Bright green-emitting nanophosphor for dual-mode up/down-conversion luminescence

Abstract

Dual-mode green-emitting nanophosphors showing upconversion and downconversion luminescence were reported. Green-emitting Gd-substituted β-NaYF4:Yb,Er upconversion nanophosphor was used as a core material and greenemitting β-NaGdF4:Ce,Tb was served as a shell material. Upconversion photoluminescence intensity was enhanced by about 11 times due to formation of the luminescent shell, and therefore strong green emission peaks attributed to 2H11/2,4S3/2 → 4I15/2 transitions of Er3+ ions were observed under the excitation of 980 nm near infrared light. In addition, bright green light was generated from 5D4 → 7F5 transition of Tb3+ ions in the shell under the exciation of 254 nm ultraviolet light.