WO2024217475A1 - 太阳能电池 - Google Patents

太阳能电池 Download PDF

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Publication number
WO2024217475A1
WO2024217475A1 PCT/CN2024/088443 CN2024088443W WO2024217475A1 WO 2024217475 A1 WO2024217475 A1 WO 2024217475A1 CN 2024088443 W CN2024088443 W CN 2024088443W WO 2024217475 A1 WO2024217475 A1 WO 2024217475A1
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layer
oxide layer
solar cell
oxide
metal oxide
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PCT/CN2024/088443
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English (en)
French (fr)
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王静
吴兆
解俊杰
林宏
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Longi Green Energy Technology Co Ltd
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Longi Green Energy Technology Co Ltd
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Priority claimed from CN202310411689.6A external-priority patent/CN118507559A/zh
Priority claimed from CN202310444710.2A external-priority patent/CN118507539A/zh
Application filed by Longi Green Energy Technology Co Ltd filed Critical Longi Green Energy Technology Co Ltd
Publication of WO2024217475A1 publication Critical patent/WO2024217475A1/zh
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/10—Semiconductor bodies
    • H10F77/12—Active materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/10—Semiconductor bodies
    • H10F77/14—Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies

Definitions

  • the present application belongs to the technical field of solar cells, and in particular, relates to a solar cell.
  • the current tunneling oxide passivated contact (TOPCon) cell front structure still uses the same structure as the emitter rear passivation (PERC) cell.
  • This structure has direct contact between the metal grid and the silicon absorption layer, resulting in a relatively high surface recombination rate on the front surface of the cell, limiting the further improvement of TOPCon cell efficiency.
  • POLO structure can improve the above problems, but the introduction of doped polysilicon transmission layer on the front of crystalline silicon cells will bring strong parasitic absorption, which also limits the improvement of cell efficiency.
  • many studies use wide bandgap materials as passivation contact layers, generally using low temperature processes and a complete silicon oxide layer as the passivation layer, which makes the interface contact resistance large and the efficiency loss serious, or use amorphous silicon passivation, resulting in serious light parasitic absorption loss.
  • HJT Current heterojunction
  • the present application provides a solar cell having a wide bandgap oxide structure on the front surface.
  • this application involves the following aspects:
  • a solar cell comprising a crystalline silicon absorption layer and a receiving The first silicon oxide layer, the first wide bandgap metal oxide layer, the first protective layer and the front surface electrode are sequentially stacked on the optical surface.
  • the first wide bandgap metal oxide layer is formed of doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer diffuse into the crystalline silicon absorption layer through the first silicon oxide layer to form a first doped region.
  • the thickness of the first silicon oxide layer is 0.5-4 nm.
  • the thickness of the first silicon oxide layer is less than or equal to 20 atomic layers, and preferably, the thickness of the first silicon oxide layer is less than or equal to 8 atomic layers.
  • the first silicon oxide layer has pores formed by calcination.
  • the first wide bandgap metal oxide layer comprises a first zinc oxide layer and a second zinc oxide layer, the first zinc oxide layer has a thickness of 3-10 nm, and the second zinc oxide layer has a thickness of 10-200 nm;
  • the second zinc oxide layer is a doped zinc oxide layer, and the doping concentration of the second zinc oxide layer is greater than the doping concentration of the first zinc oxide layer;
  • the sheet resistance of the second zinc oxide layer is smaller than the sheet resistance of the first zinc oxide layer.
  • the second zinc oxide layer has a columnar crystal structure.
  • a front surface anti-reflection layer is further provided on a side of the second zinc oxide layer away from the crystalline silicon absorption layer, and the front surface electrode penetrates the front surface anti-reflection layer and contacts the second zinc oxide layer.
  • the polycrystallization degree of the first wide bandgap metal oxide layer increases gradually from a side close to the first oxide layer to a side far from the first oxide layer.
  • the material of the first protective layer is selected from one or more of silicon nitride, titanium oxide, zinc sulfide, aluminum oxide, aluminum nitride, silicon oxide, and the like.
  • the thickness of the first protective layer is 10-100 nm.
  • the front surface electrode penetrates the first protective layer and contacts the first wide bandgap metal oxide layer.
  • a front surface anti-reflection layer is further provided on a side of the first protective layer away from the crystalline silicon absorption layer, and the front surface electrode penetrates the front surface anti-reflection layer and the first protective layer and contacts the first wide bandgap metal oxide layer.
  • the solar cell further comprises a second silicon oxide layer, a second wide bandgap metal oxide layer, a second protective layer and a back surface electrode stacked in sequence on the backlight side of the crystalline silicon absorption layer, wherein the back surface electrode penetrates the second protective layer and contacts the second wide bandgap metal oxide layer.
  • the second wide band gap metal oxide layer is formed of doped metal oxide, and the doped elements in the second wide band gap metal oxide layer diffuse into the crystalline silicon absorption layer through the second silicon oxide layer to form a second doped region.
  • the second wide band gap metal oxide layer and the first wide band gap metal oxide layer have opposite charge transport properties.
  • the second silicon oxide layer has a thickness of 0.5-4 nm.
  • the second silicon oxide layer has pores formed by calcination.
  • the metal oxide used in the first wide band gap metal oxide layer or the second wide band gap metal oxide layer is selected from one or more of zinc oxide, tin oxide, molybdenum oxide, titanium oxide, nickel oxide, gallium oxide, indium oxide, copper oxide, magnesium oxide, aluminum oxide, tungsten oxide, cerium oxide, manganese oxide, vanadium oxide, chromium oxide, cobalt oxide, germanium oxide, cadmium oxide, rhenium oxide, etc.
  • the thickness of the first wide band gap metal oxide layer or the second wide band gap metal oxide layer is 10-200 nm.
  • the polycrystallization degree of the second wide band gap metal oxide layer increases gradually from a side close to the second oxide layer to a side far from the second oxide layer.
  • the material of the second protective layer is selected from silicon nitride or aluminum nitride.
  • the thickness of the second protective layer is 10-100 nm.
  • a back anti-reflection layer is further provided on a side of the second protective layer away from the crystalline silicon absorption layer, and the back surface electrode penetrates the back anti-reflection layer and the second protective layer and contacts the second wide bandgap metal oxide layer.
  • FIG1 is a schematic structural diagram of a solar cell according to an embodiment of the present application.
  • FIG2 is a schematic structural diagram of a solar cell according to another embodiment of the present application.
  • FIG3 is a schematic structural diagram of a solar cell according to another embodiment of the present application.
  • FIG4 is a schematic structural diagram of a solar cell according to another embodiment of the present application.
  • FIG5 is a schematic structural diagram of a solar cell according to an embodiment of the present application.
  • FIG6 is a schematic structural diagram of a solar cell according to another embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of a solar cell according to another embodiment of the present application.
  • Figures 1 to 4 1 crystalline silicon absorption layer, 21 first silicon oxide layer, 22 first wide bandgap metal oxide layer, 23 first protective layer, 24 first doped region, 31 back passivation layer, 32 back anti-reflection layer; 4 front surface electrode, 5 back surface electrode, 61 back tunneling passivation layer, 62 first back transmission layer, 63 back anti-reflection layer, 71 amorphous silicon passivation layer, 72 second back transmission layer, 73 third back transmission layer, 81 second silicon oxide layer, 82 second wide bandgap metal oxide layer, 83 second protective layer, 84 second doped region;
  • the present application provides a solar cell, as shown in FIGS. 1 to 4 , comprising a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the first wide bandgap metal oxide layer 22 is formed of a doped metal oxide, and the doped element in the first wide bandgap metal oxide layer 22 diffuses into the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the first silicon oxide layer 21 is formed of silicon oxide and plays a role of chemical passivation.
  • the thickness of the first silicon oxide layer 21 is 0.5-4nm, for example, it can be 0.5nm, 1nm, 1.5nm, 2nm, 2.5nm, 3nm, 3.5nm, 4nm, or any range between these values.
  • the ultra-thin structure of the first silicon oxide layer 21 has two main functions: 1. It plays a chemical passivation role on the crystalline silicon surface and reduces surface recombination; 2. It plays a tunneling role in charge transfer, which is beneficial to charge transfer and improves battery efficiency.
  • the first silicon oxide layer 21 has holes formed by calcination. The existence of the holes allows the doped elements in the first wide bandgap metal oxide layer 22 to diffuse into the crystalline silicon absorption layer 1 to form the first doped region 24 .
  • the first wide bandgap metal oxide layer 22 covers the first silicon oxide layer 21, that is, on the side of the first silicon oxide layer 21 away from the crystalline silicon absorption layer 1.
  • the first wide bandgap metal oxide layer 22 plays the role of field effect, selective contact and carrier transport.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxides, and the dopants that can be doped are commonly used dopants known in the art, such as aluminum, gallium, indium and other elements, and trace transition metal elements or rare earth elements, such as nickel, copper, lanthanum, iridium, actinium and the like.
  • the wide bandgap material in the first wide bandgap metal oxide layer 22 can reduce the optical parasitic absorption caused by doped amorphous silicon and TCO. If this structure is used on the front surface of PERC and TOPCon cells, the interface contact between the electrode and crystalline silicon can be optimized to reduce contact recombination.
  • the metal oxide used in the first wide bandgap metal oxide layer 22 is selected from one or more of zinc oxide, tin oxide, molybdenum oxide, titanium oxide, nickel oxide, gallium oxide, indium oxide, copper oxide, magnesium oxide, aluminum oxide, tungsten oxide, cerium oxide, manganese oxide, vanadium oxide, chromium oxide, cobalt oxide, germanium oxide, cadmium oxide, rhenium oxide, etc.
  • the thickness of the first wide bandgap metal oxide layer 22 is 10-200 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, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, or any range between these values.
  • the polycrystallization degree of the first wide bandgap metal oxide layer 22 increases gradually from a side close to the first oxide layer 21 to a side far from the first oxide layer 21 (ie, a side close to the first protective layer 23 ).
  • the first wide band gap metal oxide layer 22 gradually transitions from an amorphous structure to a polycrystalline structure from a side close to the first oxide layer 21 to a side far from the first oxide layer 21 .
  • the material of the first protective layer 23 can be selected from one or more of silicon nitride, titanium oxide, zinc sulfide, aluminum oxide, aluminum nitride, etc., which plays a stabilizing and anti-reflection function.
  • the first protective layer 23 includes dopant components, such as aluminum, gallium, indium, etc., and trace amounts of transition metal elements or rare earth elements, such as nickel, copper, lanthanum, iridium, actinium, etc.
  • the thickness of the first protective layer 23 is 10-100 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or any range between these values.
  • the first doping region 24 is a region formed by diffusion of elements doped in the first wide bandgap metal oxide layer 22 to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21, and extends from a side of the first wide bandgap metal oxide layer 22 close to the crystalline silicon absorption layer 1 to the crystalline silicon absorption layer 1.
  • the first doping region 24 can optimize the interface resistance, passivate the crystalline silicon, and reduce interface recombination.
  • the crystalline silicon absorption layer 1 can be an n-type or p-type silicon wafer known in the art, with a thickness of 60-150 ⁇ m. ⁇ m.
  • the front surface electrode 4 is disposed on the light-receiving surface of the solar cell and penetrates through the first protective layer 23 to contact the first wide bandgap metal oxide layer 22 .
  • a front surface anti-reflection layer may be provided on the side of the wide bandgap metal oxide layer 22 away from the crystalline silicon absorption layer 1 , and the front surface electrode 4 penetrates the front surface anti-reflection layer and the first protective layer 23 and contacts the wide bandgap metal oxide layer 22 .
