In situ growth of lanthanides-doped nanoparticles inside zeolites with enhanced upconversion emission for gallic acid detection.

The combination of upconversion nanoparticles (UCNPs) with porous zeolites could enable the development of multifunctional composites and extend their optical applications in sensing, detection and biomedical monitoring. Herein, a series of high luminescent UCNPs@Zeolites nano-micro composites were constructed via the in situ growth strategy, by taking the low phonon-energy fluoride nanoparticles of NaLnF ₄ (Ln = Y, Gd) as doping hosts for Er ³⁺ /Yb ³⁺ , desilicated FAUY and ZSM-5 as the target zeolites. Benefiting from the formation of tightly combined interfaces between the UCNPs and the target zeolites that effectively passive the surface defects of UCNPs, three orders of magnitude of improved upconversion emission in maximum was obtained under 980 nm excitation through afterward heat treatment at 400 ℃. Moreover, the pre-exchange of Yb ³⁺ into target zeolites before the in situ growth of UCNPs is another feasible approach to drastically improve the upconversion emission intensity of the UCNPs@Zeolites nano-micro composites. By taking NaGdF ₄ :Yb,Er@DSZSM-5/HT as an example probe, the detection of GA was demonstrated and the detection ability of which is super than that of the corresponding bare NaGdF ₄ :Yb,Er UCNPs. This research provided a universal approach to construct the UCNPs@Zeolites nano-micro composites with varied upconversion emission colors simply by choosing activator ions, which therefore indicates wide potential applications.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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