Research Journal of Chemical Sciences ________________________________________ ISSN 2231-606X Vol. 1(6), 80-83, Sept. (2011) Res.J.Chem.Sci. International Science Congress Association 80 Short CommunicationTL Glow Curve and Kinetic study of Eu3+ doped SrY4 Phosphors Kaur Jagjeet, Suryanarayana N.S., Dubey Vikas and Neha RajputDepartment of Physics, Govt. Vishwanath Yadav Tamaskar Post Graduate Autonomous College, Durg (C.G.), INDIA Available online at: www.isca.in (Received 04th July 2011, revised 12th July 2011, accepted 23rd July 2011)Abstract The present paper reports TL glow curve of Eu3+ doped SrY phosphor with different UV exposure time. The glow peak shows second order kinetics and evaluations of kinetic parameter were done by peak shape method. Calculations of trap depth were done with different methods and order of kinetics, activation energy and frequency factor are calculated. The recorded glow curve shifts longer temperature side with respect to UV exposure. The peaks were found 155C, 160C, 164C and 168C respectively using the heating rate 3C/s. Keywords:Thermoluminescent property, kinetic parameter, rare earth doped phosphor. IntroductionSrY:Eu3+ is one of the promising red phosphors for FED applications. Upon excitation with 250 and 260 nm light, all the powder samples of SrY2(1 :Eu show bright red emission due to the 4f–4f transitions of Eu3+ ions and the highest photoluminescence intensity at 610 and 615 nm was found at a content of about 9 mol% Eu3+. Splitting of the and transitions revealed that the Eu3+ ions occupied two nonequivalent sites in the crystallite by substituting Y3+ ions . Luminescence spectra of SrY:Eu show two kinds of Eu3+ emissions, which could be assigned to Eu3+ ions in the Sr-site and the Y-sites with the dependence of emission spectra on Eu3+concentration. The SrY lattice of the CaFe structure has two types of Y sites. One is an almost undistorted octahedral site and the other is a substantially distorted one. Strontium occupies the bicapped trigonal prismatic site. In this study, various isomorphic compounds doped with Eu3+ ions have been prepared and their luminescent spectra have been measured in order to identify Eu3+ sites in SrY: Eu. Rare earth oxides (RE) are the most stable rare earth compounds, in which the rare earth ions hold typically a trivalent state. Because of their optical, electronic and chemical properties resulting from their 4f electrons, rare earth oxides have been widely used in the field of luminescent devices, optical transmission, bio-chemical probes, medical diagnosis and so for. Thermoluminescence characteristics of phosphors have been widely used as a means of investigating the mechanism of luminescence. The often significant information about the kinetics involved in the process and serve as a tool for evaluating the various trapping parameters. TL curves are markedly sensitive to the presence of impurities and thermal treatment, the role of impurities as traps or centres and of thermal treatment probably being different in different systems. Extremely low concentration of defects can be studied in principle, using sensitive TL recording arrangements. The effect of impurities on the TL process has been extensively studied. Material and MethodsThe specimen SrY doped with Eu3+ has been prepared by the solid state reaction. The appropriate oxides and carbonates (SrCO3, , Eu and HBO) were thoroughly grinded in a mortar for 30 minutes and fired at 1000C for 2 hours at 1350C for 3 hours. Thermally stimulated luminescence glow curves were recorded at room temperature by using TLD reader I1009 supplied by Nucleonix Sys.Pvt.Ltd. Hyderabad. The obtained phosphor under the TL examination is given UV radiation 365nm. Heating rate used for TL measurement is 3.0C/s. Results and DiscussionThis paper reports the trapping parameters such as trap-depth (E), escape frequency factor (s) and “order of kinetics” for the glow peaks obtained under ultraviolet excitation. The TL glow curve SrY:Eu3+ phosphor shows second order kinetics. SrY doped with Eu is found to be very good thermoluminescence phosphor. The following are the results of present studies. The phosphor was given a UV irradiation with 365nm UV source. The heating rate is 3.0C/s. Every time 5 mg of weighed irradiated phosphor was taken for TL measurements. The TL glow curve of SrY doped with Eu has been shown in figure 1-4 and the variation of the TL glow