title: Heterogeneous core/shell fluoride nanocrystals with enhanced upconversion photoluminescence for in vivo bioimaging.
abstract: We report on heterogeneous core/shell CaF2:Yb(3+)/Ho(3+)@NaGdF4 nanocrystals of 17 nm with efficient upconversion (UC) photoluminescence (PL) for in vivo bioimaging. Monodisperse core/shell nanostructures were synthesized using a seed-mediated growth process involving two quite different approaches of liquid-solid-solution and thermal decomposition. They exhibit green emission with a sharp band around 540 nm when excited at ∼980 nm, which is about 39 times brighter than the core CaF2:Yb(3+)/Ho(3+) nanoparticles. PL decays at 540 nm revealed that such an enhancement arises from efficient suppression of surface-related deactivation from the core nanocrystals. In vivo bioimaging employing water-dispersed core/shell nanoparticles displayed high contrast against the background.
authors.affiliation: School of Chemical Engineering and Technology, Harbin Institute of Technology, Heilongjiang 150001, People's Republic of China. chenguanying@hit.edu.cn yangchh@hit.edu.cn.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Hao
authors.forename: Liming
authors.initials: L
authors.lastname: Yang
authors.forename: Hailong
authors.initials: H
authors.lastname: Qiu
authors.forename: Rongwei
authors.initials: R
authors.lastname: Fan
authors.forename: Chunhui
authors.initials: C
authors.lastname: Yang
authors.forename: Guanying
authors.initials: G
authors.lastname: Chen
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000138:chemical synthesis*; D005459:Fluorides / Q000737:chemistry*; D007089:Image Enhancement / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008853:Microscopy / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D051598:Whole Body Imaging / Q000379:methods*
chemical_list: D003287:Contrast Media; D005459:Fluorides