Nanchang Hangkong University

About: Nanchang Hangkong University is a education organization based out in Nanchang, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 7004 authors who have published 5270 publications receiving 62162 citations. The organization is also known as: Nanchang Aviation University.

Carbon quantum dot-sensitized and tunable luminescence of Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors with abundant colors via a sol–gel process

Abstract: Herein, we demonstrate the characteristic blue luminescence of carbon quantum dots embedded in the Ca19Mg2(PO4)14 nanocrystalline phosphor and carbon quantum dot-sensitized luminescence of Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors with abundant colors. A series of Ca19Mg2(PO4)14 and Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors was prepared via a Pechini-type sol–gel process. With UV light excitation, the prepared Ca19Mg2(PO4)14 nanocrystalline phosphors exhibited novel blue luminescence with a broad band from 374 to 600 nm peaking at 439 nm, which is ascribed to the embedded carbon quantum dots. Also, the obtained Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors not only exhibited the characteristic broad band emission of the carbon quantum dots, but also the characteristic narrow line emission of the doped rare earth ions, i.e., the characteristic red emission of Eu3+ (5DJ → 7FJ′ transitions, J, J′ = 0, 1, 2, 3) and the characteristic green emission of Tb3+ (5D4 → 7FJ transitions, J = 3, 4, 5, 6). Thus, energy transfer occurred from the carbon quantum dots to the doped Eu3+ and/or Tb3+ ions in the Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors. The luminescence color of the Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors could be tuned from blue to blue-green, green, white, pink, orange, red, etc. by changing the doping rare-earth ion concentration, species, and relative ratio of Eu3+ to Tb3+ ions. Furthermore, single-phase white-light luminescence was demonstrated in the Eu3+/Tb3+ codoped Ca19Mg2(PO4)14:Ln3+ nanocrystalline phosphors. Finally, the luminescence properties and mechanisms of the Ca19Mg2(PO4)14 and Ca19Mg2(PO4)14:Ln3+ (Ln3+ = Eu3+ and/or Tb3+) nanocrystalline phosphors were discussed.

Reversible wettability between superhydrophobicity and superhydrophilicity of Ag surface

Abstract: We present a facile one-step method to fabricate superhydrophobic Ag surface by electrodeposition without using any low surface energy reagent. The water contact angle of the prepared surface is 167.1° and the sliding angle is only 0.5° after heat treatment. It is demonstrated by the field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses that the dendrites of rough micro-nanostructure combined with the spontaneously adsorbed hydrocarbon make the surface exhibit superhydrophobicity. However, the superhydrophobic Ag surface becomes superhydrophilic when the surface is irradiated by UV light for several hours. It recovers superhydrophobicity after further heat treatment and can successfully implement the reversible wettability transition between superhydrophobicity and superhydrophilicity for several cycles.