Intermediate band induced by p-block metalloid antimony in SnS₂ for higher solar energy utilization

Semiconductors with intermediate bands have attracted tremendous attention due to their superior solar energy utilization. Herein, we propose a simple approach to introduce the intermediate band through substituting tin by p-block metalloid antimony in SnS₂. Experimentally, Sn_1-xSb_xS₂ (x up to 0.06) semiconductors possessing an intermediate band were successfully synthesized through solid state reactions. After antimony doping, two absorption edges appear at 2.31 eV and 1.63 eV in the visible light region, and one absorption shoulder starting at 0.68 eV emerges in the infrared region, as observed from the UV–vis-NIR absorption spectra. These typical intermediate band absorption features are consistent with our first principles calculations. The state of the intermediate band of Sn_1-xSb_xS₂ is mainly composed of the Sb-5s orbital from maximally-localized Wannier function analysis. Owing to the antimony intermediate band extending the solar absorption range, Sn_1-xSb_xS₂ semiconductors exhibit a higher utilization of solar energy compared with pristine SnS₂.