Julian Schröer | Searcharxiv

arXiv2025

Long-lived Photoluminescence of Photostable One-dimensional Picoperovskites

We study one-dimensional metal halide perovskite crystals encapsulated in single-wall nanotubes, so-called picoperovskites, using optical spectroscopy. Polarized micro-photoluminescence (PL) reveals bright emission from aligned bundles of picoperovskites with clear linear polarization along the bundle axis. This emission is red-shifted with respect to bulk perovskite samples using the same constituents. Temperature-dependent, time-resolved micro-PL shows extraordinarily long PL lifetimes of the picoperovskites at low temperatures, reaching several hundred nanoseconds and exceeding those of bulk perovskites by two orders of magnitude.

cond-mat.mes-hall↗

arXiv2023

Rapid spin depolarization in the layered 2D Ruddlesden Popper perovskite (BA)(MA)PbI

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 (TR$Δ$R) 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.

cond-mat.mes-hall↗