We report temperature-dependent spectroscopy on the layered (n=4) two-dimensional (2D) Ruddlesden-Popper perovskite (BA)(MA)PbI. Helicity-resolved steady-state photoluminescence (PL) reveals no optical degree of polarization. Time-resolved PL shows a photocarrier lifetime on the order of nanoseconds. From simultaneaously recorded time-resolved differential reflectivity (TRΔR) and time-resolved Kerr ellipticity (TRKE), a photocarrier lifetime of a few nanoseconds and a spin dephasing time on the order of picoseconds was found. This stark contrast in lifetimes clearly explains the lack of spin polarization in steady-state PL. While we observe clear temperature-dependent effects on the PL dynamics that can be related to structural dynamics, the spin dephasing is nearly T-independent. Our results highlight that spin dephasing in 2D (BA)(MA)PbI occurs at time scales faster than the exciton recombination time, which poses a bottleneck for applications aimingto utilize this degree of freedom.
@article{arxiv.2309.09784,
title = {Rapid spin depolarization in the layered 2D Ruddlesden Popper perovskite (BA)(MA)PbI},
author = {Michael Kempf and Philipp Moser and Maximilian Tomoscheit and Julian Schröer and Jean-Christophe Blancon and Rico Schwartz and Swarup Deb and Aditya Mohite and Andreas V. Stier and Jonathan J. Finley and Tobias Korn},
journal= {arXiv preprint arXiv:2309.09784},
year = {2023}
}