Exciton-like trap states limit electron mobility in TiO2 nanotubes

摘要: Nanoparticle films have become a promising low-cost, high-surface-area electrode material for solar cells and fuel production. Compared to sintered nanoparticle films, oriented polycrystalline titania nanotubes offer the advantage of directed electron transport, are expected higher mobility. However, macroscopic measurements revealed their mobility be as low that films. Here, we show, through time-resolved terahertz spectroscopy, in TiO(2) is not due scattering from grain boundaries or disorder-induced localization other nanomaterials, but instead results single sharp resonance arising exciton-like trap states. If number these states can lowered, this could lead improved transport significantly better cell performance.