TiO2 nano-tubes (N-TNT) for the preparation of DSCs photo-anodes. The none-doped TiO2
nano-tubes (TNTs) were synthesized by alkaline hydrothermal treatment of Degussa P25 TiO2 particles
in 10 M NaOH. The nano-tubes were N-doped by reflux in various concentrations of NH4NO3. The
effects of nitrogen doping on the structure, morphology, and crystallography of N-TNT were analyzed
by transmission electron microscopy (TEM), infrared spectroscopy (IR), Raman spectroscopy, and X-ray
photoelectron spectra (XPS). DSCs fabricated with doped N-TNT and TNT was characterized by J-V measurements.
Results showed that nitrogen doping significantly enhanced the efficiency of N-TNT cells,
reaching the optimum value ( = 7.36%) with 2 M nitrogen dopant, compared to = 4.75% of TNT cells.
The high efficiency of the N-TNT cells was attributed to increased current density due to the reduction of
dark current in the DSCs.