Tailored ZnO nanostructure based quasi-solid-state electrolyte and mesoporous carbon electrocatalyst for solar energy conversion

We have investigated the photoelectrochemical influence of quasi-solid-state electrolytes based on tailored ZnO nanostructures and mesoporous carbon electrocatalyst in the solar conversion performance of dye-sensitized solar cells (DSSCs). Tailored ZnO nanostructures with rod-shaped petals (ZnO nanorod) and almond-shaped petals (ZnO nanoalmond), were prepared using the hydrothermal method, respectively. Mesoporous carbon electrocatalyst with a high surface area is obtained by the carbonization of the PVDC-g-POEM double comb copolymer. The phase and structure of tailored ZnO nanostructures were investigated using scanning electron microscopy (SEM) and wide angle X-ray scattering (WAXS). Diffuse reflectance, intensity-modulated photocurrent spectroscopy (IMPS)/intensity-modulated photovoltage spectroscopy (IMVS), electrochemical impedance spectroscopy (EIS) measurements were used to investigate the optical and electrochemical properties of quasi-solid-state electrolytes. The quasi-solid-state electrolytes based on ZnO nanorod significantly improved the solar conversion performance owing to its enhanced scattering effect, ion diffusion, effective path for redox couple transfer, and sufficient penetration of quasi-solid-state electrolytes into the electrode. The quasi-solid-state electrolytes based on ZnO nanorod, ZnO nanoalmond and mesoporous carbon electrocatalyst showed a solar conversion efficiency of 6.4%, 5.4%, respectively, which is higher than that of the polymer gel electrolytes (4.7%).