International Research Journal of Engineering and Technology ( I RJET) e-ISSN: 2395 -0056 Volume: 02 Issue: 03 | June-2015 www.irjet.net p-ISSN: 2395-0072 © 2015, IRJET.NET- All Rights Reserved Page 2360 Doping effect of Mg on photoluminescence properties of YAG:Ce phosphor Manisha Upasani 1 , Bhavana Butey 2 1 Department of Applied Physics, RGCER, Nagpur, India 2 Department of Applied Physics,GHRCE,Nagpur, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - We present the investigation of Mg codoped YAG:Ce phosphors synthesized by single step combustion synthesis method by mixed fuel at 500 0 C. The XRD results show that YAG phase can even form at low temperature without further sintering. This temperature is much lower than that required to synthesize YAG phase via the solid state reaction method. The doping effect of Mg on the luminescence intensity of YAG:Ce were studied. The results show that the luminescence intensity of YAG:Ce decr eases significantly with the increase in concentration of Mg. The phenomenon of energy transfer was studied in detail. The CIE coordinates show slight red shift on expense of emission intensity. Key Wor ds: YAG:Ce, wLED, codoping, combustion synthesis 1. INTRODUCTION Yttrium aluminum garnet (Y3Al 5O12, YAG) has been known as one of the most common phosphor host materials. Rare-earth-doped yttrium aluminum garnet materials have wide applications as solid state laser media and are promising phosphor candidates. Cerium (Ce) activated yttrium aluminum garnet (YAG:Ce) is a well known phosphor that can be used in many ways[ 1 ]. Presently commercial white LEDs available in market use coating of YAG:Ce phosphor on a blue LED chip. The yellow emission is intense enough to complement the residual blue light that escapes through the phosphor and produce white light. It is the most suitable phosphor that can be utilized suitably in white LED commercial market. Therefore, any improvement in the luminescence of YAG:Ce is exceptionally valuable to raise the light efficiency for different applications. For the purpose of widening luminosity spectra, the emission of YAG:Ce phosphor may be tailored through the incorporation of an additional codoping element. The energy transfer from sensitizer to activator by rare earth ions has been investigated in many inorganic hosts. In contrast to single Ce doped YAG phosphor some co-doped YAG:Ce phosphors have been extensively studied that increase the emission efficiency and broaden luminosity spectra[ 2 ]. The materials commonly used are rare earth elements, such as Pr 3+ , Sm 3+ , Eu 3+ ,Gd 3+ or Tb 3+ ions[ 3-5 ]. Conversely, few studies examine YAG:Ce phosphors co-doped with transition elements and alkali metals. In this work, we reported the effect of doping of magnesium in optimized YAG:Ce phosphors. Their structure, luminescence and energy transfer properties were investigated. YAG phosphors are usually prepared via a solid- state reaction of yttria (Y2O3) and alumina (Al 2O3). However, it produces powders of relatively large and widely varying grain sizes and contain stable intermediate phases such as yttrium aluminium perovskite (YAP; YAlO3) and yttrium aluminium monoclinic (YAM:Y4Al 2O9). A high temperature of 1600 –1800 0 C and prolonged heating are required to obtain the pure phase, and this method also requires several hours of sintering and milling. In recent years, several wet chemical techniques such as coprecipitation method, sol-ge1, combustion, hydrothermal synthesis and spray-pyrolysis synthesis were used to prepare the single phase phosphor [ 6 ]. However, they are time-consuming and involve complex procedures. Moreover, phase pure materials are not obtained in one step and prolonged annealing at temperatures around 1400°C is necessary. In contrast, the combustion method is quite simple, and the combustion reaction lasts only for a few seconds. 2. EXPERIMENTAL In the present work, YAG:Ce have been synthesized by single step combustion synthesis (CS) with mixed fuels carried out at 500°C furnace temperature without taking recourse to any post thermal treatment. As reported in our previous paper YAG:Ce powders were synthesized and the optimal concentration of Ce in YAG have been chosen as 1mol%[ 7 ]. In optimized YAG:Ce, co- dopant Mg was introduced in various concentration at Al 3+ site to study effect on luminescence intensity. For synthesis of YAG:Ce, the starting materials used for preparation of the phosphor were Y2O3 (99.90%), Al(NO3) 3.9H2O (99.99%), Ce2(CO3) 3 (99.99%), HNO3 (69% GR), NH2CONH2 (99.99%) and C 2H5NO2 (99.99%). To study effect of codoping of Mg in the optimal concentration of Ce; MgCl 2 with SiO2 . H2O, were added.