REACTIVE & FUNCTIONAL POLYMERS
·
2023
·
IF 5.1
Siyuan Yu,Yanting Zhou,Chunyue Zhao,Han Liu,Zhiyun Xue,Jinfeng Xing
Dispersion photopolymerization was carried out under green LED irradiation to rapidly prepare monodisperse poly(methyl methacrylate) (PMMA) microspheres with small size by using a high-efficient three-component initiating system. The polymerization parameters including exposure time, MMA content, stirring speed, water ratio and PVP content were systematically investigated. Crucial parameters were further optimized by response surface method (RSM), and a corresponding polymerization mechanism was proposed. Finally, PMMA microspheres with 375.6 nm of size and 0.101 of PDI were prepared. This study provides a facile method for the rapid fabrication of PMMA microspheres.
研究领域:
材料科学
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高分子化学
·
纳米技术
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 12
·6901-6912
·
IF 3.502
Qiyun Wu,Chenxing Liao,Jinquan Pan,Xinyu Ye,Weixiong You,Libin Xia
It has been one of the hot issues to prepare the red-emitting Mn 4+ -doped fluoride phosphors with highly efficient and waterproofness for warm white-light-emitting diodes (WLEDs) by the green and environmentally friendly method. Herein, we design a novel green molten salt route to synthesize K 2 SiF 6 :Mn 4+ red powder using molten NH 4 HF 2 salt instead of HF liquor as the reaction medium. The results show that KMnO 4 and MnF 2 could produce Mn 4+ in NH 4 HF 2 molten salt through a reduction reaction, and the resulting Mn 4+ -doped K 2 SiF 6 exhibited a bright red emission peaked at 632 nm under blue light excitation. The luminescence intensity of the as-obtained product after immersing into water for 24 hours maintain nearly 100% of that before soaking and emission peak shape remains unchanged. The thermal stability of the sample was evaluated by temperature-dependent luminescence spectral intensity during heating and cooling. Furthermore, a warm white-light-emitting diodes (WLEDs) with an excellent color rendering index (Ra = 87.1), lower correlated color temperature (CCT = 3536K), and high luminous efficacy (116.99 lm·W −1 ) was fabricated based on blue chip and K 2 SiF 6 :Mn 4+ and commercial yellow phosphor (Y 3 Al 5 O 12 :Ce 3+ ).
研究领域:
材料科学
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光学工程
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DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 18
·2563
·
IF 4.7
Ningbo Yi,Xue Guan,Xiaoting Chen,Luojia Xie,Nan Zhang,Jinfeng Liao,Long Su,Yancheng Wu,Feng Gan,Guoqiang Chang,Liyong Tian,Yangfan Zhang
Perovskite is an advanced optoelectronic semiconductor material that has garnered significant attention in recent years. However, its drawback lies in its environmental instability, limiting its practical applications. To tackle this issue, this research delved into the idea of creating a space-confined structure and used electrospinning to produce a film of perovskite nanocomposite fibers. By effectively encapsulating perovskite nanocrystals into a polymer matrix, the perovskite could be shielded from water and oxygen in the environment, thereby reducing the likelihood of perovskite decomposition and enhancing the stability of its structure and properties. This study examined the influence of material composition and the spinning process on the nanofiber structure to create good spatial confinement. This strategy resulted in a high photoluminescence quantum yield of over 80% and a long-term environmental stability of as long as 1000 h over 90% of the original PLQY. By harnessing the flexibility of the composite fibers, this study demonstrated the potential applications and performance of this nanocomposite film in flexible quantum fluorescence conversion for LED applications.
研究领域:
材料科学
·
光学工程
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产品关联
DOI
PubMed
高影响因子
TALANTA
·
2019
·
IF 4.916
Wanchao Chen,Yinran Xiong,Wenming Wang,Ting Wu,Long Li,Qidi Kang,Yiping Du
A simple and sensitive fluorescence method has been developed for the determination of amiloride (AMI) in pharmaceutical tablet and human serum with a portable, cost-effective, and easy-to-operate fluorescence system. The fluorescence system was assembled with some optical and electronic devices mainly including a 370 nm light-emitting-diode (LED) as light source, a fiber spectrometer and a Raspberry Pi computer. With the system, AMI produced a strong fluorescence emission at 413 nm, and the emitted intensity can maintain good stability with in a wide pH range from 2 to 8. The proposed method was successfully applied to the determinations of AMI in pharmaceutical tablet and human serum. Their detection limits were 1.67 ng mL −1 and 1.43 ng mL −1 respectively, and the recovery was in the range of 94.06–114.0%. Those obtained results proved that the proposed methods combined with the developed fluorescence system could be employed for the routine analysis of amiloride in pharmaceutical tablet and human serum, especially for the fast analysis of them under field conditions.
