TY - JOUR
T1 - Highly Efficient Blue OLEDs Based on Metal-Assisted Delayed Fluorescence Pd(II) Complexes
AU - Zhu, Zhi Qiang
AU - Park, Choong Do
AU - Klimes, Kody
AU - Li, Jian
N1 - Funding Information:
The authors thank the National Science Foundation (CHE-0748867), Department of Energy (contract no. EE0007090), and Universal Display Corporation for partial support of this work.
Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2019/3/19
Y1 - 2019/3/19
N2 - A series of metal-assisted delayed fluorescence (MADF) palladium(II) complexes, PdN1N, PdN1N-dm, and PdN6N, are studied. Their 77 K photoluminescence emission spectra show a narrow primary emission peak at 464, 466, and 470 nm, respectively, with small vibronic peaks characteristic of many phosphorescent emitters. At room temperature (300 K), the dominant emission peaks for PdN1N, PdN1N-dm, and PdN6N are slightly redshifted to 472, 470, and 476 nm, respectively. In the meantime, a broad sideband is also shown between 410 and 450 nm due to the MADF process. A blue device employing PdN1N-dm demonstrates an electroluminescence emission peak at 476 nm and the maximum external quantum efficiency (EQE) of 25.1%. The high maximum EQE of the blue organic light-emitting diode (OLED) device indicates that both the phosphorescence and the delayed fluorescence are very efficient. In addition, a stable OLED device of PdN1N-dm gives a maximum EQE of 9.8% and the estimated operational lifetime LT 70 of 350 h at the practical luminance of 100 cd m −2 .
AB - A series of metal-assisted delayed fluorescence (MADF) palladium(II) complexes, PdN1N, PdN1N-dm, and PdN6N, are studied. Their 77 K photoluminescence emission spectra show a narrow primary emission peak at 464, 466, and 470 nm, respectively, with small vibronic peaks characteristic of many phosphorescent emitters. At room temperature (300 K), the dominant emission peaks for PdN1N, PdN1N-dm, and PdN6N are slightly redshifted to 472, 470, and 476 nm, respectively. In the meantime, a broad sideband is also shown between 410 and 450 nm due to the MADF process. A blue device employing PdN1N-dm demonstrates an electroluminescence emission peak at 476 nm and the maximum external quantum efficiency (EQE) of 25.1%. The high maximum EQE of the blue organic light-emitting diode (OLED) device indicates that both the phosphorescence and the delayed fluorescence are very efficient. In addition, a stable OLED device of PdN1N-dm gives a maximum EQE of 9.8% and the estimated operational lifetime LT 70 of 350 h at the practical luminance of 100 cd m −2 .
KW - Pd(II) complex
KW - blue organic light-emitting diodes
KW - external quantum efficiency
KW - metal-assisted delayed fluorescence
KW - operational stability
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U2 - 10.1002/adom.201801518
DO - 10.1002/adom.201801518
M3 - Article
AN - SCOPUS:85059668316
SN - 2195-1071
VL - 7
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 6
M1 - 1801518
ER -