Excited-State Dynamics in Lead Halide Perovskite Nanocrystals: Effects of Size, Shape, Doping, and Surface...

Excitation and de-excitation processes of semiconductor quantum dots have been extensively studied for decades. In comparison to the traditional chalcogenide nanocrystals (NCs), some of the optical features are reported to be different for the recently emerged halide perovskite NCs. Defect states, ligand effects, doping, and the temperature-tuned excited-state decay processes remained unique in these NCs. Combining all these parameter variations, the photophysical chemistry of the photo-excitation and relaxation processes is reported in this review. It begins with the discussion of the color tunability of NCs with halide composition variations and their decay lifetimes. Further, the impact of temperature and the relaxation processes of these NCs are correlated. In addition, the impact of size, shape, facets, and surface ligands, doping of Mn(II) and other ions for the change in photoluminescence and excited decay lifetimes are studied and reported. This information is the fundamental insight related to the photophysical processes of halide perovskites, where doping as well as temperature impact differ to the traditional quantum dots. Hence, this Review is expected to bridge the understanding of quantum dots' photophysical processes from chalcogenides to halide perovskites and helps for designing optimization of stable and highly emissive semiconductor NCs.