Room Temperature Exciton-Polaritons in High-Quality 2D Ruddlesden–Popper Perovskites (Ba)2(ma)n-1Pbni3n+1 (n = 3, 4)

Due to large binding energy and oscillator strength, 2D Ruddlesden–Popper perovskites are promising materials for the realization of room temperature coupled exciton-polaritons. Here, we demonstrate room temperature exciton-polaritons in high-quality exfoliated 2D RPP (BA)2(MA)n−1PbnI3n+1 (n = 3, 4) flakes without the use of external Distributed Bragg Reflectors. By angle-resolved PL spectroscopy, we obtain multi-mode low polariton branches and the Rabi splitting in the range of about 160 meV–180 meV for n = 3 and n = 4 flakes. The realization of room temperature exciton-polaritons in 2D RPPs with a large n value provides a potential platform for polaritonic device applications.