Vietnam Journal of Science, Technology and Engineering's Vol. 59 Number 3 (2017) is now available to all readers. 

The cover illustrates the schematic illustration of the synthesis of α-NaYF4:Yb3+/Er3+/PVP/MOF multilayer nanocrystals. The precursor PVP-capped α-NaYF4:Yb3+/Er3+ nanospheres were used as the templates for preparing the α- NaYF4:Yb3+/Er3+/PVP/MOFs multilayer nanocrystals with a self-template method. The UCL spectra studies demonstrated that the integrated intensity ratio of green to red emissions increased from 0.13 to 1.01 when adding the layers of PVP, PVP/ZIF-8 or PVP/MIL-100 on the surface of the α- NaYF4:Yb3+/Er3+ nanoparticles.


Please see the article "Synthesis, characterization and up-conversion luminescence properties of α-NaYF4:Yb3+/Er3+/PVP/MOF multilayer nanocrystals" in pages 79-84 of this issue for more details at