  • the solar cell of the present application may be any type of solar cell including the above structure on the light-receiving surface, for example, an emitter back passivation cell, a tunnel oxide layer passivation contact cell, a heterojunction cell, etc. Those skilled in the art may select the corresponding backlight surface structure according to different types of solar cells.
  • the solar cell structure is shown in FIG1 , and the solar cell is an emitter back passivation cell.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with a back passivation layer 31, a back anti-reflection layer 32 and a back surface electrode 5 on the back light side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back passivation layer 31 and the back anti-reflection layer 32 and contacts the crystalline silicon absorption layer 1.
  • the back passivation layer 31 may be a single layer of aluminum oxide or a stacked structure of aluminum oxide and silicon oxide.
  • the solar cell structure is shown in FIG1 , and the solar cell is an emitter back passivation cell.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 which are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse into the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the first silicon oxide layer 21 has a thickness of 0.5-4 nm and has pores formed by calcination; the first wide bandgap metal ... a first doping region 24.
  • the metal oxide used in the layer 22 is selected from one or more of zinc oxide, tin oxide, molybdenum oxide, titanium oxide, nickel oxide, gallium oxide, indium oxide, copper oxide, magnesium oxide, aluminum oxide, tungsten oxide, cerium oxide, manganese oxide, vanadium oxide, chromium oxide, cobalt oxide, germanium oxide, cadmium oxide, rhenium oxide, etc., with a thickness of 10-200nm.
  • the polycrystallization degree of the first wide bandgap metal oxide layer 22 increases from the side close to the first oxide layer 21 to the side away from the first oxide layer 21; the material of the first protective layer 23 is selected from silicon nitride or aluminum nitride, with a thickness of 10-100nm.
  • the solar cell is sequentially stacked with a back passivation layer 31, a back anti-reflection layer 32 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back passivation layer 31 and the back anti-reflection layer 32 and contacts the crystalline silicon absorption layer 1.
  • the solar cell structure is shown in FIG2 , and the solar cell is a tunneling oxide layer passivation contact cell.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with a back tunneling passivation layer 61, a first back transmission layer 62 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1.
  • the back tunneling passivation layer 61 is a silicon oxide layer.
  • the first back transmission layer 62 is a p-type doped polysilicon layer.
  • a back anti-reflection layer 63 is further provided on the side of the first back transmission layer 62 away from the crystalline silicon absorption layer 1 , and the back surface electrode 5 penetrates the back anti-reflection layer 63 and contacts the first back transmission layer 62 .
  • the solar cell structure is shown in FIG2 , and the solar cell is a tunneling oxide layer passivation contact cell.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxides, and the doped elements in the first wide bandgap metal oxide layer 22 are connected to the first wide bandgap metal oxide layer 22.
  • the first doping region 24 is formed by diffusion through the first silicon oxide layer 21 to the crystalline silicon absorption layer 1.
  • the thickness of the first silicon oxide layer 21 is 0.5-4nm, and has holes formed by calcination;
  • the metal oxide used in the first wide bandgap metal oxide layer 22 is selected from one or more of zinc oxide, tin oxide, molybdenum oxide, titanium oxide, nickel oxide, gallium oxide, indium oxide, copper oxide, magnesium oxide, aluminum oxide, tungsten oxide, cerium oxide, manganese oxide, vanadium oxide, chromium oxide, cobalt oxide, germanium oxide, cadmium oxide, rhenium oxide, etc., with a thickness of 10-200nm, and the polycrystallization degree of the first wide bandgap metal oxide layer 22 increases from the side close to the first oxide layer 21 to the side away from the first oxide layer 21;
  • the material of the first protective layer 23 is selected from silicon nitride or aluminum nitride, with a thickness of 10-100nm
  • the solar cell has a back tunneling passivation layer 61 , a first back transmission layer 62 , a back anti-reflection layer and a back surface electrode 5 stacked in sequence on the backlight side of the crystalline silicon absorption layer 1 .
  • the back surface electrode 5 penetrates the back anti-reflection layer and contacts the first back transmission layer 62 .
  • the solar cell structure is shown in FIG3 , and the solar cell is a heterojunction cell.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with an amorphous silicon passivation layer 71, a second back transmission layer 72, a third back transmission layer 73 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1.
  • the amorphous silicon passivation layer 71 is formed of amorphous silicon
  • the second back transmission layer 72 is formed of p-type doped amorphous silicon
  • the third back transmission layer 73 can be a silver electrode.
  • a back anti-reflection layer is further provided on the side of the third back transmission layer 73 away from the crystalline silicon absorption layer 1 , and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the third back transmission layer 73 .
  • the solar cell structure is shown in FIG3 , and the solar cell is a heterojunction cell.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 stacked in sequence on the light receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is in contact with the bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxides, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doped region 24.
  • the first silicon oxide layer 21 has a thickness of 0.5-4nm and has pores formed by calcination;
  • the metal oxide used in the first wide bandgap metal oxide layer 22 is selected from one or more of zinc oxide, tin oxide, molybdenum oxide, titanium oxide, nickel oxide, gallium oxide, indium oxide, copper oxide, magnesium oxide, aluminum oxide, tungsten oxide, cerium oxide, manganese oxide, vanadium oxide, chromium oxide, cobalt oxide, germanium oxide, cadmium oxide, rhenium oxide, etc., with a thickness of 10-200nm, and the polycrystallization degree of the first wide bandgap metal oxide layer 22 increases from the side close to the first oxide layer 21 to the side away from the first oxide layer 21;
  • the material of the first protective layer 23 is selected from silicon nitride or aluminum nitride, with a thickness of 10-100nm.
  • the solar cell is provided with an amorphous silicon passivation layer 71, a second back transmission layer 72, a third back transmission layer 73, a back anti-reflection layer and a back surface electrode 5 stacked in sequence on the backlight side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the third back transmission layer 73.
  • the solar cell structure is shown in FIG4 , and the solar cell is a double-sided wide bandgap oxide tunneling structure.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with a second silicon oxide layer 81, a second wide bandgap metal oxide layer 82, a second protective layer 83 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the second protective layer 83 and contacts the second wide bandgap metal oxide layer 82.
  • the second wide bandgap metal oxide layer 82 is formed of doped metal oxide, and the doped elements in the second wide bandgap metal oxide layer 82 diffuse to the crystalline silicon absorption layer 1 through the second silicon oxide layer 81 to form a second doped region 84.
  • the second wide bandgap metal oxide layer 82 and the first wide bandgap metal oxide layer 22 have opposite charge transport properties.
  • the function, material, thickness range, and morphology of the second silicon oxide layer 81 are the same as those of the first silicon oxide layer 21.
  • the function, material, thickness range, and polycrystalline of the second wide bandgap metal oxide layer 82 are The degree of the second wide band gap metal oxide layer 82 is the same as that of the first wide band gap metal oxide layer 22.
  • the function, material, and thickness range of the second protective layer 83 are the same as those of the first protective layer 83.
  • the function and selection of doping elements of the second doping region 84 are the same as those of the first doping region 24.
  • the charge transport properties of the second wide band gap metal oxide layer 82 and the first wide band gap metal oxide layer 22 are opposite, which means that if the first wide band gap metal oxide layer 22 is an electron selective contact layer, the second wide band gap metal oxide layer 82 is a hole selective contact layer; if the first wide band gap metal oxide layer 22 is a hole selective contact layer, the second wide band gap metal oxide layer 82 is an electron selective contact layer.
  • the solar cell structure is shown in FIG4 , and the solar cell is a double-sided wide bandgap oxide tunneling structure.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with a second silicon oxide layer 81, a second wide bandgap metal oxide layer 82, a second protective layer 83 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the second protective layer 83 and contacts the second wide bandgap metal oxide layer 82.
  • the second wide bandgap metal oxide layer 82 is formed by doped metal oxide, and the doped elements in the second wide bandgap metal oxide layer 82 diffuse to the crystalline silicon absorption layer 1 through the second silicon oxide layer 81 to form a second doped region 84.
  • the second wide bandgap metal oxide layer 82 has opposite charge transport properties to the first wide bandgap metal oxide layer 22.
  • the first silicon oxide layer 21 and the second oxide layer 81 have a thickness of 0.5-4 nm and have pores formed by calcination;
  • the metal oxide used in the first wide bandgap metal oxide layer 22 and the second wide bandgap metal oxide layer 82 is selected from one or more of zinc oxide, tin oxide, molybdenum oxide, titanium oxide, nickel oxide, gallium oxide, indium oxide, copper oxide, magnesium oxide, aluminum oxide, tungsten oxide, cerium oxide, manganese oxide, vanadium oxide, chromium oxide, cobalt oxide, germanium oxide, cadmium oxide, rhenium oxide, etc., with a thickness of 10-200 nm;
  • the material of the first protective layer 23 and the second protective layer 83 is selected from silicon nitride or aluminum nitride, with a thickness of 10-100 nm.
  • the structure of a solar cell is shown in FIG1 , and the solar cell is an emitter back passivation cell.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 which are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with a back passivation layer 31, a back anti-reflection layer 32 and a back surface electrode 5 on the back light side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back passivation layer 31 and the back anti-reflection layer 32 and contacts the crystalline silicon absorption layer 1.
  • the preparation steps of solar cells are as follows:
  • the sample substrate was a single-crystal silicon wafer (n-type) with a velvet surface on the front.
  • the substrate was cleaned using the standard RCA (Radio Corporation of America) cleaning process, then repeatedly rinsed with deionized water and blown dry with nitrogen for later use.
  • the SiO2 passivation layer 21 is oxidized on the front surface of the silicon wafer by thermal oxidation method, and its thickness is about 1.7nm. 3. Preparation of zinc oxide film
  • the ALD method was used to prepare a phosphorus-doped zinc oxide film 22 with a thickness of about 40 nm at a temperature of 160 degrees Celsius.
  • the gas sources used were diethyl zinc, deionized water, and diborane.
  • the cycle steps were: diethyl zinc pulse 0.1 second, nitrogen purge 10 seconds, deionized water pulse 0.1 second, nitrogen purge 10 seconds.
  • diborane was introduced into the reaction chamber light, and its cycle ratio with diethyl zinc was 1:2.
  • a 60 nm thick silicon nitride layer 23 is deposited on the layer 22 to form a silicon nitride capping layer on the front side of the silicon wafer.
  • a 15 nm thick aluminum oxide layer 31 is first deposited on the back of the silicon wafer by PECVD; and an 80 nm thick silicon nitride layer 32 is deposited thereon to form an aluminum oxide/silicon nitride stacked passivation film on the back of the silicon wafer.
  • a pulsed laser is used to make grooves on the front side of the silicon wafer, partially breaking through the silicon nitride film layer 23 to expose layer 22, and the metal electrode contacts layer 22 through the grooves on the film.
  • a laser is used on the back side to partially break through the aluminum oxide film layer to expose layer 1 of the silicon body region, and the metal electrode contacts layer 1 through the grooves on the film.
  • the back silver electrode, back aluminum paste, and front silver electrode are screen printed and dried, and finally the silicon wafer is sent to the sintering furnace for sintering and calcined at 930°C. During this process, the doped elements in the 22 layers will diffuse through the 21 layers to the 1 layer to form the 24 layers, completing the preparation of the solar cell.
