Highly Efficient Multicolor Up-Conversion Emissions and Their Mechanisms of Monodisperse NaYF4:Yb,Er Core and Core/Shell-Structured Nanocrystals

By H. Mai, Ya‐Wen Zhang, A. L. Sun, Chunhua Yan. 2007

589 citations recorded by the source corpus.

This paper comprehensively presents the highly efficient multicolor up-conversion (UC) emissions and related mechanisms of monodisperse NaYF4:Yb,Er core (α- and β-NaYF4:Yb,Er) and core/shell (α-NaYF4:Yb,Er@α-NaYF4 and β-NaYF4:Yb,Er@α-NaYF4) nanocrystals with controlled size (5−14 nm for α-phase nanocrystals and 20−300 nm for β-phase nanocrystals), chemical composition, and surface state. These nanoparticles were synthesized via a unique delayed nucleation pathway using trifluoroacetates as precursors in hot solutions of oleic acid/oleylamine/1-octadecene. With the naked eye and natural light the intense multicolor UC emissions (red, yellow, or green, without filters) can be observed in cyclohexane dispersions of as-prepared nanocrystals (1 wt %) excited by a 980 nm laser source (power density 1.22 W cm-2). On the basis of compositional optimization for β-NaYF4:Yb,Er nanocrystals, the intensity ratio of green to red emission (fg/r) reaches ca. 30, the highest value to our knowledge. The highly efficient mu...

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/4c57068be910ba51c651884fdb60b236ce45e20f

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In Electrical and Electronic Engineering

1. S. Aloni
2. P. J. Schuck
3. Gang Han
4. D. Milliron
5. Bruce E. Cohen
6. Shiwei Wu
7. D. Talapin
8. V. Altoé

In Materials Chemistry

1. Ling-Dong Sun
2. S. Aloni
3. P. J. Schuck
4. Gang Han
5. D. Milliron
6. Bruce E. Cohen
7. Shiwei Wu
8. D. Talapin

Citations in the corpus

• Nd(3+)-sensitized upconversion nanophosphors: efficient in vivo bioimaging probes with minimized heating effect. (2013, background): “tually lead to radiation of higher-energy photons located in the ultraviolet, visible, or NIR region.(11) 13 The relatively high pen-”
• Non-blinking and photostable upconverted luminescence from single lanthanide-doped nanocrystals (2009, background): “L nanocrystals have recently shown promise as imaging probes due to their ability to upconvert lowenergy near-infrared (NIR) radiation into higher-energy visible luminescence (1, 2).”