Fabrication of Thin-Films Composed of ZnO Nanorods Using Electrophoretic Deposition

We have investigated a template-free electrophoretic deposition (EPD) process using preformed ZnO nanorods suspended in isopropanol. The preformed ZnO nanorods were synthesized using a solvothermal reaction under different conditions of temperature and time. The length of the resulting ZnO nanorods depended on conditions of synthesis. The powders of ZnO nanorods were then suspended in isopropanol. Electrophoretic mobility of the ZnO nanorods was measured and zeta potential calculated. Thin-films comprised of ZnO nanorods were fabricated on transparent conductive oxide glass using EPD. Resulting ZnO thin-films were smooth and uniform, and film-weight was controlled by changing the voltage that was applied as well as the time of deposition. These thin-films were characterized by X-ray diffraction and scanning electron microscopy methods. To illustrate one application of these electrophoretically deposited materials, the films of both ZnO nanorods and nanopowders were used as photoelectrodes of dye-sensitized solar cells (DSCs) and their performance tested. The DSCs fabricated with a film of ZnO nanorods showed higher efficiency than those of ZnO nanopowders.