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Role of triplet‐triplet annihilation in highly efficient fluorescent devices
Author(s) -
Kondakov Denis Y.
Publication year - 2009
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1889/jsid17.2.137
Subject(s) - annihilation , anthracene , quantum efficiency , oled , fluorescence , electroluminescence , optoelectronics , materials science , current density , quantum , photochemistry , physics , optics , chemistry , nanotechnology , quantum mechanics , layer (electronics)
Abstract— A study of delayed electroluminescence in model highly efficient OLEDs based on anthracene derivatives indicate that triplet‐triplet annihilation (TTA) contributes significantly to overall efficiency. Highly efficient devices (6–9% external quantum efficiencies) based on 9,10‐bis(2‐naphthyl)‐2‐phenylanthracene show that the TTA contribution depends primarily on operating current density, reaching as much as 20–30% of the overall emission intensity at moderate current densities (>5 mA/cm 2 ). Revision of the classical estimates of maximum external quantum efficiency of fluorescent OLEDs to 8% and maximum internal quantum efficiency to 40% is recommended to account for TTA contribution (even further revision may be necessary to account for a better‐than‐20% optical outcoupling).