  • the structure of a solar cell is shown in FIG2 , and the solar cell is a tunneling oxide layer passivation contact cell.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 which are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with a back tunneling passivation layer 61, a first back transmission layer 62, a back anti-reflection layer 63 and a back surface electrode 5 on the backlight surface of the crystalline silicon absorption layer 1.
  • the preparation steps of solar cells are as follows:
  • the sample substrate was a single-crystal silicon wafer (p-type) with a velvet surface on the front.
  • the substrate was cleaned using the standard RCA (Radio Corporation of America) cleaning process, then repeatedly rinsed with deionized water and blown dry with nitrogen for later use.
  • the SiO 2 tunnel passivation layers 21 and 61 are oxidized on the front and rear surfaces of the silicon wafer by using an ultraviolet ozone oxidation method, and the thickness of the layers is 1.8 nm.
  • a boron-doped nickel oxide film 22 with a thickness of about 35 nm was prepared by ALD at a temperature of 150 degrees Celsius, wherein the nickel, boron and oxygen sources used were bis-(N,N'-di-tert-butylacetamido)nickel (II), Diborane/hydrogen mixture, deionized water, cycle steps: bis-(N,N'-di-tert-butylacetamido)nickel(II) pulse 0.1 second, nitrogen purge 10 seconds, deionized water pulse 0.1 second, nitrogen purge 10 seconds.
  • hexahydroborane/hydrogen mixture enters the reaction chamber, and its circulation ratio with bis-(N,N'-di-tert-butylacetamido)nickel(II) is 1:3.
  • the polysilicon film 62 is directly prepared by introducing hydrogen-diluted silane through the PECVD method, and the thickness of the polysilicon film 62 is about 100 nm.
  • Silicon nitride layers 23 and 63 are deposited on layers 22 and 62 respectively, with a thickness of about 80 nm, to form silicon nitride capping layers on the front and back sides of the silicon wafer.
  • the back silver electrode, back aluminum paste, and front silver electrode are screen printed and dried, and finally the silicon wafer is sent to the sintering furnace for sintering and calcined at 900°C. During this process, the doped elements in the 22 layers will diffuse through the 21 layers to the 1 layer to form the 24 layers, completing the preparation of the solar cell.
  • the structure of a solar cell is shown in FIG3 , and the solar cell is a heterojunction cell.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23 and a front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1, and the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide bandgap metal oxide layer 22.
  • the first wide bandgap metal oxide layer 22 is formed by doped metal oxide, and the doped elements in the first wide bandgap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doping region 24.
  • the solar cell is sequentially stacked with an amorphous silicon passivation layer 71, a second back transmission layer 72, a third back transmission layer 73 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1.
  • the preparation steps of solar cells are as follows:
  • the sample substrate is a double-sided textured single crystal silicon wafer (n-type).
  • the substrate is cleaned using a standard RCA (Radio Corporation of America) cleaning process, then repeatedly rinsed with deionized water, and blown dry with nitrogen for later use.
  • the SiO 2 tunnel passivation layer 21 is oxidized on the front surface of the silicon wafer by ultraviolet ozone oxidation method, and the thickness of the layer is about 1.8 nm.
  • the ALD method was used to prepare a phosphorus-doped zinc oxide film 22 with a thickness of about 40 nm at a temperature of 160 degrees Celsius.
  • the gas sources used were diethyl zinc, deionized water, and diborane.
  • the cycle steps were: diethyl zinc pulse 0.1 second, nitrogen purge 10 seconds, deionized water pulse 0.1 second, nitrogen purge 10 seconds.
  • diborane was introduced into the reaction chamber light, and its cycle ratio with diethyl zinc was 1:2.
  • the aluminum oxide thin film layer 23 is deposited on the front side by using the ALD process.
  • a high temperature calcination process is used, calcination is performed at 930° C. During this process, the doping elements in the 22 layer will diffuse through the 21 layer to the 1 layer to form the 24 layer.
  • the intrinsic amorphous silicon thin film layer 71 and the doped amorphous silicon thin film layer 72 are prepared by ion implantation, wherein the thickness of layer 71 is about 3 nm, and the thickness of layer 72 is about 30 nm, and an annealing method is used for activation process.
  • a transparent conductive film layer 73 is prepared on the surface of the silicon wafer by reactive plasma deposition or magnetron sputtering, and the thickness of the transparent conductive film layer 73 is about 40 nm.
  • a pulsed laser is used to make grooves on the front side of the silicon wafer, so as to penetrate part of the aluminum oxide film layer 23 to expose the 22 layer, and the metal electrode contacts the 22 layer through the groove on the film.
  • the back silver electrode, back aluminum paste, and front silver electrode are screen-printed and dried, and finally the silicon wafer is sent to a sintering furnace for sintering to complete the preparation of the solar cell.
  • the solar cell structure is shown in FIG4 , and the solar cell is a double-sided wide bandgap oxide tunneling structure.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first silicon oxide layer 21, a first wide bandgap metal oxide layer 22, a first protective layer 23, and a plurality of layers stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1. 23 and a front surface electrode 4, the front surface electrode 4 penetrates the first protective layer 23 and contacts the first wide band gap metal oxide layer 22.
  • the first wide band gap metal oxide layer 22 is formed of doped metal oxide, and the doped elements in the first wide band gap metal oxide layer 22 diffuse to the crystalline silicon absorption layer 1 through the first silicon oxide layer 21 to form a first doped region 24.
  • the solar cell is sequentially stacked with a second silicon oxide layer 81, a second wide band gap metal oxide layer 82, a second protective layer 83 and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the second protective layer 83 and contacts the second wide band gap metal oxide layer 82.
  • the second wide band gap metal oxide layer 82 is formed of doped metal oxide, and the doped elements in the second wide band gap metal oxide layer 82 diffuse to the crystalline silicon absorption layer 1 through the second silicon oxide layer 81 to form a second doped region 84.
  • the second wide band gap metal oxide layer 82 has opposite charge transport properties to the first wide band gap metal oxide layer 22.
  • the preparation steps of solar cells are as follows:
  • the sample substrate was a double-sided velvet-coated single-crystal silicon wafer (n-type, resistivity 0.5-2.0 ⁇ .cm, thickness 0.15-0.2mm).
  • the substrate was cleaned using the standard RCA (Radio Corporation of America) cleaning process, then repeatedly rinsed with deionized water and blown dry with nitrogen for later use.
  • the SiO 2 tunnel passivation layers 21 and 81 are oxidized on both sides of the silicon wafer by thermal oxidation method, and the thickness is 1.7 nm.
  • the boron-doped nickel oxide film 22 with a thickness of about 30 nm was prepared by the ALD method at a temperature of 150 degrees Celsius.
  • the nickel, boron and oxygen sources used were bis-(N,N'-di-tert-butylacetamido) nickel (II), diborane/hydrogen mixture, and deionized water.
  • the cycle steps were: bis-(N,N'-di-tert-butylacetamido) nickel (II) pulse 0.1 second, nitrogen purge 10 seconds, deionized water pulse 0.1 second, nitrogen purge 10 seconds.
  • hexahydroboron/hydrogen mixture enters the reaction chamber, and the circulation ratio of hexahydroboron/hydrogen mixture to bis-(N,N'-di-tert-butylacetamido) nickel (II) is 1:3.
  • a fluorine-doped zinc oxide film 82 with a thickness of about 40 nm was prepared by an ALD method at a temperature of 160 degrees Celsius.
  • the cycle steps were: diethyl zinc pulse 0.1 second, nitrogen purge 10 seconds, deionized water 10 seconds, and deionized water 10 seconds.
  • the water/hydrofluoric acid mixture was pulsed for 0.1 seconds and the nitrogen was purged for 10 seconds.
  • the PECVD process is used to deposit Al 2 O 3 passivation layers 23 and 83 on both sides.
  • a high temperature calcination process is used, calcined at 950°C. During this process, the doping elements in the 22 layer will diffuse through the 21 layer to the 1 layer to form the 24 layer.
  • a pulsed laser is used to create grooves on both sides of the silicon wafer, partially breaking through the aluminum oxide film layer to expose the aluminum oxide layers 23 and 83, and the metal electrode contacts the doped oxide layers 22 and 82 through the grooves on the film.
  • the back silver electrode and the front silver electrode are screen-printed and dried, and finally the silicon wafer is sent to a sintering furnace for sintering to complete the preparation of the solar cell.
  • the present application provides a solar cell, as shown in FIGS. 5 to 7 , comprising a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1.
  • a first silicon oxide layer (not shown) is provided between the crystalline silicon absorption layer 1 and the first zinc oxide layer 21, and the thickness of the first silicon oxide layer is less than or equal to 20 atomic layers.
  • thickness refers to the average thickness of the corresponding film layer.
  • the thickness of the first silicon oxide layer being less than or equal to 20 atomic layers, it refers to the average thickness of the first silicon oxide layer being less than or equal to 20 atomic layers, for example, it may be 20 atomic layers, 19 atomic layers, 18 atomic layers, 17 atomic layers, 16 atomic layers, 15 atomic layers, 14 atomic layers, 13 atomic layers, 12 atomic layers, 11 atomic layers, 10 atomic layers, 9 atomic layers, 8 atomic layers, 7 atomic layers, 6 atomic layers, 5 atomic layers, 4 atomic layers, 3 atomic layers, 2 atomic layers, etc., or any range between these values.
  • the thickness of the first silicon oxide layer is less than or equal to 8 atomic layers.
  • the interface silicon oxide or interface silicon-oxygen bond eliminates the dangling bonds of silicon atoms on the surface of single crystal silicon by forming bonds to passivate the strong recombination center formed by the dangling bonds.
  • the silicon oxide or silicon-oxygen bond layer itself is a dielectric, that is, an insulating material, which has an obstructive effect on the transmission of carriers; when the layer is thin, electrons can Carrier transport is achieved by tunneling through the layer, and the thinner the layer is, the higher the tunneling efficiency and the stronger the conductivity.
  • the thickness of the first silicon oxide layer can be measured by characterization methods known in the art, such as transmission electron microscopy, deep etching secondary ion mass spectrometry, deep etching ultraviolet photoelectron spectroscopy and other high-precision interface characterization techniques.
  • the zinc oxide layer of the present application consists of a first zinc oxide layer 21 and a second zinc oxide layer 22.
  • the first zinc oxide layer 21 and the second zinc oxide layer 22 are prepared by a discontinuous process, and through characterization methods known in the art, such as transmission electron microscopy, it can be observed that the first zinc oxide layer 21 and the second zinc oxide layer 22 belong to two different layers.
  • the first zinc oxide layer 21 plays the role of chemical passivation, field effect and selective contact.
  • the first zinc oxide layer 21 can be formed of undoped zinc oxide or doped zinc oxide, for example, it can include dopant components such as aluminum, gallium, indium and other elements, and trace transition metal elements or rare earth elements such as nickel, copper, lanthanum, iridium, actinium and the like.
  • the thickness of the first zinc oxide layer 21 is 3-10 nm, for example, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, or any range between these values.
  • the first zinc oxide layer 21 is obtained by atomic layer deposition (ALD).
  • an oxygen-containing metal source is used instead of an independent oxygen source such as water or ozone.
  • the oxygen-containing metal source includes one or both of zinc ethoxide and zinc isopropoxide.
  • Oxygen elements tend to combine with silicon elements, so controlling the oxygen content at the interface during the process is a key control point of the process.
  • the process using an independent oxygen source is prone to excessive oxygen content at the interface, forming a thicker interface oxide layer; the use of an oxygen-containing metal source can effectively control the oxygen concentration at the interface during the process. This avoids the first silicon oxide layer obtained in the process of preparing the first zinc oxide layer 21 from being too thick, and the thickness of the interface zinc oxide layer can be controlled within 20 atomic layers.
