title: Morphologically controlled synthesis of colloidal upconversion nanophosphors and their shape-directed self-assembly.
abstract: We report a one-pot chemical approach for the synthesis of highly monodisperse colloidal nanophosphors displaying bright upconversion luminescence under 980 nm excitation. This general method optimizes the synthesis with initial heating rates up to 100 °C/minute generating a rich family of nanoscale building blocks with distinct morphologies (spheres, rods, hexagonal prisms, and plates) and upconversion emission tunable through the choice of rare earth dopants. Furthermore, we employ an interfacial assembly strategy to organize these nanocrystals (NCs) into superlattices over multiple length scales facilitating the NC characterization and enabling systematic studies of shape-directed assembly. The global and local ordering of these superstructures is programmed by the precise engineering of individual NC's size and shape. This dramatically improved nanophosphor synthesis together with insights from shape-directed assembly will advance the investigation of an array of emerging biological and energy-related nanophosphor applications.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Xingchen
authors.initials: X
authors.lastname: Ye
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Collins
authors.forename: Yijin
authors.initials: Y
authors.lastname: Kang
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Daniel T N
authors.initials: DT
authors.lastname: Chen
authors.forename: Arjun G
authors.initials: AG
authors.lastname: Yodh
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Murray
mesh_terms: D003102:Colloids / Q000138:chemical synthesis / Q000737:chemistry; D003460:Crystallization; D005459:Fluorides / Q000138:chemical synthesis / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013053:Spectrophotometry; D014269:Trifluoroacetic Acid / Q000737:chemistry; D014961:X-Ray Diffraction; D015019:Yttrium / Q000737:chemistry*
chemical_list: D003102:Colloids; C525362:sodium yttriumtetrafluoride; D015019:Yttrium; D014269:Trifluoroacetic Acid; D005459:Fluorides