Abstract
The Pr3+/Yb3' co-doped La203 and La(OH)3 nano-phosphors have been synthesized through solution combustion method. The structure and morphology of the samples have been studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The physical and optical properties of the samples have been measured and compared. A broad intense infrared emission centered at 850 nm due to 116 1G4 transition along with sharp green emission centerd at 513 nm due to 3P0 -3H4 transition are observed on excitation with 976 nm laser. The emission intensity of Pr + is optimized with concentration and it is maximum at 0.08 mol%. The annealed samples are found to be more crystalline and emit larger photoluminescence due to removal of quenching centers. The power dependent study of green upconversion emission indicates the involvement of two photons. The phosphor in La(OH)3 phase is more stable though the photoluminescence emission is slightly weak. La(OH)3 is less toxic compared to La203 and is biocompatible. It generates more heat and can be used in biothermal treatment. 2015 Elsevier B.V. All rights reserved.