Photoluminescence of A- and B-site Eu3+-substituted (Sr Ba1−)2CaW Mo1−O6 phosphors

International audience; The photoluminescence of two series of A- and B-site Eu3+ substituted (SrxBa1-x)(2)CaWyMo1-yO6 double perovskite phosphor materials, (SrxBa1-x)(1.96)Eu0.02K0.02CaWyMo1-yO6 and (SrxBa1-x)(2)Ca0.96Eu0.02Li0.02WyMo1-yO6 (x and y=0, 0.25, 0.50, 0.75, and 1), were studied systematically as a function of stoichiometry and crystal structure. The Eu3+ lattice sites controlled by co-doping with either K or Li were confirmed by Raman spectroscopy. The variation in integrated emission intensity and emission colour over the experimental matrix was examined using statistical tools, and the observed trends were rationalized based on the physical and electronic structure of the phosphors. Phosphors with Eu on B-site with maximum Sr content had remarkably higher emission intensities than all other materials, but the emission was more orange than red due to domination of the D-5(0) - F-7(1) (595 nm) transition of Eu3+. The relative intensities of the D-5(0) - F-7(2) (615 nm) and D-3(0) - F-7(1) transitions of Eu3+, and thus the red-shift of the emission, decreased linearly with increasing Sr content in the A-site Eu-substituted phosphors, and reached a maximum for Sr1.96Eu0.02K0.02CaW0.25Mo0.75O6. A maximum external quantum efficiency of 17% was obtained for the phosphor Sr2Ca0.7Eu0.15Li0.15W0.5Mo0.5O6 with Eu on B-site. (C) 2016 Elsevier Inc. All rights reserved.