Shiping Zhan

Controllable plasmonic sensing based on Fano resonance in a cavity coupled defective MDM waveguide

We report a simple plasmonic sensor based on the Fano resonance in a cavity coupled defective metal–dielectric–metal (MDM) waveguide. A theoretical expression for characterizing the sensing property is first derived. We show the formation and evolution of Fano resonance in this cavity coupled waveguide system. Based on the derived theoretical expression and the numerical analysis, we find that the cavity length plays an important role for tuning and optimizing the sensing performance. A highest figure of merit (FOM) of ~6100 is obtained. This plasmonic sensor possesses the advantages of easy fabrication and compactness. The findings and the proposed structure may provide some guidance for the fundamental research of the integrated plasmonic nanosensor applications and designs.

Enhancement of red to orange emission ratio of YPO4：Eu3＋,Ce3＋ and its dependence on Ce3＋ concentration

Abstract Eu 3+ and Ce 3+ co-doped YPO 4 microspheres were synthesized by hydrothermal method without template. The emission spectra showed that the red emission centered at 618 nm could be readily increased relatively to the orange emission centered at 590 nm by controlling the doping concentration of Ce 3+ ion. The investigation based on excitation spectra and decay curves demonstrated that the doped Ce 3+ ions took two efficient energy transfers to Eu 3+ ions and affected the lifetime of the emission states of Eu 3+ ions so that the emission spectra of Eu 3+ ion were accordingly tuned with the Ce 3+ content increasing. This controllable red ( 5 D 0 → 7 F 2 ) to orange ( 5 D 0 → 7 F 1 ) emission ratio of YPO 4 :Eu 3+ ,Ce 3+ made it very promising for encoded anti-fake labels and bio-labels.

Core/shell upconversion nanoparticles with intense fluorescence for detecting doxorubicin in vivo

Doxorubicin (Dox) is a chemotherapy medication used to treat cancer. Herein, we report a rapid and efficient method for detecting Dox in vivo based on a NaGdF4:Yb3+,Er3+@NaYF4 core/shell upconversion nanoparticles (UCNPs) probe. We found that the intensity ratio of green to red emission (IGVRE) bands of the core/shell NaGdF4:Yb3+,Er3+@NaYF4 nanoparticles was sensitive to Dox in blood samples, and drops as the concentration of Dox increases. In addition, the proposed UCNPs probe possessed the advantage that no nanoparticles leaked into the living body, thus overcoming the intrinsic defect (difficulty in removing UCNPs from blood vessels) of the fluorescence resonance energy transfer (FRET) approach. This proposed UCNP probe design and results may provide some guidance for the real-time and efficient detection of Dox, and can be helpful in biomedical applications.