White LEDs using conjugated polymer blends

We fabricated white light-emitting devices using blends of two conjugated polymers. Poly[9,9-bis(4′-n-octyloxyphenyl)fluorene-2,7-diyl-co-10-(2′-ethylhexyl)phenomiazine-3,7-diyl] [poly(BOPF-co-PTZ)] was employed as a blue host polymer and stereo-regular poly(3-hexylthiophene) (P3HT) was employed as a red doping material. The PL emission spectra of the blend systems depended on its blend ratio. Each emission bands of poly(BOPF-co-PTZ) and P3HT were observed at 480 nm and 570 nm in the PL spectra of blend systems. As the P3HT content in the blend system increase the intensity of emission at 570 nm increases. The EL devices were fabricated with ITO/PEDOT/blend/LiF/Al configuration and white light-emission was obtained for a certain blend ratio.