Influence of m and n Parameters of Ca-α-Sialon: Eu Solid Solution on Phosphor’s Optical Properties

• DOI: 10.4028/www.scientific.net/ast.90.149
• Publication Date: 2014-10-31T13:05:15Z
• Authors: Tomasz Pawlik; Daniel Michalik; Malgorzata Sopick...; Stanisław Serkowski
• Keywords: 02 engineering and technology; 0210 nano-technology

Ca-α-sialon doped by Eu2+ is a promising material for white LED phosphors due to the strong UV absorption and a yellow broad band emission of activator. The general formula of α sialon enables changing matrix composition by altering m (Al-N) and n (Al-O) parameters of cross-substitution. Changes of the neighboring Eu ligands in the host crystal lattice would trigger important modification of the photoluminescence properties because of different crystal field splitting and the energy of the d orbital. The aim of this study was to correlate the matrix solid solution parameters with photoluminescence spectra features. The specimens of Ca-α-sialon:Eu2+ with m, n parameters in the range of 0.5-2.5 and 0.25-1.25 respectively, were prepared by the solid state reaction method in the reducing atmosphere of a graphite furnace. The phase composition of the obtained specimens was characterized by XRD, microstructure and morphology by the SEM/EDS techniques. The photoluminescence spectra (excitation, emission) were also recorded. Results show that m/n parameters have a significant influence on the final optical properties.