Strongly Enhanced Free-Exciton Luminescence in Microcrystalline CsPbBr₃ Films

Abstract

The luminescence properties of CsPbBr₃ films prepared via the amorphous phase by crystallization are dominated by free-exciton emission, and only a weak trace of emission due to trapped excitons was observed, in contrast to the case of bulk CsPbBr₃ crystals. In particular, the films in the microcrystalline state show by more than an order of magnitude stronger free-exciton emission than in the polycrystalline state. The enhanced free-exciton emission is suggestive of excitonic superradiance.