The demand for lead-free alternatives to lead-halide perovskite (LHP) solar cells has prompted extensive research efforts to explore alternative materials. Silver bismuth iodide (Ag-Bi-I) absorbers have an appropriate band gap between 1.8–1.9 eV for solar cells and exhibit a strong absorption coefficient and high stability under ambient conditions. However, it has been hard to obtain sufficient levels of power conversion efficiency (PCE) at lab-scale. The maximum PCE reported to date for Ag-Bi-I (SBI) materials is 5.56%, a much smaller PCE value than those obtained for LHP based solar cells. Various approaches have been employed to improve the properties of SBI-based solar cells, including solution engineering, additive incorporation, and cation exchange. However, trap-assisted recombination and intrinsic limitations may be the underlying factors impacting its efficiency. With an overview of previous research efforts on the SBI materials, we highlight different approaches for PCE enhancement and discusses the current state of basic research in the material preparation and analysis. Furthermore, this study offers insights and prospects for SBI as a material for solar energy applications.
