Synthesis and application of core-shell Au-TiO2 nanowire photoanode materials for dye sensitized solar cells

Dye sensitized solar cells (DSSCs) have been widely studied as alternatives for generation of electricity from sunlight due to their efficiency and cost effectiveness. Increasing the electron transport out of the metal oxide is important in achieving higher efficiency. Enhancing light absorption can also improve cell efficiency. The motive of this work was to synthesize and use Au-TiO2 core-shell nanowires as anode materials in DSSCs in order to increase cell efficiency by enhancing electron transport out of the oxide and/or increasing light collection efficiency. TiO2 nanotubes were first grown in alumina templates using a sol-gel method. Gold nanowires were subsequently grown in the pores of these tubes by electrodeposition. Resulting nano-structured arrays were characterized using electron microscopy and diffraction techniques; the results show that the wires were highly aligned and well separated. The current-voltage (J-V) behavior for the Au-TiO2 core-shell nanowire based DSSCs was compared to the J-V data for TiO2 nanotube based DSSCs, indicating substantial improvements upon incorporation of the Au core nanowires. TiCl4 treatment of the Au-TiO2 core-shell nanowire structures resulted in further efficiency improvements.