the doped layer 1174 are cross-stacked, and at the junction of the metal oxide layer 1173 and the doped layer 1174, a portion of the material of the doped layer 1174 diffuses into the metal oxide layer 1173.

[0060] When the metal oxide-doped intermediate composite layer 117 is a multilayer stacked structure, the metal oxide-doped intermediate composite layer 117 has two types of stacking order. The first arrangement is that the metal oxide layer and the doped layer are stacked alternately in sequence, and the first surface 171 and the second surface 172 are both metal oxide layers. The second arrangement is that the metal oxide layer and the doped layer are stacked alternately in sequence, and the first surface 171 is a doped layer and the second surface 172 is a metal oxide layer. Preferably, the first surface 171 and the second surface 172 are both metal oxide layers.

[0061] Specifically, in the metal oxide doped layer 117, the thickness of the metal oxide layer 1173 gradually increases or decreases in the direction from the first surface 1171 to the second surface 1172, while the thickness of the doped layer 1174 remains constant. Since some of the doped layer 1174 diffuses into the metal oxide layer 1173 on the side of the metal oxide layer 1173 near the doped layer 1174, the doping concentration in the metal oxide layer 1173 gradually decreases or increases in the direction from the first surface 1171 to the second surface 1172. This results in the work function of the metal oxide doped layer 117 gradually increasing or decreasing in the direction from the first surface 1171 to the second surface 1172.

[0062] In one specific embodiment, as the thickness of the metal oxide layer 1173 in the direction from the first surface 1171 to the second surface 1172 gradually increases, the work function in the direction from the first surface 1171 to the second surface 1172 also gradually increases.

[0063] Specifically, the metal oxide layer 1173 can be one or more of zinc oxide, indium oxide, or titanium oxide; preferably, the metal oxide layer 1173 can be one of zinc oxide, indium oxide, or titanium oxide.

[0064] Specifically, the thickness of the metal oxide layer 1173 can be 0.1-1000 nm, preferably 1-30 nm. For example, it can be 0.1 nm, 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, or 1000 nm.

[0065] Specifically, the doped layer 1174 can be one or more of aluminum oxide, boron oxide, or tin oxide. Preferably, the doped layer 1174 can be one of aluminum oxide, boron oxide, or tin oxide.

[0066] Specifically, the thickness of the doped layer 1174 is 0.1-10 nm, preferably 0.1 nm. For example, it can be 0.1 nm, 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm.

[0067] In this application, the thickness of the metal oxide doped layer 117 is 10-1000 nm. For example, it can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, or 1000 nm.

[0068] In this application, the work function of the metal oxide doped layer 117 is adjusted by modifying the structure and material of the metal oxide doped layer 117, thereby adjusting the work function of the metal oxide doped layer 117 as it gradually changes from the first surface 1171 to the second surface 1172.

[0069] Specifically, adjusting the structure and material of the metal oxide doped layer 117 includes adjusting any one or more of the following: the thickness of the metal oxide layer 1173, the thickness of the doped layer 1174, the material of the metal oxide layer 1173, the material of the doped layer 1174, and the arrangement order of the metal oxide layer 1173 and the doped layer 1174.

[0070] Once the structures of the upper and lower cells are determined (i.e., the HOMO energy level of the first carrier transport layer 121 (hole transport layer) of the perovskite cell and the conduction band of the emitter of the silicon-based heterojunction cell are determined), the work function of the gradually changing work function between the first surface 1171 and the second surface 1172 of the metal oxide doped layer 117 is adjusted by adjusting the thickness of the metal oxide layer 1173, the thickness of the doped layer 1174, the material of the metal oxide layer 1173, the material of the doped layer 1174, and the arrangement order of the metal oxide layer 1173 and the doped layer 1174.

[0071] This application discloses a method for preparing a metal oxide doped layer 117, comprising the following steps:

[0072] The metal oxide layer 1173 and the doped layer 1174 are stacked in a cross manner to form the metal oxide doped layer 117;

[0073] The work function of the metal oxide doped layer 117 gradually changes (increases or decreases) from its first surface 1171 to its second surface 1172.

[0074] Specifically, the metal oxide doped layer includes an n-layer metal oxide layer 1173 and an m-layer doped layer 1174 stacked together, where n and m are integers greater than 1.

[0075] The thickness of the n-layer metal oxide layer 1173 gradually changes;

[0076] The thickness of the doped layer 1174 in the m layer is the same.

[0077] Specifically, this application discloses a method for preparing a metal oxide doped layer 117, comprising the following steps:

[0078] Step 1: Prepare the first metal oxide layer 1173;

[0079] Step 2: Form a first doped layer 1174 on the first metal oxide layer 1173;

[0080] Step 3: Form a second metal oxide layer 1173 on the first doped layer 1174;

[0081] Step 4: Form a second doped layer 1174 on the second metal oxide layer 1173;

[0082] Step 5: Form a third metal oxide layer 1173 on the second doped layer 1174;

[0083] ···

[0084] Step 2n-1: Form the nth metal oxide layer 1173 on the mth doped layer 1174, or form the mth doped layer 1174 on the nth metal oxide layer 1173, thereby forming the metal oxide doped layer 117.

[0085] The side of the first metal oxide layer 1173 that faces away from the first doped layer 1174 is the second surface 1172;

[0086] The side of the nth metal oxide layer 1173 that faces away from the mth doped layer 1174, or the side of the mth doped layer 1174 that faces away from the nth metal oxide layer 1173, is the first surface 1171.

[0087] The work function gradually increases or decreases from the first surface 1171 to the second surface 1172;

[0088] n and m are integers greater than 1.

[0089] In this application, the thicknesses of the first metal oxide layer 1173, the second metal oxide layer 1173, the third metal oxide layer 1173, and the nth metal oxide layer 1173 gradually decrease or increase.

[0090] The first doped layer 1174, the second doped layer 1174, and the m-th doped layer 1174 have the same thickness.

[0091] In this application, the first metal oxide layer 1173, the second metal oxide layer 1173, the third metal oxide layer 1173, and the nth metal oxide layer 1173 are all selected from zinc oxide, indium oxide, or titanium oxide layers.

[0092] The first doped layer 1174, the second doped layer 1174, and the m-th doped layer 1174 are all selected from aluminum oxide, boron oxide, or tin oxide.

[0093] Specifically, when the first metal oxide layer 1173, the second metal oxide layer 1173, the third metal oxide layer 1173, and the nth metal oxide layer 1173 are all zinc oxide layers, and the first doped layer 1174, the second doped layer 1174, and the mth doped layer 1174 are all boron oxide layers, the prepared metal oxide doped layer 117 is a boron-doped zinc oxide layer (BZO layer) with a gradually changing work function.

[0094] The metal oxide doped layer 117 (BZO layer) prepared using ALD enables photogenerated carriers to travel from the perovskite layer to the silicon heterojunction. Specifically, the metal oxide doped layer 117 (BZO layer) is prepared by simultaneously using three sources: diethylzinc, water, and diborane. Diethylzinc and water sources generate the predominant zinc oxide, while water and diborane sources generate boron oxide as dopant. The doping concentration is varied by controlling the number of depositions of zinc oxide and boron oxide.

[0095] To be more specific:

[0096] In step one, a zinc oxide layer with a thickness of 0.a nm is formed by depositing a two-source mixture of diethylzinc and water for a total of a cycle.

[0097] In step two, b cycles of deposition using both water and diborane sources are used on one side surface of the zinc oxide layer to form a boron oxide layer with a thickness of 0.b nm;

[0098] In step three, a zinc oxide layer with a thickness of 0.c nm is formed by depositing c cycles of diethylzinc and water on one side surface of the boron oxide layer.

