CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Wanyin Ge,Honglei Yin,Chenhui Lu,Xinmeng Zhang,Panpan Song,Mingsheng Ma,Zhifu Liu,Ye Tian
The core issue of light emitting diodes (LEDs) for actual application is the thermal stability of phosphors. Silicon nitride (Si 3 N 4 ) is generally recognized as especially important structural material due to its excellent mechanical properties at extreme high temperature. In this work, Si 3 N 4 : Eu was demonstrated to be an excellent luminescence functional material for LEDs. The discarded corner-waster silicon raw material was utilized to act as the precursor. The Si 3 N 4 :Eu phosphor was synthesized by a facile nitriding process at elevated temperature. The pure α-Si 3 N 4 :Eu nanorods were successfully obtained by adjusting the doping concentration of Eu. It is coexistence with mixed-valence (divalent and trivalent) for Eu in α-Si 3 N 4 according to X-ray photoelectron spectroscopy. The synthesized α-Si 3 N 4 :Eu nanorods showed bright yellow under the excitation of 365 nm (UV) and white luminescence by 460 nm chip (Blue). The Si 3 N 4 :Eu nanorods possess excellent thermal stability, maintains nearly 70% of the origin intensity even at temperatures over 300 °C. The Si 3 N 4 :Eu nanorods demonstrated comparable performance to commercial YAG:Ce 3+ (YAG). Moreover, the long-term thermal stability of Si 3 N 4 :Eu nanorods is superior to commercial YAG, revealing the enhanced service performance. This work not only presents a facile Si 3 N 4 :Eu nanorods green synthesis route from waste utilization, but also offers an enhanced service performance for the high temperature LEDs application.
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高影响因子
Micromachines
·
2022
·Vol. 13
·期 11
·1949
·
IF 3.523
Chao Chang,Yaoguang Yang,Lilin Pei,Zhaoyang Han,Xiu Xiao,Yulong Ji
With the rapid development of electronic technologies towards high integration, high power and miniaturization, thermal management has become an increasingly important issue to guarantee the reliability and service life of electronic devices. The oscillating heat pipe (OHP), which was governed by thermally excited oscillating motion, was considered as a promising technology to dissipate high-density heat and had excellent application prospects in many important industrial processes. A flat-plate OHP, however, was fabricated by traditional welding methods, which were difficult and inefficient, resulting in increasing the cost and wasting the production time. In this work, we adopted a new metal 3D printing technology to develop an aluminum flat-plate OHP, which made it facile to build complex inner channels with high-precision molding at one time. AlSi10Mg powders, as raw materials, were selectively melted and solidified to form the container of the flat-plate OHP. The sintered inner surface presented excellent wettability to the working fluid, which facilitated the evaporation of the working fluid. Acetone was chosen as the working fluid, and the filling ratios with a range of 40–70% were loaded into the flat-plate oscillating heat pipe to analyze its effect on heat transfer performance. It was found that the 3D-printed flat-plate OHP with a 60% filling ratio had a better heat transfer performance and a lower thermal resistance, and it was able to work properly in both vertical and horizontal operation modes. The 3D-printed flat-plate OHP had been successfully applied for the thermal management of high-power LEDs, and the results showed that the temperature of LEDs was maintained within 60 °C, and its service life was prolonged.Keywords:3D printing;oscillating heat pipe;thermal resistance;heat transfer performance
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xiaoyong Huang,Zhe Xu,Balaji Devakumar
