(Invited) Unveiling the Stability Potential of Organic Sulfonium Cations in Perovskite Solar Cells

Although the power conversion efficiency of perovskite solar cells (PSCs) has skyrocketed, its stability remains a major roadblock to its commercialization. The susceptibility of conventional ammonium-based halide perovskites to ambient environment underscores the necessity of developing alternative aprotic materials. The substitution of protic ammoniums cations with their analogous aprotic sulfonium cations can pave the way for moisture-stable PSCs. Recently, efficiency and stability potential of sulfonium cations in PSCs has been investigated extensively through various engineering approaches. We incorporated trimethylsulfonium iodide and trimethylsulfoxonium iodide as an additive and interfacial modifier to improve the PCE and stability of MAPbI3 and FAPbI3, and FAMACsPbI3-xBrx PSCs. The structural, optoelectronic, and PV properties of sulfur-based cations and their corresponding lower dimensional perovskites are explored. This work further addresses the key challenges and strategies for advancing PSCs by incorporating various derivatives (trimethylsulfonium bromide and 2-carboxyethyl dimethyl sulfonium bromide) of organosulfonium cations.