Tin (Sn) doped ZnO nanostructures for the application of dye sensitized solar cells

The tin (Sn) doped zinc oxide (ZnO) nanostructures are synthesized by the simple hydrothermal method and the photovoltaic performances of Sn doped ZnO derived photoanodes were studied. The doping of Sn significantly alters the morphology of ZnO into spindle shape by the arrangement of small ZnO nanoparticles. The crystalline and structural properties deduce the clear decrement in the crystallite sizes from ~143.9 nm to ~82.2 nm, which might be suggested the doping of Sn-ions into ZnO nanostructures. Xray photoelectron spectroscopy (XPS) study shows Sn-O and Zn-O bonding in the synthesized spindle shaped Sn-ion doped ZnO nanostructures, which confirms Zn substitution by the Sn-ions. Dye sensitized solar cell (DSSC) fabricated with Sn-ZnO photoanode achieves a solar-to-electricity conversion efficiency of ~1.82% with short circuit current (JSC) of 5.1 mA/cm², open circuit voltage (VOC) of 0.786 V and fill factor (FF) of 0.45, which are higher than that of DSSC with ZnO photoanode. The increased conversion efficiency and the photocurrent density are attributed to the significant Sn-ion doping into ZnO nanostructures and considerable arrangement of ZnO nanoparticles into spindle shaped morphology which might improve the high charge collection and the transfer of electrons at the interfaces of doped ZnO layer and the electrolyte layer.