Synthesis and optical properties of novel blue light-emitting polymers with electron affinitive oxadiazole

A series of novel polyethers, which can be used as a blue electroluminescent material were prepared from two diarylethylene-containing emission chromophores with two oxadiazole-containing electron-transporting chromophores. The characterization and effect of different structures on optoelectric properties was investigated by use of thermal analysis and spectroscopy (infrared, ultraviolet-visible, photoluminescence, cyclic voltammetry) measurement. s-(4-fluoroaryl)-1,3,4-oxadiazole and 4,4′-dihydroxyarylethylene were used as electron transport and emission monomers, respectively. The 4,4′-dihydroxyarylethylene derivatives that contain benzene–benzene and benzene–naphthalene were synthesized by Horner–Wadsworth–Emmons olefination reaction. The emission chromophores emit blue light as expected. Aromatic polyethers were obtained by nucleophilic substitution reaction of oxadiazole-activated bis(halide) monomers with bis(phenol) monomers. Moreover, two polymers containing hexaethylene chain instead of electron transport unit were also synthesized for comparison. All the resulting polymers containing oxadiazole group were thermally stable below 470°C. The absorption peaks of these polymers varied from 310 to 370 nm, while the photoluminescent peaks varied from 377 to 456 nm. These polymers containing electron-transporting oxadiazole indeed show extra reduction potentials in CV measurements.