curve as a function of UV exposure time has been presented in figure 5. In all the glow curves, only single peaks are observed around 155C, 160C, 164C and 168C. However it is interesting to note that the peak temperature around 155C increases by increasing UV exposure time. From the table 1 it can be easily seen that the variation with UV exposure. Figure 5 shows the variation of TL glow curve with a function of UV exposure time. Research Journal of Chemical Sciences _______________________________________________________ ISSN 2231-606X Vol. 1(6), 80-83, Sept. (2011) Res.J.Chem.Sci. International Science Congress Association 81 Figure-1 TL glow curve of SrY:Eu3+ 5 min UV exposureFigure-2 TL glow curve of SrY:Eu3+ 10 min UV exposureFigure-3 TL glow curve of SrY:Eu3+ 15 min UV exposure  \n \r  \n      Research Journal of Chemical Sciences _______________________________________________________ ISSN 2231-606X Vol. 1(6), 80-83, Sept. (2011) Res.J.Chem.Sci. International Science Congress Association 82 Figure-4 TL glow curve of SrY:Eu3+ 20 min UV exposure Figure-5 Variation with UV exposure time Table-1 Shape factors (mm), Activation Energy E and Order of Kinetics b of UV irradiated SrY:Eu3+ doped phosphort t t t d d d d wwww mm\nd / wd / wd / wd / w Activation energy \r\r      \n      \n\n \n It is interesting to note the effect of single dopant displays a good TL peak having good shape intensity and temperatures the overall TL pattern observed is interesting. Since the phosphor has to be coated in the CFL of fluroscent lamp the same is also can used as a dosimeter the position of the glow peak is at 155C in both the phosphors indicating that the electron traps involved are deep enough and high energy is required to release the trapped electrons; hence long storage of trapped charge carriers at normal working temperature is achieved and thus the thermal stability is ensured.     \n \r       Research Journal of Chemical Sciences _______________________________________________________ ISSN 2231-606X Vol. 1(6), 80-83, Sept. (2011) Res.J.Chem.Sci. International Science Congress Association 83 Table-2 The trap depth for the prominent glow peaks of the studied SrY:Eu3+, evaluated from second order kineticsMethods 5 min UV 10 min UV 15 min UV 20 min UV E (eV) = T(K)/500 0.31 0.32 0.32 0.33       \n 0.30 0.31 0.32 0.33       \n 0.50 0.52 0.53 0.55  \r      \n   9.26 8.80 9.38 0.10              (2K \n ) 4.76 4.32 4.58 4.95              \r (2K \n ) 0.02 2.0 2.31 0.02      \r         \r (2K \n ) 6.76 6.42 6.74 7.16 ConclusionFollowings are the main conclusions drawn from the studies of TL in Eu dope SrY phosphors irradiated by UV source: The glow curves are found to be a second order kinetics. Trap depth calculated by different methods are found to be 0.31 eV to 7.16eV. The frequency factor was calculated and its numerical value lies between 2X10 to 1X10 References 1.Zhou Liya, Shi Jianxin and Gong Menglian, Red phosphor SrY:Eu3+ synthesized by the sol–gel method, Journal of Luminescence, (113), 285-290 (2005)2.Yang Jikai, Xiao Siguo, Ding Jianwen YangXiaoliang and Wang Xiangfu, Preparation and photoluminescence properties of SrY:Yb3+, Er3+powders, Journal of Alloys and Compounds, (474),424-427 (2009)3. Huang Cuiying, You Wansheng, Dang Liqin, LEI Zhibin, Sun Zhengang and Zhang Lancui, Effect of Nd3+ Doping on Photocatalytic Activity of TiO2 Nanoparticles for Water Decomposition to Hydrogen, Chinese Journal of Catalysis(27), 203-209 (2006)4. Jiao Qing-Ze, Tian Zhou-Ling and Zhao Yun, Preparation of nickel hydroxide nanorods/nanotubes and microscopic nanorings under hydrothermal conditions, Journal of Nanoparticle Research, (9), 519-522 (2003) 5. Murthy K.V.R. et al., Role of fluorescent lamp phosphors in accidental radiation dosimetry, Journal of Radiation Measurements, (36), 483-485(2003)6. Subramanyam R.V. et al. proc. ISLA-2000, Ed.KVR Murthy et al. Publ. by M.S., University of Baroda, (2)180-185 (2000)7. Padmaja B. et al., Proc. of ICLA-2008, (2), 45-47 (2008)8. Chen R. and Mckeever S.W.S., Theory of thermoluminescence and related phenomenon world scientificPub. Co1997, Ed. KVR Murthy et al, Dec – (2000) 9. Videa M., Xu W., Geil B. et al., High Li self diffusitivity and transport number in novel electrolute solutions, J.Electrochem. Soc.,(148), A1352 (2001)10. Park S.J., Park C.H., Yu B.Y. et al.; structure and luminescence of SrY:Eu, J.electrochem. Soc., 146, 3903 (1999)