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EP-4739038-A1 - SOLAR CELL UNIT AND MANUFACTURING METHOD THEREFOR

EP4739038A1EP 4739038 A1EP4739038 A1EP 4739038A1EP-4739038-A1

Abstract

Embodiments of the present disclosure provide a solar cell unit and a manufacturing method therefor. The solar cell unit comprises: a silicon substrate which is an n-type silicon substrate; a passivation layer; a seed layer; an interfacial energy level adjustment layer which is a p-type hydrogenated doped silicon layer; and a first p-type conductive layer. The passivation layer, the seed layer, the interfacial energy level adjustment layer, and the first p-type conductive layer are successively stacked on a first side of the silicon substrate, and the passivation layer is closest to the silicon substrate. The interfacial energy level adjustment layer contains a silicon element, an oxygen element, a carbon element, a hydrogen element, and a boron element. The band gap of the interfacial energy level adjustment layer is 1.9-2.3 eV, and the thickness of the interfacial energy level adjustment layer is 0.5-4 nm.

Inventors

  • CHEN, Xiaoye
  • ZHANG, JUNBING
  • JIANG, Xiulin

Assignees

  • Ja Solar Technology Yangzhou Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240131

Claims (20)

  1. A solar cell, comprising: a silicon substrate, which is an n-type silicon substrate; a passivation layer; a seed layer; an interface energy-level modification layer, which is a p-type hydrogenated doped silicon layer; and a first p-type conductive layer; wherein the passivation layer, the seed layer, the interface energy-level modification layer, and the first p-type conductive layer are sequentially stacked in at least a partial area of a first surface on a first side of the silicon substrate, and the passivation layer is closest to the silicon substrate, wherein the interface energy-level modification layer comprises silicon, oxygen, carbon, hydrogen and boron, wherein a bandgap width of the interface energy-level modification layer is in a range of 1.9 to 2.3 eV, and a thickness of the interface energy-level modification layer is in a range of 0.5 to 4 nm.
  2. The solar cell according to claim 1, wherein, the thickness of the interface energy-level modification layer is in a range of 0.7 to 1.8 nm.
  3. The solar cell according to claim 1 or 2, wherein, the interface energy-level modification layer is a hydrogenated amorphous silicon layer and is embedded with crystallized silicon, and a crystallization rate of the interface energy-level modification layer is in a range of 30 to 65%.
  4. The solar cell according to any one of claims 1-3, wherein, the interface energy-level modification layer includes Si-Si, Si-O, Si-C, Si-B, C-C, C-O, C=O, C-B and B-O chemical bonds.
  5. The solar cell according to claim 4, wherein, a total molar content of the carbon and the oxygen in the interface energy-level modification layer is in a range of 18 to 45%, and a concentration of active boron atoms in the interface energy-level modification layer is in a range of 5×10 17 to 5×10 19 atoms per cubic centimeter.
  6. The solar cell according to claim 5, wherein, a molar content of the carbon in the interface energy-level modification layer is in a range of 8-16%, and the carbon exists by forming Si-C, C-C, C-O, C=O, C-B and C-H chemical bonds, molar ratios of the carbon existing through Si-C, C-C, C-O, C=O, C-B and C-H chemical bonds to all carbon are 30-54%, 30-45%, 8-14%, 1-5%, 3-7% and 3-9%, respectively.
  7. The solar cell according to claim 5 or 6, wherein, a molar content of the oxygen in the interface energy-level modification layer is in a range of 18-32%, and the oxygen exists by forming Si-O, C-O and B-O chemical bonds, molar ratios of the oxygen existing through Si-O, C-O and B-O chemical bonds to all oxygen are 78-92%, 6-15% and 4-11%, respectively.
  8. The solar cell according to any one of claims 5-7, wherein, a molar content of the silicon in the interface energy-level modification layer is in a range of 50-65%, and the silicon exists by forming Si-Si, Si-O, Si-C, Si-B and Si-H chemical bonds, a molar ratio of silicon existing through Si-Si, Si-B and Si-H chemical bonds to all silicon is 40-60%, a molar ratio of silicon existing through Si-O chemical bonds to all silicon is 35-45%, and a molar ratio of silicon existing through Si-C chemical bonds to all silicon is 7-12%.
  9. The solar cell according to any one of claims 5-8, wherein, a molar content of boron in the interface energy-level modification layer is in a range of 1-5%, inactive boron atoms exist in the layer in form of B-O, B-C, B-B and B-H.
