Sponge-like porous TiO2/ZnO nanodonuts for high efficiency dye-sensitized solar cells

Porous photoanodes in dye-sensitized solar cells (DSSCs) can lead to superior photovoltaic properties due to their high dye absorption, large pore volume and superior light scattering. In this work, sponge-like TiO2/ZnO nanodonuts were synthesized by one step electrospray method, and the effects of different morphologies and ZnO concentrations on the performances of DSSCs were studied. The results indicated that porous TiO2/ZnO nanodonuts possess larger pore volume, higher dye absorption, better light scattering ability, and more efficient electron transport and electrolyte penetration properties due to their superior porous structure. Combined with the optimized ZnO concentration to suppress electrons recombination, energy conversion efficiency of 9.00% can be obtained with Jsc of 16.70 mA cm−2, Voc of 0.78 V and FF of 0.69, which is 44.4% higher than those of DSSCs based on P25 particles, and substantially higher than other TiO2/ZnO morphologies as well.