title: Preparation and upconversion luminescence of Y2SiO5:Yb3+, Ho3+ nanophosphors.
abstract: X1 type monoclinic Y2SiO5:Yb3+, Ho3+ nanophosphors with fixed (varied) Ho3+ and varied (fixed) Yb3+ concentrations were synthesized by sol-gel method. The nanophosphors presented lacunaris shape with an average size of about 47 nm measured by transmission electron microscopy and scanning electron microscopy. Up-conversion emissions have been observed at 550 nm corresponding to (5F4, 5S2)-5I8 transition and 661 nm due to 5F5-5I8 transition of Ho3+ upon 980 nm excitation at room temperature. The results indicate that both green and red luminescences are based on the two-photon process through the energy transfer from Yb3+. However, the intensity of green emission is weaker than that of the red, because the 5I7 level of Ho3+ can be effectively populated. The integrated upconversion emission intensity on the Yb3+ and Ho3+ concentrations were also studied.
authors.affiliation: Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, P. R. China.
authors.forename: Linna
authors.initials: L
authors.lastname: Guo
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Wang
authors.forename: Lingling
authors.initials: L
authors.lastname: Peng