Preparation and characterization of Yttrium based luminescence phosphors

Ce doped Yttrium aluminate modified by replacing different molar part of aluminium or gallium (Y3Al5−xGaxO12) and Yttrium silicate phosphors activated with Ce and Tb (Y2SiO5:Ce3+,Tb3+) were synthesized by solid state reaction and a gel combustion method, respectively. X-ray diffraction and Scanning electron microscope (SEM) techniques are used to identify their structures and morphologies. Luminescence characteristics are measured and spectroscopic data confirm that Y2SiO5:Ce3+, Tb3+ phosphors can be effectively excited upon UV excitation light and X-ray irradiation, resulting in intense blue and green emissions, respectively. This energy transfer takes place by means of a non-radiative process inside Ce3+-Tb3+ clusters formed in the host matrix. Tb3+ doped Y2SiO5 yields both blue emission 5D3 → 7Fj (j = 3,4,5,6) and green emission 5D4 → 7FJ (J = 3,4,5,6) of Tb3+. Y3Al5−xGaxO12:Ce3+ phosphors exhibit a broad blue emission band originating from allowed 5d-4f transition of the Ce3+ ions under different excitation sources but the broad emission band shifts with increasing of Ga3+ content. This work presents a quantitative understanding of host material's on dopant's luminescence properties and thereby provides an optimization guideline, which is extremely demanding for the development of new luminescent materials.