Investigation of luminescent properties of Ca0.3Sr0.7Al2O4:Tb3+,Eu3+ excited using different excitation sources

The structure and luminescent properties of Tb3+-Eu3+ co-activated Ca0.3Sr0.7Al2O4 powder phosphor prepared via solution combustion (SC) method were investigated. The phosphor was analyzed using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron (XPS), time of flight secondary ion mass spectroscopy (ToF-SIMS), photoluminescence spectroscopy, synchrotron radiation spectroscopy and cathodoluminescence spectroscopy. In particular, the unintended reduction of Eu3+ to Eu2+ was illustrated from the ToF-SIMS, XPS and luminescent spectroscopy data. This reduction is known to occur under certain conditions and possible mechanisms for the reduction are discussed. The chemical imaging performed with ToF-SIMS illustrated how individual ions were distributed in the crystal. Tunable luminescence was observed when the phosphor was optically-excited by different excitation sources including a 325 nm He-Cd laser, synchrotron radiation and high energy electrons. This phosphor was evaluated for application in different types of light emitting devices.