Synthesis and Luminescence Studies of Eu doped AlSrLaO 4 Phosphor
AlSrLaO4 phosphors were synthesized using standard solid state reaction [SSR] method with varying Eu molar concentration as 0.1, 0.2, 0.3, 0.4, 0.7, 1.0, 1.5, 2.0 and 2.5%. The mixture of reagents was ground together to obtain a homogeneous powder in acetone base. To prepare Aluminum Strontium Lanthanate (ASL) doped with various concentrations of Eu, consists of heating stoichiometric amounts of reactants at 1000°C for 2 h in a muffle furnace. The received powder being ground thoroughly using an agate mortar, to ensure the best homogeneity and reactivity, powder was transferred to alumina crucible, and then reheated in a muffle furnace at 1200°C for 4 hours. The phosphor materials were cooled to room temperature naturally. All samples were found out to be white who are studied for photoluminescence [PL]. Photoluminescence spectra were recorded at room temperature using Shimadzu-5301 Spectrofluorophotometer. The phosphors are characterized using XRD and SEM. The effect of doping of Eu in ASL on the PL emission/excitation was also studied. Eu shows all its primary allowed emissions hence it is concluded that this phosphor can be used in display devices.
Inorganic Phosphors: Compositions, Preparation and Optical Properties
Inorganic Phosphors: Compositions, Preparation and Optical Properties addresses practical and theoretical aspects of inorganic phosphors used in lighting and display applications. Authors Yen and Weber present the synthesis of phosphors in a ...cookbook... style that features nearly 300 ...recipes... using the most up-to-date guidelines and methods. They also categorize nearly 500 phosphors in terms of chemical composition and luminescence output wavelengths, summarizing their physical and emissive optical properties. This book is the first of its kind to provide a combined practical and technical foundation that can be used in commercial and academic research and development of new phosphors and applications.
Recalculation of Mass Defects
THE well-known mass defect curve of the old nuclear scheme calculated with regard to α-particles and protons presented a difficulty with its minimum of binding energy for tin and an increasing portion between tin and lead. On the other hand, the mass defect values against protons give a rather smoothly decreasing curve.1 As has already been pointed out,2 the number of α-particles must be considerably reduced from the point of view of the new scheme, which does not admit any electrons in nuclei, but only neutrons and protons (presumably joined as α-particles). The curve of mass defect against protons and neutrons (perhaps with a single ‘central’ α-particle) is very similar to the old curve against protons, but decreases less rapidly. Clearly the new mass defect values relatively to α-particles, neutrons and protons must lie somewhere between the old values computed relative to protons and α-particles respectively (because the number of α-particles is decreased). We may emphasise that this new mass defect curve shows no increasing portion between tin and lead. For illustration we give two typical values: Old: 50Sn124 = 31α + 12&#38;epsiv;; mass defect = 0.158 (in mass units); 82Pb208 = 52α + 22&#38;epsiv;; mass defect = 0.035. New: 50Sn124= 25α + 24ω (ω = neutron); mass defect = 0.304; 82Pb208 = 41α + 44ω; mass defect = 0.366.