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Updated: Apr 4, 2026

Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes
Published on: November 16, 2018
Origin of Sub-Bandgap Electroluminescence in Organic Light-Emitting Diodes
Chaoyu Xiang1, Cheng Peng1, Ying Chen1
1Department of Materials Science and Engineering, University of Florida, Gainesville, FL, 32611, USA.
Abstract:
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/C60 devices, charge transfer excitons are generated at the rubrene/C60 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.
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