[0099] In step four, b cycles of deposition using both water and diborane sources are used on one side surface of the zinc oxide layer to form a boron oxide layer with a thickness of 0.bnm;

[0100] In step five, a zinc oxide layer with a thickness of 0.d nm is formed by depositing d cycles of diethylzinc and water on one side surface of the boron oxide layer.

[0101] ···

[0102] In step 2n-1, g cycles of deposition using diethylzinc and water sources are used on one side of the m-th boron oxide layer to form a zinc oxide layer with a thickness of 0.g nm, thereby obtaining a metal oxide doped layer 117, in which the values ​​of a, c, d and g gradually increase or decrease.

[0103] Specifically, when the first metal oxide layer 1173, the second metal oxide layer 1173, the third metal oxide layer 1173, and the nth metal oxide layer 1173 are all zinc oxide layers, and the first doped layer 1174, the second doped layer 1174, and the mth doped layer 1174 are all aluminum oxide, the prepared metal oxide doped layer 117 is an aluminum-doped zinc oxide layer (AZO layer) with a gradually changing work function.

[0104] The metal oxide doped layer 117 (AZO layer) prepared using ALD enables photogenerated carriers to travel from the perovskite layer to the silicon heterojunction. Specifically, it utilizes three sources simultaneously: diethylzinc, water, and trimethylaluminum. The diethylzinc and water sources generate the predominant zinc oxide, while the water and trimethylaluminum sources generate aluminum oxide as dopant. The doping concentration is altered by controlling the number of zinc oxide and aluminum oxide depositions. The specific preparation method for this metal oxide doped layer 117 can be found above.

[0105] Specifically, when the first metal oxide layer 1173, the second metal oxide layer 1173, the third metal oxide layer 1173, and the nth metal oxide layer 1173 are all zinc oxide layers, and the first doped layer 1174, the second doped layer 1174, and the mth doped layer 1174 are all tin oxide layers, the prepared metal oxide doped layer 117 is a tin-doped zinc oxide layer (TZO layer) with a gradually changing work function.

[0106] The TZO layer prepared using ALD enables photogenerated carriers to travel from the perovskite layer to the silicon heterojunction. Specifically, it utilizes three sources simultaneously: diethylzinc, water, and tetra(dimethylamino)tin. The diethylzinc and water sources generate the predominant zinc oxide, while the water and tetra(dimethylamino)tin sources generate doped tin oxide. The doping concentration is altered by controlling the number of zinc oxide and tin oxide depositions. The specific preparation method for this metal oxide doped layer 117 can be found above.

[0107] The metal oxide doped layer 117 prepared by the method described in this application is the aforementioned metal oxide doped layer 117. Therefore, the specific parameters of the metal oxide doped layer 117 prepared by this method can be referred to the aforementioned description of the metal oxide doped layer 117.

[0108] This application provides a solar cell, comprising an upper cell, a metal oxide doped layer 117, and a lower cell stacked sequentially from top to bottom. The metal oxide doped layer 117 is located between the upper and lower cells. Since the work function of the metal oxide doped layer 117 gradually increases or decreases from its first surface 171 to its second surface 172, the gradually changing work function can be matched with both the upper and lower cells, facilitating charge transfer between them and thereby improving the conversion efficiency of the solar cell.

[0109] Specifically, this application provides three types of tandem solar cells for illustration: perovskite / silicon heterojunction solar cells, perovskite / P-type PERC tandem solar cells, and perovskite / N-type PERT tandem solar cells.

[0110] The first is perovskite / silicon-based heterojunction solar cells.

[0111] like Figure 1 As shown, the perovskite / silicon heterojunction solar cell of this application includes an upper cell, a metal oxide doped layer 117, and a lower cell stacked sequentially from top to bottom. The upper cell includes a front transparent conductive layer 124, a second carrier transport layer 123, a perovskite absorber layer 122, and a first carrier transport layer 121 stacked sequentially from top to bottom. The lower cell includes an N-type silicon layer 116 (which can be an N-type amorphous silicon layer or an N-type microcrystalline silicon layer), a second intrinsic amorphous silicon layer 115, an N-type crystalline silicon substrate, a first intrinsic amorphous silicon layer 113, a P-type silicon layer 112 (which can be a P-type amorphous silicon layer or a P-type microcrystalline silicon layer), and a back transparent conductive layer 111 stacked sequentially from top to bottom. The solar cell comprises, from top to bottom, a front transparent conductive layer 124, a second carrier transport layer 123, a perovskite absorber layer 122, a first carrier transport layer 121, a metal oxide doped layer 117, an N-type silicon layer 116, a second intrinsic amorphous silicon layer 115, an N-type crystalline silicon substrate, a first intrinsic amorphous silicon layer 113, a P-type silicon layer 112, and a back transparent conductive layer 111. A metal electrode 131 is disposed on the surface of the front transparent conductive layer 124 opposite to the second carrier transport layer 123, and a metal electrode 131 is disposed on the surface of the back transparent conductive layer 111 opposite to the P-type silicon layer 112.

[0112] Both the front transparent conductive layer 124 and the back transparent conductive layer 111 are used to collect charge carriers and transport them to the metal electrode 131. The front transparent conductive layer 124 can be an ITO layer, an IWO layer, an IZO layer, an ITiO layer, etc., including but not limited to these. The back transparent conductive layer can be an ITO layer, an IWO layer, an IZO layer, an ITiO layer, etc., including but not limited to these.

[0113] The first carrier transport layer 121 is a hole transport layer, and the second carrier transport layer 123 is an electron transport layer. The first carrier transport layer 121 can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer, or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer, or a CuSCN layer. The second carrier transport layer 123 can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, or

[60] PCBM([6,6]-phenyl-C 61 butyric acid methyl ester, Chinese name [6,6]-phenyl-C 61 -Isomethyl butyrate) layer,

[70] PCBM([6,6]-Phenyl-C 71 -butyric acidmethyl ester, Chinese name is [6,6]-phenyl-C 71 - Isomethyl butyrate) layer, bis

[60] PCBM(Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C 62 Layers such as

[60] ICBA(1',1”,4',4”-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2”,3”][5,6]fullerene-C60) and others, including but not limited to these, as long as they can achieve the functions in this application.

[0114] The perovskite absorber layer 122 can be an organic-inorganic hybrid halide perovskite layer, a fully inorganic halide perovskite layer, a lead-free perovskite layer, etc., including but not limited to these. Its band gap is generally around 1.5-1.8 eV.

[0115] The metal oxide doped layer 117 is the aforementioned metal oxide doped layer 117.

[0116] The N-type silicon layer 116 can be prepared by PECVD and can form the emitter stage of a heterojunction cell.

[0117] Both the first intrinsic amorphous silicon layer 113 and the second intrinsic amorphous silicon layer 115 are prepared by PECVD and mainly serve to passivate the dangling bonds on the surface of the N-type crystalline silicon substrate layer 114.

[0118] The N-type crystalline silicon substrate 114 serves as the light absorption layer of the lower battery, converting photons into photogenerated carriers.

[0119] The P-type silicon layer 112 is prepared by PECVD and can form the back electric field of a silicon heterojunction solar cell.

[0120] In this application, the first surface 1171 of the metal oxide doped layer 117 is stacked with the first carrier transport layer 121, and the second surface 1172 of the metal oxide doped layer 117 is stacked with the N-type silicon layer 116.

