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Synthesis and characterization of Ag doped CaWO4 powder phosphors for optical blue emission

U. RAMBABU1,* , N. R. MUNIRATHNAM1, T. L. PRAKASH1

Affiliation

  1. Centre for Materials for Electronics Technology (C-MET), IDA Phase – III, Cherlapally, HCL (Post), Hyderabad – 500051, India

Abstract

This paper reports on the synthesis of Ca(1-x) WO 4 : Agx (0 ≤ x ≤ 0.05 mol %) powder phosphors by a hydrothermal method and followed by calcinations. The effect of Ag-content on photoluminescence (PL) spectra of CaWO 4 was investigated. The phase nature of the synthesized powder phosphors have been examined from X-ray diffractometry. Thermal decomposition behaviors of the dried CaWO 4 powder phosphors have been studied from TG/DTA profiles and thus noticed that there exists a polymorphic transition at 800 o C. Based on the PL results, the dopant Ag content in the phosphors has been optimized to be 0.001 mol %, displaying a prominent blue emission from the phosphor. From the FT-IR spectrum, a strong peak at 845 cm -1 has been obtained due to the stretching vibration of WO 42- in scheelite structure, and a weak but sharp band at 445 cm -1 has also been noticed due to the metal, oxygen (Ca-O) band. Scanning Electron Microscopic (SEM) studies reveal that the synthesized CaWO 4 and Ag-doped CaWO 4 particles are in plate shape in the range from 400 nm to 1 micron. From SEM images, it has been noted that the agglomeration of synthesized powder phosphors has been increased with the change in Ag content, owing to the density variation..

Keywords

Optical materials, Chemical synthesis, FT-IR, Luminescence.

Submitted at: April 24, 2009
Accepted at: Nov. 19, 2009

Citation

U. RAMBABU, N. R. MUNIRATHNAM, T. L. PRAKASH, Synthesis and characterization of Ag doped CaWO4 powder phosphors for optical blue emission, Journal of Optoelectronics and Advanced Materials Vol. 11, Iss. 11, pp. 1841-1842 (2009)