Upconversion luminescence of colloidal solution of Y2O3 nano-particles doped with trivalent rare-earth ions

We have studied upconversion luminescence of colloidal solution of Y2O3 nano-particles codoped with 1 mol% Er3+ and 5 mol% Yb3+. Y2O3 nano-particles codoped with 1 mol% Er3+ and 5 mol% Yb3+ show sintering and agglomeration, because they are synthesized by firing a hydroxy carbonate precursor. Colloidal solution of Y2O3 nano-particles codoped with 1 mol% Er3+ and 5 mol% Yb3+ is prepared through two-step dispersion process and the average diameter of the primary nano-particles is about 50 nm. Under excitation with 980-nm laser diode, upconversion luminescence of colloidal solution of the primary Y2O3 nano-particles codoped with 1 mol% Er3+ and 5 mol% Yb3+ in methyl isobuthyl ketone strongly appeared near 660 nm and weakly near 550 nm.