Application of Bunchy TiO2 Hierarchical Microspheres as a Scattering Layer for Dye-Sensitized Solar Cells

A novel bunchy TiO2 hierarchical microspheres composite nanostructure with strings of anatase TiO2 hierarchical micro-spheres and rutile nanobelts framework (HSN) was synthesized via an one-pot hydrothermal process. This new structure presents great specific surface area, large pore size distribution, homogeneous three-dimensional (3D) structure, high crystallinity and excellent light scattering performance simultaneously. The bi-layer photoanode film was successfully prepared which TiO2 P25 as absorption layer and HSN as an efficient scattering layer on the top of TiO2 P25 film in dye sensitized solar cells (DSSC). The bi-layer DSSC taken on a great progress in the power conversion efficiency (PCE) achieved 8.08%. However, the PCE of single and double layer TiO2 film DSSCs just showed 6.72% and 3.67% respectively. Such improvement was mainly because of the efficient scattering centers (HSN) which can bring the enhanced dye loading, fast charge transfer and excellent light harvesting efficiency.

Ag nanoparticle-decorated SiO2@TiO2 hierarchical microspheres improve the efficiency of dye-sensitized solar cells

SiO2@TiO2-Ag (STA) microspheres decorated with Ag nanoparticles (Ag NPs) were prepared and assembled into the photoanode. The photoanode composed of STA microspheres and TiO2 nanoparticles (P25) was prepared by doctor blade method. UV-vis measurement indicates that the introduction of a few STA microspheres observably enhance the light scattering and capturing ability of the photoanode. The photoelectric conversion efficiency of the DSSCs with 2wt% STA photoanode increased to 7.4% from 4.3% comparing with pure P25 TiO2 nanoparticles. The configuration DSSCs have the maximum short circuit current density (Jsc) of 16.0 mA cm− 2 and open circuit voltage (Voc) of 0.780 V, which are significantly higher than the pure TiO2 DSSCs. The significant improvement of the DSSCs performance can be due to the synergistic effect of the superior light scattering of STA and the localized surface plasma resonance (LSPR) effect of Ag NPs modified on the microspheres surface.