CaWO4 : Eu3+, Dy3+, Tb3+ Phosphor Crystals for Solid-State Lighting Applications

Calcium tungstate (CaWO4) phosphor crystals doped with Ln3+ (Ln = Eu, Dy, Tb) were grown from high temperature solutions (NaWO4 flux) and their properties compared with powders synthesized using traditional solid-state reaction technique. The flux-grown crystals exhibited enhanced excitation and emission intensities as compared to the powders. An optimized flux to solute ratio of 2:1 at growth temperatures in the 1100-1200 °C range results in the largest size optically clear crystals.