  • the temperature used is 150-400°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, or any range between these values.
  • a metal source known in the art such as ZnCl2, Zn(CH3)2, Zn(C2H5)2, ZnCHCl, etc., can be used.
  • the first zinc oxide layer 21 is obtained by atomic layer deposition (ALD).
  • ALD atomic layer deposition
  • an oxygen-containing metal source is used instead of an independent oxygen source, and the oxygen-containing metal source includes one or both of zinc ethoxide and zinc isopropoxide; the metal source used is ZnCl2, Zn(CH3)2, Zn(C2H5)2, or ZnCHCl; and the temperature used is 150-400°C.
  • the second zinc oxide layer 22 covers the first zinc oxide layer 21, that is, on the side of the first zinc oxide layer 21 away from the crystalline silicon absorption layer 1.
  • the second zinc oxide layer 22 plays the role of selective regulation and carrier transport.
  • the second zinc oxide layer 22 can be formed of undoped zinc oxide or doped zinc oxide, for example, it can include dopant components, such as aluminum, gallium, indium and other elements, and trace transition metal elements or rare earth elements, such as nickel, copper, lanthanum, iridium, actinium and the like.
  • the thickness of the second zinc oxide layer 22 is 10-200 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, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, or any range between these values.
  • the second zinc oxide layer 22 is a columnar crystal structure.
  • the columnar crystal structure is conducive to the vertical transport of carriers, that is, the transport process from the inside of the crystalline silicon to the outside.
  • the mobility of electrons inside the zinc oxide crystal is high, that is, the electrons are small, and the existence of grain boundaries between crystals will hinder the migration of electrons, that is, resistance is formed.
  • the columnar crystal has small electrons in the vertical direction and slightly higher resistance in the lateral direction, but it is controllable. Therefore, the columnar crystal is conducive to the second layer of zinc oxide to realize the function of electron transport outward.
  • the second zinc oxide layer 22 is a doped zinc oxide layer, and the doping concentration of the second zinc oxide layer 22 is greater than the doping concentration of the first zinc oxide layer 21 .
  • the sheet resistance of the second zinc oxide layer 22 is smaller than the sheet resistance of the first zinc oxide layer 21 .
  • the crystalline silicon absorption layer 1 may be an n-type or p-type silicon wafer known in the art, with a thickness of 60-150 ⁇ m.
  • the front surface electrode 5 is arranged on the light-receiving surface of the solar cell and is in contact with the second zinc oxide layer 22. touch.
  • a front surface anti-reflection layer may be provided on the side of the second zinc oxide layer 22 away from the crystalline silicon absorption layer 1 , and the front surface electrode 5 penetrates the front surface anti-reflection layer and contacts the second zinc oxide layer 22 .
  • the solar cell of the present application may be any type of solar cell including the above structure on the light-receiving surface, for example, an emitter back passivation cell, a tunnel oxide layer passivation contact cell, a heterojunction cell, etc. Those skilled in the art may select the corresponding backlight surface structure according to different types of solar cells.
  • the solar cell structure is shown in FIG5 , and the solar cell is an emitter back passivation cell, and the solar cell includes a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell is stacked with a back passivation layer 31, a back anti-reflection layer 32, and a back surface electrode 5 on the back light side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back passivation layer 31 and the back anti-reflection layer 32 and contacts the crystalline silicon absorption layer 1.
  • the back passivation layer 31 may be a single layer of aluminum oxide or a stacked structure of aluminum oxide and silicon oxide.
  • the structure of a solar cell is shown in FIG5 , and the solar cell is an emitter back passivation cell, and the solar cell comprises a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22 and a front surface electrode 4 which are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the thickness of the first silicon oxide layer is less than or equal to 20 atomic layers; the thickness of the first zinc oxide layer 21 is 3-10nm; the thickness of the second zinc oxide layer 22 is 10-200nm, the second zinc oxide layer 22 is a columnar crystal structure, and the second zinc oxide layer 22 is a doped zinc oxide layer.
  • the solar cell is sequentially stacked with a back passivation layer 31, a back anti-reflection layer 32 and a back surface electrode 5 on the back light side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back passivation layer 31 and the back anti-reflection layer 32 and contacts the crystalline silicon absorption layer 1.
  • the solar cell structure is shown in FIG6 , wherein the solar cell is a tunneling oxide layer passivation contact cell, and the solar cell comprises a crystalline silicon absorption layer 1, and
  • the first zinc oxide layer 21, the second zinc oxide layer 22 and the front surface electrode 4 are sequentially stacked on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell is sequentially stacked on the backlight side of the crystalline silicon absorption layer 1 with a back tunneling passivation layer 61, a first back transmission layer 62 and a back surface electrode 5.
  • the back tunneling passivation layer 61 is a silicon oxide layer.
  • the first back transmission layer 62 is a p-type doped polysilicon layer.
  • a back anti-reflection layer is further provided on the side of the first back transmission layer 62 away from the crystalline silicon absorption layer 1 , and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the first back transmission layer 62 .
  • the structure of a solar cell is shown in FIG6 , and the solar cell is a tunneling oxide layer passivation contact cell, and the solar cell includes a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • first silicon oxide layer between the crystalline silicon absorption layer 1 and the first zinc oxide layer 21, and the thickness of the first silicon oxide layer is less than or equal to 20 atomic layers; the thickness of the first zinc oxide layer 21 is 3-10nm; the thickness of the second zinc oxide layer 22 is 10-200nm, the second zinc oxide layer 22 is a columnar crystal structure, and the second zinc oxide layer 22 is a doped zinc oxide layer.
  • the solar cell is stacked with a back tunneling passivation layer 61, a first back transmission layer 62, a back anti-reflection layer, and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1, and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the first back transmission layer 62.
  • the solar cell structure is shown in FIG7 , and the solar cell is a heterojunction cell, and the solar cell includes a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell includes a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell is stacked with an amorphous silicon passivation layer 71, a second back transmission layer 72, a third back transmission layer 73, and a back surface electrode 5 on the backlight side of the crystalline silicon absorption layer 1.
  • the amorphous silicon passivation layer 71 is formed of amorphous silicon.
  • the second back transmission layer 72 is formed of p-type doped amorphous silicon.
  • the third back transmission layer 73 can be made of ITO material, or a material used as a back transmission layer in the art. Other transparent conductive film materials.
  • a back anti-reflection layer is further provided on the side of the third back transmission layer 73 away from the crystalline silicon absorption layer 1 , and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the third back transmission layer 73 .
  • the structure of a solar cell is shown in FIG7 , and the solar cell is a heterojunction cell, and the solar cell includes a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • first silicon oxide layer between the crystalline silicon absorption layer 1 and the first zinc oxide layer 21, and the thickness of the first silicon oxide layer is less than or equal to 20 atomic layers; the thickness of the first zinc oxide layer 21 is 3-10nm; the thickness of the second zinc oxide layer 22 is 10-200nm, the second zinc oxide layer 22 is a columnar crystal structure, and the second zinc oxide layer 22 is a doped zinc oxide layer.
  • the solar cell is stacked in sequence on the backlight side of the crystalline silicon absorption layer 1 with an amorphous silicon passivation layer 71, a second back transmission layer 72, a third back transmission layer 73, a back anti-reflection layer, and a back surface electrode 5, and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the third back transmission layer 73.
  • the solar cell structure is shown in FIG5 , and the solar cell is an emitter back passivation cell.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell is stacked in sequence on the backlight surface of the crystalline silicon absorption layer 1 with a back passivation layer 31, a back anti-reflection layer 32, and a back surface electrode 5, and the back surface electrode 5 penetrates the back passivation layer 31 and the back anti-reflection layer 32 and contacts the crystalline silicon absorption layer 1.
  • the preparation steps of solar cells are as follows:
  • the front surface After the p-type silicon wafer is diffused by conventional battery mood texturing, the front surface obtains a pn junction to form an n-type surface, and the first zinc oxide layer 21 is deposited on the n-type surface by ALD process.
  • ALD process zinc ethoxide is used as the oxygen-containing metal source, and the temperature used is 250° C.
  • the thickness of the prepared first zinc oxide layer 21 is 5 nm.
  • This process can obtain a first zinc oxide layer with almost no interfacial silicon oxide.
  • the first silicon oxide layer is thickened during the subsequent process, and the overall thickness does not exceed 20 atomic layers.
  • the second zinc oxide layer 22 is prepared by long-distance plasma magnetron sputtering.
  • the thickness of the second zinc oxide layer is 30 nm.
  • a gradient doping scheme is adopted, and the doping concentration gradually increases from the side close to the first zinc oxide layer 21 to the side far from the first zinc oxide layer 21.
  • the other parts of the solar cell are prepared using the general process of PERC cells.
  • the solar cell structure is shown in FIG6 , and the solar cell is a tunneling oxide layer passivation contact cell.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22 and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell is stacked in sequence on the backlight side of the crystalline silicon absorption layer 1 with a back tunneling passivation layer 61, a first back transmission layer 62, a back anti-reflection layer and a back surface electrode 5, and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the first back transmission layer 62.
  • the preparation steps of solar cells are as follows:
  • the pn junction is not diffused, and the first zinc oxide layer 21 is deposited on the n-type surface by ALD process.
  • Zn(CH3)2 is used as the oxygen-containing metal source, and the temperature used is 200°C.
  • the thickness of the prepared first zinc oxide layer 21 is 5nm.
  • This process can obtain a first zinc oxide layer with almost no interfacial silicon oxide.
  • the first silicon oxide layer is thickened during the subsequent process, and the overall thickness does not exceed 20 atomic layers.
  • the second zinc oxide layer 22 is prepared by long-distance plasma magnetron sputtering.
  • the thickness of the second zinc oxide layer is 30 nm.
  • a gradient doping scheme is adopted, and the doping concentration gradually increases from the side close to the first zinc oxide layer 21 to the side far from the first zinc oxide layer 21.
  • the other parts of the solar cell are prepared using the general process of back-junction TOPCon cells.
  • the solar cell structure is shown in FIG7 , and the solar cell is a heterojunction cell.
  • the solar cell comprises a crystalline silicon absorption layer 1, and a first zinc oxide layer 21, a second zinc oxide layer 22, and a front surface electrode 4 stacked in sequence on the light-receiving surface of the crystalline silicon absorption layer 1.
  • the solar cell is stacked in sequence on the backlight surface of the crystalline silicon absorption layer 1 with an amorphous silicon passivation layer 71, a second back transmission layer 72, a third back transmission layer 73, a back anti-reflection layer, and a back surface electrode 5, and the back surface electrode 5 penetrates the back anti-reflection layer and contacts the third back transmission layer 73.
  • the preparation steps of solar cells are as follows:
  • the pn junction is not diffused, and the first zinc oxide layer 21 is deposited on the n-type surface by ALD process.
  • Ethoxide zinc is used as the oxygen-containing metal source in the preparation process, and the temperature used is 350° C.
  • the thickness of the prepared first zinc oxide layer 21 is 5 nm.
  • This process can obtain a first silicon oxide layer with a thickness of about 8 atomic layers. Since other processes do not involve high-temperature processes, the first silicon oxide layer will not change during subsequent processes.
  • the second zinc oxide layer 22 is prepared by long-distance plasma magnetron sputtering.
