Preparation of yttrium oxysulfide phosphor nanoparticles with infrared-to-green and -blue upconversion emission using an emulsion liquid membrane system

摘要

Yttrium oxysulfide upconverting phosphor nanoparticles,doped with Yb as a sensitizer and Er(or Ho,Tm)as an activator,have been prepared via a solid-gas reaction using precursor oxalate particles obtained in an emulsion liquid membrane(ELM,water-in-oil-in-water(W/O/W)emulsion)system.The resulting Y2O2S:Yb,Er particles,mainly smaller than 50 nm in diameter,demonstrated green upconversion emission under infrared excitation(lambda_ex=980 nm)via a two-photon process.Distinct green and blue upconversion emission were also demonstrated under the same infrared excitation from Y_2O_2S:Yb,Ho and Y_2O_2S:Yb,Tm nanoparticles,respectively.These upconverting phosphor nanoparticles,together with Y_2O_3:Yb,Er infrared-to-red upconverting phosphor particles,with different emission under the same infrared excitation may be applied to the luminescent reporter materials for the detection of the targeted analyte in multiplexed assays.