An efficient six-junction solar cell grown on double sides and a preparation method thereof

Abstract

The invention discloses a efficient six-junction solar cell grown on double sides and a preparation method thereof, by means of metal organic chemical vapor deposition, based on a double-sided polished n-type GaAs single crystal wafer, a GaAs buffer layer, a GaAs sub-cell, an AlGaAs sub-cell and an AlGaInP sub-cell are sequentially arranged on the first surface of the GaAs substrate from bottom totop, the second side of the GaAs substrate is sequentially provided with a first GaInNAs sub-cell, a second GaInNAs sub-cell, and a GaxIn<1-x>P Gradient Transition Layer and GaxIn<1-x>As sub-batteryfrom top to bottom, each sub-battery being connected through a tunnel junction. The band gaps of the six-junction solar cells are 2.2 eV, 1.7 eV, 1.42 eV, 1.1 eV, 0.9 eV and 0.7 eV, respectively. Thecurrent mismatch of each sub-cell is small, which reduces the heat loss in the photoelectric conversion process, increases the open-circuit voltage of the cell and improves the photoelectric conversion efficiency.

Description

technical field [0001] The invention relates to the technical field of solar photovoltaic power generation, in particular to a high-efficiency six-junction solar cell grown on both sides and a preparation method thereof. Background technique [0002] From the perspective of the development of photovoltaic power generation technology, solar cells can be roughly divided into three categories: first-generation crystalline silicon solar cells, second-generation thin-film solar cells, and third-generation GaAs multi-junction solar cells. At present, gallium arsenide multi-junction solar cells are widely used in concentrated photovoltaic systems and space power systems because their conversion efficiency is significantly higher than that of crystalline silicon cells. The mainstream structure of traditional gallium arsenide multi-junction solar cells is a GaInP / GaInAs / Ge triple-junction solar cell composed of GaInP, GaInAs and Ge sub-cells. The cell structure maintains lattice matc...

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Problems solved by technology

[0005] However, in the process of preparing GaInNAs sub-cells, it is necessary to combine high-temperature annealing process to improve the photoelectric performance of GaInNAs cells. If it is based on Ge substrates, high-temperature annealing will also affect the structure of Ge sub-cells, reducing its open circuit voltage.

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