[0121] More specifically, the first carrier transport layer 121 is a hole transport layer, and the second carrier transport layer 123 is an electron transport layer. That is, the first surface 1171 of the metal oxide doped layer 117 is stacked with the hole transport layer, and the second surface 1172 of the metal oxide doped layer 117 is stacked with the N-type silicon layer 116.

[0122] In existing perovskite / silicon heterojunction tandem solar cells, a total charge transport layer (TCO) is typically fabricated on a-Si:H(n+) as the composite layer, with inorganic materials such as MoOx, NiOx, and Cu2O used as the hole transport layer. When fabricating the TCO as the composite layer, materials such as BZO, AZO, ITO, FTO, IWO, and IZO can be selected. Most TCO materials can be fabricated using methods such as magnetron sputtering or reactive plasma deposition. The conduction band of a-Si:H(n+) is approximately -3.7 eV, and the HOMO energy level of the hole transport layer of inorganic materials is approximately -5.3 eV. The work function of TCO materials is generally between -4.0 and -5 eV, falling between -3.7 eV and -5.3 eV, which allows for charge transport. However, the conduction band of a single TCO material is a fixed value, and charge tends to accumulate at the interface during transport, leading to recombination losses and affecting the cell's electrical performance. In this application, the work function of the first surface 1171 of the metal oxide doped layer 117 is consistent with the HOMO energy level of the hole transport layer, and the work function of the second surface 1172 of the metal oxide doped layer 117 is consistent with the conduction band of the N-type silicon layer 116. In this embodiment, since the work function of the metal oxide doped layer 117 gradually increases from the first surface 1171 to the second surface 1172, the charge transport between the hole transport layer and the N-type silicon layer 116 is smooth and will not accumulate at the interface, thereby improving the conversion efficiency of the solar cell. Therefore, the performance of the solar cell is better.

[0123] This application provides a method for preparing a solar cell, comprising the following steps:

[0124] Step 1: Provide the lower-level battery;

[0125] Step 2: Prepare the metal oxide doped layer 117;

[0126] Step 3: Provide the upper battery layer;

[0127] Specifically, the metal oxide doped layer 117 is prepared on the surface of the lower battery, and the upper battery is prepared on the surface of the metal oxide doped layer 117 away from the lower battery. The surface of the metal oxide doped layer 117 that is in contact with the lower battery is the second surface 1172, and the surface that is in contact with the upper battery is the first surface 1171.

[0128] The work function of the metal oxide doped layer 117 gradually changes from its first surface 1171 to its second surface 1172.

[0129] The lower battery is a silicon-based silicon heterojunction battery, and the specific preparation method is existing technology, which is not specifically limited in this application.

[0130] The upper battery is a perovskite battery, and the specific preparation method is existing technology, which is not specifically limited in this application.

[0131] The preparation method of the metal oxide doped layer 117 can refer to the aforementioned preparation method of the metal oxide doped layer 117.

[0132] Secondly, there are perovskite / P-type PERC tandem solar cells.

[0133] like Figure 2 As shown, the perovskite / P-type PERC tandem solar cell of this application includes an upper cell, a metal oxide doped layer 217, and a lower cell stacked sequentially from top to bottom. The upper cell includes a front transparent conductive layer 224, a second carrier transport layer 223, a perovskite absorber layer 222, and a first carrier transport layer 221 stacked sequentially from top to bottom. The lower cell includes an N-type emitter 215, a P-type crystalline silicon substrate 214, an aluminum oxide layer 213, a silicon nitride layer 212, and an Al back field 211 stacked sequentially from top to bottom. A metal electrode 231 is disposed on the surface of the front transparent conductive layer 224 opposite to the second carrier transport layer 223, and a metal electrode 231 is disposed on the surface of the Al back field 211 opposite to the silicon nitride layer 212.

[0134] The front transparent conductive layer 22-4 may be an ITO layer, an IWO layer, an IZO layer, an ITiO layer, etc., including but not limited to these.

[0135] The first carrier transport layer 221 is a hole transport layer, which can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer, or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer, or a CuSCN layer.

[0136] The second carrier transport layer 223 is an electron transport layer, which can be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, or

[60] PCBM([6,6]-phenyl-C 61 butyric acid methyl ester, Chinese name [6,6]-phenyl-C 61 -Isomethyl butyrate) layer,

[70] PCBM([6,6]-Phenyl-C 71 -butyric acidmethyl ester, Chinese name is [6,6]-phenyl-C 71 - Isomethyl butyrate) layer, bis

[60] PCBM(Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C 62 ) layer,

[60] ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]full erene-C 60 Layers, etc., including but not limited to these, as long as they can achieve the functions in this application.

[0137] The perovskite absorber layer 222 can be an organic-inorganic hybrid halide perovskite layer, a fully inorganic halide perovskite layer, a lead-free perovskite layer, etc., including but not limited to these. Its band gap is generally around 1.5-1.8 eV.

[0138] The metal oxide doped layer 217 can be the aforementioned metal oxide doped layer 117.

[0139] The aluminum oxide layer 213 is prepared by ALD and can passivate the P-type crystalline silicon substrate 214.

[0140] The silicon nitride layer 212 is prepared by PECVD and mainly serves to reduce the reaction.

[0141] The Al back field 211 is screen printed and mainly serves as a field passivation function.

[0142] The N-type emitter 215 is prepared by a diffusion process.

[0143] In this application, the first surface 2171 of the metal oxide doped layer 217 is stacked with the hole transport layer, and the second surface 2172 of the metal oxide doped layer 217 is stacked with the N-type emitter 215.

[0144] In existing perovskite / P-type PERC tandem solar cells, a total charge transport layer (TCO) is typically fabricated on the N-type emitter as the composite layer, with inorganic materials such as MoOx, NiOx, and Cu2O used as the hole transport layer. When fabricating the TCO as the composite layer, materials such as BZO, AZO, ITO, FTO, IWO, and IZO can be selected. Most TCO materials can be fabricated using methods such as magnetron sputtering or reactive plasma deposition. The conduction band of a-Si:H(n+) is approximately -3.7 eV, while the HOMO energy level of the hole transport layer in inorganic materials is approximately -5.3 eV. The work function of TCO materials is generally between -4.0 and -5 eV, falling between -3.7 eV and -5.3 eV, which allows for charge transport. However, the conduction band of a single TCO material is a fixed value, and charge tends to accumulate at the interface during transport, leading to recombination losses and affecting the cell's electrical performance. In this application, the work function of the first surface 2171 of the metal oxide doped layer 217 is consistent with the HOMO energy level of the hole transport layer, and the work function of the second surface 2172 of the metal oxide doped layer 217 is consistent with the conduction band of the N-type emitter 215. Therefore, charge can be transported smoothly between the hole transport layer and the N-type emitter 215 without accumulating at the interface, thereby improving the conversion efficiency of the solar cell. As a result, the performance of the solar cell is better.

[0145] This application provides a method for preparing a solar cell, comprising the following steps:

[0146] Step 1: Provide the lower-level battery;

[0147] Step 2: Prepare the metal oxide doped layer 217;

[0148] Step 3: Provide the upper battery layer;

[0149] Specifically, the metal oxide doped layer 217 is prepared on the surface of the lower battery, and the upper battery is prepared on the surface of the metal oxide doped layer 217 away from the lower battery. The surface of the metal oxide doped layer 217 that is in contact with the lower battery is the second surface 2172, and the surface that is in contact with the upper battery is the first surface 2171.

[0150] The work function of the metal oxide doped layer 217 gradually changes from its first surface 2171 to its second surface 2172.