  • the second zinc oxide layer has a thickness of 30 nm and adopts a gradient doping scheme.
  • the doping concentration gradually increases from the side close to the first zinc oxide layer 21 to the side far from the first zinc oxide layer 21.
  • the other parts of the solar cell are prepared using the general process of back-junction HJT cells.

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Abstract

一种太阳能电池，其包括晶体硅吸收层，以及在所述晶体硅吸收层的受光面依次层叠设置的第一氧化硅层、第一宽带隙金属氧化物层、第一保护层和前表面电极，其中，所述第一宽带隙金属氧化物层由掺杂的金属氧化物形成，所述第一宽带隙金属氧化物层中掺杂的元素通过所述第一氧化硅层向所述晶体硅吸收层扩散，形成第一掺杂区。采用多层氧化硅/宽带隙氧化物结构作为硅太阳能电池的选择性接触与传输层，使用高温工艺，使得氧化硅形成空洞结构，宽带隙氧化物中掺杂的元素进一步扩散到晶体硅表面。从而避免了较大的光寄生性吸收，获得更优的场钝化效果，提升太阳能电池的效率。

Description

太阳能电池
相关申请的交叉引用
本申请要求在2023年4月17日提交中国专利局、申请号为202310411689.6、发明名称为“前表面具有宽带隙氧化物结构的太阳能电池”的中国专利申请的优先权，在2023年4月23日提交中国专利局、申请号为202310444710.2、发明名称为“前表面具有多层氧化锌结构的太阳能电池”的中国专利申请的优先权其全部内容通过引用结合在本申请中。
技术领域
本申请属于太阳能电池技术领域，具体地，涉及一种太阳能电池。
背景技术
目前的隧穿氧化层钝化接触(TOPCon)电池正面结构仍采用与发射极背面钝化(PERC)电池相同的结构，该结构存在金属栅线与硅吸收层的直接接触，导致电池前表面仍旧存在较高的表面复合速率，限制了TOPCon电池效率的进一步提升。
采用POLO结构可以改善上述问题，但是在晶体硅电池正面引入掺杂多晶硅传输层会带来较强的寄生性吸收，同样限制了电池效率的提升。当前，许多研究使用宽带隙材料作为钝化接触层，一般采用低温工艺，采用完整的氧化硅层作为钝化层，使得界面接触电阻较大，效率损失严重，或使用非晶硅钝化，导致光寄生吸收损失严重。
当前异质结(HJT)电池采用TCO等材料作为传输层，同样引起较强的光学寄生吸收，导致电池效率损失。
发明内容
针对现有技术存在的问题，本申请提供一种前表面具有宽带隙氧化物结构的太阳能电池。
具体来说，本申请涉及如下方面：
一种太阳能电池，其包括晶体硅吸收层，以及在所述晶体硅吸收层的受 光面依次层叠设置的第一氧化硅层、第一宽带隙金属氧化物层、第一保护层和前表面电极，
其中，所述第一宽带隙金属氧化物层由掺杂的金属氧化物形成，所述第一宽带隙金属氧化物层中掺杂的元素通过所述第一氧化硅层向所述晶体硅吸收层扩散，形成第一掺杂区。
可选地，其中所述第一氧化硅层的厚度为0.5-4nm。
可选地，所述第一氧化硅层的厚度小于等于20个原子层，优选地，所述第一氧化硅层的厚度小于等于8个原子层。
可选地，其中所述第一氧化硅层具有通过煅烧形成的孔洞。
可选地，其中所述第一宽带隙金属氧化物层包括第一氧化锌层和第二氧化锌层，所述第一氧化锌层的厚度为3-10nm，所述第二氧化锌层的厚度为10-200nm；
或，所述第二氧化锌层是掺杂的氧化锌层，所述第二氧化锌层的掺杂浓度大于所述第一氧化锌层的掺杂浓度；
或，所述第二氧化锌层的方阻小于所述第一氧化锌层的方阻。
可选地，所述第二氧化锌层为柱状晶体结构。
可选地，在所述第二氧化锌层远离所述晶体硅吸收层的一侧还设置有前表面减反射层，所述前表面电极贯穿所述前表面减反射层与所述第二氧化锌层接触。
可选地，其中所述第一宽带隙金属氧化物层的多晶化程度从靠近所述第一氧化物层的一侧到远离所述第一氧化物层的一侧递增。
可选地，其中所述第一保护层的材料选自氮化硅、氧化钛、硫化锌、氧化铝、氮化铝、氧化硅等中的一种或两种以上。
可选地，其中所述第一保护层的厚度为10-100nm。
可选地，其中所述前表面电极贯穿所述第一保护层与所述第一宽带隙金属氧化物层接触。
可选地，其中在所述第一保护层远离所述晶体硅吸收层的一侧还设置有前表面减反射层，所述前表面电极贯穿所述前表面减反射层和所述第一保护层与所述第一宽带隙金属氧化物层接触。
可选地，其中所述太阳能电池还包括在所述晶体硅吸收层的背光面依次层叠设置的第二氧化硅层、第二宽带隙金属氧化物层、第二保护层和背表面电极，所述背表面电极贯穿所述第二保护层与所述第二宽带隙金属氧化物层接触，
其中，所述第二宽带隙金属氧化物层由掺杂的金属氧化物形成，所述第二宽带隙金属氧化物层中掺杂的元素通过所述第二氧化硅层向所述晶体硅吸收层扩散，形成第二掺杂区，
所述第二宽带隙金属氧化物层和所述第一宽带隙金属氧化物层的电荷传输性质相反。
可选地，其中所述第二氧化硅层的厚度为0.5-4nm。
可选地，其中所述第二氧化硅层具有通过煅烧形成的孔洞。
可选地，其中所述第一宽带隙金属氧化物层，或所述第二宽带隙金属氧化物层所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上。
可选地，其中所述第一宽带隙金属氧化物层，或所述第二宽带隙金属氧化物层的厚度为10-200nm。
可选地，其中所述第二宽带隙金属氧化物层的多晶化程度从靠近所述第二氧化物层的一侧到远离所述第二氧化物层的一侧递增。
可选地，其中所述第二保护层的材料选自氮化硅或氮化铝。
可选地，其中所述第二保护层的厚度为10-100nm。
可选地，其中在所述第二保护层远离所述晶体硅吸收层的一侧还设置有背面减反射层，所述背表面电极贯穿所述背面减反射层和所述第二保护层与所述第二宽带隙金属氧化物层接触。
上述说明仅是本发明技术方案的概述，为了能够更清楚了解本发明的技术手段，而可依照说明书的内容予以实施，并且为了让本发明的上述和其它目的、特征和优点能够更明显易懂，以下特举本发明的具体实施方式。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作一简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本申请的一种实施方式的太阳能电池的结构示意图；
图2为本申请的另一种实施方式的太阳能电池的结构示意图；
图3为本申请的另一种实施方式的太阳能电池的结构示意图；
图4为本申请的另一种实施方式的太阳能电池的结构示意图；
图5为本申请的一种实施方式的太阳能电池的结构示意图；
图6为本申请的另一种实施方式的太阳能电池的结构示意图；
图7为本申请的另一种实施方式的太阳能电池的结构示意图。
附图标记：
图1至图4，1晶体硅吸收层，21第一氧化硅层，22第一宽带隙金属氧化物层，23第一保护层，24第一掺杂区，31背钝化层，32背面减反射层；4前表面电极，5背表面电极，61背隧穿钝化层，62第一背传输层，63背面减反射层，71非晶硅钝化层，72第二背传输层，73第三背传输层，81第二氧化硅层，82第二宽带隙金属氧化物层，83第二保护层，84第二掺杂区；
图5至图7，1晶体硅吸收层，21第一氧化锌层，22第二氧化锌层，31背钝化层，32背面减反射层；4前表面电极，5背表面电极，61背隧穿钝化层，62第一背传输层，71非晶硅钝化层，72第二背传输层，73第三背传输层。
具体实施例
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
下面结合实施例进一步说明本申请，应当理解，实施例仅用于进一步说明和阐释本申请，并非用于限制本申请。
除非另外定义，本说明书中有关技术的和科学的术语与本领域内的技术人员所通常理解的意思相同。虽然在实验或实际应用中可以应用与此间所述相似或相同的方法和材料，本文还是在下文中对材料和方法做了描述。在相冲突的情况下，以本说明书包括其中定义为准，另外，材料、方法和例子仅供说明，而不具限制性。以下结合具体实施例对本申请作进一步的说明，但不用来限制本申请的范围。
本申请提供一种太阳能电池，如图1-图4所示，其包括晶体硅吸收层1，以及在所述晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4。其中，所述第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，所述第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。
第一氧化硅层21由氧化硅形成，起到化学钝化的功能。在一个具体的实施方式中，第一氧化硅层21的厚度为0.5-4nm，例如可以为0.5nm、1nm、1.5nm、2nm、2.5nm、3nm、3.5nm、4nm，或这些数值之间的任何范围。第一氧化硅层21这种超薄的结构主要有两个作用：1.对晶体硅表面起到化学钝化作用，降低表面复合；2.在电荷传输中起到隧穿作用，有利于电荷传输，提高电池效率。
在一个具体的实施方式中，第一氧化硅层21具有通过煅烧形成的孔洞。孔洞的存在使得第一宽带隙金属氧化物层22中掺杂的元素可以向晶体硅吸收层1扩散，形成第一掺杂区24。
第一宽带隙金属氧化物层22覆盖在第一氧化硅层21之上，即在第一氧化硅层21远离晶体硅吸收层1的一侧。第一宽带隙金属氧化物层22起到场效应，选择性接触以及载流子传输的功能。第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，可掺杂的掺杂剂为本领域已知的常用掺杂剂，例如可以为铝、镓、铟等元素，以及微量的过渡金属元素或稀土元素，如镍、铜、镧、铱、锕等。
第一宽带隙金属氧化物层22中的宽带隙材料可以减少由掺杂非晶硅和TCO引起的光学寄生吸收，如果对PERC和TOPCon电池进行前表面使用该结构，还可以优化电极与晶硅界面接触，减少接触复合。
在一个具体的实施方式中，第一宽带隙金属氧化物层22所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上。
在一个具体的实施方式中，第一宽带隙金属氧化物层22的厚度为10-200nm，例如可以为10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm、200nm，或这些数值之间的任何范围。
在一个具体的实施方式中，第一宽带隙金属氧化物层22的多晶化程度从靠近第一氧化物层21的一侧到远离第一氧化物层21的一侧(即靠近第一保护层23的一侧)递增。
在一个具体的实施方式中，第一宽带隙金属氧化物层22从靠近第一氧化物层21的一侧到远离第一氧化物层21的一侧由非晶结构逐渐过渡到多晶结构。
第一保护层23的材料可以选自氮化硅、氧化钛、硫化锌、氧化铝、氮化铝等中的一种或两种以上，起到稳定以及减反射功能。第一保护层23以包括掺杂剂成分，如铝、镓、铟等元素，以及微量的过渡金属元素或稀土元素，如镍、铜、镧、铱、锕等。
在一个具体的实施方式中，第一保护层23的厚度为10-100nm，例如可以为10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm，或这些数值之间的任何范围。
