Hong, A-Ra Kim, Youngsun Lee, Tae Sup Kim, Sehoon Lee, Kwangyeol Kim, Gayoung Jang, Ho Seong 2024-01-19T23:01:34Z 2024-01-19T23:01:34Z 2021-09-03 2018-04-18 1944-8244 https://pubs.kist.re.kr/handle/201004/121468 In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near-infrared (NIR) light are reported. When a NaYF4:Nd,Yb active-shell is formed on the 12.7 nm sized NaGdF4:Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red, depending on the Ce3+ concentration under excitation with 800 nm NIR light. Ce(3+)doped C/S UCNPs (30 mol %) exhibit single-band red emission peaking at 644 nm via a F-5(5) -> I-5(8) transition of Ho3+. A high Nd3+ concentration in the shell results in strong absorption at around 800 nm NIR light, even though the shell thickness is not large, and small-sized C/S UCNPs (16.3 nm) emit bright red light under 800 nm excitation. The formation of a thin NaGdF4 shell on the C/S UCNPs further enhances the upconversion (UC) luminescence and sub-20 nm sized core/double-shell (C/D-S) UCNPs exhibit 2.8 times stronger UC luminescence compared with C/S UCNPs. Owing to the strong UC luminescence intensity and Gd3+ ions on the surface of nanocrystals, they can be applied as a UC luminescence imaging agent and a T-1 contrast agent for magnetic resonance (MR) imaging. In vivo UC luminescence and high-contrast MR images are successfully obtained by utilizing the red-emitting C/D-S UCNPs. English American Chemical Society FACILE SYNTHESIS NANOCRYSTALS NANOPARTICLES THERAPY DESIGN PROBES Intense Red-Emitting Upconversion Nanophosphors (800 nm-Driven) with a Core/Double-Shell Structure for Dual-Modal Upconversion Luminescence and Magnetic Resonance in Vivo Imaging Applications Article 10.1021/acsami.7b18078 1 ACS Applied Materials & Interfaces, v.10, no.15, pp.12331 - 12340 ACS Applied Materials & Interfaces 10 15 12331 12340 scie scopus 000430642100023 2-s2.0-85045658922 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article FACILE SYNTHESIS NANOCRYSTALS NANOPARTICLES THERAPY DESIGN PROBES core/shell/shell upconversion nanophosphors in vivo fluorescence imaging in vivo magnetic resonance imaging