Three dimensional-TiO2 nanotube array photoanode architectures assembled on a thin hollow nanofibrous backbone and their performance in quantum dot-sensitized solar cells

Facile synthesis of TiO2 nanotube branched (length ∼0.5 μm) thin hollow-nanofibers is reported. The hierarchical three dimensional photoanodes (H-TiO2-NFs) (only ∼1 μm thick) demonstrate their excellent candidature as photoanodes in QD-sensitized solar cells, exhibiting ∼3-fold higher energy conversion efficiency (η = 2.8%, Jsc = 8.8 mA cm−2) than that of the directly grown nanotube arrays on a transparent conducting oxide (TCO) substrate (η = 0.9%, Jsc = 2.5 mA cm−2).