Room-temperature polariton condensate in a quasi-2D hybrid perovskite.

Struve, Marti; Bennenhei, Christoph; Pashaei Adl, Hamid; Song, Kok Wee; Shan, Hangyong; Matukhno, Nadiya; Drawer, Jens-Christian; Stephan, Sven et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Quasi-2D halide perovskites are chemically synthesized realizations of quantum well stacks with giant exciton oscillator strengths, tunable emission spectra, and very large exciton binding energies. While these features render quasi-2D halide perovskites a promising platform for room-temperature polaritonics, bosonic condensation and polariton lasing in quasi-2D perovskites have so far remained elusive at ambient conditions. Here, we demonstrate room-temperature cavity exciton-polariton condensation in mechanically exfoliated crystals of the quasi-2D Ruddlesden-Popper iodide perovskite (BA)<sub>2</sub>(MA)<sub>2</sub>Pb<sub>3</sub>I<sub>10</sub> in an open optical microcavity. We observe a polariton condensation threshold of 0.41 µJ cm<sup>-2</sup> per pulse and detect a strong non-linear response. Interferometric measurements confirm the spontaneous emergence of spatial coherence across the condensate with an associated first-order autocorrelation reaching 0.6 with 1 ps coherence time and an effective de Broglie wavelength of 13 µm. Our results lay the foundation for a new class of room-temperature polariton lasers based on quasi-2D halide perovskites with great potential for hetero-integration with other van-der-Waals materials and combination with photonic crystals or waveguides.