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.