第一掺杂区24为第一宽带隙金属氧化物层22中掺杂的元素，通过第一氧化硅层21向晶体硅吸收层1扩散形成的区域，从第一宽带隙金属氧化物层22靠近晶体硅吸收层1的一侧延伸到晶体硅吸收层1。第一掺杂区24可以起到优化界面电阻，钝化晶体硅，减少界面复合的作用。
晶体硅吸收层1可以为本领域已知的n型或p型硅片，厚度为60-150 μm。
前表面电极4设置在太阳能电池的受光面，并贯穿第一保护层23与第一宽带隙金属氧化物层22接触。
本领域人员可以理解，根据实际需要，还可以在宽带隙金属氧化物层22远离晶体硅吸收层1的一侧设置前表面减反射层，前表面电极4贯穿所述前表面减反射层和第一保护层23与宽带隙金属氧化物层22接触。
本申请的太阳能电池可以是在受光面包含上述结构的任何类型的太阳能电池，例如可以为发射极背面钝化电池、隧穿氧化层钝化接触电池、异质结电池等。本领域技术人员可以根据不同的太阳能电池类型，选择相应的背光面结构。
在一个具体的实施方式中，太阳能电池结构如图1所示，太阳能电池为发射极背面钝化电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背钝化层31、背面减反射层32和背表面电极5，背表面电极5贯穿背钝化层31和背面减反射层32与晶体硅吸收层1接触。
其中，背钝化层31可以为氧化铝单层或氧化铝与氧化硅的叠层结构。
在一个具体的实施方式中，太阳能电池结构如图1所示，太阳能电池为发射极背面钝化电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。第一氧化硅层21的厚度为0.5-4nm，并具有通过煅烧形成的孔洞；第一宽带隙金属氧化物 层22所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上，厚度为10-200nm，第一宽带隙金属氧化物层22的多晶化程度从靠近第一氧化物层21的一侧到远离第一氧化物层21的一侧递增；第一保护层23的材料选自氮化硅或氮化铝，厚度为10-100nm。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背钝化层31、背面减反射层32和背表面电极5，背表面电极5贯穿背钝化层31和背面减反射层32与晶体硅吸收层1接触。
在一个具体的实施方式中，太阳能电池结构如图2所示，所述太阳能电池为隧穿氧化层钝化接触电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背隧穿钝化层61、第一背传输层62和背表面电极5。
其中，背隧穿钝化层61为氧化硅层。第一背传输层62，为p型掺杂多晶硅层。
本领域技术人员可以理解，根据实际需要，在第一背传输层62远离晶体硅吸收层1的一侧还设置有背面减反射层63，背表面电极5贯穿所述背面减反射层63与第一背传输层62接触。
在一个具体的实施方式中，太阳能电池结构如图2所示，所述太阳能电池为隧穿氧化层钝化接触电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通 过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。第一氧化硅层21的厚度为0.5-4nm，并具有通过煅烧形成的孔洞；第一宽带隙金属氧化物层22所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上，厚度为10-200nm，第一宽带隙金属氧化物层22的多晶化程度从靠近第一氧化物层21的一侧到远离第一氧化物层21的一侧递增；第一保护层23的材料选自氮化硅或氮化铝，厚度为10-100nm。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背隧穿钝化层61、第一背传输层62、背面减反射层和背表面电极5，背表面电极5贯穿所述背面减反射层与第一背传输层62接触。
在一个具体的实施方式中，太阳能电池结构如图3所示，所述太阳能电池为异质结电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有非晶硅钝化层71、第二背传输层72、第三背传输层73和背表面电极5。
其中，非晶硅钝化层71由非晶硅形成。第二背传输层72由p型掺杂非晶硅形成。第三背传输层73可以为银电极。
本领域技术人员可以理解，根据实际需要，在第三背传输层73远离晶体硅吸收层1的一侧还设置有背面减反射层，背表面电极5贯穿所述背面减反射层第三背传输层73接触。
在一个具体的实施方式中，太阳能电池结构如图3所示，所述太阳能电池为异质结电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽 带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。第一氧化硅层21的厚度为0.5-4nm，并具有通过煅烧形成的孔洞；第一宽带隙金属氧化物层22所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上，厚度为10-200nm，第一宽带隙金属氧化物层22的多晶化程度从靠近第一氧化物层21的一侧到远离第一氧化物层21的一侧递增；第一保护层23的材料选自氮化硅或氮化铝，厚度为10-100nm。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有非晶硅钝化层71、第二背传输层72、第三背传输层73、背面减反射层和背表面电极5，背表面电极5贯穿所述背面减反射层第三背传输层73接触。
在一个具体的实施方式中，太阳能电池结构如图4所示，所述太阳能电池为双面宽带隙氧化物隧穿结构。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有第二氧化硅层81、第二宽带隙金属氧化物层82、第二保护层83和背表面电极5，所述背表面电极5贯穿所述第二保护层83与所述第二宽带隙金属氧化物层82接触。其中，第二宽带隙金属氧化物层82由掺杂的金属氧化物形成，第二宽带隙金属氧化物层82中掺杂的元素通过第二氧化硅层81向晶体硅吸收层1扩散，形成第二掺杂区84。第二宽带隙金属氧化物层82和第一宽带隙金属氧化物层22的电荷传输性质相反。
其中，第二氧化硅层81的作用、材料、厚度范围、形态与第一氧化硅层21相同。第二宽带隙金属氧化物层82的作用、材料、厚度范围、多晶化 程度与第一宽带隙金属氧化物层22相同。第二保护层83的作用、材料、厚度范围与第一保护层83相同。第二掺杂区84的作用、掺杂元素的选择与第一掺杂区24相同。第二宽带隙金属氧化物层82和第一宽带隙金属氧化物层22的电荷传输性质相反是指，如果第一宽带隙金属氧化物层22为电子选择性接触层，则第二宽带隙金属氧化物层82为空穴选择性接触层；如果第一宽带隙金属氧化物层22为空穴选择性接触层，则第二宽带隙金属氧化物层82为电子选择性接触层。
在一个具体的实施方式中，太阳能电池结构如图4所示，所述太阳能电池为双面宽带隙氧化物隧穿结构。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有第二氧化硅层81、第二宽带隙金属氧化物层82、第二保护层83和背表面电极5，所述背表面电极5贯穿所述第二保护层83与所述第二宽带隙金属氧化物层82接触。其中，第二宽带隙金属氧化物层82由掺杂的金属氧化物形成，第二宽带隙金属氧化物层82中掺杂的元素通过第二氧化硅层81向晶体硅吸收层1扩散，形成第二掺杂区84。第二宽带隙金属氧化物层82和第一宽带隙金属氧化物层22的电荷传输性质相反。第一氧化硅层21和第二氧化物层81的厚度为0.5-4nm，并具有通过煅烧形成的孔洞；第一宽带隙金属氧化物层22和第二宽带隙金属氧化物层82所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上，厚度为10-200nm；第一保护层23和第二保护层83的材料选自氮化硅或氮化铝，厚度为10-100nm。
实施例
实施例1
太阳能电池结构如图1所示，所述太阳能电池为发射极背面钝化电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背钝化层31、背面减反射层32和背表面电极5，背表面电极5贯穿背钝化层31和背面减反射层32与晶体硅吸收层1接触。
具体地，太阳能电池的制备步骤如下：
1.硅片清洗
样品衬底为正面绒面的单晶硅片(n型)，采用标准的RCA(Radio Corporation of America)清洗工艺对衬底进行清洗，然后用去离子水反复冲洗，并用氮气吹干待用。
2.氧化硅薄膜制备
利用热氧氧化法在硅片前表面氧化出SiO2钝化层21，其厚度约为1.7nm。3.氧化锌薄膜制备
采用ALD方法制备厚度约为40nm的掺磷氧化锌薄膜22，温度为160摄氏度，其中使用的气源为二乙基锌、去离子水、乙硼烷，循环步骤：二乙基锌脉冲0.1秒、氮气吹扫10秒、去离子水脉冲0.1秒，氮气吹扫10秒，在上述循环过程中，将乙硼烷引入反应腔室光，其与二乙基锌的循环比为1：2。
4.正面氮化硅制备
在22层上面沉积一层60nm厚度的氮化硅层23，在硅片正面形成氮化硅盖层。
5.背面氧化铝/氮化硅制备
采用PECVD的方式在硅片背面先沉积一层15nm厚度的氧化铝层31；在其上面沉积一层80nm厚度的氮化硅层32，在硅片背面形成氧化铝/氮化硅叠层钝化膜。
6.正反两面的氧化铝薄膜上激光开槽
利用脉冲激光在硅片的正面进行开槽，将部分氮化硅薄膜层23击穿露出22层，金属电极通过薄膜上的槽与22层实现接触。背面激光将部分氧化铝薄膜层击穿露出硅体区1层，金属电极通过薄膜上的槽与1层实现接触。
7.电极制备
丝网印刷背面银电极、背面铝浆、正面银电极并烘干，最后将硅片送入烧结炉进行烧结，在930℃进行煅烧。在此过程中，22层中掺杂元素会经过21层扩散到1层形成24层，完成太阳能电池的制备。
实施例2
太阳能电池结构如图2所示，所述太阳能电池为隧穿氧化层钝化接触电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背隧穿钝化层61、第一背传输层62、背面减反射层63和背表面电极5。
具体地，太阳能电池的制备步骤如下：
1.硅片清洗
样品衬底为正面绒面的单晶硅片(p型)，采用标准的RCA(Radio Corporation of America)清洗工艺对衬底进行清洗，然后用去离子水反复冲洗，并用氮气吹干待用。
2.氧化硅薄膜制备
利用紫外臭氧氧化法在硅片前、后表面氧化出SiO2隧穿钝化层21、61，其厚度均为1.8nm。
3.氧化镍薄膜制备
采用ALD方法制备厚度约为35nm的掺硼氧化镍薄膜22，温度为150摄氏度，其中使用的镍、硼、氧源为双-(N,N'-二叔丁基乙酰氨基)镍(II)、 乙硼烷/氢气混合气、去离子水，循环步骤：双-(N,N'-二叔丁基乙酰氨基)镍(II)脉冲0.1秒、氮气吹扫10秒、去离子水脉冲0.1秒、氮气吹扫10秒。在此过程中，六氢化二硼/氢气混合气进入反应腔室，其与双-(N,N'-二叔丁基乙酰氨基)镍(II)的循环比例为1：3。
4.背面非晶硅制备
通过PECVD方法，通入氢气稀释的硅烷直接制备多晶硅薄膜62，其厚度约为100nm。
5.氮化硅薄膜制备
在22和62层上面分别沉积氮化硅层23，63层，其厚度约为80nm，在硅片正、背面形成氮化硅盖层。
6.电极制备
丝网印刷背面银电极、背面铝浆、正面银电极并烘干，最后将硅片送入烧结炉进行烧结，在900℃进行煅烧。在此过程中，22层中掺杂元素会经过21层扩散到1层形成24层，完成太阳能电池的制备。
