In the last decade, a large research effort has been devoted to the development and optimization of Dye-Sensitized Solar Cell (DSSC) as a potential alternative for the traditional Si solar cell due to its low cost and easy fabrication. For commercial purpose, the flexible DSSC with plastic substrate has attracted great interest. As the main part of the DSSC, the working electrode, on which most of the research is based on TiO₂, has been well studied to improve the overall efficiency. However, the sintering of TiO₂, requires high temperature (around 450 °C), such temperatures would damage plastic substrates. Alternatively, well crystallized ZnO nanorods can be synthesized via a low temperature hydrothermal process. In addition, the ordered 1D crystallite is favourable for collection of electrons. However, the low surface area limits the performance of the DSSC due to the low adsorption of dye.

Here we employed different processes to modify the surface properties and morphology of the ZnO nanorods, with an aim to increase the surface area of the electrode and hence the overall efficiency of the ZnO based DSSC. For example, coated ZnO nanorods and branched ZnO nanorods were synthesized. The materials were characterized via X-ray diffraction to check the crystals structure. Electron microscopy was applied to investigate the surface morphology. Gas sorption was used to measure the surface area along with the dye sorption test. Finally, the materials were assembled in DSSC to compare their performance, which was correlated with the surface properties of the ZnO nanorods.