Synthesis, Structure, Photoluminescence, and Electroluminescence Properties of a New Dysprosium Complex
journal contributionposted on 08.02.2007 by Zhe-Feng Li, Liang Zhou, Jiang-Bo Yu, Hong-Jie Zhang, Rui-Ping Deng, Ze-Ping Peng, Zhi-Yong Guo
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A new dysprosium complex Dy(PM)3(TP)2 [where PM = 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone and TP = triphenyl phosphine oxide] was synthesized, and its single-crystal structure was also studied. Its photophysical properties were studied by absorption spectra, emission spectra, fluorescence quantum efficiency, and decay time of the f−f transition of the Dy3+ ion. In addition, the antenna effect was introduced to discuss the energy transfer mechanism between the ligand and the central Dy3+ ion. Finally, a series of devices with various structures was fabricated to investigate the electroluminescence (EL) performances of Dy(PM)3(TP)2. The best device with the structure ITO/CuPc 15 nm/Dy complex 70 nm/BCP 20 nm/AlQ 30 nm/LiF 1 nm/Al 100 nm exhibits a maximum brightness of 524 cd/m2, a current efficiency of 0.73 cd/A, and a power efficiency of 0.16 lm/W, which means that a great improvement in the performances of the device was obtained as compared to the results reported in published literature. Being identical to the PL spectrum, the EL spectrum of the complex also shows characteristic emissions of the Dy3+ ion, which consist of a yellow band at 572 nm and a blue emission band at 480 nm corresponding to the 4F9/2−6H13/2 and 4F9/2−6H15/2 transition of the Dy3+ ion, respectively. Consequently, an appropriate tuning of the blue/yellow intensity ratio can be presumed to accomplish a white luminescent emission.