Microscopic picture of electron-phonon interaction in two-dimensional halide perovskites

TL;DR

This paper provides a detailed theoretical and experimental analysis of excitonic states and phonon interactions in monolayered hybrid organic perovskites, revealing temperature effects and phonon sidebands in optical spectra.

Contribution

It introduces a microscopic approach to excitonic properties in 2D halide perovskites, including Rydberg series, phonon sidebands, and temperature-dependent linewidths, supported by experimental data.

Findings

Pronounced phonon sideband contribution up to 50 K

Temperature-dependent linewidths of excitonic transitions

Agreement between theoretical spectra and experimental photoluminescence

Abstract

Perovskites have attracted much attention due to their remarkable optical properties. While it is well established that excitons dominate their optical response, the impact of higher excitonic states and formation of phonon sidebands in optical spectra still need to be better understood. Here, we perform a theoretical study on excitonic properties of monolayered hybrid organic perovskites -- supported by temperature-dependent photoluminescence measurements. Solving the Wannier equation, we obtain microscopic access to the Rydberg-like series of excitonic states including their wavefunctions and binding energies. Exploiting the generalized Elliot formula, we calculate the photoluminescence spectra demonstrating a pronounced contribution of a phonon sideband for temperatures up to 50 K -- in agreement with experimental measurements. Finally, we predict temperature-dependent linewidths of the three energetically lowest excitonic transitions and identify the underlying phonon-driven scattering processes.