Remarkable Isomeric Effects on Optical and Optoelectronic Properties of N-Phenylcarbazole-Capped 9,10-Divinylanthracenes

We synthesized three N-phenylcarbazole-capped 9,10-divinylanthrane isomers by changing the linking positions of N-phenylcarbazole, 9,10-bis(N-phenylcarbazol-2-/3-71-vinyl-2)anthracenes (CZ2/CZ3), and 9,10-bis(4-(carbazol-9-yl)styryl)anthracene (CZ9) to examine isomeric effects on the fluorescence and electroluminescence properties. The results showed that their fluorescence emission properties in both crystalline and amorphous states were affected by the linking position of N-phenylcarbazole. The three isomers were all strong crystallization-enhanced emission (CEE) dyes, whereas the strongest and the weakest fluorescence efficiencies were measured in crystalline and amorphous states of CZ9, respectively. When the isomers were used as bulk emitting layers by vapor deposition, the maximal luminous efficiency, luminance, and the turn-on voltage of CZ9-based device were 0.10 cd A(-1), 550 cd cm(-2), and 7.8 V, respectively. In sharp a contrast, CZ3 afforded the best EL performance, and the corresponding performances were 3.1 cd A(-1), 13770 cd cm(-2), and 3.2 V, respectively. The obvious isomeric effect indicated that subtle manipulation of peripheral groups was indeed a feasible and efficient way for tuning the optical and optoelectronic properties of CEE dyes.