Solvent Annealing Enabling Reconstruction of Cadmium Sulfide Film for Improved Heterojunction Quality and Photovoltaic Performance of Antimony Selenosulfide Solar Cells

Antimony selenosulfide, Sb-2(S,Se)(3), has been considered as new-generation light-harvesting material for high-efficiency photovoltaic applications due to its adjustable bandgap, high absorption coefficient, and excellent stability. In terms of device operation, the electron transfer from the electron transporting layer to Sb-2(S,Se)(3) layer plays a critical role in improving the photovoltaic energy conversion efficiency of solar devices. Intricately manipulating the surface and interface properties has been a great challenge in solar cell fabrications. Herein, an effective approach toward the reconstruction of the CdS interfacial layer, and the following Sb-2(S,Se)(3) absorber film by utilizing polar ethylenediamine (EDA) solvent annealing at room temperature is developed. It is found that the presence of nitrogen-containing functional groups of EDA on the CdS surface not only promotes the grain growth and crystallization of CdS, but also induces optimized deposition of Sb-2(S,Se)(3) films in terms of interfacial contact and defect formation. Finally, the Sb-2(S,Se)(3) solar cell based on EDA-CdS achieves a top efficiency of 10.10%. This study provides an efficient method and a new understanding of chemically healing inorganic thin films.