Vertically aligned ZnO nanowires (NWs) were prepared inside an autoclave by a hydrothermal procedure at temperatures above 100°C (HP). The effects of synthesis temperature and time on the morphology of ZnO NWs were carefully studied. The performance of HP ZnO NWs was compared with that of ZnO NWs grown by a conventional ambient pressure hydrothermal method at temperatures below 100°C (LP) as photoanodes in dye-sensitised solar cells (DSCs). HP ZnO NWs provided DSCs with more than two-fold higher power conversion efficiencies than LP ZnO NWs. Improved efficiencies are associated to the larger higher aspect ratio and improved crystallinity of HP ZnO NWs.
Keywords: ZnO nanowires, hydrothermal, photovoltaics, dye-sensitised solar cells, nanotechnology.