SPECTROSCOPY OF LUMINESCENT CRYSTALS CONTAINING RARE EARTH ELEMENTS

Abstract

We have studied the spectroscopy of luminescent crystals containing rare earth elements such as KEuGe$_2$O$_6$, Cs$_3$EuSi$6$O${15}$,, 5743 (2005).} K$_4$[(UO$_2$)Eu$_2$(Ge$_2$O$_7$)$_2$], and R$_2$(C$8$H${10}$O$_4$)$_3$ (R= Y, Tb, or Eu). The emission and excitation spectra of these compounds were recorded at ambient temperature. These spectra are consistent with the structures which were determined by single crystal X-ray diffraction. Crystals containing hybrid luminescent centers were also synthesized and interesting energy transfer mechanisms were observed. For example, dramatic luminescence quenching was found in KEu$x$Nd${1-x}$Ge$_2$O$6$ (x= 0.98, 0.96, 0.94, and 0.84) as well as in Cs$3$Eu${0.98}$Nd${0.02}$Si$6$O${15}$, while different compositions of Y$_x$Eu$y$Tb${2-x-y}$(C$8$H${10}$O$_4$)$_3$ exhibit different emission colors. Emission lifetimes were also measured for these compounds, and the results shed light on the energy transfer mechanisms. Detailed results of our research will be presented.