  10. The solar cell according to any one of claims 5-9, wherein, in the interface energy-level modification layer, in a direction away from the silicon substrate, a concentration of the active boron atoms increases and a crystallization rate of the interface energy-level modification layer increases.
  11. The solar cell according to any one of claims 1-10, wherein, the passivation layer is a hydrogenated amorphous silicon layer, and in the passivation layer, a concentration of hydrogen atoms decreases in a direction away from the silicon substrate.
  12. The solar cell according to any one of claims 1-11, wherein, the first p-type conductive layer is a p-type microcrystalline silicon layer, a crystallization rate of the first p-type conductive layer is in a range of 30-70%, in the first p-type conductive layer, a crystallization rate increases in a direction away from the silicon substrate.
  13. The solar cell according to any one of claims 1-12, wherein, the passivation layer is a hydrogenated amorphous silicon layer, the first p-type conductive layer is a p-type microcrystalline silicon layer, a thickness of the passivation layer is in a range of 5-8 nm, a thickness of the seed layer is smaller than 1 nm, a thickness of the first p-type conductive layer is in a range of 20-38 nm.
  14. The solar cell according to any one of claims 1-13, further comprises: a second p-type conductive layer, disposed on the first p-type conductive layer and further away from the silicon substrate than the first p-type conductive layer.
  15. The solar cell according to claim 14, wherein, the second p-type conductive layer is a boron-doped amorphous silicon layer, wherein a concentration of active boron atoms in the second p-type conductive layer is in a range of 2×10 18 -1×10 19 atoms per cubic centimeter, a thickness of the second p-type conductive layer is in a range of 0.5-3 nm.
  16. The solar cell according to any one of claims 1-15, wherein, the first side is a backlight side of the solar cell.
  17. The solar cell according to any one of claims 1-16, further comprising: a second passivation layer; and an n-type conductive layer, wherein the second passivation layer and the n-type conductive layer are sequentially stacked on a second surface on a second side of the silicon substrate, the second side is opposite to the first side, and the second passivation layer is closest to the silicon substrate.
  18. The solar cell according to any one of claims 1-17, further comprising: a second passivation layer; and an n-type conductive layer, wherein the passivation layer, the seed layer, the interface energy-level modification layer, the first p-type conductive layer and the second p-type conductive layer are sequentially stacked in a p area on the first surface on the first side of the silicon substrate, the second passivation layer and the n-type conductive layer are sequentially stacked in an n area different from the p area on the first surface of the silicon substrate.
  19. A manufacturing method of a solar cell, used for manufacturing the solar cell according to any one of claims 1-18, the method comprising: providing a silicon substrate; and sequentially stacking a passivation layer, a seed layer, an interface energy-level modification layer, and a first p-type conductive layer in at least a partial area of the first surface on the first side of the silicon substrate, wherein a bandgap width of the interface energy-level modification layer is in a range of 1.9 to 2.3 eV, and a thickness of the interface energy-level modification layer is in a range of 0.5 to 4 nm.
  20. The manufacturing method according to claim 19, wherein: the interface energy-level modification layer is formed by using reaction gas under the conditions that a pressure of reaction cavity is in a range of 2.5-3.5 Torr and a radio frequency power density is in a range of 260-340 mW/cm 2 , the silicon of the interface energy-level modification layer is from one or more selected from a group consisting of SiH 4 and Si2H 6 , the boron of the interface energy-level modification layer is from one or more selected from a group consisting of TMB, B 2 H 6 and BF 3 , the hydrogen of the interface energy-level modification layer is from one or more selected from a group consisting of H 2 , SiH 4 , B 2 H 6 and TMB, the oxygen of the interface energy-level modification layer is from one or more selected from a group consisting of N 2 O, O 2 , CO and CO 2 , and the carbon of the interface energy-level modification layer is from one or more selected from a group consisting of CO 2 , CO, CH 4 , C 2 H 6 , C 3 H 10 and C 2 H 4 .

