Self-assembly monolayer of anatase titanium oxide from solution process on indium tin oxide glass substrate for polymer photovoltaic cells

Titanium dioxide (TiO2) thin films were deposited on indium tin oxide (ITO) coated glass substrates by a liquid phase deposition method using two different precursor concentrations of 0.01 M and 0.005 M [NH4]2TiF6. Characterizations of the deposited TiO2 films were performed by using different spectroscopic techniques including X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. From scanning electron microscopy observation, the surface of the TiO2 films show a ricelike morphology. We have fabricated polymer-based photovoltaic cells (PCs) using the studied TiO2 films and compared their performances to those using bare ITO-coated glass substrates. The structure of the PCs is glass/ITO/TiO2/PCBM:P3HT/Au where PCBM:P3HT is poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester. The power conversion efficiency of these devices is determined to be 0.85%, which is higher than that of similar devices without TiO2 films (0.13%).