Novel Down-converting single-phased white light Pr3+ doped BaWO4 Nanophosphors material for DSSC applications

Abstract

White Nanophosphors based on praseodymium doped barium tungstate matrix (y mol Pr3+: BaWO4 (PBWO) (y = 0.01, 0.03, 0.05, 0.07 mol) were synthesized by ultrasound assisted hydrothermal method in the presence of citric acid and characterized as novel down-conversion materials for dye-sensitized solar cells (DSSCs) applications. The different prepared PBWO Nanophosphors show high crystalline tetragonal phase with nano-cubic morphology. The PBWO photoluminescence spectra give strong emission peaks at 486, 529, 615, 623 and 643 nm are corresponding to the 3P0→3H4, 3P1→3H5, 1D2→3H4, 3P0→3H6 and 3P0→3F2 transitions of Pr3+, respectively. These photoluminescence spectra are assigned to blue, green and red-light regions which cover the whole visible light region. It means that these Nanophosphor materials are promising materials for down-conversion applications. By varying the Pr3+ ion conc., it was found that the optimum conc. of Pr3+ ion was 0.05 mol which gives the highest photoluminescence intensity. The prepared Nanophosphors were applied in DSSCs as a top down-converting layer on the photoactive TiO2 electrode. A high conversion efficiency (η) of 8.08% was achieved by the application of top (PBWO: 0.05 mol Pr3+) down-converting material compared with a 4.17% efficiency of the non-modified DSSC. This enhancement is probably due to the improved UV radiation harvesting via a down-conversion luminescence process.