Chao Quan,Wentao Xu,Youfu Zhou,Decai Huang,Zhonghua Deng
A novel Eu-doped strontium magnesium aluminate phosphor (Sr 2 MgAl 22 O 36 :Eu 2+ , SMAO:Eu 2+ ) and its partial nitridation compound (Sr 2 MgAl 22 O 36-3/2x N x :Eu 2+ , SMAON:Eu 2+ ) have been synthesized successfully via a solid state reaction with Al 2 O 3 partly substituted by AlN. The specimen preserves the main phase of Sr 2 MgAl 22 O 36 as a certain amount of AlN incorporated. SMAON:Eu 2+ phosphors showed a broad blue emission band around 460 nm under ultraviolet-light excitation (340 nm), arising from the variation of emission energy between nitrogen doped and un-doped phosphor. The emission intensity of SMAON:Eu 2+ phosphors are increased up to 153% compared with that of SMAO:Eu 2+ . With the increase of Eu 2+ concentration, luminescent intensity of the phosphors increases continuously and reaches a maximum value at the concentration of 0.16 Eu 2+ . It is noteworthy that the PL intensity of SMAON:Eu 2+ increases to 129% at 200 °C in comparison with that of room temperature ( vs 58% for SMAO:Eu 2+ comparably), exhibiting excellent thermal stability.
Zongliang Xiao,Weizhen Liu,Gan Wan,Jianlei Liu,Lu Yu,Qian Zhang,Lei Han
The quest for advanced full-spectrum lighting technologies has driven the development of W-LEDs, while challenges remain in finding effective cyan emitters and ensuring outstanding thermostability. This study detailed the synthesis of the europium-doped CaO-Al 2 O 3 -SiO 2 -YF 3 glass-ceramics (GCs), which demonstrated efficient cyan emission when irradiated by 419 nm light, with a spectacular internal quantum efficiency of up to 83.24 %, and outstanding thermal stability of 90.2 %@100℃ compared to room temperature intensity. In practical applications, this GC was integrated with a 420 nm LED chip, (Sr, Ca)AlSiN 3 : Eu 2+ red and Y 3 Al 5 O 12 : Ce 3+ yellow phosphor in a prototype full-spectrum W-LED device. The device achieved an excellent color rendering index (94), appropriate chromaticity coordinates (0.3789, 0.3950), and a well-defined correlated color temperature (4163 K). This study not only advances the application of GCs within W-LED technology but also reveals their potential in driving energy-saving and eco-friendly lighting solutions, thus providing a path to achieve superior full-spectrum lighting technology.
Given the threat to human health posed by the abuse of tetracycline (TC), the development of a portable, on-site methods for highly sensitive and rapid TC detection is crucial. In this work, we initially synthesized europium-doped silicon nanoparticles (Si Eu NPs) through a facile one-pot microwave-assisted method. Due to its blue-red dual fluorescence emission (465 nm/621 nm), which was respectively attributed to the silicon nanoparticles and Eu 3+ , Si Eu NPs were designed as a ratiometric fluorescent sensor for TC detection. For the dual-signal reverse response mechanism: TC quenched the blue emission from silicon nanoparticles through inner filter effect (IFE), and enhanced the red emission through “antenna effect” (AE) between TC and Eu 3+ , the nanoprobe was able to detect TC within a range of 0.2–10 μM with a limit of detection (LOD) of 10.7 nM. Notably, the equilibrium detection time was only 1 min, achieving rapid TC detection. Furthermore, TC was also measured in real samples (tap water, milk and honey) with recoveries ranging from 95.7 % to 117.0 %. More importantly, a portable smartphone-assisted on-site detection platform was developed, enabling real-time qualitative identification and semi-quantitative analysis of TC based on fluorescence color changes. This work not only provided a novel doped silicon nanoparticles strategy, but also constructed a ratiometric sensing platform with dual-signal reverse response for intuitive and real-time TC detection.
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