Luminescent investigations of Li6Lu(BO3)3:Tb3+, Dy3+ phosphors

In our novel work we report the luminescence properties of Terbium (Tb3+) and Dysprosium (Dy3+) ions in Li6Lu(BO3)3 (lithium lutetium borate) phosphors with its specific and productive use in various luminescent display systems. We have synthesized Tb3+ and Dy3+ doped Li6Lu(BO3)3 phosphors by the solid state reaction method. Concentration based optimization of activators is attained i.e. 2 mol% for Tb3+ and 5 mol% for Dy3+. XRD (X-ray diffraction) and FE-SEM (Field emission-scanning electron microscopy) were used to analyze the overall morphologies, crystalline structures and the grain sizes of the prepared phosphors. Moreover, the grain size of 20 μm is confirmed via Scherrer's formula. In order to characterize the luminescence properties of the synthesized phosphors, we measured its X-ray induced luminescence, proton induced luminescence and UV induced photoluminescence. Under UV luminescence Dy3+ doped phosphor, it displayed seven obvious peaks corresponding to transitions from 6H15/2 (f9) ground state to higher energy state of 4f9 whereas, UV-emission spectrum of Li6Lu(BO3)3:Tb3+ phosphor has shown five major transitions with each peak consists of several smaller lines, confirming the complicated transition (5Dj → 7Fj) behavior of Tb3+. The light yield calculated for Li6Lu(BO3)3:Tb3+ is 75% that of (Y,Gd)2O3:Eu3+ phosphor which is a well known commercially available material for PDP (Plasma Display Panel). It is observed that due to the presence of Lutetium, the synthesized phosphor has high effective atomic number (Zeff = 52) as well as high molecular weight (M.Wt = 393 g/mol) which makes lithium lutetium borate one of the promising candidates for X-ray imaging in medical field. Furthermore, the presence of 6Li and 10B could make Li6Lu(BO3)3 phosphor as a potential neutron detector.