TiO2 nanotubes: Structure optimization for solar cells

This review starts with a brief introduction to TiO2 nanotubes (NTs), and then discusses in more detail how to optimize the structure of TiO2 NTs for the fabrication of highly efficient solar cells, including the controllable fabrication of perfectly aligned TiO2 NTs, optimizing the tube parameters, strategies of sensitization, improvement of the interface adhesion in polymer/TiO2 solar cells and how to make devices flexible. Some key challenges and perspectives for future research are also tentatively discussed.