Application of nitrogen-doped TiO2 nano-tubes in dye-sensitized solar cells

Our research aimed to improve the overall energy conversion efficiency of DSCs by applying nitrogen doped 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 IOM 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 (eta= 7.36%) with 2 M nitrogen dopant, compared to eta =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. (C) 2016 Elsevier B.V. All rights reserved.