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Microcavity-like exciton-polaritons can be the primary photoexcitation in bare organic semiconductors.

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Pandya, Raj 
Chen, Richard YS 
Gu, Qifei 
Sung, Jooyoung 
Schnedermann, Christoph  ORCID logo


Strong-coupling between excitons and confined photonic modes can lead to the formation of new quasi-particles termed exciton-polaritons which can display a range of interesting properties such as super-fluidity, ultrafast transport and Bose-Einstein condensation. Strong-coupling typically occurs when an excitonic material is confided in a dielectric or plasmonic microcavity. Here, we show polaritons can form at room temperature in a range of chemically diverse, organic semiconductor thin films, despite the absence of an external cavity. We find evidence of strong light-matter coupling via angle-dependent peak splittings in the reflectivity spectra of the materials and emission from collective polariton states. We additionally show exciton-polaritons are the primary photoexcitation in these organic materials by directly imaging their ultrafast (5 × 106 m s-1), ultralong (~270 nm) transport. These results open-up new fundamental physics and could enable a new generation of organic optoelectronic and light harvesting devices based on cavity-free exciton-polaritons.



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Nat Commun

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Springer Science and Business Media LLC


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Engineering and Physical Sciences Research Council (EP/M006360/1)
European Research Council (758826)
Engineering and Physical Sciences Research Council (EP/L027151/1)
European Commission Horizon 2020 (H2020) ERC (883703)
Royal Commission for the Exhibition of 1851 (RF499/2018)
European Research Council (639088)
European Research Council (670405)
EPSRC (EP/R025517/1), EPSRC (EP/M025330/1), ERC Horizon 2020 (grant agreements No 670405 and No 758826), ERC (ERC-2014-STG H2020 639088), Netherlands Organisation for Scientific Research, Swedish Research Council (VR, 2014-06948), Knut and Alice Wallenberg Foundation 3DEM-NATUR (no. 2012.0112), Royal Commission for the Exhibition of 1851, CNRS (France), US Department of Energy, Office of Science, Basic Energy Sciences, CPIMS Program, Early Career Research Program (DE-SC0019188).