A silicon-based heterojunction solar cell and its preparation method

Abstract

The invention discloses a silicon-based heterojunction solar cell which comprises grid electrodes, a transparent conductive film, a boron-doped amorphous silicon, an intrinsic amorphous silicon, an N-type monocrystalline and a back electrode in sequence, wherein the back electrode is formed by a distributed Bragg reflector and an aluminum thin film, the distributed Bragg reflector is formed by arranging niobium-doped titanium dioxide thin films and aluminum-doped zinc oxide thin films at intervals, and the aluminum thin film is arranged on the surface layer of the aluminum-doped zinc oxide thin film on the outermost layer of the distributed Bragg reflector. The distributed Bragg reflector used as the back electrode consists of two transparent conductive films with different refraction indexes, so that the resistance of the cell device connected in series is reduced, the collection of current carriers is facilitated, and the photoelectric conversion efficiency of the cell is high; and by adopting the back-reflecting electrode formed by combining the distributed Bragg reflector and the aluminum anode, the long wave band of the near infrared part with characteristic wavelength can be reflected to the inside of the crystalline silicon wafer to be reabsorbed through the two layers of conductive films with different refractive indexes, so that both the current and the photoelectric conversion efficiency of the cell are improved.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a thin-film silicon / crystalline silicon heterojunction cell with a high back reflection electrode and a preparation method thereof. Background technique [0002] Thin-film silicon / crystalline silicon heterojunction solar cells combine the advantages of thin-film solar cells and crystalline silicon solar cells, and have excellent application prospects. Based on crystalline silicon wafers as photoelectric absorption layers, they have high current density and good photoelectric conversion stability. The preparation process is mainly a low-temperature process in the process of thin-film solar cells, so that compared with the high-temperature process of crystalline silicon preparation, its cost can be effectively controlled at a low level. In addition, the photoelectric conversion efficiency of the heterojunction cell is much higher than that of thin-film The solar cell needs to b...

AI Technical Summary

Problems solved by technology

However, the existing distributed Bragg reflector is composed of transparent conductive films and semiconductor thin films with different refractive indices from the transparent conductive films. Its resistivity is too large and its conductivity is not good. When the back reflection electrode of thin film silicon / crystalline silicon heterojunction cells is used, the actual use effect is not good

In the prior art, there is no transparent conductive film for both layers, because the refractive index of the two materials is required to be different, and the existing transparent conductive film has little difference in refractive index, which can be considered the same

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