Structural and optical evolution of highly confined lead halide perovskite nanoplatelets

Abstract: Quantum confinement has the ability to significantly modulate structural and optical parameters of interest in many material systems. This presentation will describe the properties of ultrathin nanoplatelets of lead halide perovskites consisting of just two lead halide monolayers in the confined dimension. Focal points include anomalous thermal expansion and dark exciton dynamics in these materials. By varying the central A-site cation, composition- and structure-based mechanisms for engineering of the excitons in these materials are revealed. Specifically, structural asymmetry is correlated to the magnitude of negative thermal expansion, excitonic transition energy, spectral purity, emission rate, and splitting between bright and dark excitonic levels. This work provides fundamental design rules for fine-tuning the crystal and electronic structure of lead halide perovskite materials.

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