The effects of metal doped TiO2 and dithizone-metal complexes on DSSCs performance

Different metal (Fe, Ni, Co or Zn) doped TiO2 nanoparticles and dithizone-metal (Fe, Ni, Co or Zn)-gallic acid complexes were prepared and used in dye sensitized solar cells (DSSCs). The TiO2 and metal doped TiO2 nanoparticles were synthesized by microwave assisted hydrothermal method. Synthesized TiO2 nanoparticles were characterized with SEM, EDS, XRD and DRS. Prepared dithizone-metal-gallic acid complexes were characterized via UV-Vis and FTIR techniques. Photoanode of DSSC was prepared with TiO2 or metal doped TiO2 coating on FTO-glass using spin coater. The dithizone and dithizone-metal-gallic acid complexes were adsorbed on bare TiO2, and dithizone or N719 were adsorbed on metal doped TiO2. Then, sandwich type DSSCs were prepared and electrochemical characterization of DSSCs was made. When the N719 and dithizone sensitized metal doped TiO2 nanoparticles were compared with undoped TiO2, Fe doped TiO2 gave lower efficiency, Ni, Co and Zn doped TiO2 gave higher efficiency than that of undoped TiO2. Co doped samples showed the highest efficiencies with both N719 and dithizone. Co doped TiO2 which was sensitized with dithizone gave nearly three times more conversion efficiency than undoped TiO2. These results show that doping procedure can enhance binding dyes to semi conductor surface. In summary, various metals show different characteristics when doped to TiO2 nanoparticles.