Double-knot-film solar battery component and manufacturing method thereof

Abstract

The invention discloses a double-knot-film solar battery component and a manufacturing method thereof. The solar battery component comprises a plurality of battery units connected in series. Each battery unit comprises a bottom cell and a top cell. The bottom cell is provided with a back face metal electrode layer. The top cell is provided with a graphical front face metal electrode layer. The bottom cell is a polycrystalline Ge base cell layer; the top cell is a GaAs (gallium arsenide) cell. From the polycrystalline Ge base cell layer to the top cell, the following elements grow in order: an N-type diffusion layer, an N-type buffer layer, a tunnel junction N-type region and a tunnel junction P-type region. An antireflective layer is formed on the front face metal electrode layer. According to the invention, the GaAs substrate, the polycrystalline germanium and the GaAs are utilized as the bottom cell and the double-knot cells of the top cell respectively wherein firstly, the band gap of the polycrystalline germanium bottom cell is 0.65eV while the band gap of the top cell GaAs is 1.4eV. This combination is more favorable for segmenting solar spectrums, for forming proper current matching and for further absorbing the light rays whose wavelengths range from 900nm to 2000nm. The battery conversion efficiency could be as high as 32% (AM1.5).

Description

technical field [0001] The present invention relates to a manufacturing method of a III-V double-junction thin-film solar cell assembly, more specifically, relates to a double-junction thin-film solar cell assembly with polycrystalline germanium as the bottom cell and gallium arsenide as the top cell and its manufacturing method . Background technique [0002] In 1954, it was first discovered that GaAs material has photovoltaic effect in the world. In the 1960s, Gobat et al. developed the first zinc-doped GaAs solar cell, with a conversion rate of only 9% to 10%, far lower than the theoretical value of 27%. The earliest monocrystalline GaAs cells were basically the same as the current monocrystalline silicon, but as a direct bandgap semiconductor, the thickness of the absorbing layer only needs to be a few microns, and crystalline GaAs is undoubtedly a huge waste. [0003] In the 1970s, research institutes represented by IBM and the Ioffe Technical Physics Institute of the ...

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Problems solved by technology

[0007] In addition, the thickness of the absorption layer of the double-junction GaAs and GaInP is relatively large, resulting in the overall thickness of the cell being greater than 10 μm

However, the thickness of flexible thin-film batteries is generally required to be between 1-10 μm, and this type of double-junction battery cannot achieve battery flexibility.

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