Centrifugation-assisted preparation of nanoparticle decorated hierarchical nanowire arrays for improved solar cell performance

Abstract

Considering the fact that large surface areas and fast electron transport properties of photoanodes play an essential role in determining dye sensitized solar cell efficiency. A centrifugation-assisted method was designed to fabricate nanoparticle decorated hierarchical nanowire arrays. The hierarchical nanostructure arrays enable the fast charge transport properties of the photoanode. At the same time, the nanoparticles and the hierarchical nanostructures work together to guarantee the large surface areas of the photoanodes. During the fabrication process, TiO2 hierarchical nanowire arrays were firstly fabricated on fluorine doped tin oxide substrates via a hydrothermal method and then nanoparticles were deposited subsequently in the interval spaces among the neighboring nanostructures. Field-emission scanning electron microscopy and X-ray diffraction were used to characterize the morphology and structure of the obtained products, respectively. The results show that the nanoparticles do deposit in the interval spaces among the hierarchical nanowires forming a hybrid structure composed of anatase and rutile TiO2. The obtained nanoparticle decorated hierarchical nanowire arrays have been successfully applied in dye sensitized solar cells. A power conversion efficiency of 5.52% was achieved with the photoanode film thickness of about 20µm.