Novel rod-Y2O3:Eu3+@0.01YVO4:Eu3+ with open core/shell nanostructure and “off-and-on” fluorescent performance

Abstract

Herein, we develop a novel sensitive fluorescent probe with an open core/shell nanostructure (OCSNS), rod-Y₂O₃:Eu³⁺@0.01YVO₄:Eu³⁺, in which a YVO₄:Eu³⁺ shell with a thickness of less than 5 nm partially covers an anisotropic core of rod-Y₂O₃:Eu³⁺. The photo-luminescent performance of the OCSNS is sensitive to trace ions or molecules. High-resolution transmission electron microscopy (HR-TEM) observations clearly confirm that this OCSNS has an open quantum shell of YVO₄:Eu³⁺. In contrast to closed core Y₂O₃:Eu³⁺@shell YVO₄:Eu³⁺, which has only one excitation band peaking at ∼308 nm, this novel nanostructure has a wide-wavelength excitation response that can be decomposed into two components centered at ∼254 and ∼280 nm, which stem from open core rod-Y₂O₃:Eu³⁺ and the YVO₄:Eu³⁺ quantum shell, respectively. As expected, this OCSNS shows “off-and-on” fluorescence properties due to the strong surface effect of this open quantum shell: it is “off” when detecting trace Cu(II) ions and “on” when detecting trace amino acids, at levels as low as 10⁻⁸ mol L⁻¹. Hence, rod-Y₂O₃:Eu³⁺@0.01YVO₄:Eu³⁺ could be an excellent candidate for sensitive fluorescent probes, showing similar performance to most quantum dots for the detection of ions and molecules. Moreover, it is both easier to fabricate and more stable than quantum dots.