[0151] The lower battery is a P-type PERC battery, and the specific preparation method is existing technology, which is not specifically limited in this application.

[0152] The upper battery is a perovskite battery, and the specific preparation method is existing technology, which is not specifically limited in this application.

[0153] The preparation method of the metal oxide doped layer 217 can refer to the preparation method of the aforementioned metal oxide doped layer 117.

[0154] Next is the perovskite / N-type PERT tandem solar cell.

[0155] like Figure 3 As shown, the perovskite / N-type PERT tandem solar cell of this application includes an upper cell, a metal oxide doped layer 317, and a lower cell stacked sequentially from top to bottom. The upper cell includes a front transparent conductive layer 324, a second carrier transport layer 323, a perovskite absorber layer 322, and a first carrier transport layer 321 stacked sequentially from top to bottom. The lower cell includes a boron-diffused P-type silicon layer 315, an N-type silicon substrate 314, a phosphorus-diffused back field layer 313, an aluminum oxide layer 312, and a silicon nitride layer 311 stacked sequentially from top to bottom.

[0156] The solar cell comprises, from top to bottom, a front transparent conductive layer 324, a second carrier transport layer 323, a perovskite absorber layer 322, a first carrier transport layer 321, a metal oxide doped layer 317, a boron-diffused P-type silicon layer 315, an N-type silicon substrate 314, a phosphorus-diffused back field layer 313, an aluminum oxide layer 312, and a silicon nitride layer 311. A metal electrode 331 is disposed on the surface of the front transparent conductive layer 324 facing away from the second carrier transport layer 323, and a metal electrode 331 is disposed on the surface of the silicon nitride layer 311 facing away from the aluminum oxide layer 312.

[0157] The front transparent conductive layer 324 may be an ITO layer, an IWO layer, an IZO layer, an ITiO layer, etc., including but not limited to these.

[0158] The second carrier transport layer 323 is a hole transport layer, which can be a molybdenum oxide layer, a [bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) layer, a copper iodide layer, or a Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) layer, a PEDOT layer, a PEDOT:PSS layer, a P3HT layer, a P3OHT layer, a P3ODDT layer, a NiOx layer, or a CuSCN layer.

[0159] The first carrier transport layer 321 is an electron transport layer, which may be a titanium oxide layer, a tin oxide layer, a C60 layer or a C60-PCBM layer, or

[60] PCBM([6,6]-phenyl-C 61 butyric acid methyl ester, Chinese name [6,6]-phenyl-C 61 -Isomethyl butyrate) layer,

[70] PCBM([6,6]-Phenyl-C 71 -butyric acidmethyl ester, Chinese name is [6,6]-phenyl-C 71 - Isomethyl butyrate) layer, bis

[60] PCBM(Bis(1-[3-(methoxycarbonyl)propyl]-1-phenyl)-[6,6]C 62 ) layer,

[60] ICBA(1',1",4',4"-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2",3"][5,6]full erene-C 60 Layers, etc., including but not limited to these, as long as they can achieve the functions in this application.

[0160] The perovskite absorber layer 32-2 can be an organic-inorganic hybrid halide perovskite layer, a fully inorganic halide perovskite layer, a lead-free perovskite layer, etc., including but not limited to these. Its band gap is generally around 1.5-1.8 eV.

[0161] The metal oxide doped layer 317 is the aforementioned metal oxide doped layer 117.

[0162] The aluminum oxide layer is prepared by ALD.

[0163] The silicon nitride layer is prepared by PECVD and mainly serves to reduce the reaction.

[0164] The boron-diffused P-type silicon layer 315 can be prepared by a diffusion process.

[0165] In this application, the first surface 3171 of the metal oxide doped layer 317 is stacked with the electron transport layer, and the second surface 3172 of the metal oxide doped layer 317 is stacked with the boron-diffused P-type silicon layer 315.

[0166] In existing perovskite / PERT junction tandem solar cells, a total charge transport layer (TCO) is typically fabricated on a boron-diffused p-type silicon layer as the composite layer, with inorganic materials such as SnO2, TiO2, and ZnO used as the electron transport layer. When fabricating the TCO as the composite layer, materials such as BZO, AZO, ITO, FTO, IWO, and IZO can be selected, and most TCO materials can be prepared using methods such as magnetron sputtering or reactive plasma deposition. The valence band of the boron-diffused p-type silicon layer is approximately -5.0 eV, and the LUMO level of the inorganic material's electron transport layer is approximately -4.0 eV. The work function of the TCO material is generally between -4.1 and -5 eV, enabling charge transport. However, the conduction band of a single TCO material is a fixed value, and charge tends to accumulate at the interface during transport, leading to recombination losses and affecting the cell's electrical performance. In this application, the work function of the first surface 3171 of the metal oxide doped layer 317 is consistent with the LUMO energy level of the electron transport layer, and the work function of the second surface 3172 of the metal oxide doped layer 317 is consistent with the valence band of the boron-diffused p-type silicon layer 315. Therefore, charge can be transported smoothly between the electron transport layer and the boron-diffused p-type silicon layer 315 without accumulating at the interface, thereby improving the conversion efficiency of the solar cell. As a result, the performance of the solar cell is better.

[0167] This application provides a method for preparing a solar cell, comprising the following steps:

[0168] Step 1: Provide the lower-level battery;

[0169] Step 2: Fabrication of the 317 metal oxide doped layer

[0170] Step 3: Provide the upper battery layer;

[0171] Specifically, the metal oxide doped layer 317 is prepared on the surface of the lower battery, and the upper battery is prepared on the surface of the metal oxide doped layer 317 away from the lower battery. The surface of the metal oxide doped layer 317 that is in contact with the lower battery is the second surface 3172, and the surface that is in contact with the upper battery is the first surface 3171.

[0172] The work function of the metal oxide doped layer 317 gradually changes from its first surface 3171 to its second surface 3172. The preparation method of the metal oxide doped layer 317 can refer to the preparation method of the aforementioned metal oxide doped layer 117.

[0173] The lower battery is an N-type PERT battery, and the specific preparation method is existing technology, which is not specifically limited in this application.

[0174] The upper battery is a perovskite battery, and the specific preparation method is existing technology, which is not specifically limited in this application.

[0175] Example

[0176] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0177] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0178] Example 1

[0179] The solar cell described in this embodiment is a perovskite / silicon-based heterojunction tandem solar cell, comprising, from top to bottom, a front transparent conductive layer 124, a second carrier transport layer 123, a perovskite absorber layer 122, a first carrier transport layer 121, a metal oxide doped layer 117, an N-type amorphous silicon layer 116, a second intrinsic amorphous silicon layer 115, an N-type crystalline silicon substrate, a first intrinsic amorphous silicon layer 113, a P-type amorphous silicon layer 112, and a back transparent conductive layer 111. A metal electrode 131 is disposed on the surface of the front transparent conductive layer 124 facing away from the second carrier transport layer 123, and a metal electrode 131 is disposed on the surface of the back transparent conductive layer 111 facing away from the P-type amorphous silicon layer 112.

[0180] The front transparent conductive layer 124 is an ITO layer with a thickness of 100 nm.

[0181] The second carrier transport layer 123 is an electron transport layer, specifically a SnO2 / PCBM composite layer, wherein the thickness of the SnO2 layer is 20nm and the thickness of the PCBM layer is 10nm.

[0182] The perovskite absorber layer 122 is (Cs) 0.15 FA 0.85 )Pb(I 0.7 Br 0.3 It has 3 layers with a band gap of 1.6 eV and a thickness of 600 nm.

