Organic-inorganic layered perovskites are two-dimensional quantum wells with layers of lead halide octahedra stacked between organic ligand barriers. The combination of their dielectric confinement and ionic sublattice results in excitonic excitations with substantial binding energies that are strongly coupled to the surrounding soft, polar lattice, results in strong photoluminescence properties. In this talk, I will present the effect of the ligand environment in layered perovskites which can significantly alter their optical properties due to the complex dynamic disorder of soft perovskite lattice. We observed the dynamic disorder in layered perovskites through the subsequent phonon dephasing dynamics in a variety of layered perovskite compositions using high-resolution resonant impulsive stimulated Raman spectroscopy. This work provides a molecular and time domain depiction of the relaxation of nascent optical excitations and opens opportunities to understand how they couple to the complex layered perovskite lattice, elucidating design principles for optoelectronic devices.

Vibrational relaxation dynamics in layered 2D perovskites

ACS Spring Meeting 2021

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