586 International Journal of Luminescence and applications Vol9 (1) February, 2019, ISSN 2277 – 6362 Luminescence Properties of Calcium Aluminate Phosphors M. Z. Khan, Nameeta Brahme 1 , D. P. Bisen 1 S. J. Dhoble 2 , Anil Kumar Choubey 3 Department of Physics, Dr. C. V. Raman University, Kota, Bilaspur, Chhattisgarh, India. 1 SOS in Physics & Astrophysics, Pt Ravishankar Shukla University, Raipur, India. 2 Department of Physics, RTM University, Nagpur, Maharashtra, India. 3 Department of Physics, CCET, Bhilai, Chattisgarh, India Corresponding author: mzkhan077@gmail.com Abstract Luminescence properties of CaAl2O4 were studied. Rare earth Eu 2+ doped alkaline earth aluminate CaAl2O4 phosphor was prepared by combustion synthesis using urea as a fuel at 600 °C. It was found that firstly the TL intensity increases with increase in UV irradiation time and it attains a maximum value for 15 minute irradiation time. TL intensity decreases with further increase in irradiation time. In photoluminescence (PL) spectrum, a broad emission peak of Eu 2+ ion was observed in blue region at 441 nm, under 363 nm excitation due to transition from the 4f 6 5d 1 to the 4f 7 configuration of the Eu 2+ ion. Optimum intensity of photoluminescence (PL) was found to be 0.05 mol% concentration of Eu 2+ . Keywords: Thermoluminescence (TL), Photoluminescence (PL), Aluminate phosphors 1.0 INTRODUCTION Alkali halides have been a subject of study for the past six decades. They have lent a helping hand in understanding the physics of the solid state. The alkaline earth aluminates MAl2O4 are an important class of phosphorescence materials because of their high quantum efficiency in visible region [1], long persistence of phosphorescence, good stability, color purity and good chemical, thermal and radiation resistance [2-3]. Rare earth and non-rare earth inorganic phosphors are widely used in a variety of applications, such as light industry, radiation measurement, X-ray imaging technique and colour display [4]. Several aluminates are used as hosts for doping rare earth ions in luminescent applications. The luminescence in the visible region of Eu 2+ doped alkaline earth aluminates MAl2O4:Eu 2+ (M = Ca, Ba, Sr) phosphor is of special interest in recent years due to these compounds, which are chemically stable and safe with very bright photoluminescence properties. Several scholars have made extensive investigations concerning the next generation of displays and lighting devices [5–7]. The rare earth metal ion-doped calcium aluminate phosphors, because of their high quantum efficiency, anomalous long phosphorescence and good stability, have been studied in depth and used widely. In particular BaAl2O4:Eu 2+ , Nd 3+ has been considered as a useful violet phosphor in the application of luminous clocks and watches as well as potential outdoor night time displays [8]. Aluminates of Ca, Ba and Sr doped with Eu 2+ activator ion possess safe, chemically stable and intense photoluminescence in visible light [9, 10] compared with the conventional sulfide-based phosphors. These properties make them useful in many applications, such as luminous paints in highway, airport, buildings and ceramic products, in textile, dial plate of glow watch, warning signs and the escape routes [11]. Recently many studies on phosphors with calcium aluminate as host based on their persistent luminescence and photoconductivity spectrum have been reported [12]. Many phosphors such as CaAl2O4:Eu 2+ , Dy 3+ [13] and CaAl2O4: Ce 3+ [14] were developed for their photoluminescence and high chemical stability.