Advances in bismuth halide perovskite solar cells

Due to the inherent toxicity of lead (Pb) and the severe structural instability of lead halide perovskites (LHPs), the advancement of LHPs solar cells (LHPSCs) has been significantly impeded. Consequently, the search for environmentally friendly alternative materials has become a key focus of current research. Bismuth (Bi) halide perovskites (BHPs) have gained considerable attention as viable alternatives in photovoltaic (PV) applications owing to their lower toxicity, excellent PV performance, and tunable structural properties. This review categorizes BHPs based on their elemental composition into ternary A_aBi_bX_a+3b (A = MA⁺, FA⁺, Ag⁺, Cu⁺, Cs⁺; X = Br⁻, Cl⁻, I⁻) and quaternary A₂AgBiX₆ (A = Cs⁺, Cu⁺; X = Br⁻, Cl⁻, I⁻) structures, as well as Cu_aAg_bBi_cI_d, and presents a detailed overview of the current research progress and future development prospects of these materials in the field of solar cells. Furthermore, strategies for preparing high-performance BHP solar cells (BHPSCs) are summarized, addressing aspects such as fabrication process, component engineering and additive engineering, interface modification and device structure optimization. Through this review, we strive to establish a systematic framework for a comprehensive understanding of the current research on BHPs and their potential applications in PV field, and offer reference and guidance for future research and development.