Photovoltaic properties of blend composites, composed of N,N′ didodecy1 3,4,9,10 perylene biscarboximide (PDI) and a soluble conductive polymer poly(3 hexylthiophene) (PHT), are reported. PDI can form the interpenetrating network structure with PHT chains, as evidenced in the UV Vis spectrum. The investigation of the photoluminescence (PL) spectra revealed that PL of PHT was quenched when it was blended with PDI. The photovoltaic devices using PHT as both the sensitizer and hole conductor, and PDI films as the electron conductor were prepared to estimate the photovoltaic performance of the blend films. An improvement of conversion efficiency in the blending cells compared with that of the pure PHT cells was observed. Spectral properties and current voltage( I\|V) characteristics of the PHT/PDI composite films showed that the perylene diimide dopant can improve the photovoltaic performance of PHT films significantly through the increase of visible light absorption, exciton dissociation, diffusion and transportation.
