Glowing selenates: novel alkaline earth nanoparticles

Up to now, no selenate nanoparticles have been described even though much research has been done on respective oxidic compounds such as sulfates and phosphates. For the first time, alkaline earth selenates of the composition MSeO 4 (M = Ca, Sr, Ba) were synthesized as nanoparticles or nanorods as described in this publication. For this purpose, a micro emulsion method was applied using CTAB as a surfactant. Using X-ray diffraction measurements (XRD) phase purity of the materials could be proven. Furthermore, the nanoparticles were analyzed by raster electron microscopy (REM) and dynamic light scattering (DLS) measurements. Finally, the products were doped with small amounts of Eu 3+ to obtain luminescent materials. Successful doping was demonstrated by luminescence investigations in the region of 18 000 to 14 000 cm −1 (550-715 nm). Incorporation of Eu 3+ led to strong red-emitting nanoparticles. Low temperature measurements at 10 K allowed conclusions about the site symmetry of Eu 3+ ions located on the alkaline earth sites. Alkaline earth selenate nanoparticles like SrSeO 4 and SrSeO 4 :Eu 3+ could be synthesized for the first time using a micro emulsion method combined with an in situ -sintering step.