Two-color emission of Zn2SiO4:Mn from ionic liquid mediated synthesis

Yellow emitting beta-Zn2SiO4:Mn2+ and green emitting alpha-Zn2SiO4:Mn2+ nanoparticles are synthesized by nucleation applying a zinc-containing ionic liquid. As-prepared material is non-agglomerated and very uniform with a mean diameter of 32 nm. According to X-ray diffraction (XRD) two crystallographic different modifications of Zn2SiO4 can be realized by annealing of as-prepared and non-crystalline nanomaterial at 750 and 1000 degrees C. Surprisingly, these crystalline materials are still nanosized, non-agglomerated and redispersible. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) confirm particle diameters of 18 nm (beta-Zn2SiO4:Mn2+) and 14 nm (alpha-Zn2SiO4:Mn2+). Photoluminescence indicates Mn2+-related emission at an average wavelength of 579 nm and 528 nm, and a quantum yield of 7% and 12% for beta-Zn2SiO4:Mn2+ and alpha-Zn2SiO4:Mn2+, respectively. (c) 2008 Elsevier Masson SAS. All rights reserved.