(180ba) Quantum Dot Sensitized Titanium Dioxide Thin Films for Photovoltaic Applications

A tremendous amount of attention in the field of photovoltaics, photocatalysis, and photoelectrochromics has been placed on titanium dioxide. Unmodified anatase titanium dioxide, and Cadmium Selenide (CdSe) functionalized titanium dioxide thin films on indium tin oxide glass (ITO) substrates have been synthesized. CdSe quantum dots ranging from 2.5 nm to 7 nm in radius were used to maximize absorption in the UV and visible range of the solar spectrum. The colloidal semiconductors were prepared by the hot injection synthesis method, with samples being removed at specified intervals to obtain the variation in particle size. The thin films were prepared by spin coating nanocrystalline titanium dioxide onto etched ITO glass. The quantum dots were then attached to the thin film by functionalizing the surface with a sulfide based linker, and immersing the substrate and thin film in the organic solvent containing the colloidal CdSe. Photovoltaic performance was then analyzed using a solar simulator to emulate natural sunlight. Characterization of the films was accomplished using X-ray diffraction, while the solutions were analyzed using transmission electron microscopy, ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy.