Photoluminescence Properties Of Eu3+, Ce3+ Doped LaPO4 Phosphors

¹Department of Physics, Government Junior College, Sathupally, Khammam District, A. P. 507303, India

²Department of Physics, Rajiv Gandhi University Knowledge Technologies, IIIT, Basara 504101, AP, India

³Display Materials Laboratory, Applied Physics Department, Faculty of Technology and Engineering, M. S. University of Baroda, Baroda 390001, India

Adv. Mater. Lett., 2014, 5 (12), pp 722-727

DOI: 10.5185/amlett.2014.5572

Publication Date (Web): Dec 02, 2014

Copyright © IAAM-VBRI Press

E-mail: sk.niyaz@gmail.com

Abstract

Pure LaPO₄ and LaPO₄: Eu (0.5 mol %) Ce (0.5 mol %) phosphors were synthesized by the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) spectra and the particle size analysis were used to characterize these samples. The XRD results reveal that the synthesized LaPO4:Eu (0.5 mol%) Ce (0.5 mol%) phosphors are well crystalline and assigned to the monoclinic structure with a main (120) diffraction peak. The calculated crystallite size of pure LaPO4 and LaPO₄:Eu, Ce phosphors were 67.6nm and 64nm respectively. Upon excitation at 254nm wavelength, the emission spectrum of pure  LaPO₄ phosphor emits a maximum intensity peak at 470 (blue) nm. In the emission spectrum of LaPO₄:Eu³⁺Ce³⁺ phosphor, the low contributions of the red (613nm) 5D0-7F2 emissions and the high intensity of the orange-red (589nm)5D0-7F1 emission results in high color purities.The most intense emissions appearing in the 580-620nm region is responsible for the strong orange-red luminescence observed in the Eu,Ce doped LaPO₄ phosphor whose CIE colour coordinates are x = 0.57 and y = 0.43.Thus the prepared phosphors can be used as an orange-red emitting material in the field of illuminations and display devices.

Keywords

Photoluminescence, XRD, SEM, FTIR,phosphor, rare-earth ions,solid state reaction technique, CIE, particle size analysis