Enhanced efficiency in dye-sensitized solar cells with La(OH)3:Yb3+/Er3+ and large particles scatting layer hybrid double photoanodes

A double-layer composite film (DLCF) that consists of upconversion composite La(OH) 3 :Er 3+ /Yb 3+ +P25 (UC + P25) as underlayer and large TiO 2 spheres (LS-TiO 2 ) as overlayer is designed as the photoelectrode of dye-sensitized solar cells (DSSCs). The upconversion luminescent material La(OH) 3 :Er 3+ /Yb 3+ can convert near-infrared region to visible light to improve the light absorption, and LS-TiO 2 has been used as light-scattering layer to increase the optical length in the film and enhance light harvesting. The DLCF with lower absorbed dye achieved the highest conversion efficiency due to the synergistic effect of the upconversion luminescent layer and the light-scattering layer, and with an optimum mixing ratio, a conversion efficiency of 9.24% is attained, which is a significant improvement of 68.3% compared with the pure P25 film photoelectrode.