Robust Room-Temperature Polariton Condensation and Lasing in Scalable FAPbBr3 Perovskite Microcavities

Abstract

Exciton-polariton condensation in direct bandgap semiconductors strongly coupled to light enables a broad range of fundamental studies and applications such as low-threshold and electrically driven lasing. Yet, materials hosting exciton-polariton condensation in ambient conditions are rare, with fabrication protocols that are often inefficient and nonscalable. Here, room-temperature exciton-polariton condensation and lasing is observed in a microcavity with embedded formamidinium lead bromide (FAPbBr₃) perovskite film. This optically active material is spin-coated onto the microcavity mirror, which makes the whole device scalable up to large lateral sizes. The sub-μm granulation of the polycrystalline FAPbBr₃ film allows for observation of polariton lasing in a single quantum-confined mode of a polaritonic “quantum dot”. Compared to random photon lasing, observed in bare FAPbBr₃ films, polariton lasing exhibits a lower threshold, narrower line width, and an order of magnitude longer coherence time. Both polariton and random photon lasing are observed under the conditions of pulsed optical pumping and persist without significant degradation for up to 6 and 17 h of a continuous experimental run, respectively. This study demonstrates the excellent potential of the FAPbBr₃ perovskite as a new material for room-temperature polaritonics, with the added value of efficient and scalable fabrication offered by the solution-based spin-coating process.