Design of multi-layered TiO2 nanotube/nanoparticle hybrid structure for enhanced efficiency in dye-sensitized solar cells

A high-performance bi-layered TiO2 nanotube membrane possessing simultaneously large surface areas for dye anchoring, excellent electron transport and strong light scattering is proposed to achieve high power conversion efficiency in dye-sensitized solar cells. The bi-layered TiO2 nanotube arrays with different diameters are fabricated by a versatile and simple electrochemical anodization approach. The large diameter nanotube layer provides strong light-scattering while the small diameter layer provides efficient electron transport and large surface area. When the bi-layered TiO2 nanotube membrane is attached to a conventional TiO2 nanoparticle absorption layer to form a hybrid structured photoanode, a high power conversion efficiency of 6.52% can be achieved.