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Effects of emitting layer host composition profile on the recombination zone of blue phosphorescent organic light emitting diodes
Author(s) -
Lee Sangmin,
Tang Ching. W.,
Rothberg Lewis. J.
Publication year - 2013
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 - 10.1002/jsid.141
Subject(s) - phosphorescence , recombination , optoelectronics , materials science , oled , layer (electronics) , diode , quenching (fluorescence) , doping , light emitting diode , electron transport chain , electron , optics , chemistry , physics , nanotechnology , fluorescence , biochemistry , quantum mechanics , gene
The spatial distribution of charge recombination in blue phosphorescent organic light‐emitting diodes with linearly graded, step‐graded and uniformly mixed host architectures was identified by selective doping of the emissive layer. Using TCTA and UGH‐3 for hole and electron transporting hosts in the emitting layer, the recombination zones were found to be near the interface with electron transport layer due to the relatively high hole mobility of TCTA. For linearly graded host concentration profiles, however, the recombination region extends much further into the emissive layer. Expansion of the recombination region increases device efficiency by reducing quenching at the interface with the electron transport layer or by reducing triplet diffusion into the electron transport layer.