A series of CaLa 1- x LiTeO 6 : x Dy 3+ phosphors were synthesized via a conventional solid-state reaction method, and the effects of different Dy 3+ doping concentrations on the luminescence properties of the phosphors were studied. The excitation spectrum indicated that these synthesized phosphors had strong absorption bands in near-ultraviolet (n-UV) region in the range from 300 to 500 nm. There were two sharp emission peaks in the visible region, which were located at 483 nm, 574 nm, corresponding to transitions of 4 F 9/2 → 6 H 15/2 (magnetic dipole transition) and 4 F 9/2 → 6 H 13/2 (electric dipole transition), respectively. The phosphor CaLa 0.95 LiTeO 6 :0.05Dy 3+ shows superior thermal stability. When the temperature rises to 425 K, the luminous intensity remains at 79% compared with the initial intensity of 300 K. These results demonstrate that the CaLa 1- x LiTeO 6 : x Dy 3+ phosphors have great potential as a single-phase luminescence material for near-ultraviolet (n-UV) excitation.
Longfei Zhang,Ying Wang,Limin Peng,Zhilin Chen,Shaoyi Lyu,Siqun Wang
Long-term relief of indoor volatile pollution has become a competitive issue worldwide in both visible and dark environments. A novel self-luminous wood coating with carbon dots (CDs)/titanium dioxide (TiO2) nanomaterial coated SrAl2O4: Eu2+, Dy3+(CDs/TiO2@SAO) composite was prepared for the long-term degradation of formaldehyde through a simple sol-gel method. The microstructure, chemical composition, ultraviolet-visible (UV-vis) spectra, and long-lasting fluorescence of the CDs/TiO2@SAO photocatalyst were analyzed to illustrate the mechanism for degrading formaldehyde. The obtained CDs with a particle size of ~2–7 nm have a good graphite structure and presented good absorption in visible light. In addition, owing to the synergistic effect of the CDs/TiO2nanomaterial coating layer and the long-afterglow luminescence of the SAO phosphor, the CDs/TiO2@SAO composite can absorb a part of the visible light for photocatalytic degradation and store luminous energy efficiently at daytime so as to give out visible luminescence continuously for a few hours in the darkness. Furthermore, the functional wood coatings with CDs/TiO2@SAO composite presented continuous and efficient photocatalytic activity in the presence and absence of light exposure. The current research could provide a new strategy for designing an efficient photocatalyst for degrading formaldehyde pollution in the daytime with a visible light supply and in an indoor dark environment without an external light source.Keywords:carbon dots;core-shell microspheres;SrAl2O4: Eu2+, Dy3+phosphor;titanium dioxide;surface modification;photocatalytic degradation
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