Annealing Effect on Photovoltaic Performance of CdSe Quantum‐Dots‐Sensitized TiO₂ Nanorod Solar Cells

Abstract

Large area rutile TiO 2 nanorod arrays were grown on F:SnO 2 (FTO) conductive glass using a hydrothermal method at low temperature. CdSe quantum dots (QDs) were deposited onto single‐crystalline TiO 2 nanorod arrays by a chemical bath deposition (CBD) method to make a photoelectrode. The solar cell was assembled using a CdSe‐TiO 2 nanostructure as the photoanode and polysulfide solution as the electrolyte. The annealing effect on optical and photovoltaic properties of CdSe quantum‐dots‐sensitized TiO 2 nanorod solar cells was studied systematically. A significant change of the morphology and a regular red shift of band gap of CdSe nanoparticles were observed after annealing treatment. At the same time, an improved photovoltaic performance was obtained for quantum‐dots‐sensitized solar cell using the annealed CdSe‐TiO 2 nanostructure electrode. The power conversion efficiency improved from 0.59% to 1.45% 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 annealing treatment.