About Carrier's Self-Trapping and Dynamical Rashba Splitting in the 2D Hybrid Perovskite (BA)₂(MA)₂Pb₃l₁₀

Time- and Angle-Resolved Photoelectron Spectroscopy (tr-ARPES) is employed to monitor photoexcited electrons in the 2D hybrid perovskite (BA) (Formula presented.) (MA) (Formula presented.) (Formula presented.) (Formula presented.). Photoelectron intensity maps are in good agreement with ab-initio calculations of the band structure. The effective mass is (Formula presented.) and (Formula presented.) 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 (Formula presented.) eVÅ. 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.