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Title: Low-voltage polariton electroluminescence from an ultrastrongly coupled organic light-emitting diode

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.4871271· OSTI ID:22300036
;  [1];  [2]
  1. Experimental Solid State Group, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)
  2. Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Quebec H3C 3A7 (Canada)

We demonstrate electroluminescence from Frenkel molecular excitons ultrastrongly coupled to photons of a metal-clad microcavity containing a 2,7-bis[9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl)fluorene emissive layer. Thin layers of molybdenum oxide and 4,7-diphenyl-1,10-phenanthroline are used as hole and electron injection layers, respectively. The fabricated devices exhibit an electroluminescence threshold of 3.1 V, a value that is below the bare exciton energy. This result is found to be independent of detuning and consistent with a two-step process for polariton formation. Moreover, we investigate the quantum efficiency of carrier to polariton to photon conversion and obtain an external quantum efficiency of 0.1% for the fabricated structures, an improvement of 5 orders of magnitude over previous reports.

OSTI ID:
22300036
Journal Information:
Applied Physics Letters, Vol. 104, Issue 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
Country of Publication:
United States
Language:
English