Luminescence of Tb-doped Ca3Y2(Si3O9)2 oxide upon UV and VUV synchrotron radiation excitation

Powders of calcium yttrium silicate, Ca3Y2(Si3O9)2, containing 0.1–3% Tb3+ were prepared using a sol-gel method and characterized with XRD, IR, UV–vis and UV–VUV spectroscopies at room temperature and 10 K. Structural analysis revealed pure monoclinic phase of Ca3Y2(Si3O9)2 after heat-treatment at 1000 °C. Infrared spectroscopy showed that between 800 and 900 °C a short-range structural organization of the components proceeded, yet without crystallization. A strong emission of Tb3+ had been observed both in the green part of the spectrum due to the 5D4→7FJ transitions and in the blue-violet region owing to the 5D3→7FJ radiative relaxation. The color of the light could be tuned from yellowish-green to bluish-white both by means of the dopant content and the temperature of synthesis. Efficient luminescence of Tb3+-doped Ca3Y2(Si3O9)2 phosphors could also be obtained upon stimulation with vacuum ultraviolet synchrotron radiation demonstrating that an energy transfer from the host to the Tb3+ ions takes place.