Synthesis and characterization of 1,2,4-oxadiazole-based deep-blue and blue color emitting polymers

Abstract

Two donor-acceptor-donor monomers such as 3,5-bis(4-bromophenyl)-1,2,4- oxadiazole (BOB) and 3,5-bis(5-bromothiophen-2-yl)-1,2,4-oxadiazole (TOT) incorporating electron transporting and hole blocking 1,2,4-oxadiazloe moiety were copolymerized with light emitting fluorene derivative via Suzuki polycondensation toafford two new polymers, PFBOB and PFTOT, respectively. The optical studies for polymers PFBOB andPFTOT revealed that the band gaps are 3.10 eV and 2.72 eV, respectively, and polymer PFBOB exhibited a deep-blue emission while polymer PFTOT showed blue emission in chloroform and as thin film. The photoluminescence quantum efficiencies (Φf) of polymers PFBOB and PFTOT in chloroform calculated against highly blue emitting 9,10-diphenylanthracene (DPA, Φf = 0.90) were 1.00 and 0.44, respectively.