Synthesis, structure, EPR studies and up-conversion luminescence of ZnO:Er-Yb@GdO nanostructures

• Published in: RSC advances 2016-09, Vol.6 (92), p.8935-89312
• Main Authors: Babayevska, N, Pepli ska, B, Jarek, M, Yate, L, Tadyszak, K, Gapi ski, J, Iatsunskyi, I, Jurga, S
• Format: Article
• ISSN: 2046-2069
• DOI: 10.1039/c6ra18393j

ZnO:Er 3+ -Yb 3+ @Gd 2 O 3 nanostructures were obtained by " wet " chemistry methods - the sol-gel technique for the preparation of ZnO and ZnO:Er 3+ -Yb 3+ nanoparticles (NPs), and the seed deposition method for obtaining Gd 2 O 3 . The crystal structure, morphology, phase and elemental composition, resonant microwave absorption of rare earth ions, point defects in the ZnO:Er 3+ -Yb 3+ @Gd 2 O 3 crystal structure and up-conversion luminescence were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy, and optical spectroscopy. The crystallization temperature (600 °C) of the Gd 2 O 3 phase on the ZnO surface was found. As-obtained ZnO:Er 3+ -Yb 3+ NPs (with size ∼7 nm) are highly crystalline and monodispersed. ZnO:Er 3+ -Yb 3+ NPs annealing at 900 °C leads to the formation of highly polydispersed ZnO:Er 3+ -Yb 3+ NPs, covered by a Gd 2 O 3 shell. The process of the incorporation of the rare earth ions into the ZnO structure, as well as the effect of Gd 2 O 3 content on the morphology and visible up-conversion (UC) luminescence in ZnO:Er 3+ -Yb 3+ matrices were studied. ZnO:Er 3+ -Yb 3+ @Gd 2 O 3 nanostructures were obtained by " wet " chemistry methods - the sol-gel technique for the preparation of ZnO and ZnO:Er 3+ -Yb 3+ nanoparticles (NPs), and the seed deposition method for obtaining Gd 2 O 3 .