Preparation method of solar cell

Abstract

The invention discloses a preparation method of a solar cell, and belongs to the field of solar cells. The method further comprises the following steps: S1, sequentially carrying out a gettering process and a texturing process on the two surfaces of the N-type crystalline silicon substrate, so that a textured surface is formed on the surface of the N-type crystalline silicon substrate; s2, sequentially setting an amorphous process and a microcrystal process on the surface of the N-type crystalline silicon substrate to form a PN junction; s3, preparing a first transparent conductive film on the N surface of the PN junction through a conventional ITO target material; s4, preparing a second transparent conductive film on the P surface of the PN junction through a doped ITO target material; s5, metal electrodes are evaporated on the N surface and the P surface of the PN junction; according to the scheme, the crystal structure of the thin film can be changed by doping ITO, film layer absorption and crystal boundary reflection are enhanced, and then the short-circuit current of the cell is effectively improved; compared with conventional high-mobility ITO which is high in price and prone to nodulation, the lightly-doped ITO has the obvious advantage in price, nodulation is not prone to occurring, and the effect of reducing cost is achieved.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and more specifically, to a method for preparing a solar cell. Background Art

[0002] At present, the structure of HJT solar cells in the industry is as follows: an intrinsic amorphous / microcrystalline silicon thin film layer, an n-type amorphous / microcrystalline silicon layer, and a boron-doped p-type amorphous / microcrystalline silicon layer are successively deposited on both sides of an n-type silicon wafer substrate to form a heterojunction PN junction; then, a transparent conductive oxide layer is deposited on the doped amorphous / microcrystalline silicon thin film by magnetron sputtering method, and finally, silver paste grid lines are printed on the transparent conductive oxide layer to form electrodes.

[0003] In HJT solar cells, the N side is the light-receiving surface and the P side is the non-light-receiving surface; however, when preparing the conventional TCO film layer, the same doped ITO target is used for both the N and P sides. Due to the special structure of HJT cells, using the same doped ITO target for both the N and P sides is not beneficial to the cell efficiency. The TCO thin film prepared in this way has small grain size and low short-circuit current, and there are large contact problems with the amorphous / microcrystalline silicon film layer and even the silver paste interface, which also limits the further improvement of cell efficiency. At present, the conventional TCO target in the industry is a high-doped target, which has high procurement cost and is prone to nodulation, seriously affecting subsequent production.

[0004] However, in the prior art, when using a conventional ITO target for the P side, H2 needs to be doped, the process atmosphere is unstable, and water vapor is difficult to control. Too high or too low water vapor will cause poor interfacial contact between the TCO film layer and the amorphous / microcrystalline silicon and silver paste, resulting in a decrease in efficiency; and the film layer has slightly lower reflectivity, smaller grain size, and low short-circuit current.

[0005] Therefore, a method for preparing a solar cell is proposed. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing a solar cell.

[0007] To solve the above problems, the present invention adopts the following technical solutions.

[0008] A method for preparing a solar cell, including an n-type crystalline silicon substrate;

[0009] The method further includes the following steps:

[0010] S1. Perform a gettering process and a texturing process on both sides of the n-type crystalline silicon substrate in sequence to form a textured surface on the surface of the n-type crystalline silicon substrate;

[0011] S2. Set an amorphous and microcrystalline process on the surface of the n-type crystalline silicon substrate in sequence to form a PN junction;

[0012] On the N side of the PN junctions in S3 and S2, a first transparent conductive thin film is prepared using a conventional ITO target.

[0013] On the P side of the PN junctions in S4 and S2, a second transparent conductive thin film is prepared using a doped ITO target.

[0014] In S5, metal electrodes are deposited on the N side and the P side of the PN junctions.

[0015] Further, the doping components in S4 are oxides of In2O3, SnO2, X, ZrO2, and HfO2 in a certain ratio; a multi - oxide - doped indium oxide - based target is prepared by doping indium oxide, where X is any one or several of Mo, V, W, Ta, Nb, and Cr.

[0016] Further, in S4, the second transparent conductive thin film is prepared on the P side of the PN junction by magnetron sputtering; the thickness of the second transparent conductive thin film is 80 nm to 110 nm.

[0017] Further, in S4, the magnetron sputtering gas pressure is 0.3 Pa to 1.0 Pa;

[0018] the oxygen content is 1% to 40%;

[0019] the power is 1 to 15 KW;

[0020] the water vapor value pressure is 5×10^(-2) to 5×10^(-5) Pa.

