Radiative properties of Eu 2C in BaGa 2 S 4

AbstractA photoluminescence study of the blue-green emitting BaGa 2 S 4 :Eu 2C phosphor is reported. Diffuse reflectance, excitation and emissionspectra were examined with the aim to enlarge the fundamental knowledge about the emission of the Eu 2C rare earth ion in this lattice. Thethermal dependence of the radiative properties and the influence of the Eu 2C concentration were investigated. The Stokes shift, the crystalfield splitting and the activation energy of the thermal quenching were determined. By combining these results with data available inliterature, we discussed the radiative properties of the BaAl 2 S 4 :Eu 2C blue phosphor in relation with those determined in this study for theisostructural BaGa 2 S 4 :Eu 2C phosphor.q 2005 Elsevier Ltd. All rights reserved. Keywords: A. Inorganic compounds; A. Chalcogenides; D. Luminescence 1. IntroductionInorganic electroluminescent (iEL) devices are one ofthe most attractive candidates for full-colour flat paneldisplays. iEL devices present many attractive features,including self emission, stability, wide viewing angle, highcontrast, fast response time and high resolution [1]. For full-colour iEL displays, red, green and blue emitting phosphorswith suitable colour coordinates and high luminance arenecessary. The lack of phosphor for the blue component wasone of the main difficulties to commercialise full-colourdevices. Blue emitting phosphors based on alkaline-earthbinary compounds such as SrS:Ce and SrS:Cu have beeninvestigated [2,3]. In parallel, many studies have concernedthe development of alkaline earth thiogallates with theformula M