title: Lanthanide-doped Na(x)ScF(3+x) nanocrystals: crystal structure evolution and multicolor tuning.
abstract: Rare-earth-based nanomaterials have recently drawn considerable attention because of their unique energy upconversion (UC) capabilities. However, studies of Sc(3+)-based nanomaterials are still absent. Herein we report the synthesis and fine control of Na(x)ScF(3+x) nanocrystals by tuning of the ratio of oleic acid (OA, polar surfactant) to 1-octadecene (OD, nonpolar solvent). When the OA:OD ratio was increased from low (3:17) to high (3:7), the nanocrystals changed from pure monoclinic phase (Na(3)ScF(6)) to pure hexagonal phase (NaScF(4)) via a transition stage at an intermediate OA:OD ratio (3:9) where a mixture of nanocrystals in monoclinic and hexagonal phases was obtained and the coexistence of the two phases inside individual nanocrystals was also observed. More significantly, because of the small radius of Sc(3+), Na(x)ScF(3+x):Yb/Er nanocrystals show different UC emission from that of NaYF(4):Yb/Er nanocrystals, which broadens the applications of rare-earth-based nanomaterials ranging from optical communications to disease diagnosis.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
authors.forename: Xue
authors.initials: X
authors.lastname: Teng
authors.forename: Yihan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Wei
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authors.lastname: Wei
authors.forename: Shuchao
authors.initials: S
authors.lastname: Wang
authors.forename: Jingfeng
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authors.lastname: Huang
authors.forename: Rafik
authors.initials: R
authors.lastname: Naccache
authors.forename: Wenbo
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authors.lastname: Hu
authors.forename: Alfred Iing Yoong
authors.initials: AI
authors.lastname: Tok
authors.forename: Yu
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authors.lastname: Han
authors.forename: Qichun
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authors.lastname: Zhang
authors.forename: Quli
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authors.lastname: Fan
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: John A
authors.initials: JA
authors.lastname: Capobianco
authors.forename: Ling
authors.initials: L
authors.lastname: Huang