Preparation method of absorption layer of thin film solar cell

Abstract

The invention provides a preparation method of an absorption layer of a thin film solar cell, comprising the following steps of: providing a substrate which is provided with a p-type silica-based thin film layer; and repeatedly and alternatively carrying out hydrogenation treatment on the p-type silica-based thin film layer and depositing an intrinsic silica-based thin film layer, wherein the hydrogenation treatment comprises hydrogen plasma treatment. In the preparation method, the hydrogenation treatment can enable dangling bonds in the p-type or intrinsic silica-based thin film layer to be saturated by hydrogen, which can effectively reduce the defect states at a p-i interface and inside the intrinsic silica-based thin film and ensures that the comprehensive performance of the absorption layer is optimized, thereby improving the cell property; secondly, the deposition rate of the intrinsic silica-based thin film layer gradually increases in the process of repeatedly and alternatively carrying out the hydrogenation treatment and depositing the intrinsic silica-based thin film layer, and the deposition rate of the intrinsic silica-based thin film layer in every deposition process is greater than the former deposition rate, therefore, the average deposition rate can be improved, and the manufacturing capacity of solar cells can be promoted.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a method for preparing an absorbing layer of a thin-film solar cell. Background technique [0002] At present, thin-film solar cells mainly include: amorphous silicon single-junction or double-junction thin-film batteries, amorphous silicon and microcrystalline silicon stacked thin-film batteries, and triple-junction silicon-based thin-film batteries. Material. Amorphous silicon thin-film batteries are relatively mature in industrialization and have low manufacturing costs, but there is a serious problem of efficiency attenuation; amorphous silicon and microcrystalline silicon stacked thin-film batteries have the characteristics of high efficiency and high stability, and have won a lot of attention in recent years. Rapid development. [0003] figure 1 It is a schematic diagram of an amorphous silicon and microcrystalline silicon stacked thin film battery, in which the stac...

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Problems solved by technology

However, there are still some problems in the amorphous silicon and microcrystalline silicon stacked thin film battery itself: first, the interface problem, due to the introduction of the microcrystalline silicon layer, the number of heterojunction interfaces in the absorber layer increases, such as p-type microcrystalline silicon layer and The interface of the intrinsic microcrystalline silicon layer (p-i interface), due to the structure and composition mismatch on the interface (lattice constant mismatch), will cause the increase of series resistance, the decrease of photocurrent density, and the decrease of fill factor, etc. The second is the problem of the material of the absorbing layer itself. Fig. 2 is a schematic diagram of the microstructure of the amorphous silicon layer and the microcrystalline silicon layer material. As shown in the figure, there are many dangling bonds ( As shown by the black dots in the figure), it is necessary to introduce hydrogen atoms to saturate these dangling bonds. When the introduced hydrogen is excessive or insufficient, holes or residual dangling bonds will be formed, which will become the final defect state of the absorbing layer, resulting in battery efficiency. and the decline of stability; the third is the problem of production efficiency. Usually, the thickness of the absorbing layer of laminated thin-film batteries is usually 1-2 microns, which is several times higher than the thickness of the absorbing layer (300-500nm) of amorphous silicon thin-film batteries. The improvement of production efficiency, so the production cost is high, which is not conducive to industrial mass production

However, the above solutions can only solve the interface problem, and the buffer layer needs to be deposited by Hot Wires Chemical Vapor Deposition (HWCVD). This deposition method has problems such as high process temperature, which is not conducive to the production of industrial microcrystalline silicon cells. Produce

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