کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5190523 | 1381208 | 2006 | 8 صفحه PDF | دانلود رایگان |
We prepared three new poly(9,9-dihexylfluorene) derivatives (P1-P3) containing kinked aromatic triazole (triphenyl-1,2,4-triazole derivative) via Suzuki coupling polymerization. These copolymers were soluble in common organic solvents and showed high decomposition temperatures (Td = 416-454 °C). The optical and electrochemical properties of P1-P3 were compared with poly(9,9-dihexylfluorene) (PFO) and P4 and P5 in which the linkages of the aromatic triazole were different. After introducing the triazole units, absorption spectra showed blue shift (388 nm â 372 nm) due to reduced conjugation, but PL spectra remained almost unchanged (417-418 nm). The linkages of triazole with fluorene segments in P1-P5 were different: (1) fluorene segments linked with triazole through a kinked angle (P1 and P2), (2) triazole as a branch unit (P3) and as terminal groups (P4), (3) fluorene segments linked with triazole in a linear way (P5). As estimated from semi-empirical MNDO calculation, two twisted conformations (ca. 90° each) exist between triazole core and fluorene groups. These kinked conformation and twisted structure increased the PL efficiency (ΦPL = 0.60-0.73, ΦPL = 0.58 for PFO) and partially inhibited annealing-induced excimer formation. From cyclic voltammetric results, P1-P3 exhibited better electron affinity (LUMO: â2.75 to â2.82 eV) than PFO (LUMO: â2.52 eV).
Journal: Polymer - Volume 47, Issue 26, 8 December 2006, Pages 8436-8443