Infrared to-visible upconversion luminescence in Er:Yb:SrFBr nanocrystals

Abstract

The ability of SrFBr nanocrystals codoped with ∼1 mol% of Er³⁺ and Yb³⁺ to perform infrared-to-visible light upconversion is demonstrated. The average and local crystal structures conform to those expected on the basis of the P4/nmm tetragonal space-group. Excitation of Yb³⁺ at 980 nm results in two-photon upconversion and green-yellow luminescence from Er³⁺. The ²H_11/2, ⁴S_3/2, and ⁴F_9/2 excited states of the Er³⁺ activator in the SrFBr host exhibit a biexponential decay with lifetimes in the 100–200 and 300–400 μs ranges.