Excitonic Transitions Studies of High-Quality Quasi-2D Halide Perovskites*

Organic–inorganic halide perovskites (OIHPs), in which perovskite layers are separated by an organic spacer material, are among an exciting new class of quasi-2D materials. They have shown great potential for future photovoltaic devices and offer promises for nonlinear optics and quantum light applications. OIHPs offer broad tunability of their properties, by controlling the number of atomic layers. In this study, we will report on the photoluminescence (PL) emissions of a quasi-2D, BA₂PbI₄, and provide new insights into the temperature dependence of their excitonic dynamics and the fine structure of their PL emissions. Furthermore, in this talk, we will report on our growth methods that allowed us to synthesize high-quality materials with improved optical properties. The signature of our high-quality materials is reflected in our PL, where we were able to resolve significant fine structure. Furthermore, using time-resolved PL measurements we observed long carrier lifetimes, which can result from the formation of large polarons, screening the Coulomb interactions of the charge carriers and reducing the scattering of the carriers with charge defects.