Solvothermal growth of Zn2SnO4 for efficient dye-sensitized solar cells

Zn2SnO4 plates, particles and spheres are successfully prepared via a facile synthesis way by carefully adjusting the solvothermal conditions, which are further applied as photoanodes in dye-sensitized solar cells (DSSCs) to explore the relationships between the photoanode nanostructure and the photovoltaic performances. As a result, the DSSCs based on Zn2SnO4 spheres photoanode showcased the best power conversion efficiency (PCE, 4.85%), compared to Zn2SnO4 plates (3.80%) and particles (4.13%). It is found that Zn2SnO4 spheres exhibit the highest light-scattering abilities, as evidenced by ultraviolet-visible (UV-Vis) diffuse reflectance spectra. Additionally, investigations on dynamic electron transport and recombination properties via intensity-modulated photovoltage/photocurrent spectroscopy (IMVS/IMPS), and electrochemical impedance spectroscopy (EIS) measurements demonstrate that the Zn2SnO4 spheres-based DSSCs possess the fastest electron transport rate, the longest electron lifetime, the highest electron collection efficiency (eta(cc)), and the largest charge recombination resistance, compared with the Zn2SnO4 plates and particles, all of which are highly beneficial for the powder conversion efficiency enhancements.