实施例3
太阳能电池结构如图3所示，所述太阳能电池为异质结电池。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有非晶硅钝化层71、第二背传输层72、第三背传输层73和背表面电极5。
具体地，太阳能电池的制备步骤如下：
1.硅片清洗
样品衬底为双面绒面的单晶硅片(n型)，采用标准的RCA(Radio Corporation of America)清洗工艺对衬底进行清洗，然后用去离子水反复冲洗，并用氮气吹干待用。
2.氧化硅薄膜制备
利用紫外臭氧氧化法在硅片前表面氧化出SiO2隧穿钝化层21，其厚度约为1.8nm。
3.氧化锌薄膜制备
采用ALD方法制备厚度约为40nm的掺磷氧化锌薄膜22，温度为160摄氏度，其中使用的气源为二乙基锌、去离子水、乙硼烷，循环步骤：二乙基锌脉冲0.1秒、氮气吹扫10秒、去离子水脉冲0.1秒，氮气吹扫10秒，在上述循环过程中，将乙硼烷引入反应腔室光，其与二乙基锌的循环比为1：2。
4.氧化铝层制备
采用ALD工艺在正面沉积氧化铝薄膜层23。采用高温煅烧工艺，930℃煅烧，在此过程中，22层中掺杂元素会经过21层扩散到1层形成24层。
5.非晶硅沉积
采用离子注入法制备本征非晶硅薄膜层71以及掺杂非晶硅薄膜层72，其中71层厚度约为3nm，72层厚度约为30nm，并采用退火法进行活化工艺。
6.TCO沉积
利用反应等离子体沉积或磁控溅射的方法在上述硅片的表面制备透明导电薄膜层73，其厚度约为40nm。
7.正面的氧化铝薄膜上激光开槽
利用脉冲激光在硅片的正面进行开槽，将部分氧化铝薄膜层23击穿露出22层，金属电极通过薄膜上的槽与22层实现接触。
8.电极制备
丝网印刷背面银电极、背面铝浆、正面银电极并烘干，最后将硅片送入烧结炉进行烧结，完成太阳能电池的制备。
实施例4
太阳能电池结构如图4所示，所述太阳能电池为双面宽带隙氧化物隧穿结构。太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化硅层21、第一宽带隙金属氧化物层22、第一保护层 23和前表面电极4，前表面电极4贯穿第一保护层23与第一宽带隙金属氧化物层22接触。其中，第一宽带隙金属氧化物层22由掺杂的金属氧化物形成，第一宽带隙金属氧化物层22中掺杂的元素通过第一氧化硅层21向晶体硅吸收层1扩散，形成第一掺杂区24。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有第二氧化硅层81、第二宽带隙金属氧化物层82、第二保护层83和背表面电极5，所述背表面电极5贯穿所述第二保护层83与所述第二宽带隙金属氧化物层82接触。其中，第二宽带隙金属氧化物层82由掺杂的金属氧化物形成，第二宽带隙金属氧化物层82中掺杂的元素通过第二氧化硅层81向晶体硅吸收层1扩散，形成第二掺杂区84。第二宽带隙金属氧化物层82和第一宽带隙金属氧化物层22的电荷传输性质相反。
具体地，太阳能电池的制备步骤如下：
1.硅片清洗
样品衬底为双面绒面的单晶硅片(n型，电阻率0.5～2.0Ω.cm，厚度0.15～0.2mm)，采用标准的RCA(Radio Corporation of America)清洗工艺对衬底进行清洗，然后用去离子水反复冲洗，并用氮气吹干待用。
2.氧化硅薄膜制备
利用热氧氧化法在硅片两面氧化出SiO2隧穿钝化层21和81，厚度为1.7nm。
3.氧化镍薄膜制备
采用ALD方法制备厚度约为30nm的掺硼氧化镍薄膜22，温度为150摄氏度，其中使用的镍、硼、氧源为双-(N,N'-二叔丁基乙酰氨基)镍(II)、乙硼烷/氢气混合气、去离子水，循环步骤：双-(N,N'-二叔丁基乙酰氨基)镍(II)脉冲0.1秒、氮气吹扫10秒、去离子水脉冲0.1秒、氮气吹扫10秒。在此过程中，六氢化二硼/氢气混合气进入反应腔室，其与双-(N,N'-二叔丁基乙酰氨基)镍(II)的循环比例为1：3。
4.氧化锌薄膜制备
采用ALD方法制备厚度约为40nm的掺氟氧化锌薄膜82，温度为160摄氏度，其中使用的锌、氟、氧源为二乙基锌、去离子水与氢氟酸的混合物(v:v＝200:1)，循环步骤：二乙基锌脉冲0.1秒、氮气吹扫10秒、去离子 水/氢氟酸混合物脉冲0.1秒，氮气吹扫10秒。
5.氧化铝层制备
采用PECVD工艺在双面沉积Al2O3钝化层23与83。采用高温煅烧工艺，950℃煅烧，在此过程中，22层中掺杂元素会经过21层扩散到1层形成24层。
6.正反两面的氧化铝薄膜上激光开槽
利用脉冲激光在硅片的正反两面进行开槽，将部分氧化铝薄膜层击穿露出氧化铝层23和83，金属电极通过薄膜上的槽与掺杂氧化物22，82层实现接触。
7.正反两面电极制备
丝网印刷背面银电极、正面银电极并烘干，最后将硅片送入烧结炉进行烧结，完成太阳能电池的制备。
本申请提供一种太阳能电池，如图5-图7所示，其包括晶体硅吸收层1，以及在所述晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层(未示出)，所述第一氧化硅层的厚度小于等于20个原子层。
本领域技术人员可以理解，当在本申请中提及厚度时，指的是相应膜层的平均厚度。对于第一氧化硅层的厚度小于等于20个原子层，指的是第一氧化硅层的平均厚度小于等于20个原子层，例如可以为20个原子层、19个原子层、18个原子层、17个原子层、16个原子层、15个原子层、14个原子层、13个原子层、12个原子层、11个原子层、10个原子层、9个原子层、8个原子层、7个原子层、6个原子层、5个原子层、4个原子层、3个原子层、2个原子层等，或这些数值之间的任何范围。
在一个具体的实施方式中，第一氧化硅层的厚度小于等于8个原子层。
过厚的第一氧化硅层会造成较大的界面电阻，阻碍载流子的选择性接触。界面氧化硅或者界面硅氧键是通过成键的形式消除单晶硅表面硅原子的悬挂键来钝化悬挂键形成的强烈复合中心，氧化硅或者硅氧键层本身为电介质既绝缘材料，对载流子的传输有阻碍作用；当该层较薄时，电子可 以通过隧穿效应通过该层，实现载流子传输，且该层越薄隧穿效率越高既导电能力越强。
第一氧化硅层的厚度可以通过本领域已知的表征方式测量，例如透射电镜、深度刻蚀二次离子质谱、深度刻蚀紫外光电子能谱等高精度界面表征技术。
本申请的氧化锌层由第一氧化锌层21和第二氧化锌层22组成。第一氧化锌层21和第二氧化锌层22由不连续的工艺制备得到，通过本领域已知的表征方法，如透射电镜可以观察到第一氧化锌层21和第二氧化锌层22属于不同的两层。
第一氧化锌层21起到化学钝化、场效应以及选择性接触的功能。第一氧化锌层21可以由不掺杂的氧化锌形成，也可以由掺杂的氧化锌形成，例如可以包括掺杂剂成分，如铝、镓、铟等元素，以及微量的过渡金属元素或稀土元素，如镍、铜、镧、铱、锕等。
在一个具体的实施方式中，第一氧化锌层21的厚度为3-10nm，例如可以为3nm、4nm、5nm、6nm、7nm、8nm、9nm、10nm，或这些数值之间的任何范围。
在一个具体的实施方式中，第一氧化锌层21通过原子层沉积法(ALD)得到。
在一个具体的实施方式中，在ALD法中，使用含氧金属源代替独立氧源如水或臭氧等。其中，所述含氧金属源包括乙醇锌、异丙醇锌中的一种或两种。氧元素倾向于与硅元素结合，因此控制工艺过程中界面处氧元素含量是该工艺的关键控制点，采用独立氧源的工艺过程易导致界面处氧含量过多，形成较厚的界面氧化层；采用含氧金属源可以有效控制工艺过程中界面处的氧元素浓度。从而避免在制备第一氧化锌层21过程中得到的第一氧化硅层过厚，可以控制界面氧化锌层的厚度在20个原子层内。
在一个具体的实施方式中，在ALD法中，所采用的温度为150-400℃，例如可以为150℃、160℃、170℃、180℃、190℃、200℃、210℃、220℃、230℃、240℃、250℃、260℃、270℃、280℃、290℃、300℃、310℃、320℃、330℃、340℃、350℃、360℃、370℃、380℃、390℃、 400℃，或这些数值之间的任何范围。
在ALD法中，可以使用本领域已知的金属源，例如ZnCl2、Zn(CH3)2、Zn(C2H5)2、ZnCHCl等。
在一个具体的实施方式中，第一氧化锌层21通过原子层沉积法(ALD)得到。在ALD法中，使用含氧金属源代替独立氧源，所述含氧金属源包括乙醇锌、异丙醇锌中的一种或两种；使用的金属源为ZnCl2、Zn(CH3)2、Zn(C2H5)2、或ZnCHCl；所采用的温度为150-400℃。
第二氧化锌层22覆盖在第一氧化锌层21之上，即在第一氧化锌层21远离晶体硅吸收层1的一侧。第二氧化锌层22起到选择性调节及载流子传输的功能。第二氧化锌层22可以由不掺杂的氧化锌形成，也可以由掺杂的氧化锌形成，例如可以包括掺杂剂成分，如铝、镓、铟等元素，以及微量的过渡金属元素或稀土元素，如镍、铜、镧、铱、锕等。
在一个具体的实施方式中，第二氧化锌层22的厚度为10-200nm，例如可以为10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm、200nm，或这些数值之间的任何范围。
在一个具体的实施方式中，第二氧化锌层22为柱状晶体结构。柱状晶体结构有利于载流子的垂直输运，既从晶体硅内部向外部的输运过程。氧化锌晶体内部电子的迁移率较高既电子较小，晶体之间存在晶界会阻碍电子的迁移，也就是形成了电阻，柱状晶体在垂直方向电子小、横向方向电阻稍高但是可控，因此柱状晶体有利于第二层氧化锌实现电子向外输运的功能。
在一个具体的实施方式中，第二氧化锌层22是掺杂的氧化锌层，第二氧化锌层22的掺杂浓度大于第一氧化锌层21的掺杂浓度。
在一个具体的实施方式中，第二氧化锌层22的方阻小于第一氧化锌层21的方阻。
晶体硅吸收层1可以为本领域已知的n型或p型硅片，厚度为60-150μm。
前表面电极5设置在太阳能电池的受光面，并与第二氧化锌层22接 触。
本领域人员可以理解，根据实际需要，还可以在第二氧化锌层22远离晶体硅吸收层1的一侧设置前表面减反射层，前表面电极5贯穿所述前表面减反射层与第二氧化锌层22接触。
本申请的太阳能电池可以是在受光面包含上述结构的任何类型的太阳能电池，例如可以为发射极背面钝化电池、隧穿氧化层钝化接触电池、异质结电池等。本领域技术人员可以根据不同的太阳能电池类型，选择相应的背光面结构。
在一个具体的实施方式中，太阳能电池结构如图5所示，所述太阳能电池为发射极背面钝化电池，所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层，所述第一氧化硅层的厚度小于等于20个原子层。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背钝化层31、背面减反射层32和背表面电极5，背表面电极5贯穿背钝化层31和背面减反射层32与晶体硅吸收层1接触。
其中，背钝化层31可以为氧化铝单层或氧化铝与氧化硅的叠层结构。
在一个具体的实施方式中，太阳能电池结构如图5所示，所述太阳能电池为发射极背面钝化电池，所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层，所述第一氧化硅层的厚度小于等于20个原子层；第一氧化锌层21的厚度为3-10nm；第二氧化锌层22的厚度为10-200nm，第二氧化锌层22为柱状晶体结构，第二氧化锌层22是掺杂的氧化锌层。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背钝化层31、背面减反射层32和背表面电极5，背表面电极5贯穿背钝化层31和背面减反射层32与晶体硅吸收层1接触。
