Synthesis and characterization of ZnO nanoparticles using sol gel technique for dye sensitized solar cells applications

Abstract

ZnO nanoparticles were synthesized using sol gel technique at different calcination temperature. The effect of calcination temperature on the structure and optical properties of ZnO NPs were studied in detail by using different techniques, X-ray diffraction, high-resolution transmission electron microscope, UV-VIS spectroscopy and photoluminescence spectroscopy. X-ray diffraction analysis revealed that the ZnO NPs were crystalized in a wurtzite structure and the estimated average particle size increased from 24.7 to 40.4 nm with increasing calcination temperature. In addition, the d spacing increased from 0.28196 nm to 0.28213 nm. High-resolution transmission electron microscopy analysis image showed spherical ZnO NPs were formed. UV-VIS absorption measurement was employed to evaluate the absorption edge and the optical band gap using Tauc plot. Energy gap revealed a red shift from 3.15 to 2.96 eV when the calcination temperature was increased. Dye sensitized solar cells were fabricated using synthesized ZnO NPs as a semiconducting layer that were dyed with different Xanthene (CH2[C6H4]2O) dyes separately; (Eosin B, Eosin Y and Rhodamine B) which are low cost dyes. Thin layer of ZnO were deposited on transparent fluorine doped tin oxide conductive glass using doctor blade method. Eosin Y exhibited the best photosensitizing. The conversion efficiency showed a significant improvement from 0.1% to 1.08%.