About carrier's self-trapping and dynamical Rashba splitting in the two-dimensional hybrid perovskite (BA)${}_2$(MA)${}_2$Pb${}_3$I${}_{10}$

Abstract

Time- and Angle-Resolved Photoelectron Spectroscopy (tr-ARPES) is employed to monitor photoexcited electrons in the two-dimensional hybrid perovskite (BA)${}_2$(MA)${}_2$Pb${}_3$I${}_{10}$. Photoelectron intensity maps are in good agreement with ab-initio calculations of the band structure. The effective mass is $-0.18\pm 0.02m_e$ and $0.12\pm 0.02m_e$ for holes and electrons, respectively. In the photoexcited state, spin-orbit splitting of the conduction band cannot be resolved. This sets the upper bound of photoinduced Rashba coupling to $\hat{I}{\pm }_C<2.5$ eVÃ . The correlated electron-hole plasma evolves in Wannier excitons with Bohr radius of 2.8 nm, while no sign of self-trapping in small polarons is found within the investigated time window of up to 120 ps following photoexcitation.