CdS/CdSe Co-Sensitized Solar Cells Based on a New SnO2 Photoanode with a Three-Dimensionally Interconnected Ordered Porous Structure

Highly ordered SnO2 inverse opal films with different thicknesses are prepared by our newly developed doctor-blading technique combined with liquid-phase deposition, which have been applied in CdS/CdSe co-sensitized solar cells for the first time. Up to 4.37% of light-to-electricity conversion efficiency with a high open-circuit photovoltage of 700 mV has been achieved under AM 1.5 (100 mW cm(-2)) illumination. A careful comparison of two SnO2 photoanodes (inverse opal structure and conventional disordered film composed of submicrometer particles) is performed by analysis of optical and photoelectrochemical properties and electrochemical impedance spectra. The comparison reveals that the highly ordered SnO2 inverse opal structure can effectively reduce the charge recombination and increase the open-circuit photovoltage, fill factor, and cell performance.