研究领域:
分析化学
·
药物分析
·
生物医学工程
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产品关联
DOI
PubMed
高影响因子
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
·
2024
·
IF 1.6
Zhang Xiaoning,Han Qingxin,Hu Xiaoqing,Zhang Lei,Kang Xiaoya,Li Ming,Gao Qiang,Liu Fengyi,Sun Jingyao,Zhu Jingxian,Zhuang Jian
This article proposes a new process for fabricating a polymer microneedles (MNs) patch integrated with an LED light source (LED-HEMA/MN, LH-MN) using ultraviolet (UV) curing technology. Hydroxyethyl methacrylate (HEMA) is used as the base material, with a focus on studying the active integrated fabrication process of the MNs patch. The study also investigates the morphology, size, mechanical properties, ex vivo skin penetration performance, operating temperature, and performance optimization of the LH-MN. The experimental results show that the LH-MN fabricated using the optimal process has a good appearance, high molding rate, short production cycle, and excellent mechanical properties. It can effectively penetrate the skin without the risk of thermal injury. In addition, the MNs patch (LED-HEMA/HEA-MN, LHH-MN) prepared by optimizing and modifying with hydroxyethyl acrylate (HEA) possesses good flexibility and mechanical properties. It can adapt to different shapes and locations of the affected area, greatly enhancing the practicality of the MNs.
研究领域:
生物医学工程
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材料科学
·
医学
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产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2025
·
IF 3.6
Wei Wan,Man Li,Jingyan Jiang,Yifei Zhao,Yayun Zhou
Broadband near-infrared (NIR) light sources have emerged as crucial components in a wide array of technological applications, spanning from advanced imaging systems to night vision devices and healthcare therapy. The advent of light-emitting diodes (LEDs) has unlocked new opportunities for broadband NIR phosphor-converted LEDs (NIR pc-LEDs), characterized by improved efficiency, compact form factors, and low operating temperatures. However, high-performance NIR phosphors for high-power LEDs remain scarce. In this work, Cr 3+ -doped fluorides BaSiF 6 : x Cr 3+ (where x ranges from 2.5% to 15%) have been designed and synthesized, which offer high quantum efficiency and thermal stability to maintain ∼80% intensity at 450 K. Theoretical simulations demonstrate that BaSiF 6 , with a sufficiently large electronic bandgap of 7.8 eV, possesses the full potential to host NIR luminescent activators. Furthermore, molecular dynamics (MD) simulations validate its good thermal stability, enduring high temperatures exceeding 600 K annealing. The fabricated NIR pc-LED device using BaSiF 6 :Cr 3+ demonstrates high light output power and photoelectric efficiency under multiple driven currents, making it suitable for a wide range of applications as NIR light source. Capitalizing on the above merits, a prototype NIR transmission detector is demonstrated for potential applications in material inspection, medical diagnostics, and security systems. This research expands the repertoire of high-performance NIR phosphors for multifunctional use.
