TY - JOUR
T1 - Highly efficient electroluminescence from purely organic donor-acceptor systems
AU - Shizu, Katsuyuki
AU - Lee, Jiyoung
AU - Tanaka, Hiroyuki
AU - Nomura, Hiroko
AU - Yasuda, Takuma
AU - Kaji, Hironori
AU - Adachi, Chihaya
PY - 2015/7/1
Y1 - 2015/7/1
N2 - Thermally activated delayed fluorescence (TADF) emitters are third-generation electroluminescent materials that realize highly efficient organic light-emitting diodes (OLEDs) without using rare metals. Here, after briefly reviewing the principles of TADF and its use in OLEDs, we report a sky-blue TADF emitter, 9-(4-(benzo[d]thiazol-2-yl)phenyl)-N3,N3,N6,N6-tetraphenyl-9H-carbazole-3,6-diamine (DAC-BTZ). DAC-BTZ is a purely organic donor-acceptor-type molecule with a small energy difference between its lowest excited singlet state and lowest triplet state of 0.18-0.22 eV according to fluorescence and phosphorescence spectra of a DAC-BTZ-doped film. In addition, the doped film exhibits a high photoluminescence quantum yield of 0.82. Time-resolved photoluminescence measurements of the doped film confirm that DAC-BTZ emits TADF. An OLED containing DAC-BTZ as an emitter exhibits a maximum external quantum efficiency (EQE) of 10.3%, which exceeds those obtained with conventional fluorescent emitters (5-7.5%). TADF from DAC-BTZ makes a large contribution to the high EQE of its OLED.
AB - Thermally activated delayed fluorescence (TADF) emitters are third-generation electroluminescent materials that realize highly efficient organic light-emitting diodes (OLEDs) without using rare metals. Here, after briefly reviewing the principles of TADF and its use in OLEDs, we report a sky-blue TADF emitter, 9-(4-(benzo[d]thiazol-2-yl)phenyl)-N3,N3,N6,N6-tetraphenyl-9H-carbazole-3,6-diamine (DAC-BTZ). DAC-BTZ is a purely organic donor-acceptor-type molecule with a small energy difference between its lowest excited singlet state and lowest triplet state of 0.18-0.22 eV according to fluorescence and phosphorescence spectra of a DAC-BTZ-doped film. In addition, the doped film exhibits a high photoluminescence quantum yield of 0.82. Time-resolved photoluminescence measurements of the doped film confirm that DAC-BTZ emits TADF. An OLED containing DAC-BTZ as an emitter exhibits a maximum external quantum efficiency (EQE) of 10.3%, which exceeds those obtained with conventional fluorescent emitters (5-7.5%). TADF from DAC-BTZ makes a large contribution to the high EQE of its OLED.
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U2 - 10.1515/pac-2015-0301
DO - 10.1515/pac-2015-0301
M3 - Article
AN - SCOPUS:84937952265
VL - 87
SP - 627
EP - 638
JO - Pure and Applied Chemistry
JF - Pure and Applied Chemistry
SN - 0033-4545
IS - 7
ER -