[0183] The first carrier transport layer 121 is a hole transport layer, specifically a NiOx layer with a thickness of 25 nm. The HOMO energy level is -5.1 eV.

[0184] The thickness of the N-type amorphous silicon layer 116 is 10 nm, and the conduction band is -3.7 eV.

[0185] The second intrinsic amorphous silicon layer 115 has a thickness of 5 nm.

[0186] The thickness of the N-type crystalline silicon substrate is 150 μm.

[0187] The thickness of the first intrinsic amorphous silicon layer 113 is 5 nm.

[0188] The thickness of the P-type amorphous silicon layer 112 is 10 nm.

[0189] The back transparent conductive layer 111 is an ITO layer with a thickness of 100 nm.

[0190] The metal oxide doped layer 117 is a boron-doped zinc oxide layer (BZO layer) with a thickness of 250 nm.

[0191] The specific method for preparing the metal oxide doped layer 117 is as follows:

[0192] Process settings: substrate temperature 150℃, carrier gas flow rate 100sccm, process pressure 25Pa.

[0193] First, a zinc oxide layer with a thickness of about 30 nm was deposited using two sources: diethylzinc and water, for 300 cycles.

[0194] A boron oxide layer was formed by depositing one cycle of water and diborane sources on one side of a zinc oxide layer with a thickness of 30 nm.

[0195] On the side of the boron oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 28 nm is formed by depositing 280 cycles using both diethylzinc and water sources.

[0196] A second boron oxide layer is formed by depositing a combination of water and diborane sources on the side of the 28 nm thick zinc oxide layer facing away from the boron oxide layer for one cycle.

[0197] On the side of the boron oxide layer facing away from the zinc oxide layer, 260 cycles of deposition were performed using both diethylzinc and water sources to form a zinc oxide layer with a thickness of approximately 26 nm.

[0198] A second boron oxide layer is formed by depositing a combination of water and diborane sources on the side of the 26 nm thick zinc oxide layer facing away from the boron oxide layer for one cycle.

[0199] On the side of the boron oxide layer facing away from the zinc oxide layer, the number of deposition cycles for diethylzinc and water sources is reduced sequentially, and then one deposition cycle is performed using water and diborane sources to form a boron oxide layer.

[0200] ···

[0201] On the side of the boron oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 2 nm is formed by 20 cycles of deposition using both diethylzinc and water sources.

[0202] A boron oxide layer is formed by depositing one cycle of water and diborane sources on the side of a 2 nm thick zinc oxide layer facing away from the boron oxide layer.

[0203] Ten cycles of deposition using diethylzinc and water were applied to the surface of the boron oxide layer on the side opposite to the zinc oxide layer to form a zinc oxide layer with a thickness of approximately 1 nm.

[0204] After the process is completed, the metal oxide doped layer 117 is obtained, wherein a zinc oxide layer with a thickness of 1 nm is the first surface 1171, and a zinc oxide layer with a thickness of 30 nm is the second surface 1172. In the metal oxide doped layer 117, the thickness of the zinc oxide layer gradually increases from the first surface 1171 to the second surface 1172, and the doping concentration of boron oxide diffused into the zinc oxide layer gradually decreases. Therefore, the work function of the metal oxide doped layer 117 gradually increases from the first surface 1171 to the second surface 1172. The work function of the first surface 1171 is approximately -4.7 eV, and the work function of the second surface 1172 is -3.8 eV. The work function of the first surface 1171 is optimally matched with the HOMO energy level of the first carrier transport layer 121, and the work function of the second surface 1172 is optimally matched with the N-type amorphous silicon layer 16. The performance of the solar cell is shown in Table 2.

[0205] Example 2

[0206] The solar cell in this embodiment differs from the solar cell in Example 1 in that it has a metal oxide doped layer 117.

[0207] In this embodiment, the metal oxide doped layer 117 is an aluminum-doped zinc oxide (AZO) layer with a thickness of 110 nm.

[0208] The specific method for preparing the metal oxide doped layer 117 is as follows:

[0209] Process settings: substrate temperature 100℃, carrier gas flow rate 100sccm, process pressure 25Pa.

[0210] First, a zinc oxide layer with a thickness of about 24 nm was deposited using two sources: diethylzinc and water, for 240 cycles.

[0211] An aluminum oxide layer was formed by depositing one cycle of water and trimethylaluminum as two sources on one side of a zinc oxide layer with a thickness of 24 nm.

[0212] On the side of the alumina layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 21 nm is deposited for 210 cycles using two sources: diethylzinc and water.

[0213] A second aluminum oxide layer is formed by depositing water and trimethylaluminum as two sources on the side of the zinc oxide layer with a thickness of 21 nm away from the aluminum oxide layer for one cycle.

[0214] On the side of the alumina layer opposite to the zinc oxide layer, 180 cycles of deposition using diethylzinc and water sources were performed to form a zinc oxide layer with a thickness of approximately 18 nm.

[0215] A second aluminum oxide layer is formed by depositing water and trimethylaluminum as two sources on the side of the zinc oxide layer that is 18 nm thick, away from the aluminum oxide layer, for one cycle.

[0216] On the side of the alumina layer facing away from the zinc oxide layer, the deposition cycle number of diethylzinc and water sources is reduced sequentially, and then one deposition cycle is performed using water and trimethylaluminum sources to form an alumina layer.

[0217] ···

[0218] On the side of the alumina layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 3 nm is formed by depositing 30 cycles using both diethylzinc and water sources.

[0219] An aluminum oxide layer is formed by depositing one cycle of water and trimethylaluminum on the side of a zinc oxide layer with a thickness of 3 nm away from the aluminum oxide layer.

[0220] Ten cycles of deposition using diethylzinc and water were applied to the surface of the alumina layer on the side opposite to the zinc oxide layer to form a zinc oxide layer with a thickness of approximately 1 nm.

[0221] After the process is completed, the metal oxide doped layer 117 is obtained, wherein a zinc oxide layer with a thickness of 1 nm is the first surface 1171, and a zinc oxide layer with a thickness of 24 nm is the second surface 1172. In the metal oxide doped layer 117, the thickness of the zinc oxide layer gradually increases from the first surface 1171 to the second surface 1172, and the doping concentration of aluminum oxide diffused into the zinc oxide layer gradually decreases. Therefore, the work function of the metal oxide doped layer 117 gradually increases from the first surface 1171 to the second surface 1172. The work function of the first surface 1171 is approximately -4.5 eV, and the work function of the second surface 1172 is -3.8 eV. The work function of the first surface 1171 is optimally matched with the HOMO energy level of the first carrier transport layer 121, and the work function of the second surface 1172 is optimally matched with the N-type amorphous silicon layer 16. The performance of the solar cell is shown in Table 2.

[0222] Example 3

[0223] The solar cell in this embodiment differs from the solar cell in Example 1 in that it has a metal oxide doped layer 117.

[0224] In this embodiment, the metal oxide doped layer 117 is a tin-doped zinc oxide (TZO) layer with a thickness of 200 nm.

[0225] The specific method for preparing the metal oxide doped layer 117 is as follows:

[0226] Process settings: substrate temperature 120℃, carrier gas flow rate 100sccm, process pressure 25Pa.

[0227] First, 200 cycles of deposition were performed using two sources: diethylzinc and water, to form a zinc oxide layer with a thickness of about 20 nm at the interface with the N-type amorphous silicon layer 16.

[0228] A tin oxide layer was formed by depositing one cycle of water and tetra(dimethylamino)tin sources on one side of a 20 nm thick zinc oxide layer.

