Preparation of Ce-doped ZnO hollow spheres and their application as a light scattering layer in dye-sensitized solar cells

Abstract

Ce-doped ZnO hollow spheres (Ce@ZHSp) with various Ce-contents of 0, 0.25, 0.50 and 1.0 mol% were synthesized via a template-free hydrothermal method. The calcined samples were characterized using XRD, FESEM, TEM, BET–BJH and UV–Vis spectroscopic techniques. The analytical results showed that all the samples possessed a hexagonal wurtzite structure. The crystallite size of Ce@ZHSp decreased with increasing Ce-content. Calcined samples had a hollow sphere morphology with an average diameter range of 4.63–5.16 µm. Diffuse reflectance was increased by adding an appropriate Ce-dopant of 0.25 mol% into the ZnO hollow spheres. The energy-conversion efficiency of a dye-sensitized solar cell was examined under the A.M. 1.5 direct spectrum. These results showed that the highest efficiency was derived from a bilayer photoanode using 0.25 mol% Ce-doped ZnO hollow spheres as a light scattering layer. This finding was related to an increase in the amount of dye adsorption and a photonic reflection effect originating from the relatively larger particle sizes with higher porosity compared to the other samples.