Synthesis, structure and upconversion luminescence of Yb3+, Ho3+ co-doped Gd3Al5O12 garnet phosphor prepared by the Pechini sol–gel method

Abstract

A pure-phase phosphor of Gd₃Al₅O₁₂ garnet (GAG) co-doped with Yb³⁺ and Ho³⁺ ions has been synthesized by the Pechini sol–gel method. Phase evolution upon the calcination temperature has been studied and the structural parameters of the garnet phase have been refined by the Rietveld method based on powder XRD measurements. The FE-SEM micrographs show that the phosphor crystalized in spherical shaped particles with mean diameter smaller than 200 nm when the calcination temperature was not higher than 1200 °C. After the doping of Yb³⁺ and Ho³⁺, on the one hand the GAG phase shows very good thermal stability and on the other hand, yellow-green upconversion luminescence with color coordinates of (0.355, 0.626) was generated under the pumping with a LD centered at 976 nm. Results have indicated that the phosphor has potential applications in some upconversion based lighting and displays.