pi-Conjugated twin molecules based on 9,9-diethyl-1-phenyl-1,9-dihydrofluoreno[2,3-d]imidazole module: synthesis, characterization, and electroluminescence properties

摘要

A series of well-defined, pi-conjugated twin molecules by connecting two 9,9-diethyl-1-phenyl-1,9-dihydrofluoreno[2,3-d]imidazole units via an ortho-, meta-, or para-benzene with high quantum efficiency of fluorescence is synthesized and fully characterized. The detailed thermal, electrochemical, photophysical, and electro-luminescence properties have been investigated. The electro-luminescence properties of the obtained materials are studied by fabricated the device using the configuration ITO/HATCN (5 nm)/NPB (20 nm)/TCTA (10 nm)/CBP: 5% doping (20 nm)/TMPYPB (40 nm)/LiQ (1 nm)/Al (80 nm). The doped OLED based on the compound with para-benzene as the emitting layer shows the best performance with the maximum current efficiency of 2.30 cd/A, maximum power efficiency of 1.52 lm/W, located in the deep-blue region with CIE (x, y) value of (0.1572, 0.0587) with relatively lower onset voltage of 4.25 V.