在一个具体的实施方式中，太阳能电池结构如图6所示，所述太阳能电池为隧穿氧化层钝化接触电池，所述太阳能电池包括晶体硅吸收层1，以及 在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层，所述第一氧化硅层的厚度小于等于20个原子层。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背隧穿钝化层61、第一背传输层62和背表面电极5。
其中，背隧穿钝化层61为氧化硅层。第一背传输层62，为p型掺杂多晶硅层。
本领域技术人员可以理解，根据实际需要，在第一背传输层62远离晶体硅吸收层1的一侧还设置有背面减反射层，背表面电极5贯穿所述背面减反射层与第一背传输层62接触。
在一个具体的实施方式中，太阳能电池结构如图6所示，所述太阳能电池为隧穿氧化层钝化接触电池，所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层，所述第一氧化硅层的厚度小于等于20个原子层；第一氧化锌层21的厚度为3-10nm；第二氧化锌层22的厚度为10-200nm，第二氧化锌层22为柱状晶体结构，第二氧化锌层22是掺杂的氧化锌层。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背隧穿钝化层61、第一背传输层62、背面减反射层和背表面电极5，背表面电极5贯穿所述背面减反射层与第一背传输层62接触。
在一个具体的实施方式中，太阳能电池结构如图7所示，所述太阳能电池为异质结电池，所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层，所述第一氧化硅层的厚度小于等于20个原子层。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有非晶硅钝化层71、第二背传输层72、第三背传输层73和背表面电极5。
其中，非晶硅钝化层71由非晶硅形成。第二背传输层72由p型掺杂非晶硅形成。第三背传输层73可以为ITO材料，或者本领域用作背传输层的 其他透明导电薄膜材料。
本领域技术人员可以理解，根据实际需要，在第三背传输层73远离晶体硅吸收层1的一侧还设置有背面减反射层，背表面电极5贯穿所述背面减反射层第三背传输层73接触。
在一个具体的实施方式中，太阳能电池结构如图7所示，所述太阳能电池为异质结电池，所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。其中，所述晶体硅吸收层1和所述第一氧化锌层21之间具有第一氧化硅层，所述第一氧化硅层的厚度小于等于20个原子层；第一氧化锌层21的厚度为3-10nm；第二氧化锌层22的厚度为10-200nm，第二氧化锌层22为柱状晶体结构，第二氧化锌层22是掺杂的氧化锌层。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有非晶硅钝化层71、第二背传输层72、第三背传输层73、背面减反射层和背表面电极5，背表面电极5贯穿所述背面减反射层第三背传输层73接触。
实施例
实施例1
太阳能电池结构如图5所示，所述太阳能电池为发射极背面钝化电池。所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背钝化层31、背面减反射层32和背表面电极5，背表面电极5贯穿背钝化层31和背面减反射层32与晶体硅吸收层1接触。
具体地，太阳能电池的制备步骤如下：
p型硅片采用常规电池情绪制绒扩散后，前表面获得pn结形成n型面，在n型面采用ALD工艺沉积第一氧化锌层21，在制备过程中采用乙醇锌作为含氧金属源，所采用的温度为250℃。制备得到的第一氧化锌层21的厚度为5nm。
该工艺可以获得几乎无界面氧化硅的第一氧化锌层，第一氧化硅层在后续工艺过程中有所增厚，总体厚度不超过20原子层。
第二氧化锌层22采用远距离等离子体磁控溅射制备，第二氧化锌层的厚度为30nm，并采用梯度掺杂方案，掺杂浓度从靠近第一氧化锌层21的一侧到远离第一氧化锌层21的一侧逐步提升。
太阳能电池其他部分的制备采用PERC电池通用工艺。
实施例2
太阳能电池结构如图6所示，所述太阳能电池为隧穿氧化层钝化接触电池。所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有背隧穿钝化层61、第一背传输层62、背面减反射层和背表面电极5，背表面电极5贯穿所述背面减反射层与第一背传输层62接触。
具体地，太阳能电池的制备步骤如下：
n型硅片采用常规电池清洗制绒后，不扩散pn结，在n型面采用ALD工艺沉积第一氧化锌层21，在制备过程中采用Zn(CH3)2作为含氧金属源，所采用的温度为200℃。制备得到的第一氧化锌层21的厚度为5nm。
该工艺可以获得几乎无界面氧化硅的第一氧化锌层，第一氧化硅层在后续工艺过程中有所增厚，总体厚度不超过20原子层。
第二氧化锌层22采用远距离等离子体磁控溅射制备，第二氧化锌层的厚度为30nm，并采用梯度掺杂方案，掺杂浓度从靠近第一氧化锌层21的一侧到远离第一氧化锌层21的一侧掺杂浓度逐步提升。
太阳能电池其他部分的制备采用背结TOPCon电池通用工艺。
实施例3
太阳能电池结构如图7所示，所述太阳能电池为异质结电池。所述太阳能电池包括晶体硅吸收层1，以及在晶体硅吸收层1的受光面依次层叠设置的第一氧化锌层21、第二氧化锌层22和前表面电极4。所述太阳能电池在晶体硅吸收层1的背光面依次层叠设置有非晶硅钝化层71、第二背传输层72、第三背传输层73、背面减反射层和背表面电极5，背表面电极5贯穿所述背面减反射层第三背传输层73接触。
具体地，太阳能电池的制备步骤如下：
n型硅片采用常规电池清洗后，不扩散pn结，在n型面采用ALD工艺沉积第一氧化锌层21，在制备过程中采用乙醇锌作为含氧金属源，所采用的温度为350℃。制备得到的第一氧化锌层21的厚度为5nm。
该工艺可以获得具备厚度约8个原子层的第一氧化硅层，由于其他工艺无高温过程，第一氧化硅层在后续工艺过程中不会发生变化。
第二氧化锌层22采用远距离等离子体磁控溅射制备，第二氧化锌层厚度30nm，并采用梯度掺杂方案，掺杂浓度从靠近第一氧化锌层21的一侧到远离第一氧化锌层21的一侧掺杂浓度逐步提升。
太阳能电池其他部分的制备采用背结HJT电池通用工艺。
在上述实施方式的描述中，具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (21)

  1. 一种太阳能电池，其包括晶体硅吸收层，以及在所述晶体硅吸收层的受光面依次层叠设置的第一氧化硅层、第一宽带隙金属氧化物层、第一保护层和前表面电极，
    其中，所述第一宽带隙金属氧化物层由掺杂的金属氧化物形成，所述第一宽带隙金属氧化物层中掺杂的元素通过所述第一氧化硅层向所述晶体硅吸收层扩散，形成第一掺杂区。
  2. 根据权利要求1所述的太阳能电池，其中所述第一氧化硅层的厚度为0.5-4nm。
  3. 根据权利要求1所述的太阳能电池，所述第一氧化硅层的厚度小于等于20个原子层，优选地，所述第一氧化硅层的厚度小于等于8个原子层。
  4. 根据权利要求1或2所述的太阳能电池，其中所述第一氧化硅层具有通过煅烧形成的孔洞。
  5. 根据权利要求1-4中任一项所述的太阳能电池，其中所述第一宽带隙金属氧化物层包括第一氧化锌层和第二氧化锌层，所述第一氧化锌层的厚度为3-10nm，所述第二氧化锌层的厚度为10-200nm；
    或，所述第二氧化锌层是掺杂的氧化锌层，所述第二氧化锌层的掺杂浓度大于所述第一氧化锌层的掺杂浓度；
    或，所述第二氧化锌层的方阻小于所述第一氧化锌层的方阻。
  6. 根据权利要求5所述的太阳能电池，所述第二氧化锌层为柱状晶体结构。
  7. 根据全要求6所述的太阳能电池，在所述第二氧化锌层远离所述晶体硅吸收层的一侧还设置有前表面减反射层，所述前表面电极贯穿所述前表面减反射层与所述第二氧化锌层接触。
  8. 根据权利要求1-7中任一项所述的太阳能电池，其中所述第一宽带隙金属氧化物层的多晶化程度从靠近所述第一氧化物层的一侧到远离所述第一氧化物层的一侧递增。
  9. 根据权利要求1-8中任一项所述的太阳能电池，其中所述第一保护层的材料选自氮化硅、氧化钛、硫化锌、氧化铝、氮化铝、氧化硅等中的一种或两种以上。
  10. 根据权利要求1-9中任一项所述的太阳能电池，其中所述第一 保护层的厚度为10-100nm。
  11. 根据权利要求1-10中任一项所述的太阳能电池，其中所述前表面电极贯穿所述第一保护层与所述第一宽带隙金属氧化物层接触。
  12. 根据权利要求1-11中任一项所述的太阳能电池，其中在所述第一保护层远离所述晶体硅吸收层的一侧还设置有前表面减反射层，所述前表面电极贯穿所述前表面减反射层和所述第一保护层与所述第一宽带隙金属氧化物层接触。
  13. 根据权利要求1-12中任一项所述的太阳能电池，其中所述太阳能电池还包括在所述晶体硅吸收层的背光面依次层叠设置的第二氧化硅层、第二宽带隙金属氧化物层、第二保护层和背表面电极，所述背表面电极贯穿所述第二保护层与所述第二宽带隙金属氧化物层接触，
    其中，所述第二宽带隙金属氧化物层由掺杂的金属氧化物形成，所述第二宽带隙金属氧化物层中掺杂的元素通过所述第二氧化硅层向所述晶体硅吸收层扩散，形成第二掺杂区，
    所述第二宽带隙金属氧化物层和所述第一宽带隙金属氧化物层的电荷传输性质相反。
  14. 根据权利要求13所述的太阳能电池，其中所述第二氧化硅层的厚度为0.5-4nm。
  15. 根据权利要求13或14所述的太阳能电池，其中所述第二氧化硅层具有通过煅烧形成的孔洞。
  16. 根据权利要求13-15中任一项所述的太阳能电池，其中所述第一宽带隙金属氧化物层，或所述第二宽带隙金属氧化物层所使用的金属氧化物选自氧化锌、氧化锡、氧化钼、氧化钛、氧化镍、氧化镓、氧化铟、氧化铜、氧化镁、氧化铝、氧化钨、氧化铈、氧化锰、氧化钒、氧化铬、氧化钴、氧化锗、氧化镉、氧化铼等中的一种或两种以上。
  17. 根据权利要求13-16中任一项所述的太阳能电池，其中所述第一宽带隙金属氧化物层，或所述第二宽带隙金属氧化物层的厚度为10-200nm。
  18. 根据权利要求13-17中任一项所述的太阳能电池，其中所述第二宽带隙金属氧化物层的多晶化程度从靠近所述第二氧化物层的一侧到远离所述第二氧化物层的一侧递增。
  19. 根据权利要求13-18中任一项所述的太阳能电池，其中所述第 二保护层的材料选自氮化硅或氮化铝。
  20. 根据权利要求13-19中任一项所述的太阳能电池，其中所述第二保护层的厚度为10-100nm。
  21. 根据权利要求13-20中任一项所述的太阳能电池，其中在所述第二保护层远离所述晶体硅吸收层的一侧还设置有背面减反射层，所述背表面电极贯穿所述背面减反射层和所述第二保护层与所述第二宽带隙金属氧化物层接触。
PCT/CN2024/088443 2023-04-17 2024-04-17 太阳能电池 Ceased WO2024217475A1 (zh)

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CN202310444710.2A CN118507539A (zh) 2023-04-23 2023-04-23 前表面具有多层氧化锌结构的太阳能电池
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