Color-Tunable Upconversion Luminescence in Er³⁺-Yb³⁺ Co-Doped Sodium Lutetium Fluoride Glass-Ceramics

摘要

In this work, the study of the near infrared to visible upconversion (UC) emission in transparent sodium lutetium fluoride glass-ceramics doped with ErF3 and co-doped with YbF3 is reported. Intense UC green and red emissions due to (²H11/2,⁴S3/2)^→4I15/2 and ⁴F9/2^→4I15/2 transitions respectively together with a more weak blue emission due to the ²H9/2^→4I15/2 transition have been observed under excitation at 980 nm. The influence of Yb³⁺ co-doping and excitation power density on the upconversion emissions is investigated. The addition of Yb³⁺ ions greatly enhances the overall UC emission intensity and can be used to tune the UC emission from green to yellow due to an increase of the red-to-green ratio.