Rapid hydrothermal synthesis of SrMo1−xWxO4 powders: Structure and luminescence characterization

Abstract Strontium molybdate, strontium tungstate particles and their solid solutions (SrMo 1− x W x O 4 ) with 0 ⩽  x  ⩽ 1.0, were synthesised by means of a hydrothermal process. Crystallisation of SrMo 1− x W x O 4 particles took place rapidly using SrSO 4 as the Sr precursor under hydrothermal conditions involving stirring (130 rpm) at 150 or 200 °C for 2 h. Structural analyses of the powders were conducted by XRD with Rietveld refinement and FT-Raman spectroscopy, and the particle shape was observed by FE-SEM. Lattice parameter measurements indicated a linear dependence of both “ a 0 ” and “ c 0 ” in the scheelite structured SrMo 1− x W x O 4 with a changing W content following Vegard’s law. These analyses also provided evidence of the structural variation localised in the tetrahedral site as a result of the simultaneous incorporation of MoO 4 and WO 4 in the solid solutions formed in the compositional range of 9 ⩽  x  ⩽ 60 mol%. The SrMo 1− x W x O 4 particles exhibited a predominantly euhedral shuttle-shaped morphology and particle sizes varying between 0.75 and 1.5 μm. The particle growth was affected by increasing the reaction temperature and the tungsten concentration. Photoluminescence analysis (PL) revealed a marked attenuation of the blue and green emissions preferentially for the powder containing 48.5 mol% of W, which makes it potentially useful for optoelectronic applications.