研究领域:
材料科学
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光学工程
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电子器件
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产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 2
·326-332
·
IF 1.248
Sun Yang,Liu Weiqu,Wang Zhengfang,Tan Jianquan
An oligo-fluoropolymer(PFM) with functional cycloaliphatic epoxy and fluorinated groups was obtained via free radical polymerization and applied to the modification of cycloaliphatic epoxy resins(CE). The chemical structure of PFM was characterized by Fourier transform infrared(FTIR) spectroscopy, gel permeation chromatogra-phy(GPC) and nuclear magnetic resonance(NMR) spectroscopy, and the effects of different PFM concentra-tions(0.5%—6%, mass fraction) on the thermal resistance, mechanical properties, surface dewettability, light trans-mission, refractive index and various cured polymer properties were studied in detail. The DSC and TGA results demonstrate that the modified epoxy resins possess a higher thermal resistance than the neat epoxy resin. The im-provements in the surface dewettability and water resistance are caused by the high crosslinking density and the enrichment of the oligo-fluorinated random copolymers dispersed in the matrix. The fracture surface morphologies of the thermosets were investigated by scanning electron microscopy(SEM) and transmission electron microsco-py(TEM). It was observed that the optical transmittance of the composites was maintained even though microphase separation occurred during the curing process. With respect to the corresponding properties of the neat epoxy resins, the 2 phr(parts per hundreds of resin) PFM thermoset exhibited relatively better comprehensive properties, making the cured material a good candidate for light-emitting diode(LED) encapsulation.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2020
·Vol. 20
·期 3
·1936-1940
·
IF 1.134
Chen Guochang,Zhu Mingming,Wang Lichun,Wu Xingrong
In this investigation, AgBr/g-C3N4 composite as an effective LED-irradiation photocatalyst was synthesized via a one-pot method. In this composite, the colloidal spheres of AgBr were uniformly dispersed on the g-C3N4 nanosheets, which were
characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffused reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The introduction of g-C3N4
nanosheets improved the stability and optimized the spatial charge carrier transfer compared to pristine AgBr, hence exhibited excellent activities toward the degradation of methyl orange (MO) as evidenced by the discoloration rate of MO by 94.8% after 120 min of irradiation. Also, the mechanism
based on the band structures and microstructures of the catalysts was then proposed.
研究领域:
材料科学
·
环境科学
·
光化学
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DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Wenzhi Su,Shoujun Ding,Chuancheng Zhang,Miaomiao Wang,Hao Ren,Haitang Hu,Yong Zou,Wenpeng Liu
A series of trivalent samarium ions (Sm 3+ ) doped double perovskite Sr 2 LuNbO 6 ( x at% Sm 3+ :Sr 2 LuNbO 6 , x = 0.5–15) phosphors have been prepared via high-temperature solid-state method. The structural characterization of these phosphors was conducted employing X-ray diffraction (XRD), XRD Rietveld refinement , scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. Density functional theory calculations utilizing the Vienna ab initio simulation package (VASP) were employed to unveil the electronic structures, encompassing the band structure and density of states (DOS). Photoluminescence (PL) spectroscopy was employed to scrutinize the luminescent properties, while the thermal stability of the PL spectra was also evaluated. The most prominent emission peak, exhibiting an orange-reddish hue, was observed at 601 nm upon excitation at 406 nm. The quenching mechanism of Sm 3+ ions within the Sr 2 LuNbO 6 host lattice was identified as a dipole-dipole interaction, with the quenching concentration of 3 at%. Moreover, the phosphors demonstrated excellent thermal stability, with an activation energy ( E a ) value of 0.126 eV. These findings collectively underscore the promising potential of Sm 3+ :Sr 2 LuNbO 6 orange-reddish phosphors for applications in white light-emitting diodes (w-LEDs).
研究领域:
材料科学
·
光学
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产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 26
·7906-7914
·
IF 6.641
Jun Gao,Haomiao Zhu,Renfu Li,Decai Huang,Benlong Luo,Wenwu You,Jianxi Ke,Xiaodong Yi,Xiaoying Shang,Jin Xu,Zhonghua Deng,Li Xu,Wang Guo,Xueyuan Chen
Mn4+-Doped fluoride red phosphors with excellent moisture-resistant properties and high emission efficiency are highly desired for warm white LEDs and wide gamut liquid crystal displays. Herein, we synthesized a K2NaGaF6:Mn4+ red phosphor through a co-precipitation method at room temperature. The crystallographic structure of the K2NaGaF6 host was determined based on single crystal X-ray diffraction data for the first time. A high internal photoluminescence quantum yield of 82% was achieved for the 1.81 at% K2NaGaF6:Mn4+ sample. Through low-temperature and high-resolution spectroscopic analysis, we revealed that Mn4+ ions occupy at least four distinct sites in the K2NaGaF6 crystal. One of them is assigned to the Ga3+ site with high Oh site symmetry and the other three ones possess low non-centrosymmetric site symmetries. By employing 5.51 at% K2NaGaF6:Mn4+ as a red phosphor, a warm white LED with a low correlated color temperature of 3760 K, a high color rendering index of 92 (Ra) and a luminous efficacy of 156 lm W−1 was packaged. Aging tests at 85 °C and 85% relative humidity on the fabricated LEDs demonstrated that K2NaGaF6:Mn4+ has a better moisture-resistant property than that of the popular K2SiF6:Mn4+ phosphor. These findings demonstrate the great potential of K2NaGaF6:Mn4+ as a highly efficient red phosphor with excellent moisture-resistant performance.
