Improve the Optical Properties of Yb/Er: NaGdF$_{\mathrm{4}}$ Nanocrystals

ORAL

Abstract

Ln$^{\mathrm{3+}}$-doped NaGdF$_{\mathrm{4}}$ UC nanocrystals (NCs) have been widely investigated as bio-imaging and magnetic resonance imaging agents recently. We provide a facile and straightforward strategy to modify the size and uniformity of NaGdF$_{\mathrm{4}}$ NCs \textit{via} alkaline-earth doping for the first time. By increasing of alkaline-earth doping content, the size of NaGdF$_{\mathrm{4}}$ NCs increases gradually, while the size-uniformity is still retained. Importantly, adopting the Ca$^{\mathrm{2+}}$-doped Yb/Er: NaGdF$_{\mathrm{4}}$ NCs as cores, the complete Ca/Yb/Er: NaGdF$_{\mathrm{4}}$@NaYF$_{\mathrm{4}}$ core-shell particles with excellent size-uniformity can be easily achieved. As a result, UC emission intensity of the complete core-shell NCs increases for about 30 times in comparison with that of the cores, owing to the effective surfaces passivation of the Ca$^{\mathrm{2+}}$-doped cores and therefore protection of Er$^{\mathrm{3+}}$ in the cores from the non-radiative decay. To further enhance the upconversion efficiency, we are combining the core-shell NCs and gold NCs into nano-structured optical fiber that provide an unique and novel platform for studying NC UC effects.

–

Authors

  • Lei Lei

    China Jiliang University

  • Arthur Sweeney

    Lee College, Baytown, TX, Lamar University, University of Texas at Arlington, Angelo State University, Rice University, Texas State University, College of William and Mary and National Institute of Aerospace, Nanyang Technological University, China Jiliang University, Baylor University, Louisiana State University, College of William and Mary, University of Oklahoma, University of Texas at Dallas, Univ of Texas, Austin, Texas State Univ-San Marcos, University of Cambridge, University of Texas at Austin, Indiana University - Bloomington, Lamar Univiversity, University of Cincinnati, Deartment of Physics, University of Texas, Arlington, Texas A&M University, College Station, University of Texas - Dallas, University of Dallas