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/Fe ₂O₃. A solar-to-electric energy conversion efficiency of 0.499% was attained with the system.