Electroluminescent devices using polymer blend thin films

We report the thin film electroluminescent devices made from polymer blends composed of the luminescent conjugated polymer poly(3-n-butyl-p-pyridyl vinylene) (Bu-PPyV), a hole-transporting polymer poly(9-vinyl carbazole) (PVK), and an electron-transporting material 2-(4-biphenyl)-5-(4-tert-butyl-phenyl)-1,3,4-oxadiazole (PBD). Through the blends, we show that the self-quenching of the luminescence of the luminescent polymer is reduced and the luminescent efficiency is much increased. Carrier transport materials provide better match of hole and electron injection into the blends and therefore raise the electroluminescent efficiency by over one order of magnitude higher than the pure material. By tuning the composition of the blends, the emission color can be changed across the whole visible spectrum.