Zinc oxide was prepared by the supercritical fluid drying (SCFD) method. A series of conducting polymer complexes, poly (3-octylthiophene)/zinc oxide (POT/ZnO) with different proportions were first synthesized by chemical method. Transmission electron microscope (TEM) and scanning electron microscope (SEM) depict the morphology of the samples, defining that ZnO was successfully coated by poly (3-octylthiophene) molecules: X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR) showed the chemical interaction of poly (3-octylthiophene) and nano-zinc oxide in the complexes; cyclic voltammetry (CV) curves show that the forbidden band gap of the POT/ZnO composite is 0.742 eV which is the smallest when POT:ZnO = 1:2, realizing the complementary advantages of in and p semiconductor: ultraviolet-visible spectra (UV) and fluorescence spectra (PL) show that its optical performance is far Superior to poly 3-octyl thiophene and zinc oxide separately. Solar cell was sensitized by POT/ZnO. A solar-to-electric energy conversion efficiency of 0.210% was attained with the system. (C) 2009 Elsevier B.V. All rights reserved.