Synthesis and light-emitting properties of solution-processable oligothiophenes containing triazole moiety

The aromatic triazole is an interesting electron-injection/transport chromophore because it possesses high electron affinity and thermal stability. In organic lighting-emitting diodes (OLEDs), highly electron-deficient triazole (Tz) derivates have been demonstrated to have more efficient electron-transport and hole-blocking characteristics and have a higher stability to high current density than the oxadiazole derivates. In this study, we have successfully synthesized a star-shaped soluble oligomer,4-(4-butylphenyl)-3,5-bis(4- (5′-hexyl-2,2′-bithiophen-5-yl)phenyl)-4H-1,2,4-triazole(Tz-2 T-Hex) via Suzuki coupling reaction. The Tz-2T-Hex shows a red-shifted UV-vis absorption spectrum than Tz-Br with a maximum at 380 nm, due to the introduction of two bithiophene units at both ends. As film, Tz-2T-Hex showed the PL maximum at 530 nm. Tz-2T-Hex emitted light of a white color with the CIE coordinates (0.32 and 0.34).