A simple and effective strategy has been carried out to design a ratiometric temperature sensor in this work. Carbon dots (CDs), which benefit from surface methoxysilyl groups after using an organosilane as a coordinating solvent, are highly reactive intermediates responsible for bonding with silanols and hydroxyl groups from the silica-coated SrAl2O4:Eu,Dy phosphor (SAO). Hence, a CD-grafted SrAl2O4:Eu,Dy phosphor (CD–SAO) could be realized using a facile one-step sol–gel method. The as-prepared CD–SAO shows the characteristic fluorescence emissions of CDs (blue) and SAO (green) at a single excitation wavelength. The temperature dependence of the fluorescence intensity ratios for the two emission bands was studied, and it turned out that the composite has a wide linear temperature sensing range, which matches well with physiologically relevant temperatures. This rather simple approach for creating dual emission enables a completely new strategy for the application of these composites in temperature sensing.
Long afterglow nanoparticles, a type of luminescence material, may gradually release stored light energy even after the excitation light has stopped. The modification of polymer membranes by introducing long afterglow nanoparticles via an inorganic particle mixtures, broaden their uses in biomedicine field. In this study, a new membrane modification approach was employed to reduce the loss of physical–mechanical performance, caused by inherent strontium aluminate inorganic particle aggregation. Moreover, eugenol, a cross-linking agent, was used to interact with acrylate monomers to form locally cross-linked compounds using an ex situ approach that improves strontium aluminate particle dispersion. Furthermore, the soap-free emulsion polymerization method used, regulates the degree of cross-linking in the membrane, hence addressing nanoparticles agglomeration. Results showed that the cross-linked structure of the membrane produced improves the heat stability and the hydrophobicity of the material produced while also increasing the nanoparticles dispersion as evidenced by the XRD study. Nevertheless, membranes with cross-linking agents outperformed in water droplet trials by not breaking or whitening the droplets. Furthermore, the generated membranes exhibit high antibacterial activity, making them attractive for paramedical applications such as protective membranes applied on the top of the skin or on the surface areas of sensors, microneedles and metal fasteners.
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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