Microcavity-like exciton-polaritons can be the primary photoexcitation in bare organic semiconductors
Raj Pandya, Richard Y. S. Chen, Qifei Gu, Jooyoung Sung, Christoph Schnedermann, Oluwafemi Stephen Ojambati, Rohit Chikkaraddy, J.A. Gorman, Gianni Jacucci, Olimpia D. Onelli, Tom Willhammar, Duncan N. Johnstone, Sean M. Collins, Paul A. Midgley, Florian Auras, Tomi K. Baikie, Rahul Jayaprakash, Fabrice Mathevet, Richard Soucek, Matthew Du, Antonios M. Alvertis, Arjun Ashoka, Silvia Vignolini, David G. Lidzey, Jeremy J. Baumberg, Richard H. Friend, Thierry Barisien, Laurent Legrand, Alex W. Chin, Joel Yuen-Zhou, Semion K. Saikin, Philipp Kukura, Andrew J. Musser, Akshay Rao
Abstract
Abstract 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 × 10 6 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