title: Phonon-assisted energy back transfer-induced multicolor upconversion emission of Gd2O3:Yb(3+)/Er(3+) nanoparticles under near-infrared excitation.
abstract: Manipulation of upconversion (UC) emission is of particular importance for multiplexed bioimaging. Here, we precisely manipulate the UC color output by utilizing the phonon-assisted energy back transfer (EBT) process in ultra-small (sub-10 nm) Gd2O3:Yb(3+)/Er(3+) UC nanoparticles (UCNPs). We synthesized the Gd2O3:Yb(3+)/Er(3+) UCNPs by adopting the laser ablation in liquid (LAL) technique. The synthesized Gd2O3:Yb(3+)/Er(3+) UCNPs are small spherical and monoclinic structures. Continuous color-tunable (from green to red) UC fluorescence emission is achieved by increasing the concentration of Yb(3+) ions from 0 to 15 mol%. A phonon-assisted energy back transfer (EBT) process from Er(3+) ((4)S3/2 → (4)I13/2) to nearby Yb(3+) ((2)F7/2 → (2)F5/2), which can significantly enhance red emission at 672 nm and decrease green emission, is responsible for the color-tunable UC emission by increasing the Yb(3+) concentration in Gd2O3:Yb(3+)/Er(3+) UC nanoparticles.
authors.affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P. R. China. stscdh@mail.sysu.edu.cn stssyz@mail.sysu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Huawei
authors.initials: H
authors.lastname: Deng
authors.forename: Zhanyun
authors.initials: Z
authors.lastname: Huang
authors.forename: Yueli
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dihu
authors.initials: D
authors.lastname: Chen
authors.forename: Yuanzhi
authors.initials: Y
authors.lastname: Shao
mesh_terms: D004735:Energy Transfer; D004871:Erbium / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry; D007259:Infrared Rays; D053758:Nanoparticles / Q000737:chemistry*; D060739:Phonons; D011789:Quantum Theory; D015018:Ytterbium / Q000737:chemistry
chemical_list: D004871:Erbium; D005682:Gadolinium; D015018:Ytterbium