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Triplet–Polaron‐Interaction‐Induced Upconversion from Triplet to Singlet: a Possible Way to Obtain Highly Efficient OLEDs
Author(s) -
Obolda Ablikim,
Peng Qiming,
He Chuanyou,
Zhang Tian,
Ren Jiajun,
Ma Hongwei,
Shuai Zhigang,
Li Feng
Publication year - 2016
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201504601
Subject(s) - singlet state , photon upconversion , diphenylamine , oled , materials science , carbazole , polaron , phosphorescence , photochemistry , doping , optoelectronics , electron , nanotechnology , physics , fluorescence , chemistry , atomic physics , quantum mechanics , excited state , layer (electronics) , metallurgy
Two D–A‐type molecules, 4‐ N ‐[4‐(9‐phenylcarbazole)]‐3,5‐bis(4‐diphenylamine)phenyl‐4 H ‐1,2,4‐triazole and 4,4′‐(9‐(4‐(1‐phenyl‐1 H ‐phenanthro[9,10‐d]imidazol‐2‐yl)phenyl)‐9 H ‐carbazole‐3,6‐diyl) bis‐( N,N ‐diphenylaniline) , are designed and synthesized. Organic lightemitting diodes based on them exhibit deep‐blue emission and the singlet formation ratios are higher than the simple spin‐statistics of 25%. A triplet‐polaroninteraction‐induced upconversion from triplet to singlet through a one‐electron transfer mechanism is proposed, and is proven by magnetocurrent measurement and quantum‐chemistry computation.