Wenpeng Xia,Jie Xiong,Li Jiang,Rui Ye,Yini Mao,Shanshan Hu,Jun Yang
KYb3F10:Ln3+ (Ln = Er, Ho, Tb, Gd, Eu, Sm, Ce and La) micro/nanocrystals with abundant morphologies were synthesized via a one-step hydrothermal route without employing any surfactants. Furthermore, the homogeneous and well-defined KYb3F10 crystals with truncated tetragonal bipyramidal, nanoparticle, nanospherical, microtubular and rugby ball shapes were achieved by manipulating the different environments of crystal growth, such as increasing the concentration of F−, adjusting the pH, using different fluorine sources and adding trisodium citrate. XRD, SEM, EDS and PL as well as lifetime analysis were used to characterize the products. The obtained KYb3F10:Ln3+ products showed bright emission colors red (Eu3+) and green (Tb3+), respectively. It has been found that larger crystal shapes/sizes can greatly enhance their luminescence properties and lifetimes due to their high crystallinity and few defects on the crystal surface. The as-synthesized KYb3F10:Eu3+/Tb3+ products might be potentially applied in multicolor lighting and displays.
Wenpeng Xia,Yufeng Zhang,Jie Xiong,Shanshan Hu,Jie Yu,Yanfei Zhang,Yuxin Wan,Jun Yang
A series of BaMgF4:Ce3+/Tb3+/Eu3+ phosphors were successfully prepared via a facile hydrothermal process. X-ray diffraction (XRD), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM), n-UV–UV-vis photoluminescence (PL) and fluorescence decays were employed to investigate the structure, composition, morphology, luminescence properties and energy transfer processes. The as-prepared BaMgF4 phosphors exhibit a rod-like morphology and the size of the product can be effectively regulated by changing the amount of NH4F in the original solution. Under n-UV–UV light excitation, the Ce3+, Tb3+ and Eu3+ singly-doped BaMgF4 phosphors all show good characteristic luminescence; the Ce3+–Tb3+ and Tb3+–Eu3+ co-doped BaMgF4 phosphors both show tunable emission colors from blue (green) to green (orange-red) because of the energy transfer of Ce3+ → Tb3+ and Tb3+ → Eu3+, respectively. Moreover, the efficient energy transfer from Ce3+ (Tb3+) to Tb3+ (Eu3+) ions in the co-doped samples was confirmed by investigating the excitation/emission spectra and decay lifetimes. The results indicate that the phosphors may be potentially used as single-component multi-color phosphors for white light-emitting diodes.
Recent advances in inorganic negative thermal expansion (NTE) materials have highlighted their potential for multifunctional applications, yet challenges remain in optimizing their luminescent properties for practical use. Based on Y 2 W 3 O 12 :Tb 3+ /Eu 3+ NTE ceramics, we present a thermally regulated optical encoding and encryption approach. Under 254 nm UV excitation, the distinctive high-temperature thermal enhancement effect of red emission and the thermal quenching phenomenon of green emission were discovered in these ceramics, enabling an effective temperature-controlled color change phenomenon. Optical information encoding and readout were realized through the synergistic modulation effect of UV light and heat, and the encryption and decoding process of multivariate codes and alphabets at high temperatures was accomplished. The encoding was accomplished by modulating the Tb 3+ /Eu 3+ doping concentration ratio and regulating the luminescent color of the ceramics over a wide range. Furthermore, the ceramic demonstrates a wide temperature range of 363‒603 K for temperature sensing effect. This offers a research idea for achieving multifunctional ceramics of coding and temperature sensing.
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