(397ae) Application of Core-Shell Titania-ITO Nanowires in DSSCs

With increasing demand for more energy, fossil fuel depletion, and global warming, finding alternative energy sources have been the focus of research for the scientific community for decades. Compared with other sources, solar energy offers advantages such as being completely renewable, low operating cost, and environmental friendliness. The solar cell is an important class of devices that harvest solar energy and produce electricity. Among different types of solar cells, dye sensitized solar cells (DSSCs) are promising and conventionally the photo-sensitized anode and the cathode are made of thin films. Nanowires (NWs) are widely investigated because of their potential applications in nanoscale devices and sensors. Nanowire-based DSSCs are more advantageous than their thin-film or nanoparticle-based counterparts due to the former’s enhanced charge collection efficiency in the radial direction and faster charge transport in the axial direction. Tin-doped indium oxide (ITO) nanowires boast high conductivity and high transmittance in the visible spectra of sunlight and plays critical roles in DCCSs. In this work, free-standing ITO nanowires were synthesized via a vapor transport method on ITO-coated glass substrate. These nanowires have uniform diameters of ~ 200 nm and their length can be tailored in the range of 5-50 µm by controlling the growth time. A liquid phase deposition technique is used to deposit ~ 20nm-thick TiO₂ layers on NW surfaces. The coating crystallizes in anatase phase upon calcination, as evidenced by Raman spectroscopy and transmission electron microscopy. The electrical and optical properties of these core-shell nanowires are presented, which make them promising materials as the photoanode in DSSCs.