Strong Light-Matter Coupling and Photoluminescence Properties of 2D and quasi-2D Perovskite Microcavities

Light-matter coupling in microcavities with 2D and quasi-2D perovskite single crystals were systematically studied by angle-resolved photoluminescence spectroscopies. The coupling strength was estimated to be as large as ~400 meV and varied with the dimensionality of perovskite. The energy cooling of the excitations from reservoir exciton states to the lower polariton branch was found to be efficient when the photonic and excitonic fractions of the coupled state are comparable. Our results demonstrate that the perovskite microcavities are promising for the room temperature polariton devices and that control of perovskite dimensionality and cavity thickness are important factors to tune the excitonic nature of coupled state that enables the efficient population of the polariton particles.