Synthesis and photovoltaic property of poly(3-octylthiophene)/titanium dioxide/ferric oxide composite

Titanium dioxide and ferric oxide were prepared by the supercritical fluid drying (SCFD) method. A conducting polymer composite, poly(3-octylthiophene)/titanium dioxide/ferric oxide (POT/TiO2/Fe2O3) was first synthesized by chemical method. Transmission electron microscope (TEM) and scanning electron microscope (SEM) depicted the morphology of the samples, defining that TiO2 and Fe2O3 were successfully coated by poly(3-octylthiophene) molecules. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR) showed the chemical interaction between poly(3-octylthiophene) and inorganic compounds in the composite. Cyclic voltammetry (CV) curves showed that the forbidden band gap of the POT/TiO2/Fe2O3 composite is 0.691 eV, realizing the complementary advantages of n and p semiconductor. UV-vis spectra (UV) and fluorescence spectra (PL) showed that its optical performance is far superior to poly(3-octyl thiophene), titanium dioxide and ferric oxide separately. Solar cell was sensitized by POT/TiO2/Fe2O3. A solar-to-electric energy conversion efficiency of 0.499% was attained with the system.