[0229] On the side of the tin oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 19 nm is formed by depositing 190 cycles using both diethylzinc and water sources.

[0230] A tin oxide layer is formed by depositing a water and tetra(dimethylamino)tin source for one cycle on the side of the zinc oxide layer that is 19 nm thick away from the tin oxide layer.

[0231] On the side of the tin oxide layer opposite to the zinc oxide layer, 180 cycles of deposition using diethylzinc and water sources were performed to form a zinc oxide layer with a thickness of approximately 18 nm.

[0232] A tin oxide layer is formed by depositing a water and tetra(dimethylamino)tin source for one cycle on the side of the zinc oxide layer that is 18 nm thick away from the tin oxide layer.

[0233] On the side of the tin oxide layer opposite to the zinc oxide layer, the deposition cycles of diethylzinc and water sources are sequentially reduced, and then one cycle is deposited using water and tetra(dimethylamino)tin sources to form a tin oxide layer.

[0234] ···

[0235] On the side of the tin oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 2 nm is formed by 20 cycles of deposition using diethylzinc and water sources.

[0236] A tin oxide layer is formed by depositing one cycle of water and tetra(dimethylamino)tin sources on the side of the zinc oxide layer opposite to the tin oxide layer with a thickness of 2 nm.

[0237] Ten cycles of deposition using diethylzinc and water were applied to the surface of the tin oxide layer on the side opposite to the zinc oxide layer to form a zinc oxide layer with a thickness of approximately 1 nm.

[0238] A tin oxide layer is formed by depositing one cycle of water and tetra(dimethylamino)tin sources on the side of the zinc oxide layer opposite to the tin oxide layer with a thickness of 1 nm.

[0239] After the process is completed, the metal oxide doped layer 117 is obtained, wherein a 1 nm thick tin oxide layer is the first surface 1171, and a 20 nm thick zinc oxide layer is the second surface 1172. In the metal oxide doped layer 117, the thickness of the zinc oxide layer gradually increases from the first surface 1171 to the second surface 1172, and the doping concentration of tin oxide diffusing into the zinc oxide layer gradually decreases. Therefore, the work function of the metal oxide doped layer 117 gradually increases from the first surface 1171 to the second surface 1172. The work function of the first surface 1171 is approximately -4.2 eV, and the work function of the second surface 1172 is -3.8 eV. The work function of the first surface 1171 is optimally matched with the HOMO energy level of the first carrier transport layer 121, and the work function of the second surface 1172 is optimally matched with the N-type amorphous silicon layer 16. The performance of the solar cell is shown in Table 2.

[0240] Example 4

[0241] The solar cell in this embodiment is a perovskite / P-type PERC tandem solar cell, comprising, from top to bottom, a front transparent conductive layer 224, a second carrier transport layer 223, a perovskite absorber layer 222, a first carrier transport layer 221, a metal oxide doped layer 217, an N-type emitter 215, a P-type crystalline silicon substrate 214, an aluminum oxide layer 213, a silicon nitride layer 212, and an Al back field 211. A metal electrode 231 is disposed on the surface of the front transparent conductive layer 224 facing away from the second carrier transport layer 223, and a metal electrode 231 is disposed on the surface of the Al back field 211 facing away from the silicon nitride layer 212.

[0242] The front transparent conductive layer 224 is an ITO layer with a thickness of 100nm.

[0243] The second carrier transport layer 223 is an electron transport layer, specifically a SnO2 / PCBM composite layer, wherein the thickness of the SnO2 layer is 20nm and the thickness of the PCBM layer is 10nm.

[0244] The perovskite absorber layer is (Cs) 0.15 FA 0.85 )Pb(I 0.7 Br 0.3 It has 3 layers with a band gap of 1.6 eV and a thickness of 600 nm.

[0245] The first carrier transport layer 221 is a hole transport layer, specifically a NiOx layer with a thickness of 25 nm. The HOMO energy level is -5.1 eV.

[0246] The N-type emitter 215 is phosphorus diffused, with a thickness of 10 nm and a conduction band of -3.7 eV.

[0247] The thickness of the P-type crystalline silicon substrate 214 is 190 μm.

[0248] The thickness of the aluminum oxide layer 213 is 5 nm.

[0249] The thickness of the silicon nitride layer 212 is 20 nm.

[0250] The thickness of the Al back field 211 is 2 μm.

[0251] The metal oxide doped layer 217 in this embodiment is the same as the metal oxide doped layer 117 in Example 1. The specific preparation method is the same as that in Example 1.

[0252] The metal oxide doped layer 217 is a boron-doped zinc oxide layer (BZO layer) with a thickness of 250 nm.

[0253] The first surface 2171 of the metal oxide doped layer 217 is a zinc oxide layer with a thickness of 1 nm and a work function of approximately -4.7 eV. The second surface 2172 is a zinc oxide layer with a thickness of 30 nm and a work function of -3.8 eV. The work function gradually increases from the first surface 2171 to the second surface 2172 in the metal oxide doped layer 217. The work function of the first surface 2171 is optimally matched with the HOMO energy level of the first carrier transport layer, and the work function of the second surface 2172 is optimally matched with the N-type emitter. The performance of the solar cell is shown in Table 2.

[0254] Example 5

[0255] The solar cell in this embodiment differs from the solar cell in Embodiment 4 in that it has a metal oxide doped layer 217.

[0256] The metal oxide doped layer 217 in this embodiment is the same as the metal oxide doped layer 117 in Embodiment 2. For details, please refer to Embodiment 2.

[0257] The performance of the solar cell in this embodiment is shown in Table 2.

[0258] Example 6

[0259] The solar cell in this embodiment differs from the solar cell in Embodiment 4 in that it has a metal oxide doped layer 217.

[0260] The metal oxide doped layer 217 in this embodiment is the same as the metal oxide doped layer 117 in embodiment 3. For details, please refer to embodiment 3.

[0261] The performance of the solar cell in this embodiment is shown in Table 2.

[0262] Example 7

[0263] The solar cell described in this embodiment is a perovskite / N-type PERT tandem solar cell, comprising, from top to bottom, a front transparent conductive layer 324, a second carrier transport layer 323, a perovskite absorber layer 322, a first carrier transport layer 321, a metal oxide doped layer 317, a boron-diffused P-type silicon layer 315, an N-type silicon substrate 314, a phosphorus-diffused back field layer 313, an aluminum oxide layer 312, and a silicon nitride layer 311. A metal electrode 331 is disposed on the surface of the front transparent conductive layer 324 facing away from the second carrier transport layer 323, and a metal electrode 331 is disposed on the surface of the silicon nitride layer 311 facing away from the aluminum oxide layer.

[0264] The front transparent conductive layer 324 is an ITO layer with a thickness of 100nm.

[0265] The second carrier transport layer 323 is a hole transport layer, specifically a Spiro-OMeTAD layer with a thickness of 100nm.

[0266] The perovskite absorber layer 322 is (Cs) 0.15 FA 0.85 )Pb(I 0.7 Br 0.3 It has 3 layers with a band gap of 1.6 eV and a thickness of 600 nm.

[0267] The first carrier transport layer 321 is an electron transport layer, specifically a TiO2 layer with a thickness of 30 nm and a LUMO energy level of -4.1 eV.

[0268] The boron-diffused P-type silicon layer 315 has a thickness of 10 nm and a conduction band of -4.9 eV.

[0269] The thickness of the N-type silicon substrate 314 is 170 μm.