Efficient broadband green-emitting phosphors are promising for application in high color rendering white light-emitting diodes (LEDs). In this paper, we report on the preparation, crystal structure and photoluminescence properties of a novel green-emitting Ca 2 LaHf 2 GaAl 2 O 12 :Ce 3+ (CLaHGA) garnet-type phosphor. All these CLaHGA: x Ce 3+ ( x = 4, 6, 8, 10, and 12 mol%) phosphors have been synthesized through using the conventional high-temperature solid-state reaction method. It has been found that the optical property of phosphors critically depends on Ce 3+ content, and the optimal doping concentration of Ce 3+ ions is 6 mol%. The optimal CLaHGA:6%Ce 3+ sample has a cubic structure with the space group Ia 3 ‾ d and lattice parameters of a = b = c = 12.62662 Å and V = 2013.08 Å 3 . The CLaHGA: x Ce 3+ phosphors exhibit an intense absorption band in the 300–485 nm range with a peak at 421 nm, due to the spin-allowed and parity-allowed 4f→5d transition of Ce 3+ ions. Upon 421 nm excitation, CLaHGA: x Ce 3+ phosphors give rise to bright broad green emission bands in the 435–750 wavelength region with peak ranging from 519 to 531 nm, owing to the spin-allowed and parity-allowed 5d→4f transition of Ce 3+ ions. For the optimal CLaHGA:6%Ce 3+ sample, its CIE color coordinates and internal quantum efficiency are determined to be (0.3135, 0.4851) and 40.7%, respectively. The full width at half maximum of CLaHGA:6%Ce 3+ is much larger than the commercial (Ba,Sr) 2 SiO 4 :Eu 2+ green phosphor (124 nm versus 71 nm), while its emission intensity is only about 39% of that of (Ba,Sr) 2 SiO 4 :Eu 2+ . Besides, the thermal stability of CLaHGA:6%Ce 3+ has also been studied. A white LED device is fabricated using the synthesized CLaHGA:6%Ce 3+ green phosphors, showing a bright warm-white light emission with high color rendering index of Ra = 89.7 and low correlated color temperature of 4058 K.
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高影响因子
Laser & Photonics Reviews
·
2023
·
IF 11
Jiurong Li,Shuyang Zheng,Shiwei Zhang,Xiao Gong
Carbon nanodots (CDs) are a new type of carbon-based fluorescent nanomaterials, but they are limited in many applications due to the inherent fluorescence weakening and quenching problems suffered in solid state. Herein, ZIF-8, a class of metal–organic framework (MOF) is employed as a matrix to immobilize fluorescent CDs, resulting in the strong luminescence of CDs achieved in solid state. The as-synthesized CDs@ZIF-8 fluorescent powders possess blue, green, and red emissions with the main emission at ≈495, 528, and 600 nm, and the corresponding photoluminescence quantum yields (PLQYs) are as high as 25.89%, 52.24%, and 15.42%, respectively. It is found that the encapsulation of ZIF-8 with CDs will increase the excitation dependence of the product fluorescence, which may be attributed to the carrier effect of ZIF-8 as a carrier of CDs and some surface defects or surface functional groups change of the CDs introduced by ZIF-8. In addition, the encapsulation of CDs with ZIF-8 may result in the charge transfer. Importantly, the prepared CDs@ZIF-8 phosphors present a promising application in the fabrication of monochromatic light-emitting diodes (LEDs). The synthesis design is expected to provide technical support for future solid-state fluorescent CDs preparation and applications.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 105
·期 2
·1300-1317
·
IF 3.784
Yan Xie,Xue Geng,Yuan Wang,Jiang Guo,Yuhui Lu,Qiuyi Lv,Zhijiang Ma,Dan zhang,Jin Zhao,Bin Deng,Ruijin Yu
High-efficiency and far-red light phosphors based on Mn 4+ -doped inorganic luminescence materials are beneficial to plant cultivation. However, Mn 4+ -doped oxide phosphors have a common problem of low quantum efficiency. Alkali metal ion codoping can effectively improve the luminescence properties of Mn 4+ -activated oxide phosphors. Herein, a series of Sr 2 InSbO 6 :Mn 4+ , M (SISO:Mn 4+ , M) (M = Li + , Na + , and K + ) far-red-emitting phosphors codoped alkali metal ions were first synthesized. Density functional theory calculation indicated that SISO is a kind of indirect bandgap material with a bandgap of ∼1.60 eV. The SISO:Mn 4+ samples showed a far-red light at 698 nm upon 365 nm, which perfectly matched the absorption spectrum of the far-red-phytochrome (Pfr) of plants. The doping concentration of the SISO:Mn 4+ samples was optimized to be 0.006 mol. The concentration quenching mechanism was defined as dipole–dipole interaction by combining the Dexter theory and the Inokuti–Hirayama model. Optimizing the sintering temperature and codoped with alkali metal ions (Li + , Na + , and K + ) could improve the luminescent intensity of SISO:Mn 4+ . The optimum sintering temperature was 1300°C. The internal quantum efficiencies of SISO:0.006Mn 4+ and SISO:0.006Mn 4+ , 0.006Li + phosphors are 22.67% and 60.56%, respectively. SISO:Mn 4+ , Li + phosphors-based plant growth light-emitting diodes (LEDs) demonstrate excellent optical stability and long lifetime. Thus, these phosphors are promising candidates for plant cultivation LEDs.
