Direct solution deposition of device quality Sb2S3-xSex films for high efficiency solar cells

Sb2S3-xSex (0 <= x <= 3) is promising for practically applicable solar cell since it possesses excellent stability, suitable band gap, high extinction coefficient and abundant elemental storage. This study demonstrates a novel methodology towards simultaneous dissolution of Se and Sb2O3 for direct deposition of Sb2S3-xSex films. Mechanistic study shows that the formation of selenium-nitrogen free radical in sulfur-containing complex is responsible for the dissolution of selenium. The energy levels of the as-synthesized Sb2S3-xSex were examined by synchrotron radiation photoemission spectroscopy, revealing that more Se in the Sb2S3-xSex leads to the valence band shifting considerably upward while the conduction band remaining nearly unchanged. Moreover, for the first time we present that the solution processed Sb2S3-xSex can generate photovoltaic performance with an efficiency of 5.8%. This research provides a straightforward strategy for the fabrication of Sb2S3-xSex solar cells and offers an effective method for the synthesis of metal selenosulfide films.