[0021] Further, the thickness of the metal electrodes in S5 is 80 - 500 nm

[0022] Further, the metal electrode is any one of Au, Ag, Cu, and Al.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] In this solution, doping ITO can change the crystal structure of the thin film, enhance the film absorption and grain - boundary reflection, and thus effectively improve the short - circuit current of the battery; compared with the conventional high - mobility ITO which is expensive and prone to nodulation, the lightly - doped ITO of the present invention has an obvious price advantage and is not prone to nodulation, playing a role in reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flowchart for preparing a solar cell according to the present invention;

[0026] Figure 2 is a schematic structural diagram of the solar cell according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Embodiment 1:

[0029] Please refer to Figures 1 to 2 , a preparation method of a solar cell, including an N-type crystalline silicon substrate;

[0030] The method further includes the following steps:

[0031] S1. Perform a gettering process and a texturing process on both sides of the N-type crystalline silicon substrate in sequence to form a textured surface on the surface of the N-type crystalline silicon substrate;

[0032] S2. Set an amorphous and microcrystalline process on the surface of the N-type crystalline silicon substrate in sequence to form a PN junction;

[0033] S3. Prepare a first transparent conductive film on the N surface of the PN junction in S2 through a conventional ITO target;

[0034] S4. Prepare a second transparent conductive film on the P surface of the PN junction in S2 through a doped ITO target;

[0035] S5. Evaporate metal electrodes on the N surface and the P surface of the PN junction.

[0036] As Figure 1 shown, the doping components in S4 are oxides of In2O3, SnO2, X, ZrO2, and HfO2 in a certain ratio; a multi-component oxide-doped indium oxide-based target is prepared by doping indium oxide, where X is any one or more of Mo, V, W, Ta, Nb, and Cr.

[0037] As Figure 2 shown, in S4, the P surface of the PN junction is sputtered with a second transparent conductive film by magnetron sputtering; the thickness of the second transparent conductive film is 80 nm to 110 nm.

[0038] As Figure 1 shown, in S4, the magnetron sputtering gas pressure is 0.3 Pa to 1.0 Pa;

[0039] the oxygen content is 1% to 40%;

[0040] the power is 1 to 15 KW;

[0041] the water vapor value pressure is 5×10⁻² to 5×10⁻⁵ Pa.

[0042] AsFigure 2 As shown, the thickness of the metal electrode in S5 is 80 - 500 nm

[0043] As Figure 2 shown, the metal electrode is any one of Au, Ag, Cu, and Al.

[0044] As mentioned above, it is only a preferred specific embodiment of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and its improved concept of the present invention, making equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a solar cell, comprising an N-type crystalline silicon substrate; Features: The following steps are also included: S1, performing a gettering process and a texturing process on both sides of an N-type crystalline silicon substrate in sequence, so that a textured surface is formed on the surface of the N-type crystalline silicon substrate; S2, sequentially setting amorphous and microcrystalline processes on the surface of the N-type crystalline silicon substrate to form a PN junction; The N-side of the PN junction in S3 and S2 is used to prepare the first transparent conductive film through a conventional ITO target material; The P surface of the PN junction in S4 and S2 is prepared as a second transparent conductive film by using a doped ITO target material; S5. Evaporate metal electrodes on the N-side and P-side of the PN junction.

2. The method for preparing a solar cell according to claim 1, characterized in that: The doping components in the S4 are In2O3, SnO2, X oxide, ZrO2, and HfO2 in a certain ratio; indium oxide is doped to obtain a multi-oxide doped indium oxide-based target.

3. The method for preparing a solar cell according to claim 2, characterized in that: In the above S4, the P surface of the PN junction is coated with a second transparent conductive film by magnetron sputtering; the thickness of the second transparent conductive film is 80 nm to 110 nm.

4. The method for preparing a solar cell according to claim 3, characterized in that: In S4, the magnetron sputtering gas pressure is 0.3Pa to 1.0Pa; Oxygen content is 1% to 40%; Power is 1~15KW; Water vapor pressure value 5*E-2~5*E-5Pa.

5. The method for preparing a solar cell according to claim 4, characterized in that: The thickness of the metal electrode in S5 is 80-500nm.

6. The method for preparing a solar cell according to claim 5, characterized in that: The metal electrode is any one of Au, Ag, Cu and Al.

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