Facile wet chemical synthesis of Er3+/Yb3+ co-doped BaSnO3 nano-crystallites for dye-sensitized solar cell application

We report synthesis of pure and rare earth ion Er3+/Yb3+ co-doped barium stannate (BaSnO3) nano-crystallites by facile wet chemical route. The nano-crystallites at the Ba3+ lattice site substitution of 0.1 and Er/Yb ratio of 0.00, 0.11, 0.18 and 0.25 exhibited band gap of 3.64, 3.66, 3.67 and 3.68 eV, respectively. The electrical conductivity of the nano-crystallites was found to increase with increase in Er/Yb content ratio. All samples revealed a broad emission peak between 380 and 400 nm at the excitation wavelength of 350 nm. The up-conversion emission intensity has been found to increase with Er3+/Yb3+ content for the excitation wavelength of 980 nm. Further, the influence of the up-conversion behavior on the photovoltaic performance of dye-sensitized solar cell has been investigated. The highest photon conversion efficiency of 4.2% was observed for the composition of Ba(Er/Yb: 0.25)SnO3 with J(sc) = 9.69 mA/cm(2), V-oc = 0.63 V, FF = 0.690, which was about 40% increase in efficiency in comparison to pristine BaSnO3 (3.0%).