TY - JOUR
T1 - Ultrahigh Power Efficiency Thermally Activated Delayed Fluorescent OLEDs by the Strategic Use of Electron-Transport Materials
AU - Sasabe, Hisahiro
AU - Sato, Ryo
AU - Suzuki, Katsuaki
AU - Watanabe, Yuichiro
AU - Adachi, Chihaya
AU - Kaji, Hironori
AU - Kido, Junji
N1 - Funding Information:
This study was partially supported by the Center of Innovations (COI) Program of the Japan Science and Technology Agency. H.S. and Y.W. acknowledge financial support from JSPSKAKENHI, Grant Numbers 17H03131 and 15J08167, respectively.
Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/9/4
Y1 - 2018/9/4
N2 - Thermally activated delayed fluorescent (TADF) emitters are one of the most promising candidates for developing low-cost organic light-emitting devices (OLEDs) that can achieve an internal quantum efficiency of 100%. However, the power efficiency values are still significantly lower than that of their phosphorescent counterparts. To achieve high power efficiency, both a high external quantum efficiency and low drive voltage are required. Here, TADF OLEDs with an ultrahigh power efficiency of 133 lm W−1 and an unprecedented low turn-on voltage of 2.22 V are successfully developed via the strategic use of electron-transport materials (ETMs). 9-[4-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl]-N,N,N′,N′-tetraphenyl-9H-carbazole-3,6-diamine as a TADF emitter is used. A series of green TADF OLEDs are fabricated using two different types of pyrimidine-based ETMs as an exciplex host partner and electron-transport layer to minimize the drive voltages. The optimized device shows an external quantum efficiency of 29.2% and maximum power efficiency of 133.2 lm W−1 without any light-outcoupling enhancement. The device also shows 124.0 lm W−1 at 100 cd m−2 and 95.2 lm W−1 at a high brightness of 1000 cd m−2. The drive voltages are 2.48 V at 100 cd m−2 and 2.88 V at 1000 cd m−2.
AB - Thermally activated delayed fluorescent (TADF) emitters are one of the most promising candidates for developing low-cost organic light-emitting devices (OLEDs) that can achieve an internal quantum efficiency of 100%. However, the power efficiency values are still significantly lower than that of their phosphorescent counterparts. To achieve high power efficiency, both a high external quantum efficiency and low drive voltage are required. Here, TADF OLEDs with an ultrahigh power efficiency of 133 lm W−1 and an unprecedented low turn-on voltage of 2.22 V are successfully developed via the strategic use of electron-transport materials (ETMs). 9-[4-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl]-N,N,N′,N′-tetraphenyl-9H-carbazole-3,6-diamine as a TADF emitter is used. A series of green TADF OLEDs are fabricated using two different types of pyrimidine-based ETMs as an exciplex host partner and electron-transport layer to minimize the drive voltages. The optimized device shows an external quantum efficiency of 29.2% and maximum power efficiency of 133.2 lm W−1 without any light-outcoupling enhancement. The device also shows 124.0 lm W−1 at 100 cd m−2 and 95.2 lm W−1 at a high brightness of 1000 cd m−2. The drive voltages are 2.48 V at 100 cd m−2 and 2.88 V at 1000 cd m−2.
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U2 - 10.1002/adom.201800376
DO - 10.1002/adom.201800376
M3 - Article
AN - SCOPUS:85052727220
SN - 2195-1071
VL - 6
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 17
M1 - 1800376
ER -