[0270] The thickness of the phosphorus diffusion back field layer 313 is 10 nm.

[0271] The thickness of the aluminum oxide layer 312 is 5 nm.

[0272] The thickness of the silicon nitride layer 311 is 20 nm.

[0273] The metal oxide doped layer 317 is a boron-doped zinc oxide layer (BZO layer) with a thickness of 245 nm.

[0274] The specific method for preparing the metal oxide doped layer 317 is as follows:

[0275] Process settings: substrate temperature 150℃, carrier gas flow rate 100sccm, process pressure 25Pa.

[0276] First, a zinc oxide layer with a thickness of about 4 nm is deposited using two sources: diethylzinc and water, for 40 cycles.

[0277] A boron oxide layer was formed by depositing one cycle of water and diborane sources on one side of a zinc oxide layer with a thickness of 4 nm.

[0278] On the side of the boron oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of about 6 nm is formed by depositing 60 cycles using two sources: diethylzinc and water.

[0279] A second boron oxide layer is formed by depositing a combination of water and diborane sources on the side of the 6 nm thick zinc oxide layer facing away from the boron oxide layer for one cycle.

[0280] On the side of the boron oxide layer facing away from the zinc oxide layer, 80 cycles of deposition were performed using both diethylzinc and water sources to form a zinc oxide layer with a thickness of approximately 8 nm.

[0281] A second boron oxide layer is formed by depositing a zinc oxide layer with a thickness of 8 nm on the side of the zinc oxide layer facing away from the boron oxide layer using both water and diborane sources for one cycle.

[0282] ···

[0283] On the side of the boron oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 28 nm is formed by depositing 280 cycles using both diethylzinc and water sources.

[0284] A boron oxide layer was formed by depositing one cycle of water and diborane sources on the side of the zinc oxide layer with a thickness of 28 nm away from the boron oxide layer.

[0285] On the side of the boron oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 30 nm is formed by depositing 300 cycles using both diethylzinc and water sources.

[0286] After the process is completed, the metal oxide doped layer 317 is obtained, wherein a zinc oxide layer with a thickness of 30 nm is the first surface 3171, and a zinc oxide layer with a thickness of 4 nm is the second surface 3172. In the metal oxide doped layer 317, the thickness of the zinc oxide layer gradually decreases from the first surface 3171 to the second surface 3172, and the doping concentration of boron oxide diffused into the zinc oxide layer gradually increases. Therefore, the work function of the metal oxide doped layer 317 gradually decreases from the first surface 3171 to the second surface 3172. The work function of the first surface 3171 is approximately -4.1 eV, and the work function of the second surface 3172 is -4.7 eV. The work function of the first surface 3171 forms an optimal match with the LUMO energy level of the electron transport layer, and the work function of the second surface 3172 forms an optimal match with the boron-diffused p-type silicon layer 315. The performance of the solar cell is shown in Table 2.

[0287] Example 8

[0288] The solar cell in this embodiment differs from the solar cell in Embodiment 7 in that it has a metal oxide doped layer 317.

[0289] In this embodiment, the metal oxide doped layer 317 is an aluminum-doped zinc oxide (AZO) layer with a thickness of 105 nm.

[0290] The specific method for preparing the metal oxide doped layer 317 is as follows:

[0291] Process settings: substrate temperature 100℃, carrier gas flow rate 100sccm, process pressure 25Pa.

[0292] First, a zinc oxide layer with a thickness of about 4 nm is deposited using two sources: diethylzinc and water, for 40 cycles.

[0293] An aluminum oxide layer was formed by depositing one cycle of water and trimethylaluminum as two sources on one side of a zinc oxide layer with a thickness of 4 nm.

[0294] On the side of the alumina layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of about 6 nm is deposited for 60 cycles using two sources: diethylzinc and water.

[0295] A second aluminum oxide layer is formed by depositing water and trimethylaluminum as two sources on the side of the zinc oxide layer that is 6 nm thick, away from the aluminum oxide layer, for one cycle.

[0296] On the side of the alumina layer opposite to the zinc oxide layer, 80 cycles of deposition were performed using both diethylzinc and water sources to form a zinc oxide layer with a thickness of approximately 8 nm.

[0297] An aluminum oxide layer is formed by depositing a second layer of water and trimethylaluminum on the side of the zinc oxide layer that is 8 nm thick, away from the aluminum oxide layer.

[0298] ···

[0299] On the side of the alumina layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 22 nm is formed by depositing 220 cycles using both diethylzinc and water sources.

[0300] An aluminum oxide layer is formed by depositing one cycle of water and trimethylaluminum on the side of a zinc oxide layer with a thickness of 28 nm away from the aluminum oxide layer.

[0301] On the side of the alumina layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 24 nm is formed by depositing 240 cycles using both diethylzinc and water sources.

[0302] After the process is completed, the metal oxide doped layer 317 is obtained. A 24 nm thick zinc oxide layer forms the first surface 3171, and a 4 nm thick zinc oxide layer forms the second surface 3172. In the metal oxide doped layer 317, the thickness of the zinc oxide layer gradually decreases from the first surface 3171 to the second surface 3172, while the doping concentration of aluminum oxide diffused into the zinc oxide layer gradually increases. Therefore, the work function of the metal oxide doped layer 317 gradually decreases from the first surface 3171 to the second surface 3172. The work function of the first surface 3171 is approximately -4.1 eV, and the work function of the second surface 3172 is -4.7 eV. The work function of the first surface 3171 is optimally matched with the LUMO energy level of the electron transport layer, and the work function of the second surface 3172 is optimally matched with the boron-diffused p-type silicon layer 315. The performance of the solar cell is shown in Table 2.

[0303] Example 9

[0304] The solar cell in this embodiment differs from the solar cell in Embodiment 7 in that it has a metal oxide doped layer 317.

[0305] In this embodiment, the metal oxide doped layer 317 is a tin-doped zinc oxide (TZO) layer with a thickness of 200 nm.

[0306] The specific method for preparing the metal oxide-doped intermediate composite layer 17 is as follows:

[0307] Process settings: substrate temperature 120℃, carrier gas flow rate 100sccm, process pressure 25Pa.

[0308] First, a zinc oxide layer with a thickness of about 1 nm is deposited using two sources: diethylzinc and water, for 10 cycles.

[0309] A tin oxide layer was formed by depositing one cycle of water and tetra(dimethylamino)tin sources on one side of a zinc oxide layer with a thickness of 1 nm.

[0310] On the side of the tin oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of about 2 nm is deposited for 20 cycles using two sources: diethylzinc and water.

[0311] A tin oxide layer is formed by depositing a water and tetra(dimethylamino)tin source for one cycle on the side of the zinc oxide layer that is 2 nm thick away from the tin oxide layer.

[0312] On the side of the tin oxide layer opposite to the zinc oxide layer, 30 cycles of deposition using diethylzinc and water sources were performed to form a zinc oxide layer with a thickness of approximately 3 nm.

[0313] A tin oxide layer is formed by depositing a water and tetra(dimethylamino)tin source for one cycle on the side of the zinc oxide layer that is 4 nm thick away from the tin oxide layer.

[0314] On the side of the tin oxide layer opposite to the zinc oxide layer, 40 cycles of deposition were performed using both diethylzinc and water sources to form a zinc oxide layer with a thickness of approximately 4 nm.

[0315] A tin oxide layer is formed by depositing a 4 nm thick zinc oxide layer on the side of the zinc oxide layer facing away from the tin oxide layer using both water and tetrakis(dimethylamino)tin sources for one cycle.

