Optimization of quantum dots for solar cell applications

The quantum dots-sensitized solar cells (QDSSC) provide an alternative concept to present day photovoltaic devices. Cadmium sulfide/Zinc sulfide-sensitized solar cells have been synthesized by chemical bath deposition, based on an aqueous medium involving cadmium sulphate, zinc acetate, thiourea and ammonium hydroxide. To improve the luminescence efficiency and photo stability of the quantum dots (QDs), coating the quantum dots with another wide bandgap semiconductor is a usual procedure. In particular, for CdS quantum dots, the particles were covered with ZnS to establish a core/shell system. This CdS/ZnS quantum dots are assembled onto nanoporous TiO2 films for quantum dots-sensitized solar cell applications. Physical and chemical properties of the formed nanoparticles were analyzed using field emission scanning electron microscope (FESEM), ultraviolet-visible light (UV-VIS) spectrometer, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). An efficiency as high as 1.80% for the CdS/ZnS quantum dots-sensitized solar cells was achieved using the present method