Continuous flame synthesis of near surface nitrogen doped TiO2 for dye-sensitized solar cells

A novel rapid and continuous process has been designed to synthesize near surface nitrogen doped TiO2 (NSND-TiO2) using a modified flame spray pyrolysis (FSP) equipment. NSND-TiO2 was obtained by simply introducing a spray of ammonia water above the flame in which TiO2 nanoparticles were just formed. The introduction of N elements into TiO2 nanocrystalline results in a reducing of energy band gap to 2.90eV and a strong enhance of visible light absorption. The generation structure of O-Ti-N in NSND-TiO2 can suppress the charge recombination at the TiO2/dye/electrolyte interface. These properties can improve the short-circuit current (Jsc) and open-circuit voltage (Voc) of dye sensitized solar cells (DSCs), and the DSCs of NSND-TiO2 electrode exhibits a power conversion efficiency of 6.03%, much higher than that of undoped TiO2. This work provides a high yield and promising method to prepare NSND-TiO2 nanoparticles with improved DSCs performance. © 2014 Elsevier B.V.