Exquisite morphology, highly emissive yellow Sr_1.44Ba_0.46SiO₄:0.1Eu²⁺ phosphor synthesized by a liquid phase precursor process

Yellow phosphors are the major components of contemporary solid-state lights. YAG:Ce³⁺ is a widely adopted yellow phosphor component; however, it too has limitations. Here, we report the synthesis and application of a very highly efficient yellow-emitting orthosilicate phosphor. Yellow-emitting Sr_1.44Ba_0.46SiO₄:0.1Eu²⁺ was synthesized by an unconventional cellulose template liquid phase precursor process (CTLPP). The naturally abundant and nonhazardous cellulose template facilitates efficient synthesis at lower temperatures. The synthesized phosphor was indexed to α-Sr₂SiO₄ phase and exhibited broad excitation and broad emission with a peak at 545 nm, very high intensity, almost 130% of commercial YAG upon excitation at 450 nm. The morphology of the phosphors was also nearly spherical, which also enables their use in WLEDs. Use of non-stoichiometric Si precursors (i.e. Sr_1.44Ba_0.46Si_xO₄:0.1Eu²⁺, x = 0.95, 1.0 and 1.05) in the process resulted in remarkable effects on the morphology (size and surface) and luminescent characteristics and exceptional quantum efficiencies of the phosphors.