The luminescence properties of CaS : EU2+ excited by pico-second laser pulse

CaS:Eu2+ materials were prepared by using sulfur-flux method and analyzed w ith X-ray diffraction technology. The photoluminescence spectra of the samp le excited by 532 nm pico-second laser pulse were investigated. The lumines cence of Eu3+ as well as Eu2+ was observed. It revealed that some EU2+ ions could be ionized to become Eu3+ ions when the sample was excited by the pi co-second laser pulse. The dependence of the luminescence intensity of Eu3 and that of Eu2+ the concentration of Eu2+ was also observed. As luminesce nce peaks of Eu3+ were just in the region of Eu2+ absorption, the energy tr ansfer from Eu3+ to Eu2+ would take place. (C) 2001 Elsevier Science B.V. A ll rights reserved.