To investigate the effect of trifluoromethyl groups in enhancing electron affinity of aromatic oxadiazole and triazole chromophores, we prepared four new copoly(aryl ether)s (P1-P4) consisting of bis(3-(trifluoromethyl) phenyl)-1,3,4-oxadiazole (ETO) or bis(3-(trifluoromethyl)phenyl)-4-(4-hexyloxyphenyl)-4H-1,2,4-triazole (ETT) segments and hole-transporting segments [2,5-distyrylbenzene (HTB) or bis-(styryl)fluorine (HTF)]. Molecular spectra (absorption and photoluminescence) and cyclic voltammetry were used to investigate their optical and electrochemical properties. The emissions of P1-P4 are dominated by the hole-transporting fluorophores with longer emissive wavelengths around 442-453 nm via efficient excitation energy transfer. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of P1-P4, estimated from electrochemical data, are -5.15, -5.18, -5.30, -5.27, -3.39, -3.49, -3.36, and -3.48 eV, respectively. The LUMO levels of ETO and ETT segments are significantly reduced to -3.39 ∼ -3.36 eV and -3.48 ∼ -3.49 eV, respectively, as compared with -2.45 eV of P5 containing a 2,5-diphenyl-l,3,4-oxadiazole segment. Moreover, electron and hole affinity can be enhanced simultaneously by introducing isolated hole- and electron-transporting segments in the backbone.
|Number of pages||11|
|Journal||Journal of Polymer Science, Part A: Polymer Chemistry|
|Publication status||Published - 2004 Dec 1|
All Science Journal Classification (ASJC) codes
- Polymers and Plastics
- Organic Chemistry
- Materials Chemistry