Study of Se/Te-doped Cu₂O as a hole transport material in perovskite solar cells

Theoretically, cuprous oxide (Cu₂O) is a particularly excellent potential material, for the hole transport layer (HTL) of perovskite solar cells (PSCs). However, the photoelectric conversion efficiency (PCE) of its experimental samples is still not ideal. The main reasons for this include the material, and inherent and interface defects of Cu₂O, but this can be improved by doping. In this research, Te- and Se/Te-doped Cu₂O were experimentally and numerically studied to check the improvement of the material and interface properties. It was found that, for both the electrical and optical properties, the Se/Te-doped Cu₂O performed considerably better than that which had been Te-doped and the pure Cu₂O. Compared with the pure Cu₂O thin film, the carrier mobility of the Se/Te-doped Cu₂O thin film is improved from 60 cm² V^-1 s^-1 to 1297 cm² V^-1 s^-1, and the bandgap changed from 2.05 eV to 1.88 eV. According to the results calculated using solar cell simulation software SCAPS, the cell efficiency of the Se/Te-doped Cu₂O is improved by 22% when compared to that of pure Cu₂O. This efficiency can be further improved to 34% by optimizing the thickness of the Se/Te-doped Cu₂O thin film and the defect density of states between the material interfaces.