Efficient up-converted white emission in Er³⁺, Tm³⁺ and Yb³⁺ tridoped NaYF₄ powders

Excerpt

Much interest has been motivated in the conversion of near infrared radiation into visible light in rare earth doped materials because of its potential applications, such as color display, optical data storage, biomedical diagnostics, sensors, under sea optical communications [1‐5]. More recently, white up-conversion emission has especially attracted much attention due to its wide variety of applications, from compact light source to photonic devices [6]. For quite some time, NaYF₄ host lattice has been recognized as one of the most efficient up-conversion lattices [7‐9]. Efficient up-converted green and blue emission has been previously reported in Er³⁺, Yb³⁺ co-doped and Tm³⁺, Yb³⁺ co-doped NaYF₄ matrix, respectively [7‐10]. However, no white emission is reported in this efficient host. In this paper, we will report an up-conversion in Er³⁺, Tm³⁺ and Yb³⁺ co-doped NaYF₄ powder. In this material doped with three kinds of rare earth ions, intense multicolor up-converted emission has been observed. It has also been proved that the intensity of up-conversion emission can be adjusted by changing the doping concentration. More noticeably, bright white luminescence has been realized in this Er³⁺, Tm³⁺ and Yb³⁺ co-doped NaYF₄ powder for the first time. …