Origin of Exciton-Polariton Interactions and Decoupled Dark States Dynamics in 2D Hybrid Perovskite Quantum Wells

Nano Lett. 2024 Jul 10;24(27):8240-8247. doi: 10.1021/acs.nanolett.4c00418. Epub 2024 Jun 26.

Abstract

The realization of efficient optical devices depends on the ability to harness strong nonlinearities, which are challenging to achieve with standard photonic systems. Exciton-polaritons formed in hybrid organic-inorganic perovskites offer a promising alternative, exhibiting strong interactions at room temperature (RT). Despite recent demonstrations showcasing a robust nonlinear response, further progress is hindered by an incomplete understanding of the microscopic mechanisms governing polariton interactions in perovskite-based strongly coupled systems. Here, we investigate the nonlinear properties of quasi-2D dodecylammonium lead iodide perovskite (n3-C12) crystals embedded in a planar microcavity. Polarization-resolved pump-probe measurements reveal the contribution of indirect exchange interactions assisted by dark states formation. Additionally, we identify a strong dependence of the unique spin-dependent interaction of polaritons on sample detuning. The results are pivotal for the advancement of polaritonics, and the tunability of the robust spin-dependent anisotropic interaction in n3-C12 perovskites makes this material a powerful choice for the realization of polaritonic circuits.

Keywords: 2D perovskite; dark states dynamics; exciton-polariton; microcavity polaritons; spin-dependent interactions.