Structural and luminescent study of TeO_2-BaO-Bi_2O_3-Ag glass system doped with Eu~(3+) and Dy~(3+) for possible color-tunable phosphor application

摘要

Tellurite glass systems of 73TeO(2)-4BaO-3Bi(2)O(3)-1Ag:xEu(2)O(3)-(2-x)Dy2O3 (where x = 0.5, 1, 1.5, 2 in molar ratio) composition have been successfully synthesized. In order to acquire Ag nanoparticles, materials have been heat treated at 350 degrees C in the air atmosphere. Structural properties of obtained samples were evaluated with various techniques. X-Ray Diffraction (XRD) measurements indicated that obtained materials are amorphous in nature. UV vis results presented transitions characteristic to Dy3+ and Eu3+ ions. Additionally, X-Ray Photoelectron Spectroscopy (XPS) analysis indicated the presence of silver in metallic form. Photoluminescence measurements shown influence of Ag nanoparticles on emission characteristics. Simultaneous emission of Dy3+ and Eu3+ has been observed when samples were excited with lambda(exc) = 390 nm. Change of the emission color induced by heat treatment has been observed and described in case of x =1 glass series. According to CIE results emission color changes as Eu/Dy ratio and heat treatment time are changed. Emission shifts from reddish-orange to yellowish white color. Obtained photoluminescence results confirm that synthesized materials are good candidates for color tunable phosphors. (C) 2018 Elsevier B.V. All rights reserved.