Sea urchin TiO2-nanoparticle hybrid composite photoelectrodes for CdS/CdSe/ZnS quantum-dot-sensitized solar cells

The sea urchin TiO2 (SU TiO2) particles composed of radially aligned rutile TiO2 nanowires are successfully synthesized through the simple solvothermal process. SU TiO2 was incorporated into the TiO2 nanoparticle (NP) network to construct the SU-NP composite film, and applied to the CdS/CdSe/ZnS quantum-dot-sensitized solar cells (QDSSCs). A conversion efficiency of 4.2% was achieved with a short-circuit photocurrent density of 18.2 mA cm(-2) and an open-circuit voltage of 531 mV, which corresponds to similar to 20% improvement as compared with the values obtained from the reference cell made of the NP film. We attribute this extraordinary result to the light scattering effect and efficient charge collection.