Semiconductor Physics, Quantum Electronics & Optoelectronics. 2007. V. 10, N 1. P. 077-082.
1,4-bis(2,2-diphenylethenyl)benzene as an efficient emitting material
for organic light emitting diodes
1Center for Future Chemistry, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
Abstract. We report on the photophysical properties of 1,4-bis(2,2-diphenyl-
ethenyl)benzene (PEB) in a solution and a solid state. A poor blue photoluminescence
efficiency of PEB in a solution dramatically increases in the deposited film. We explain
such properties in terms of molecular dynamics and degrees of intramolecular freedom in
various molecular environments. PEB as an electron-transport and emitting layer in
organic light-emitting diodes (OLEDs) shows bright blue-green electroluminescence
(EL) with the peak wavelength at λ max ~ 495 nm. The maximum external EL quantum
efficiency of η EL = 2.5 % and maximum luminance of 41600 cd/m 2 in the optimized
device were obtained, indicating that PEB possesses superior electron-transport ability.
Keywords: electroluminescence, electrical transport characteristics, OLED, 1,4-bis(2,2-
diphenylethenyl)benzene (PEB).
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