AVS 59th Annual International Symposium and Exhibition
    Surface Science Wednesday Sessions
       Session SS+OX-WeM

Paper SS+OX-WeM11
Synthesis and Characterization of White Light Emitting CaxSr1-xAl2O4:Tb3+,Eu3+ Phosphor

Wednesday, October 31, 2012, 11:20 am, Room 22

Session: Synthesis and Characterization of Oxides
Presenter: O.M. Ntwaeaborwa, University of the Free State, South Africa
Authors: S.K. Shaat, University of the Free State, South Africa
H.C. Swart, University of the Free State, South Africa
O.M. Ntwaeaborwa, University of the Free State, South Africa
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Today, many researchers are making efforts to develop white light emitting phosphors that can be used in solid state lighting applications such as phosphor lamps and light emitting diodes. Aluminates with a general formula MAl2O4 (M = Ba, Ca, Mg, Sr) have emerged as preferred hosts for divalent (Mn2+ and Eu2+) and trivalent (Ce3+,Tb3+, Dy3+) ions to prepare such phosphors. We have prepared a potential white light emitting CaxSr1-xAl2O4:Tb3+,Eu3+ (x = 0, 0.3, 0.7, 1) phosphor by combustion method and we are evaluating it for application in solid state lighting. Depending on the concentration of Ca2+ or Sr2+, the X-ray diffraction data showed that monoclinic structures of either CaAl2O4 or SrAl2O4 were crystallized and the stretching modes of Sr-Al-O and Ca-Al-O bonds were confirmed from the Fourier transform infrared spectroscopy data. The chemical compositions and electronic states of each elements of the CaxSr1-xAl2O4:Tb3+,Eu3+ phosphor were determined using X-ray photoelectron spectroscopy. White photoluminescent was observed when CaxSr1-xAl2O4:Tb3+,Eu3+ was excited at 227 nm using a monochromatized xenon lamp. This was a result of the combination of blue and green emissions from Tb3+ and red emission from Eu3+. It is likely that Tb3+ and Eu3+ ions were simultaneously excited by a single photon of sufficiently high energy absorbed in CaxSr1-xAl2O4 host.