Possibility of adjusting the photoluminescence spectrum of Ca scheelites to the emission spectrum of incandescent lamps: [nCaWO4–(1–n)CaMoO4]: Eu3+ solid solutions

Abstract

The specific features of the photoluminescence of [nCaWO₄–(1–n)CaMoO₄]:Eu³⁺ solid solutions with the scheelite structure are examined using X-ray phase analysis and photoluminescence, Raman scattering, and diffuse reflectance spectroscopy. The studied features are associated with a change in the long- and short-range orders of the crystal lattice upon variations in the composition of solutions in the range n = 0–1.0 (with a pitch of 0.2) at a concentration of red photoluminescence activator Eu³⁺ of 2 mol %. The mechanism of the modification of photoluminescence of solid solutions upon variations in their composition has been discussed. Anomalies in the variations in parameters of the crystal lattice, its short-range order, and luminescence spectra have been observed in the transition from pure compounds CaMoO₄:Eu³⁺ and CaWO₄:Eu³⁺ to solutions; the concentration of Eu³⁺ ions in the centrosymmetric localization increases (decreases) in the transition from the molybdate (tungstate). It has been demonstrated that the spectral radiant emittance of solid solution [0.4CaWO₄–0.6CaMoO₄]:Eu³⁺ (2 mol %) is the closest to that of an incandescent lamp.