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Origin of Sub‐Bandgap Electroluminescence in Organic Light‐Emitting Diodes
Author(s) -
Xiang Chaoyu,
Peng Cheng,
Chen Ying,
So Franky
Publication year - 2015
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201501355
Subject(s) - electroluminescence , rubrene , materials science , optoelectronics , band gap , photoluminescence , exciton , oled , diode , light emitting diode , common emitter , nanotechnology , physics , condensed matter physics , layer (electronics)
Sub‐bandgap electroluminescence in organic light emitting diodes is a phenomenon in which the electroluminescence turn‐on voltage is lower than the bandgap voltage of the emitter. Based on the results of transient electroluminescence (EL) and photoluminescence and electroabsorption spectroscopy measurements, it is concluded that in rubrene/C 60 devices, charge transfer excitons are generated at the rubrene/C 60 interface under sub‐bandgap driving conditions, leading to the formation of triplet excitons, and sub‐bandgap EL is the result of the subsequent triplet–triplet annihilation process.