title: Study of energy transfer mechanism from ZnO nanocrystals to Eu(3+) ions.
abstract: In this work, we investigate the efficient energy transfer occurring between ZnO nanocrystals (ZnO-nc) and europium (Eu(3+)) ions embedded in a SiO2 matrix prepared using the sol-gel technique. We show that a strong red emission was observed at 614 nm when the ZnO-nc were excited using a continuous optical excitation at 325 nm. This emission is due to the radiative (5)D0 → (7)F2 de-excitation of the Eu(3+) ions and has been conclusively shown to be due to the energy transfer from the excited ZnO-nc to the Eu(3+) ions. The photoluminescence excitation spectra are also examined in this work to confirm the energy transfer from ZnO-nc to the Eu(3+) ions. Furthermore, we study various de-excitation processes from the excited ZnO-nc and their contribution to the energy transfer to Eu(3+) ions. We also report the optimum fabrication process for maximum red emission at 614 nm from the samples where we show a strong dependence on the annealing temperature and the Eu(3+) concentration in the sample. The maximum red emission is observed with 12 mol% Eu(3+) annealed at 450 °C. This work provides a better understanding of the energy transfer mechanism from ZnO-nc to Eu(3+) ions and is important for applications in photonics, especially for light emitting devices.
authors: OPTIMUS, Centre for OptoElectronics and Biophotonics, School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Block S2, 50 Nanyang Avenue, Singapore, 639798, Singapore. vivek014@e.ntu.edu.sg.
authors: Vivek
authors: http://orcid.org/0000-0002-4601-6767
authors: V
authors: Mangalam
authors: OPTIMUS, Centre for OptoElectronics and Biophotonics, School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Block S2, 50 Nanyang Avenue, Singapore, 639798, Singapore. ekpita@ntu.edu.sg.|CINTRA, CNRS-NTU-Thales UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore, 637553, Singapore. ekpita@ntu.edu.sg.
authors: Kantisara
authors: K
authors: Pita
authors: CINTRA, CNRS-NTU-Thales UMI 3288, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, Singapore, 637553, Singapore. christophe.couteau@utt.fr.|Laboratory for Nanotechnology, Instrumentation and Optics (LNIO), Charles Delaunay Institute CNRS UMR 6281, University of Technology of Troyes (UTT), 12 rue Marie Curie, 10000, Troyes, France. christophe.couteau@utt.fr.|School of Electrical and Electronic Engineering, Nanyang Technological University (NTU), Block S2, 50 Nanyang Avenue, Singapore, 639798, Singapore. christophe.couteau@utt.fr.
authors: Christophe
authors: C
authors: Couteau
keywords: Energy transfer mechanism; Europium(III) ions; Photoluminescence; Zinc oxide nanocrystals