Highly dispersed mesoporous TiO2 spheres via acid treatment and its application for dye-sensitized solar cells

Photoelectrodes composed of mesoporous TiO2 spheres as scattering centers and TiO2 nanoparticles as the binder were fabricated and tested with the aim of improving the energy conversion efficiency of dye-sensitized solar cells (DSSCs). In order to achieve the dispersion of the TiO2 spheres in suspension and improve their connectivity in the electrodes, acid treatment and a compression method were applied. These electrodes composed of TiO2 spheres and nanoparticles enable the fabrication of high performance DSSCs, because of the light scattering of the TiO2 spheres and the dye-loading capacity of their high surface areas. The energy conversion efficiency of composite-type photoelectrode was found to be 7.66%, which is higher than that of nanocrystal electrode (4.50%). We can thus conclude that high energy conversion efficiency was achieved with a composite-type photoelectrode, without the use of an anti-reflection coating or a back-scattering layer.