Synthesis and characterization of novel blue light emitting poly[4,4′-biphenylylene(α-phenylvinylene)]

Novel blue light emitting poly[4,4'-biphenylylene(alpha-phenylvinylene)] (PBPPV) was synthesized using the well-known nickel coupling reaction. PBPPV containing an asymmetric monophenyl group at the vinylene of the main chain was highly soluble in common organic solvents and was found to be thermally stable. The polymer containing suitable electron a donating monophenyl substituent gives rise to bright blue fluorescence both in solution and thin solid films. The solid photoluminescence quantum efficiency of the PBPPV was 0.43(+/-10%). The EL spectra of PBPPV and the blend with PVK had similar maxima at about 460 nm in the blue region. The maximum brightness of devices of structure ITO/PBPPV/Al-Li and ITO/PBPPV : PVK (3 : 7)/Al-Li were 250 cd m(-2) and 2700 cd m(-2), respectively.