Color Tunable Electroluminescence From Polymer Blends Containing Carbazole Unit

The electro-optical properties of poly(phenylenevinylene-alt-N-hexyl-carbazolevinylene), [Poly(PPV-N-hexylCvz)], poly[1′,4′-phenylene-1″, 4″-(2″-(2″″-ethylhexyloxy))phenylene-2,5-(1″′,4″′-phenylene)-1,3,4-oxadiazolyl](PPEPPO) and their blends were characterized. The photoluminescence and electroluminescence spectra of the blend films composed of Poly(PPV-N-hexylCvz) and PPEPPO were mainly contributed from the luminance of Poly(PPV-N-hexylCvz) even at low Poly(PPV-N-hexylCvz) ratios. Remarkably enhanced EL efficiency was observed as the ratio of PPEPPO increased. As the ratio of PPEPPO was increased from 50 to 83%, the EL emission was changed from green to blue color.