Photoconductive properties of TiO2 films prepared by the sol-gel method and its application

The Photoconductive characteristics of TiO2 films prepared by the sol-gel method, and the photovoltaic characteristics fabricated with the resulting TiO2 film and phthalocyanine nickel (NiPc) are investigated. For a TiO2 film with hydroxypropyl cellulose (Hpc) heat treated at 500 degrees C for 10 min, the relative sensitivity is about ten times higher than that without Hpc. A space-charge-limited current is observed in the dark current-voltage characteristic of the TiO2 film with Hpc. It is found that the TiO2 film with Hpc has a photosensitizing effect. The photovoltaic characteristics of TiO2(Hpc)/NiPc are as follows: the short-circuit current density, J(sc) is 5.6 x 10(-7) A cm(-2), the open-circuit voltage, V-oc is 0.24 V, the fill factor (F.F) is 0.64 and the power conversion efficiency, eta is 0.73. furthermore, the carrier transport mechanisms of the TiO2(Hpc)/NiPc photovoltaic cell are discussed.