Ga3+ Doping Induced Simultaneous Size/Shape Control, Enhanced Red Upconversion Luminescence, and Improved X-ray Imaging of ZnO:Yb/Tm for Multifunctional Nanoprobes.

We report that the efficient Ga3+-doped ZnO:Yb/Tm (7/0.5 mol %) upconversion nanoparticles (UCNPs) can simultaneously control size/shape and enhance red upconversion luminescence (UCL) by transition-metal Ga3+ doping. The dynamic decay time reveals that the intensity of red upconversion luminescence increases with increasing Ga3+ content. Furthermore, upconversion nanoparticles are fabricated through silica layer with Stöber method. The lung of mouse with the ZnO:Ga/Yb/Tm@SiO2 injection can be readily visualized using X-ray imaging, which will influence the field of biological probe based on UCNPs@SiO2.