Excitons in 2D Organic–Inorganic Halide Perovskites

Layered perovskites are hybrid 2D materials, formed through the self-assembly of inorganic lead halide networks separated by organic ammonium cation layers. In these natural quantum-well structures, quantum and dielectric confinement lead to strongly bound excitonic states that depend sensitively on the material composition. In this article, we review current understanding of exciton photophysics in layered perovskites and highlight the many ways in which their excitonic properties can be tuned. In particular, we focus on the coupling of exciton dynamics to lattice motion and local distortions of the soft and deformable hybrid lattice. These effects lead to complex excited-state dynamics, presenting new opportunities for design of optoelectronic materials and exploration of fundamental photophysics in quantum confined systems. Keywords: perovskite; hybrid material; 2D material; exciton; lead halide