Distinction between SnO2 nanoparticles synthesized using co-precipitation and solvothermal methods for the photovoltaic efficiency of dye-sensitized solar cells

Nanocrystalline SnO2 powders prepared by solvothermal and co-precipitation pathways have been characterized using XRD, TEM, UV-Visible absorption, BET specific surface area (S BET) method, EIS and J-V measurements. The obtained powders have a surface area and size of 38.59 m2/g and 10.63 nm for the SnO2 powders synthesized solvothermally at a temperature of 200 °C for 24 h, while the values were 32.59 m2/g and 16.20 nm for the formed hydroxide precursor annealed at 1000 °C for 2 h by co-precipitation route. The microstructure of the formed powders appeared as tetragonal-like structure. Thus, the prepared SnO2 nanopowders using two pathways were applied as an electrode in dye-sensitized solar cell (DSSC). The photoelectrochemical measurements indicated that the cell presents short-circuit photocurrent (J sc), open circuit voltage (V oc) and fill factor (FF) were 7.017 mA/cm2, 0.690 V and 69.68%, respectively, for solvothermal route and they were 4.241 mA/cm2, 0.756 V and 66.74%, respectively, for co-precipitation method. The energy conversion efficiency of the solvothermal SnO2 powders was considerably higher than that formed by co-precipitation powders; ∼ 3.20% (solvothermal) and 2.01% (co-precipitation) with the N719 dye under 100 mW/cm2 of simulated sunlight, respectively. These results were in agreement with EIS study showing that the electrons were transferred rapidly to the surface of the solvothermal-modified SnO2 nanoparticles, compared with that of a co-precipitation-modified SnO2 nanoparticles.