Dye-sensitized solar cells based on double-layered TiO2 composite films and enhanced photovoltaic performance

Dye-sensitized solar cells (DSSCs) are fabricated based on double-layered composite films of TiO2 nanoparticles and hollow spheres. The photoelectric conversion performances of DSSCs based on nanoparticles/nanoparticles (PP), hollow spheres/hollow spheres (HH), hollow spheres/nanoparticles (HP), and nanoparticles/hollow spheres (PH) double-layered films are investigated, and their photo-electric conversion efficiencies are 4.33, 4.72, 4.93 and 5.28%, respectively. The enhanced performance of TiO2 nanoparticles/hollow spheres double-layered composite film solar cells can be attributed to the combined effect of following factors. The light scattering of overlayer hollow spheres enhances harvesting light of the DSSCs and the underlayer TiO2 nanoparticle layer ensures good electronic contact between film electrode and the F-doped tin oxide (FTO) glass substrate. Furthermore, the high surface areas and pore volume of TiO2 hollow spheres are respectively beneficial to adsorption of dye molecules and transfer of electrolyte solution.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Double-layered DSSCs were fabricated based on TiO2 nanoparticles and hollow spheres. ► Morphology of film electrodes affects photovoltaic performance of DSSCs. ► Incorporation of TiO2 hollow spheres enhances conversion efficiency of DSSCs. ► DSSC of TiO2 nanoparticles/hollow spheres had the maximum conversion efficiency.