Description

The present application claims the priority of China Patent Application No. 202310942977.4 filed on July 28, 2023, titled with "SOLAR CELL AND MANUFACTURING METHOD THEREOF", and the disclosure of the above-mentioned China Patent Application is hereby incorporated in its entirety as a part of the present application. TECHNICAL FIELD The embodiments of the present disclosure relate to a solar cell and a manufacturing method of a solar cell. BACKGROUND Crystalline silicon-based heterojunction solar cell is a semiconductor device that can convert solar energy into electric power output. Generally, a heterojunction solar cell is manufactured by using an n-type silicon substrate, the heterojunction solar cell includes a silicon substrate, two passivation layers on both sides of the silicon substrate, and doped conductive layers on the passivation layers on both sides respectively. The manufacturing process of the silicon-based heterojunction solar cell is provided as follows: depositing hydrogenated amorphous silicon layers on both sides of the textured silicon substrate, respectively depositing a phosphorus-doped silicon layer and a boron-doped silicon layer on the surfaces of the hydrogenated amorphous silicon layers on both sides, depositing transparent conductive ITO (indium tin oxide) layers on the surfaces of the doped silicon layers, and finally forming electrodes on the ITO layers. The heterojunction solar cell has many advantages: high cell efficiency, no attenuation, few process steps and low energy consumption (the temperature is below 300 degrees). At present, the main factor limiting the large-scale market occupation of heterojunction solar cells is that the manufacturing cost is slightly higher than other photovoltaic cells. Therefore, it is still the development direction of heterojunction solar cell to continuously improve the photoelectric conversion efficiency and improve the cost performance of heterojunction solar cell. SUMMARY At least one embodiment of the present disclosure provides a solar cell, which includes: a silicon substrate, which is an n-type silicon substrate; a passivation layer; a seed layer; an interface energy-level modification layer, which is a p-type hydrogenated doped silicon layer; and a first p-type conductive layer. The passivation layer, the seed layer, the interface energy-level modification layer, and the first p-type conductive layer are sequentially stacked in at least a part of an area of a first surface on a first side of the silicon substrate, and the passivation layer is closest to the silicon substrate, the interface energy-level modification layer includes silicon, oxygen, carbon, hydrogen and boron. For example, in some embodiments, a thickness of the interface energy-level modification layer is in a range of 0.5 to 4 nm. For example, in some embodiments, the thickness of the interface energy-level modification layer is in a range of 0. 7 to 1.8 nm. For example, in some embodiments, a bandgap width of the interface energy-level modification layer is in a range of 1.9 to 2.3 eV. For example, in some embodiments, the interface energy-level modification layer is a hydrogenated amorphous silicon layer and is embedded with crystallized silicon, and a crystallization rate of the interface energy-level modification layer is in a range of 30 to 65%. For example, in some embodiments, the interface energy-level modification layer includes Si-Si, Si-O, Si-C, Si-B, C-C, C-O, C=O, C-B and B-O chemical bonds. For example, in some embodiments, a total molar content of the carbon and the oxygen in the interface energy-level modification layer is in a range of 18 to 45%. A concentration of active boron atoms in the interface energy-level modification layer is in a range of 5×1017 to 5×1019 atoms per cubic centimeter. For example, in some embodiments, a molar content of the carbon in the interface energy-level modification layer is in a range of 8-16%, and the carbon exists by forming Si-C, C-C, C-O, C=O, C-B and C-H chemical bonds. Molar ratios of carbon existing through Si-C, C-C, C-O, C=O, C-B and C-H chemical bonds to all carbon are 30-54%, 30-45%, 8-14%, 1-5%, 3-7% and 3-9%, respectively. For example, in some embodiments, a molar content of the oxygen in the interface energy-level modification layer is in a range of 18-32%, and the oxygen exists by forming Si-O, C-O and B-O chemical bonds. Molar ratios of oxygens existing through Si-O, C-O and B-O chemical bonds to all oxygen are 78-92%, 6-15% and 4-11%, respectively. For example, in some embodiments, a molar content of the silicon in the interface energy-level modification layer is in a range of 50-65%, and the silicon exists by forming Si-Si, Si-O, Si-C, Si-B and Si-H chemical bonds, a molar ratio of silicon existing through Si-Si, Si-B and Si-H chemical bonds to all silicon is 40-60%, a molar ratio of silicon existing through Si-O chemical bonds to all silicon is 35-45%, and a molar ratio of silicon existing through S