Liang, JieZheng, HaoJin, FengBao, RuiqiDini, KevinRen, JiahaoLiu, YuxiKról, MateuszOstrovskaya, Elena A.Estrecho, EliezerZhang, BaileLiew, Timothy C.H.Su, Rui2026-02-142026-02-141745-2473ORCID:/0000-0002-4767-5705/work/205472366ORCID:/0000-0003-0523-6533/work/205472729https://hdl.handle.net/1885/733805549Non-Hermitian physics has recently transformed our understanding of topology by uncovering a range of effects that are unique to systems with gain and loss. The realization of non-Hermitian topology in strongly coupled light–matter systems not only offers degrees of freedom for the enhanced manipulation of topological phenomena, but is also promising for developing on-chip active photonic devices. Exciton–polaritons—strongly coupled quasiparticles from excitons and photons—emerge as a promising candidate with intrinsic non-Hermitian features. However, limited by the challenges in achieving non-reciprocity, the experimental observation of non-Hermitian topology and its associated transport features has remained elusive. Here we experimentally demonstrate the non-Hermitian topology of exciton–polaritons induced by a twist degree of freedom in a liquid-crystal-filled CsPbBr3 perovskite microcavity at room temperature. The geometric twist between birefringent perovskites and liquid crystals acts as a degree of freedom to tailor the polaritonic complex spectra, leading to non-Hermitian bands with spectral winding topology and non-reciprocity. Furthermore, the induced non-Hermitian topology gives rise to the non-Hermitian exciton–polariton skin effect in real space, manifesting as polariton accumulation at open boundaries. Our findings open new perspectives on tunable non-Hermitian phenomena and the development of on-chip polaritonic devices with enhanced functionalities.R.S. and T.C.H.L. gratefully acknowledge funding support from the Singapore Ministry of Education via the AcRF Tier 2 grant (MOE-T2EP50222-0008), AcRF Tier 3 grant (MOE-MOET32023-0003) ‘Quantum Geometric Advantage’ and Tier 1 grant (RG80/23). R.S. also gratefully acknowledges funding support from Nanyang Technological University via a Nanyang Assistant Professorship start-up grant and the Singapore Ministry of Education via Tier 1 grant (RG 90/25). R.S. and B.Z. gratefully acknowledge funding support from the Singapore National Research Foundation via a Competitive Research Program (grant number NRF-CRP23-2019-0007). K.D. and T.C.H.L. gratefully acknowledge funding support from the Singapore National Research Foundation (NRF2023-ITC004-001). M.K. and E.A.O. acknowledge support from the Australian Research Council through the Discovery Project scheme (DP230102603). E.E. acknowledges support from the ARC Discovery Early Career Researcher Award (DE220100712).7en© The Author(s), under exclusive licence to Springer Nature Limited 2025.202610.1038/s41567-025-03115-0105023994857