研究领域:
材料科学
·
光学工程
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产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Konglan Chen,Shiyu Jia,Xueliang Zhang,Zifan Shao,Yayun Zhou,Ting Fan,Ting Yu,Tingting Deng
Development of highly thermally stable broadband near-infrared (NIR) luminescence materials is crucial for advancing the prolonged stable application of smart NIR light sources. In this study, a zero-thermal-quenching and reversible temperature-dependent broadband NIR-emitting Cs2NaAl3F12:Cr3+ phosphor is demonstrated, benefiting from its stable polyhedron-cluster-building rigid structure. The excellent thermal stability of Cs2NaAl3F12:Cr3+ is rooted in its stable [Al6Na4F45] cluster building unit, which provides a rigid structure with a weak electron–phonon coupling effect and a wide band gap with a huge thermal activated barrier. Such characteristics are well revealed by multiple studies on crystal structure, electronic structure, Huang–Rhys factor S, configuration coordinate model, and Debye temperature. The incorporation of Li or K instead of Na weakens the luminescence thermal stability, directly proving the importance of the stable [Al6Na4F45] cluster for stable Cr3+ substitution and rigid structure construction. Furthermore, Cs2NaAl3F12:Cr3+ presents much superior thermal stability compared to traditional rigid garnet-type fluorides Na3X2Li3F12:Cr3+ (X = Al, Ga, In). A high-power NIR LED is presented, utilizing the high quantum efficiency (∼71%) and extremely thermally stable broadband NIR emission around 750 nm of Cs2NaAl3F12:Cr3+. It realizes clear vein and cartilage imaging in the human hand, demonstrating its potential in medical diagnosis applications. This result provides important insights for designing new-type rigid crystal structures using stable polyhedron clusters as basic units, advancing the development of highly thermally stable NIR-emitting phosphors.
研究领域:
材料科学
·
光学工程
·
生物医学工程
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产品关联
DOI
PubMed
高影响因子
Chemical Engineering and Processing-Process Intensification
·
2023
·
IF 4.3
Mohsin Pasha,Minjing Shang,Yuhan Wang,Saier Liu,Xiao Xue,Yuanhai Su
α-aminonitriles (AN) are valuable intermediates and building blocks with versatile applications in organic synthesis. Herein, we presented a visible LED-based photomicroreactor for the AN synthesis with three amine substrates, i.e., dibenzylamine (DBA), pyrrolidine (PYR) and piperidiene (PIP), using meso‑tetraphenylporphyrin (m-TPP) and trimethylsilyl cyanide (TMSCN) as photosensitizer and cyanide source, respectively. The results showed that the photooxidative cyanation is a chromoselective and wavelength-selective photochemical transformation with the optimum AN yield and selectivity of 98.2% and 99.5% at a residence time of 2.69 min. Computational studies indicated that a high energy gap between the molecular orbitals of PYP, PIR and their imine intermediates potentially led to their higher reactivity than DBA and formation of by-products with larger molecular weight. Kinetic investigation showed that the apparent rate constants of the DBA photooxidative cyantaion were improved by rising the LED input power, and the applied photosensitizer exhibited high photostability. The overall photonic efficiency of this photomicroreactor was found to be 54.3% within the wavelength range of 400–440 nm, which is higher than previously used photoreactors. Finally, linear correlations were developed between the input power of LED and apparent rate constants of DBA photooxidative cyanation, which would be beneficial for the design, optimization, and scale-up of this photochemical process.
研究领域:
有机合成
·
光化学工程
·
动力学研究
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）