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高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Wei Li,Nan Ma,Qi Sun,Shaoying Wang,Zongjie Zhang,Balaji Devakumar,Xiaoyong Huang
Novel efficient Ba 2 YTaO 6 :Mn 4+ (BYT:Mn 4+ ) far-red emitting double-perovskite phosphors for plant cultivation LEDs were reported in this article. These phosphors were successfully synthesized via a traditional high-temperature solid-state reaction method, and their crystal structure, luminescence properties, fluorescence decay lifetimes, Commission Internationale de l'Eclairage (CIE) chromaticity coordinates, internal quantum efficiency, and thermal stability have been systematically investigated. XRD Rietveld refinement demonstrated that the BYT:Mn 4+ compound crystallized into cubic crystal system with Fm 3 ‾ m space group, and the lattice parameter were a = b = c = 8.445 (7) Å, α = β = γ = 90°, and V = 602.231 (10) Å 3 . Interestingly, the obtained samples showed an intense far-red emission band centered at 690 nm under excitation of 360 nm, which matched well with the absorption band of phytochrome P FR. In BYT:Mn 4+ phosphors, the Mn 4+ ions occupied the TaO 6 octahedron by replacing the Ta 5+ site, and the optimal doping concentration of Mn 4+ ions was determined to be 0.4 mol%. The CIE chromaticity coordinates and internal quantum efficiency of BYT:0.4%Mn 4+ phosphors were (0.7283, 0.2717) and 41.5%, respectively. In addition, when the temperature reached at 423 K, the emission intensity of BYT:0.4%Mn 4+ phosphors remained 37% of that at 303 K. Therefore, all of these investigations demonstrated that BYT:Mn 4+ phosphors could be used as potential far-red emitting phosphors for plants cultivation LEDs.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Changyan Ji,Zhi Huang,Xiuying Tian,Hengping He,Jin Wen,Yangxi Peng
A series of red emitting phosphors Mg 3 Y 2-x Ge 3 O 12 :xSm 3+ (0≤x ≤ 0.06) were successfully synthesized. Samples Mg 3 Y 2-x Ge 3 O 12 :Sm 3+ exhibited a cubic structure pertaining to the I a-3d (230) space group and the particle sizes range from 1 μm to 5 μm. The optical properties displayed that the optimum doping concentration of Sm 3+ is 4%. The phosphor Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm 3+ not only exhibited a broad band gap of 5.54 eV but also showed a high color purity of 97.6%. In addition, the strongest emission intensity located at 566 nm belonged to the 4 G 5/2 → 6 H 5/2 transition when excited at 405 nm. Thermal quenching test revealed that the sample Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm 3+ are excellent powders with splendid thermal stability, in which only 3.6% of the PL intensity is quenched at 473 K in comparison with that of 298 K. As a result, the W-LEDs based on Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm 3+ yielded a high R a of 91.1, a low CCT of 4881 K, and CIE coordinates of (0.3476, 0.3466) in a 20 mA driven current. This research work provided important guidance for the synthesis of Sm 3+ doped red component with excellent luminesce properties and high thermal stability characteristics used in W-LEDs.
