A simple self-assembly route to single crystalline SnO2 nanorod growth by oriented attachment for dye sensitized solar cells

Abstract

One-dimensional (1-D) SnO₂ nanorods (NRs) with a rutile structure are grown on various substrates regardless of the lattice-mismatch by using a new nutrient solution based on tin oxalate, which generated supersaturated Sn²⁺ sources. These affluent sources are appropriate for producing a large number of SnO₂ nanoparticles, sufficient for stacking on a substrate surface by gravity, which then acts as a seed layer for subsequent nanorod growth. Single crystalline nanorods are grown along the [001] direction by the oriented attachment phenomenon in which the attached nanoparticles were rearranged to reduce the overall surface energy through sharing thermodynamically unstable crystal (001) planes. Furthermore, the grown SnO₂ NRs are covered with a TiO₂ particulate film and utilized as a photoanode in DSSCs. The power conversion efficiency is 8.61%, enhanced by 14.2% compared to the photoanode with only a TiO₂ particulate film.