Bright dual-mode green emission from selective set of dopant ions in beta-Na(Y,Gd)F-4:Yb,Er/beta-NaGdF4:Ce,Tb core/shell nanocrystals

Abstract

Bright dual-mode green-emitting core/shell nanoparticles (NPs) were synthesized by doping selective set of lanthanide ions. Up-conversion (UC) green-emitting beta-NaY0.2Gd0.6F4:Yb-0.18,Er-0.02 NPs (8.3 nm) were used as core material. Bright down-conversion (DC) green-emitting beta-NaGd0.8F4:Ce-0.15,Tb-0.05 NPs showed ca. 31 times higher photoluminescence (PL) intensity than beta-NaGdF4:Tb NPs and they were served as shell material with their excellent PL properties. The UC/DC core/shell NPs showed bright green light under excitations of 980 nm near infrared (NIR) light and 254 nm ultraviolet (UV) light, respectively. The UC/DC core/shell NPs showed ca. 11 times higher UC PL intensity than core UCNPs. Consequently, the core/shell NPs doped with selective set of lanthanide ions showed bright dual-mode green emission under excitations of NIR light and UV light, indicating that they are promising for application to optical imaging. (C) 2012 Optical Society of America