Microwave-Assisted Synthesis of SnO2 Nanosheets Photoanodes for Dye-Sensitized Solar Cells

SnO2 nanosheets were synthesized using microwave-assisted hydrothermal growth and used as photoanodes for dye-sensitized solar cells (DSCs) and demonstrated much better photoelectrical energy conversion performance than that of SnO2 synthesized with traditional hydrothermal growth, due to a significant decrease in charge diffusion distance and charge recombination. The crystallinity and microstructure of the samples were investigated by means of X-ray diffraction (XRD), scanning, and transmission electron microscopy (SEM/TEM). The specific surface area and pore size distribution were determined by means of nitrogen sorption isotherms. The interfacial charge transfer process and the charge recombination were characterized by electrochemical impedance spectrum (EIS) and intensity modulated photocurrent/photovoltage spectra (IMPS/IMVS) measurements. The DSCs assembled with SnO2 nanosheets as photoanodes from microwave-assisted synthesis exhibited much enhanced energy conversion efficiency, which is attributed to a higher open-circuit voltage due to less charge recombination, and a large short-circuit current density due to both large surface area and effective light scattering effect.