MENG-LING CHEN, KWANG-HWA LII AND BOR-CHEN CHANG, Department of Chemistry, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan.
We have studied the spectroscopy of luminescent crystals containing rare earth elements such as KEuGe2O6, Cs3EuSi6O15, K4[(UO2)Eu2(Ge2O7)2], and R2(C8H10O4)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 KEuxNd1-xGe2O6 (x= 0.98, 0.96, 0.94, and 0.84) as well as in Cs3Eu0.98Nd0.02Si6O15, while different compositions of YxEuyTb2-x-y(C8H10O4)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.