title: Multicolor barcoding in a single upconversion crystal.
abstract: We report the synthesis of luminescent crystals based on hexagonal-phase NaYF4 upconversion microrods. The synthetic procedure involves an epitaxial end-on growth of upconversion nanocrystals comprising different lanthanide activators onto the NaYF4 microrods. This bottom-up method readily affords multicolor-banded crystals in gram quantity by varying the composition of the activators. Importantly, the end-on growth method using one-dimensional microrods as the template enables facile multicolor tuning in a single crystal, which is inaccessible in conventional upconversion nanoparticles. We demonstrate that these novel materials offer opportunities as optical barcodes for anticounterfeiting and multiplexed labeling applications.
authors.affiliation: Department of Chemistry, National University of Singapore , 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: Yuhai
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
authors.forename: Renren
authors.initials: R
authors.lastname: Deng
authors.forename: Jing
authors.initials: J
authors.lastname: Tian
authors.forename: Yun
authors.initials: Y
authors.lastname: Zong
authors.forename: Dayong
authors.initials: D
authors.lastname: Jin
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Liu
mesh_terms: D003116:Color; D005459:Fluorides / Q000138:chemical synthesis / Q000737:chemistry*; D049449:Luminescence; D049408:Luminescent Agents / Q000138:chemical synthesis / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D015019:Yttrium / Q000737:chemistry*
chemical_list: D049408:Luminescent Agents; C525362:sodium yttriumtetrafluoride; D015019:Yttrium; D005459:Fluorides