Vapor Transport Deposition of Highly Efficient Sb₂(S,Se)₃ Solar Cells via Controllable Orientation Growth

The vapor transport deposition of quasi-one-dimensional antimony selenosulfide (Sb₂(S,Se)₃) has recently attracted increasing research interest for the inexpensive, high-throughput production of thin film photovoltaic devices. Further improvements in Sb₂(S,Se)₃ solar cell performance urgently require the identification of processing strategies to control the orientation, however the growth mechanism of high quality absorbers is still not completely clear. Herein, a facile and general vapor transport deposition approach to precisely control the growth of large-grained dense Sb₂(S,Se)₃ films with good crystallization and preferred orientation via the source vapor speed is utilized. It is found that defect activation energy rather than the defect concentration plays a decisive role in the Sb₂(S,Se)₃ photovoltaic performance. Admittance spectroscopy analysis is used to obtain efficient Sb₂(S,Se)₃ solar cells. By employing dual-source coordinations to optimize the absorber layer a power conversion efficiency of 8.17% is obtained which is the highest efficiency for Sb₂(S,Se)₃ solar cells fabricated by vapor transport technology. This study suggests that there are other opportunities for gaining deeper a understanding of the defect physics and carrier recombination mechanisms in other highly oriented low-dimensional materials to achieve improved device performance.