Carrier Dynamics and Recombination in Low-Dimensional Halide Perovskites: Role of Structural Fluctuations*

Low-dimensional halide perovskites have demonstrated promising luminescence properties for light-emitting diodes due to their high radiative recombination rate.^[1] However, the lack of a complete understanding of the structure-property relationship hinders the systematic design of these materials to enhance their luminescence efficiency. Combining state-of-the-art nonadiabatic molecular dynamics and time-domain density functional theory, we explore the substantial effects of structural fluctuations on the excited state dynamics and carrier recombination in these perovskites. Here, I will demonstrate how structurally rigid perovskites experience weaker electron-phonon interactions, resulting in suppressed non-radiative carrier recombination and enhanced photoluminescence quantum yield (PLQY).^[2,3] Our work revealed that stacking of the spacer cations, and halogen composition of the inorganic layers substantially tune the PLQY of these materials. Based on these understanding, we further propose a combination of suitable spacer cations and inorganic layer compositions to improve the PLQY of low-dimensional halide perovskites.
Ref.
1. Smith et al., Chem. Rev. 2019, 119, 3104
2. Ghosh et al. Under preparation, 2019
3. Leveillee et al. Submitted to Nano Lett. 2019