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 (SBET) method, EIS and J-V measurements. The obtained powders have a surface area and size of 38·59 m ²/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 (Jsc), open circuit voltage (Voc) and fill factor (FF) were 7·017 mA/cm ², 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.