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Upconversion Lifetime Imaging of Highly‐Crystalline Gd‐Based Fluoride Nanocrystals Featuring Strong Luminescence Resulting from Multiple Luminescent Centers
Author(s) -
Xu Yueshan,
Zeng Zhichao,
Zhang Dan,
Liu Songtao,
Wang Xian,
Li Sai,
Cheng Chunyan,
Wang Jianxun,
Liu Yuanyuan,
De Gejihu,
Zhang Chao,
Qin Weiping,
Du Yaping
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201901495
Subject(s) - materials science , luminescence , orthorhombic crystal system , nanocrystal , monoclinic crystal system , photon upconversion , dopant , phase (matter) , hexagonal phase , excitation , optoelectronics , doping , nanotechnology , crystal structure , crystallography , chemistry , organic chemistry , engineering , electrical engineering
Highly‐crystalline Gd‐based fluoride upconversion (UC) nanocrystals, including orthorhombic‐phase GdF 3 :Yb/Er nanoplates (NPLs), hexagonal‐phase NaGdF 4 :Yb/Er NPLs, monoclinic‐phase K 3 GdF 6 :Yb/Er nanoribbons (NRs), and orthorhombic‐phase KGdF 4 :Yb/Er NRs are controllably synthesized through a simple yet robust method, with all of the products exhibiting strong UC luminescence. Notably, the obtained K 3 GdF 6 :Yb/Er NRs have an exceptional quantum yield as high as 0.84% at a low excitation laser power (0.30 W cm −2 , 975 nm), as well as long single‐particle UC lifetimes (τ) for green (τ = 0.70 ms) and red (τ = 1.10 ms) emissions. The enhanced luminescence is attributed to the “multiple luminescent center effect,” which is verified via the laser‐selective excitation spectra of deliberately introduced Eu 3+ dopants. This method can be extended to the preparation of a number of other nanocrystals, and the UC nanocrystals featuring high luminescence efficiencies can be further tailored for biomedical applications.