The effects of the 5d energy locations of Ce3+ centers on the NIR quantum cutting process were studied in Y2SiO5 with two different substitutional Y3+ lattice sites for Ce3+ and Yb3+. Powder XRD and Rietveld refinement were used to characterize phase purity, crystal structure, lattice parameters and occupation fractions of Y2-x-yCexYbySiO5 (x = 0.002 and 0.3, y = 0-0.2). PLE and PL spectra show that both kinds of Ce3+ centers in Y2-xy CexYbySiO5 can cooperatively transfer energy to Yb3+-Yb3+ ions pair. The dependence of the integrated emission intensities of Ce3+ and Yb3+, decay lifetime (τ) of Ce3+, nonradiative energy transfer rate (KCe→Yb), cooperative energy transfer efficiency (ηCET) and quantum efficiency (ηQE) on the concentration of Yb3+ ions were studied in details. More importantly, these results demonstrate that the 5d energy locations of Ce3+ ions have a great influence on NIR quantum cutting process in Ce3+-Yb3+ system: the closer they are to twice the absorption energy (~20000 cm−1) of Yb3+, the higher the cooperative energy transfer efficiency from the lowest 5d excited state of Ce3+ to the Yb3+ Yb3+ ions pair.
Tang, Jinke; Zhou, Wenli; Yang, Jie; Wang, Jing; Li, Ye; Kuang, Xiaojun; and Liang, Hongbin (2012). "Study on the effects of 5d energy locations of Ce3+ ions on NIR quantum cutting process in Y2SiO5: Ce3+, Yb3+." OPTICS EXPRESS 20.S4, A510-A518.