TiO2-BaTiO3 nanocomposite for electron capture in dye-sensitized solar cells

Different compositions of TiO2-BaTiO3 nanocomposites are synthesized with various weight ratios for dye-sensitized solar cell (DSSC) applications. TiO2 and BaTiO3 nanoparticles (NPs) are synthesized by sol-gel and solvothermal methods, respectively and are employed as the photoanode electrodes. BaTiO3 NPs have pure cubic perovskite crystal structure with an average size of 20-40nm, while TiO2 NPs show pure anatase phase with 15-30nm size. The power conversion efficiency (PCE) enhancement of the cells is first attained by controlling the thickness of the films for light harvesting improvement. The fabricated DSSC composed of pure BaTiO3 NPs with an optimal thickness of 25m shows efficiency of 6.83%, whereas that made of pure TiO2 NPs with 14m thickness has cell efficiency of 7.24%. Further improvement of cell efficiency is achieved by preparation of binary oxide nanocomposites using TiO2 and BaTiO3 NPs with various weight ratios. The highest PCE of 9.40% is obtained for the nanocomposite with TiO2:BaTiO3=85:15 (wt%). The enhancement is assigned to less recombination of photo-generated electrons and higher incident photon to current conversion yield as a result of rapid charge collection and higher dye sensitization.