Abstract

Different structures of dye-sensitized solar cells (DSCs) were fabricated with various compositions and arrangement modes of the photoanodes. The solvothermally grown TiO2 nanoparticles and sol gel derived spherical TiO2 and BaTiO3 particles were employed as the active and scattering layers of DSCs. TiO2 nanoparticles and spherical particles had pure anatase structure with particle size of 15-30 nm and 200-400 nm, respectively, whereas 300-800 nm BaTiO3 particles showed cubic perovskite structure. The efficiency improvement of mono-layer cells made of TiO2 nanoparticles (i.e., 7.22%) was achieved by light harvesting mechanism. Further enhancement of photovoltaic performance was achieved by light scattering mechanism using two different approaches (e.g., in forms of mono- and double-layer structures). For the mono-layer cells, composed of a mixture of TiO2 nanoparticles and BaTiO3, the highest efficiency of 8.63% was achieved for BaTiO3:TiO2 = 20:80. The double-layer cell containing the active layer composed of nanoparticles and a mixture of spherical TiO2 and BaTiO3 particles as the scattering layer showed the highest efficiency of 8.81%. Such enhancements were attributed to higher incident photon to current conversion yield due to greater fraction of light scattering, high refractive index of BaTiO3 particles, as well as less recombination of photo-generated electrons. (C) 2016 Elsevier Ltd. All rights reserved.