Enhanced Efficiency and Stability in Sb2S3 Seed Layer Buffered Sb2Se3 Solar Cells

Antimony selenide (Sb2Se3) has excellent directional optical and electronic behaviors due to its quasi‐1D nanoribbons structure. The photovoltaic performance of Sb2Se3 solar cells largely depends on the orientation of the nanoribbons. It is desired to grow these Sb2Se3 ribbons normal to the substrate to enhance photoexcited carrier transport. Therefore, it is necessary to develop a strategy for the vertical growth of Sb2Se3 nanoribbons to achieve high‐efficiency solar cells. Since antimony sulfide (Sb2S3) and Sb2Se3 are from the same space group (Pbnm) and have the same crystal structure, herein an ultrathin layer (≈20 nm) of Sb2S3 has been used to assist the vertical growth of Sb2Se3 nanoribbons to improve the overall efficiency of Sb2Se3 solar cell. The Sb2S3 thin layer deposited by the hydrothermal process helps the Sb2Se3 ribbons grow normal to the substrate and increases the efficiency from 5.65% to 7.44% through the improvement of all solar cell parameters. This work is expected to open a new direction to tailor the Sb2Se3 grain growth and further develop the Sb2Se3 solar cell in the future. A thin Sb2S3 seed layer is utilized for the Sb2Se3 thin film solar cells to regulate the (Sb4Se6)n nanoribbons growth normal to the substrate. The Sb2Se3 with Sb2S3 seed layer achieves improved device performance through the improvement of all solar cell device parameters. This Sb2S3 seed layer also improves the device stability.