All-Vacuum-Processed Sb₂(S,Se)₃ Thin Film Photovoltaic Devices via Controllable Tuning Seed Orientation

Quasi-one-dimensional antimony sulfoselenide (Sb₂(S,Se)₃) semiconductor is one of the most promising light-harvesting materials owing to its simple phase and tunable absorption spectra. However, the oriented [Sb₄(S,Se)₆]_n ribbons of Sb₂(S,Se)₃ thin films nearly horizontally stacked in parallel to the substrate severely hinders the transport of carriers, yet is critical to control the absorber orientation growth for high-performance Sb₂(S,Se)₃ solar cells. Herein, a new close spaced sublimated (CSS) CdS buffer layer with high crystallization is introduced for the development of all-vacuum-processed Sb₂(S,Se)₃ solar cells that attempt to induce the orientation of Sb₂(S,Se)₃ absorbers to achieve effective carrier transport and reduce the adverse effects. The resulting Sb₂(S,Se)₃ solar cells with CSS-CdS buffer layers exhibit a prominent [221] orientation and better heterointerfaces as well as lower defect densities and longer capture lifetime compared to the commonly solar cells used chemically deposited CdS buffer layers, as a result of suppressed the non-radiative recombination. The optimized solar cells, yield up to an efficiency of 7.12%, is the first for an all-vacuum-process for Sb₂(S,Se)₃ solar cells.