Solvothermal synthesis and upconversion properties in Yb3+/Ln3+ (Ln3+=Er3+/ Ho3+/ Tm3+) codoped In2O3 nanoparticles with fine stability

Monodisperse In2O3: Yb3+/Er3+ upconverting nanoparticles (UCNPs) were firstly synthesized via solvothermal method in three-neck round-bottom flask. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) methods are used to characterize the prepared UCNPs. The size of monodisperse spheroid nanoparticles prepared can be controllable in 31 nm. The sample exhibits stronger upconversion luminescence (UCL) than reported In2O3: Yb3+/Er3+ UCNPs with similar size. Furthermore, the obtained In2O3 UCNPs, by coating the SiO2 protecting layer, display fine stability. Simultaneously, the UCL properties and possible energy transfer process of In2O3: Yb3+/Ho3+ and In2O3: Yb3+/Tm3+ NPs have also been investigated by the spectra distribution and power dependence. The results indicate Yb3+/Er3+, Yb3+/Ho3+ and Yb3+/Tm3+ codoped In2O3 UCNPs is a probable oxide upconverting material with small size and intense UCL for biological applications.