Dye-sensitized solar cells based on TiO2 hollow spheres/TiO2 nanotube array composite films

In this study, a novel double-layer electrodes with TiO2 nanotube (NT) arrays as underlayer and TiO2 hollow spheres (HSs) as overlayer film have been fabricated for application in DSSCs. Both the NTs and HSs have been synthesized and the morphology and structure were characterized by XRD, SEM and TEM. Moreover, the properties of DSSCs were investigated by UV-vis reflectance spectra, IPCE and current-voltage curves, respectively. Owing to the hollow structure, the DSSC using TiO2 HSs as light-scattering layer exhibits an enhanced light harvesting efficiency, leading to a 23% increment of cell efficiency compared to that pure TiO2 NT films.