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 36
·1-14
·
IF 2.8
Yang Jian,Xie Chenglong,Zhao Lei
A newly synthesized orange–red-emitting phosphor, K 2 Sr(MoO 4 ) 2 :Sm 3+ , was produced for the first time through high-temperature solid-state synthesis methods. Detailed analysis was conducted on the phase purity, morphology, and luminescence properties of the synthesized phosphors. The K 2 Sr(MoO 4 ) 2 :Sm 3+ phosphors let forth orange–red light when excited at 403 nm because of the 4 G 5/2 → 6 H 9/2 transition. The optimal doping concentration of the K 2 Sr(MoO 4 ) 2 : x Sm 3+ phosphor was found to be x = 3 mol%. The chromaticity coordinates of K 2 Sr(MoO 4 ) 2 :3 mol% Sm 3+ were (0.617, 0.381) with a corresponding high color purity of 99.8%. This prepared w-LED exhibited an exceptional color rendering index (CRI) of 90, while maintaining a suitable correlated color temperature (CCT) of 5825 K and CIE color coordinates were (0.325, 0.327). Hence, K 2 Sr(MoO 4 ) 2 :Sm 3+ phosphors are desirable options for creating w-LEDs and lighting based on near-ultraviolet (NUV) chips. Their unique properties show significant potential for enhancing the performance of solid-state lighting.
研究领域:
材料科学
·
光学工程
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Daomiao He,Likun Guan,Huayu Sun,Fanzhong Zeng,Fei Li,Leyi Zhang,Wenhao Li,Huajuan Deng,Dan Zhang,Ruijin Yu
A novel series of samarium-activated orange-red emitting CaY 2 Sb 2 (ZnO 4 ) 3 (CYSZO) phosphors has been successfully synthesized by the high-temperature solid-state method. The phase purity, spectroscopy, and morphological properties of the phosphors have been extensively characterized. When excited at 407 nm, CYSZO:Sm 3+ samples exhibited a pronounced orange-red emission peak at 610 nm, this corresponding to the typical 4 G 5/2 → 6 H 7/2 both magnetic-dipole and electric-dipole transitions of Sm 3+ ions. The optimal doping concentration was established as 10 mol%. The quenching mechanism is attributed to the interaction of the nearest-neighbor ions. The prepared sample showed a remarkable internal quantum efficiency (IQE) of 68.63 % and exceptional thermal stability at working temperature of the LEDs. As the Sm 3+ concentration increased, the decay time decreased correspondingly, ranging from 2.45 ms to 1.40 ms for concentrations ranging from 0.6 to 40 mol%. The phosphor materials exhibited high color purity, as evidenced by the Commission International de L'Éclairage (CIE) chromaticity coordinates. The synthesized white light-emitting diode (w-LED) exhibited an impressive color rendering index (CRI) of 96 and a desirable correlated color temperature (CCT) of 5674 K. Furthermore, the CYSZO:10 mol%Sm 3+ @oleic acid phosphor-stained latent fingerprint (LFP) images show excellent visualization capabilities on various surfaces with high contrast and long-term stability. These results highlight the potential of CYSZO:Sm 3+ phosphors to serve as a promising orange-red material for w-LED applications and LFP detection.
研究领域:
材料科学
·
光学
·
法医学
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高影响因子
Advanced Optical Materials
·
2025
·
IF 7.2
Moushira. A. Mohamed,Mohamed. A. Ali,Shaorun Guo,Xiaofeng Liu,Shengzhi Sun,Jianrong Qiu
The encapsulation of phosphor particles into a silica glass (PiSG) matrix leads to the formation of an efficient and chemically durable spectral converter, which is a promising candidate for the fabrication of stable and high-power phosphor-converted white light-emitting-diodes (pc-wLEDs). Here, high-throughput fabrication of transparent PiSG spectral converters based on Y 3 Al 5 O 12 :Ce 3+ , Mg 2 Al 4 Si 5 O 18 :Eu 2+ , and Y 3 Al 5 O 12 :Cr 3+ is demonstrated via injection molding followed by pressureless sintering. The as-fabricated PiSG exhibits broadband emission covering the visible and near-infrared (vis-NIR) spectral regions (i.e., 500–900 nm) with a high-luminescence efficiency (> 85%) and high-chemical and thermal stabilities, retaining more than 90% of its emission intensity at 200 °C. Consequently, high-power pc-vis-NIR-LEDs (10 W) are manufactured using the injection molded PiSG spectral converters, which showed excellent luminescence performance (i.e., luminous efficiency (LE) = 115 Im W −1 , correlated-color-temperature (CCT) = 4531 K, and color-rendering-index (R a ) = 90.1 at 50 mA and input power of 0.45 W). This work enables the fabrication of stable and high-power broadband LEDs with a low cost and outstanding optical properties, making the as-fabricated pc-vis-NIR-LEDs based on PiSG spectral-converter a favorable device for lighting and bioimaging applications.