[0316] ···

[0317] On the side of the tin oxide layer opposite to the zinc oxide layer, a zinc oxide layer with a thickness of approximately 19 nm is formed by depositing 190 cycles using both diethylzinc and water sources.

[0318] A tin oxide layer was formed by depositing one cycle of water and tetra(dimethylamino)tin sources on the side of the zinc oxide layer opposite to the tin oxide layer with a thickness of 19 nm.

[0319] On the side of the tin oxide layer opposite to the zinc oxide layer, 200 cycles of deposition using diethylzinc and water sources are applied to form a zinc oxide layer with a thickness of approximately 20 nm.

[0320] A tin oxide layer is formed by depositing one cycle of water and tetra(dimethylamino)tin sources on the side of the zinc oxide layer opposite to the tin oxide layer with a thickness of 1 nm.

[0321] After the process is completed, the metal oxide doped layer 317 is obtained, wherein a 1 nm thick tin oxide layer is the first surface 3171, and a 1 nm thick zinc oxide layer is the second surface 3172. In the metal oxide doped layer 317, the thickness of the zinc oxide layer gradually decreases from the first surface 3171 to the second surface 3172, and the doping concentration of tin oxide diffused into the zinc oxide layer gradually increases. Therefore, the work function of the metal oxide doped layer 317 gradually decreases from the first surface 3171 to the second surface 3172. The work function of the first surface 3171 is approximately -3.8 eV, and the work function of the second surface 3172 is -4.2 eV. The work function of the first surface 3171 forms an optimal match with the LUMO energy level of the electron transport layer, and the work function of the second surface 3172 forms an optimal match with the boron-diffused p-type silicon layer 315. The performance of the solar cell is shown in Table 2.

[0322] Comparative Example 1

[0323] The solar cell in Comparative Example 1 differs from the solar cell in Example 1 in that it has a metal oxide doping layer. In Comparative Example 1, the metal oxide doping layer is a uniformly doped boron-doped zinc oxide layer (BZO layer) with a doping degree of 3% and a thickness of 250 nm, as used in the prior art. The performance of the solar cell is shown in Table 2.

[0324] Comparative Example 2

[0325] The solar cell in Comparative Example 2 differs from the solar cell in Example 2 in that it has a metal oxide doping layer. In Comparative Example 2, the metal oxide doping layer is a uniformly doped aluminum-zinc oxide (AZO) layer with a doping degree of 5% and a thickness of 200 nm, as used in the prior art. The performance of the solar cell is shown in Table 2.

[0326] Comparative Example 3

[0327] The solar cell in Comparative Example 3 differs from the solar cell in Example 3 in that it has a metal oxide doping layer. In Comparative Example 3, the metal oxide doping layer is a uniformly doped tin-doped zinc oxide (TZO) layer with a doping degree of 10% and a thickness of 200 nm, as used in the prior art. The performance of the solar cell is shown in Table 2.

[0328] Comparative Example 4

[0329] The solar cell in Comparative Example 4 differs from the solar cell in Example 4 in that it has a metal oxide doping layer. In Comparative Example 4, the metal oxide doping layer is a uniformly doped boron-doped zinc oxide layer (BZO layer) with a doping degree of 3% and a thickness of 250 nm, as used in the prior art. The performance of the solar cell is shown in Table 2.

[0330] Comparative Example 5

[0331] The solar cell in Comparative Example 5 differs from the solar cell in Example 7 in that it has a metal oxide doping layer. In Comparative Example 5, the metal oxide doping layer is a uniformly doped boron-doped zinc oxide layer (BZO layer) with a doping degree of 3% and a thickness of 245 nm, as used in the prior art. The performance of the solar cell is shown in Table 2.

[0332] Table 1 lists the parameters for each embodiment and comparative example.

[0333]

[0334] Table 2 shows the performance parameters of the solar cells in each embodiment and comparative example.

[0335]

[0336] Summary: As shown in the table above, the metal oxide doped layer described in this application, as an intermediate layer between the upper and lower solar cells, allows for smooth charge transport between the hole transport layer of the upper solar cell and the N-type emitter of the lower solar cell, preventing charge accumulation at the interface. Therefore, it can improve the fill factor and energy conversion efficiency of the tandem solar cell, resulting in better performance of the solar cell.

[0337] Although the embodiments of this application have been described above in conjunction with the specific embodiments described, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art can make many other forms based on the teachings of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A solar cell, characterized in that, It includes an upper battery and a lower battery stacked together, with a metal oxide doped layer between the upper battery and the lower battery; The work function of the metal oxide doped layer gradually changes from a first surface on one side to a second surface on the other side. The upper battery has a first carrier transport layer, and the first surface of the metal oxide doped layer is stacked with the first carrier transport layer. The lower battery layer has an N-type silicon layer, the first carrier transport layer is a hole transport layer, and the second surface of the metal oxide doped layer is stacked with the N-type silicon layer. The work function of the metal oxide doped layer gradually increases from the first surface to the second surface. The lower battery has a P-type silicon layer, the first carrier transport layer is an electron transport layer, the second surface of the metal oxide doped layer is stacked with the P-type silicon layer, and the work function of the metal oxide doped layer gradually decreases from the first surface to the second surface. The solar cell is one of the following: perovskite / silicon heterojunction solar cell, perovskite / P-type PERC tandem solar cell, or perovskite / N-type PERT tandem solar cell.

2. The solar cell according to claim 1, characterized in that, The lower battery layer has an N-type silicon layer. The work function of the first surface of the metal oxide doped layer is consistent with the HOMO level of the hole transport layer. The work function of the second surface of the metal oxide doped layer is consistent with the conduction band of the N-type silicon layer.

3. The solar cell according to claim 1, characterized in that, The lower battery layer has a P-type silicon layer. The work function of the first surface of the metal oxide doped layer is consistent with the LUMO energy level of the electron transport layer. The work function of the second surface of the metal oxide doped layer is consistent with the valence band of the p-type silicon layer.

4. The solar cell according to any one of claims 1-3, characterized in that, The metal oxide doped layer includes at least one metal oxide layer and at least one doped layer stacked together.

5. The solar cell according to claim 4, characterized in that, The metal oxide doped layer includes n metal oxide layers and m doped layers stacked together, where n and m are integers greater than 1; The metal oxide layer and the doped layer are cross-stacked, and at the junction of the metal oxide layer and the doped layer, a portion of the material of the doped layer diffuses into the metal oxide layer.

6. The solar cell according to claim 5, characterized in that, The work function of the metal oxide doped layer is adjusted by modifying its structure and material, thereby altering the gradual change from the first surface to the second surface.

7. The solar cell according to claim 6, characterized in that, Adjusting the structure and material of the metal oxide doped layer includes adjusting any one or more of the following: the thickness of the metal oxide layer, the thickness of the doped layer, the material of the metal oxide layer, the material of the doped layer, and the arrangement order of the metal oxide layer and the doped layer.

8. The solar cell according to claim 7, characterized in that, The thickness of the metal oxide layer in layer n gradually changes; the thickness of the doped layer in layer m is the same.

9. The solar cell according to claim 8, characterized in that, The thickness of the metal oxide layer gradually increases or decreases, and the work function of the metal oxide doped layer also gradually increases or decreases.

10. A method for preparing a solar cell, characterized in that, Includes the following steps: Provides a lower-level battery; Preparation of metal oxide doped layers; Provide upper-layer batteries; The work function of the metal oxide doped layer gradually changes from the first surface on one side to the second surface on the other side. The solar cell is the solar cell according to any one of claims 1-9.

Images