Hydrothermal Synthesis of Novel ZnO Nanomushrooms for Improving the Solar Cells Performance

The aim of this study is to fabricate novel ZnO nanomushrooms (NMs) for improving the dye-sensitized solar cells (DSCs) performance. The ZnO NMs have been fabricated on ZnOseeded SnO₂ :F (FTO) glass substrate by simple and inexpensive hydrothermal method at low temperature of 150 °C. The highcrystalline ZnO seed layer prepared on the FTO substrate by the facing-target sputtering technique. The whole surface is uniformly grown by ZnO NMs, which is slightly closer to the nanonails structure. Interestingly, the cap of NMs is separately grown on hexagonal ZnO nanorods (NRs) and has an average diameter of 262 nm. The diameter of bottom NMs is ~128 nm larger than the diameter of top NMs (intersection between cap and NRs). Ruthenium-based dye and carbon counter electrode are used for the fabrication of DSCs. The photovoltaic performance of DSCs with ZnO NMs is compared with DSCs with ZnO NRs prepared by same hydrothermal process at 85 °C. The photoelectric conversion efficiency (2.38%) of ZnO NM-based DSCs is 1.7 times higher than ZnO NR-based DSCs (1.41%). For DSC with ZnO NMs, other photovoltaic parameters are also better than the solar cells with ZnO NRs.