(388a) Improving Stability and Thin-Film Fabrication Efficiency of Lead-Halide Perovskites

The excellent optoelectronic properties of Lead (Pb)‑based halide perovskites have made them promising candidates for photovoltaic applications. Despite their extraordinary performance, the lack of stability at operating conditions poses numerous challenges towards their commercialization. Reducing the dimensionality of 3D bulk halide perovskites into 2D structures by assembling them into layered structures could address chemical and phase stability challenges; however, other issues such as polydispersity are attributed to these layered halide perovskite (LHP) thin films which hinders the achieving efficient and stable perovskite devices. In this work, we focused on fabricating layered BA₂CsPb₂I₇ (BA: C₄H₉NH₃) thin films with enhanced monodispersity. We found that the choice of additive solvents in the precursor solution is crucial in enhancing the stability and monodispersity of these materials. The addition of solvents with high complexing strength with Pb atoms slows down the decomposition rate of intermediate phases within the thin film, reduces the LHP crystallite nucleation, and eventually enhances the phase purity. We demonstrated that the monodispersity could be further enhanced by applying thermal annealing techniques with a heating ramp, leading to thin films with preferential orientation parallel to the substrate, which makes them promising candidates for electronic devices such as Field Effect Transistors.