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

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.
Authors:
;  [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)
Publication Date:
OSTI Identifier:
22300036
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CARRIERS; CONVERSION; ELECTROLUMINESCENCE; ELECTRON BEAM INJECTION; EQUIPMENT; EXCITONS; FLUORENE; LAYERS; LIGHT EMITTING DIODES; METALS; ORGANIC SEMICONDUCTORS; PHENANTHROLINES; PHOTONS; QUANTUM EFFICIENCY; THIN FILMS