研究领域:
材料科学
·
光学工程
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高影响因子
SENSORS
·
2025
·Vol. 26
·期 1
·
IF 3.5
Chenglong Guo,Jiacong Xiao,Jianchun Zeng,Youjun Zeng,Yi Liu
Surface Plasmon Resonance imaging (SPRi) is a powerful label-free technique for high-throughput biochemical analysis. Wavelength modulation is particularly suitable for SPRi due to its wide dynamic range and robustness to fabrication tolerances. However, conventional systems relying on tunable filters (e.g., AOTF, LCTF) suffer from high cost, complexity, and limited temporal resolution. To overcome these drawbacks, we developed a rapid wavelength-modulation SPRi system using a multi-LED source and an adaptive second-order fitting (ASF) algorithm. The system covers the 730–805 nm spectrum with five LEDs. The ASF algorithm first performs a coarse full-spectrum scan to locate the resonance wavelength, then dynamically selects an optimal three-LED subset for fast second-order fitting, enabling accurate reconstruction of resonance wavelength without mechanical scanning. This approach significantly reduces cost and complexity while achieving a scanning cycle of 105 ms, RI resolution of 5.54 × 10−6RIU, dynamic range of 0.0241 RIU, and excellent multi-channel consistency. The system has been successfully applied to monitor multi-channel antibody–antigen interactions in real time. Furthermore, it was used to detect cartilage oligomeric matrix protein (COMP) in synovial fluid, where an elevated concentration in an osteoarthritis sample versus a control aligned with its role as a cartilage catabolism marker. This work validates a practical and reliable platform for early diagnosis of osteoarthritis.
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高影响因子
Advanced Optical Materials
·
2020
·Vol. 8
·期 6
·1901859
·
IF 8.286
Yi Wei,Zhiyu Gao,Siwei Liu,Shuoting Chen,Gongcheng Xing,Wei Wang,Peipei Dang,Abdulaziz A. Al Kheraif,Guogang Li,Jun Lin
Highly efficient green/yellowish-orange phosphors with low thermal quenching behavior are urgently required to improve the luminescence efficiency, color stability, and color rendering of phosphor-converted white light emitting diodes (w-LEDs). Herein, a novel green Cs 2 BaP 2 O 7 :0.01Eu 2+ phosphor with high luminescence efficiency (82.7%) and thermal quenching behavior (92.5% at 423 K) is reported. Besides, a further luminescence improvement in the quantum yield (98.9%) and thermal quenching resistance (120% at 448 K) is successfully achieved in green/yellowish-orange color-tunable Cs 2 MP 2 O 7 :0.01Eu 2+ (M = Ba, Sr, and Ca) phosphors. Surprisingly, these green/yellowish-orange Cs 2 MP 2 O 7 :0.01Eu 2+ (M = Ba, Sr, and Ca) phosphors even have a prior advantage over the commercial green β-SiAlON:Eu 2+ and yellow YAG:Ce 3+ phosphors. The corresponding spectral adjustment and thermal stability mechanisms are revealed, related to the optimization of local lattice symmetry. The prototype w-LEDs exhibit warm white light with CIE color coordinate at (0.337, 0.322). The color rendering index, corrected color temperature, and luminescence efficiency can reach 92.6, 4044 K, and 152.56 lm W −1 , respectively. In general, the as-reported green/yellowish-orange Eu 2+ -doped pyrophosphate phosphors are promising candidates in the future high-quality w-LEDs applications. The proposal of local lattice symmetry modulation can provide a new approach to exploit novel phosphors with excellent thermal quenching resistance.
研究领域:
材料科学
·
光学工程
·
发光材料
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高影响因子
危险品化学品经营许可证（带存储）