Hu Zhen,Guo Haiyong,Zhao Li,Wu Yadan,Wang Shimin,Wan Li
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.
Hu Zhen,Zhao Li,Guo Haiyong,Wang Shimin,Li Wenlu,Yang Xiaojie,Dong Binghai,Wan Li
A novel composite double-layer film was developed using TiO 2 /La(OH) 3 :Yb 3+ /Er 3+ nanoparticles (P25/UC) and porous-hollow TiO 2 microspheres (PHTS) for highly efficient dye-sensitized solar cells (DSSCs). P25/UC was used as the first layer and coated onto fluorine-doped tin oxide glass substrate to create a good contact and upconversion effect. The P25/UC layer can absorb and convert infrared light into visible red and green light, increasing light utilization. PHTS has a large size and a high specific surface area, was deposited onto the surface of the P25/UC film to improve the light scattering performance and dye adsorption of solar cells. The P25/UC composite double-layer film (P25/UC + PHTS) achieved the highest short-circuit current density of 20.33 mA/cm 2 and photoelectron conversion efficiency of 8.89% due to the synergistic effect of the upconversion layers and light-scattering layers, which increased by 51.26% and 38.04% compared with that of the pure P25 film photoelectrode.