In this study, ZnO nanoparticles (NPs), ZnO nanorods (NRs) and ZnO nanosheet-based hierarchical structures (NSHSs) were rapidly synthesized using three simple approaches at relatively low temperatures and without any organic surfactants. Based on their structural advantages in light absorption, reflection and electron transfer, an NP/NSHS/NR hybrid structure was fabricated and used as a photoanode in dye-sensitized solar cells (DSSCs). The photoanode was treated in fluorescein acetonitrile solution (down-conversion materials) to enhance the photovoltaic efficiency, as well as in ascorbic acid ethanol solution to inhibit fluorescence quenching, which is caused by the I-3(-)/I- electrolyte. Results showed that the NP/NSHS/NR hybrid structure plus fluorescein treatment was highly effective in improving the light harvesting capacity via an efficient electron transfer path and a down-conversion luminescence process, and the light-to-electric energy conversion efficiency of the DSSCs reached 6.54%, which increased by 34% compared with that of the ZnO NP-based DSSCs. (C) 2015 Elsevier B.V. All rights reserved.