Upconversion emission of ZrO2 nanoparticles doped with erbium (Er3+) and ytterbium (Yb3+), synthesized by hydrothermal route

This paper reports the luminescent response upconversion of zirconium oxide (ZrO2) nanoparticles doped with erbium (Er3+) and ytterbium (Yb3+) ions, synthesized by hydrothermal route. X ray diffraction (DRX) showed that the synthesized material presents the face centered cubic (FCC) structure. High resolution transmission electron microscopy (HRTEM) showed the presence of crystals size smaller than 10 nm. The photoluminescent analysis allowed to observe an intense upconversion luminescence emission of the samples doped with both ions Er3+ and Yb3+, when these are excited with 910 nm laser source, showing the electronic transitions 4F9/2 → 4I5/2; 2H11/2 → 4I5/2; 4S3/2 → 4I15/2 of Er3+. Two decay times were observed, whose behavior can be associated to the average distance between erbium ions within the nanocrystals.