title: Enhanced Upconversion Luminescence in Yb3+/Tm3+-Codoped Fluoride Active Core/Active Shell/Inert Shell Nanoparticles through Directed Energy Migration.
abstract: The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF₄:Yb3+30%/Tm3+0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF₄:Yb3+30%/Tm3+0.5%)/NaYbF₄/NaYF₄ design, which involves the use of directed energy migration in the second active shell layer. The resulting active core/active shell/inert shell nanoparticles are determined to be about 11 times brighter than that of well-investigated (NaYF₄:Yb3+30%/Tm3+0.5%)/NaYF₄ active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb3+/Tm3+-codoped NaYF₄ nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles.
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. qiuhailong2008@163.com.|Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. qiuhailong2008@163.com.
authors.forename: Hailong
authors.initials: H
authors.lastname: Qiu
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. yangchh@hit.edu.cn.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. shoxxxa@gmail.com.|Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. shoxxxa@gmail.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Shao
authors.affiliation: Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. jossanad@buffalo.edu.
authors.forename: Jossana
authors.initials: J
authors.lastname: Damasco
authors.affiliation: Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. xianlian@buffalo.edu.
authors.forename: Xianliang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Theoretical Chemistry, Royal Institute of Technology, S-10691 Stockholm, Sweden. agren@theochem.kth.se.
authors.forename: Hans
authors.initials: H
authors.lastname: Ågren
authors.affiliation: Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. pnprasad@buffalo.edu.
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. guanying@buffalo.edu.|Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA. guanying@buffalo.edu.
authors.forename: Guanying
authors.initials: G
authors.lastname: Chen
keywords: core/shell; efficiency; energy migration; upconversion