Zinc stannate nanoflower (Zn2SnO4) photoanodes for efficient dye sensitized solar cells

Ternary zinc stannate (Zn2SnO4) nanoparticles were synthesized using the green hydrothermal technique at 200 degrees C for different reaction times and they were used as photoanodes for dye sensitized solar cells (DSSCs). The photovoltaic performance of the DSSC cells was characterized by measuring the J-V curves in dark, and under illumination. Among the three DSSC cells, the photoanode based on Zn2SnO4 nanoflower synthesized at 200 degrees C for 48 h recorded the highest conversion efficiency of 3.346% under 1 sun illumination (AM 1.5 G, 100 mW cm(-2)) with improved short-circuit current density of 7.859 mA cm(-2), and comparable open-circuit photovoltage (0.626 V) and fill factor (0.679). This enhancement of characteristics is primarily attributed to the higher current density owing to its better crystalline quality as well as the larger surface area of Zn2SnO4 nanoflowers, all of which are the results of longer reaction time. The findings are further substantiated by means of open-circuit photovoltage decay experiment, dye loading behavior and electrochemical impedance spectroscopy. (C) 2013 Elsevier Ltd. All rights reserved.