Near infrared scintillation based on core/dual-shell fluoride nanocrystals

Up to now, most of the emisison wavelengths of the reported scintillators are located in ultra-violet (UV) or visible range. Herein, to further expand the X-ray excited fluorescence emission spectrum, an active core/dual-shell nanocrystal (NC) architecture is used to actualize near-infrared scintillation. Specifically, under the X-ray excitation, near-infrared emission from Nd³⁺ ions at ~1064 and Yb³⁺ ions at 980 nm are achieved. The active outer shell with the incorporation of Ce³⁺ sensitizer ions benefited the enhancement of X-ray excited NIR fluorescence emission intensity owing to the enhanced energy transfer efficiency from Ce³⁺ to Nd³⁺ or Yb³⁺ emission centers. The present studied near-infrared NC scintillator have deeper penetration depth than that of UV and visible, which might be useful for X-ray imaging with improved sensitivity.