Solar cell back passive film layer structure and preparation method thereof

Abstract

The present invention provides a solar cell back passive film layer structure. The main improvement is that: an alumina film, a first silicon nitride film and a second silicon nitride film are formed in order at the solar cell substrate back surface to form a multi-layer back passive film lamination structure; the film thickness of the alumina film is in the range of 10-40nm, and the refractive index of the alumina film is in the range of 1.55-1.70; the film thickness of the first silicon nitride film is in the range of 40-100nm, and the refractive index of the first silicon nitride film is in the range of 1.90-2.20; and the film thickness of the second silicon nitride film is in the range of 40-100nm, and the refractive index of the second silicon nitride film is in the range of 1.90-2.20. Optimally, the film thickness of the alumina film is 20nm, and the refractive index of the alumina film is 1.62nm; the film thickness of the first silicon nitride film is 75nm, and the refractive index of the first silicon nitride film is 2.10; and the film thickness of the second silicon nitride film is 75nm, and the refractive index of the second silicon nitride film is 2.00. The conversion efficiency of the solar cell is improved.

Description

technical field [0001] The invention relates to a solar cell, in particular to a back passivation film layer structure which can improve the conversion efficiency of the solar cell. Background technique [0002] In recent years, with the continuous improvement of the quality of crystalline silicon materials and the technology of the front surface of the battery, the efficiency of the battery has been greatly improved, but the serious optical and electrical losses on the back surface of the battery have become a bottleneck restricting the further improvement of the battery efficiency. The back passivation cell with aluminum oxide / silicon nitride (AlOx / SiNx) passivation can not only greatly reduce the electrical recombination rate of the back surface, but also form a good internal optical back reflection mechanism, which has become an alternative to the traditional all-aluminum back field cell. The next generation of crystalline solar cell technology. Among them, a good back ...

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Problems solved by technology

[0002] In recent years, with the continuous improvement of the quality of crystalline silicon materials and the technology of the front surface of the battery, the efficiency of the battery has been greatly improved, but the serious optical and electrical losses on the back surface of the battery have become a bottleneck restricting the further improvement of the battery efficiency.

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