Synthesis of Y_2O_3 nanophosphors by homogeneous precipitation method using excessive urea for cathodoluminescence and upconversion luminescence bioimaging

Yttrium oxide-based nanophosphors that emit both upconversion luminescence (UPL) and cathodoluminescence (CL) were synthesized by a precipitation method using excessive urea. Precursors of Y2O3 nanophosphors were synthesized with size control to less than 50 nm and a chemical yield greater than 90%. Concentrations of rare-earth co-dopants in nanophosphors were controlled with optimal molar ratios. Co-dopants Tm, Yb/Er, Yb enabled NPs to emit UPL at wavelengths around 810/660 nm and CL at wavelengths around 450/660 nm via excitation with 980 nm NIR light and an electron beam. Synthesized NPs were imaged by NIR and CL microscopy.