Annealing effect on Sb(2)S(3)-TiO(2) nanostructures for solar cell applications

Nanostructures composited of vertical rutile TiO(2) nanorod arrays and Sb(2)S(3) nanoparticles were prepared on an F:SnO(2) conductive glass by hydrothermal method and successive ionic layer adsorption and reaction method at low temperature. Sb(2)S(3)-sensitized TiO(2) nanorod solar cells were assembled using the Sb(2)S(3)-TiO(2) nanostructure as the photoanode and a polysulfide solution as an electrolyte. Annealing effects on the optical and photovoltaic properties of Sb(2)S(3)-TiO(2) nanostructure were studied systematically. As the annealing temperatures increased, a regular red shift of the bandgap of Sb(2)S(3) nanoparticles was observed, where the bandgap decreased from 2.25 to 1.73 eV. At the same time, the photovoltaic conversion efficiency for the nanostructured solar cells increased from 0.46% up to 1.47% as a consequence of the annealing effect. This improvement can be explained by considering the changes in the morphology, the crystalline quality, and the optical properties caused by the annealing treatment.