Synthesis and Electroluminescence Property of Pyrene Derivatives Including Dibenzothiophene and Imidazole Moiety

Pyrene, imidazole and dibenzothiophene were used to synthesize new blue emitters of 1-(4-Dibenzothiophen-2-yl-phenyl)-4,5-diphenyl-2-pyren-1-yl-1H-imidazole (DDPI) and 1-(3-Dibenzothiophen-4-yl-phenyl)-2-pyren-1-yl-1H-phenanthro[9,10-d]imidazole (DPPI). The optical properties of synthesized compounds were measured by UV-visible absorption and PL spectra. In the vacuum deposited film state, the PL maximum value is 463 nm for DDPI and 455, 471 nm for DPPI. The device using DDPI as emitting material showed CE of 2.38 cd/A, PE of 1.38 lm/W, and EQE of 1.54%, device using DPPI as emitting material exhibited CE of 3.65 cd/A, PE of 2.31 lm/W, and EQE of 3.07%. Also, OLED devices of DDPI and DPPI devices exhibited CIE coordinate of (0.20, 0.23) and (0.16, 0.16).