CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yukun Li,Yongfu Liu,Zhaohua Luo,Zehua Liu,Svenja Hanson,Chengheng Pang,Hui Lin,Haiming Qin,Jun Jiang
Ce/Mn/Cr: Y 3 Al 5 O 12 transparent ceramics with a pure garnet structure and a high color rendering index were prepared by a solid-state reaction method. Mn 2+ and Cr 3+ enhance the emission between 500 and 700 nm and expand the conventional Ce: YAG phosphors spectrum. The Ce 3+ can work both, as activators and sensitizers, and the intense energy transfer from Ce 3+ to Mn 2+ /Cr 3+ is realized through the non-radiative and radiative processes. In the sample with the optimized doping concentration the high color rendering index (CRI) value of 75.3 can be achieved under a 450 nm laser diode excitation. The chromaticity coordinates can be tuned from (0.3125, 0.3232) to (0.2917,0.2851) by varying the doping concentration. With the increasing Mn 2+ /Cr 3+ doping concentration, the lifetime of Ce 3+ , quantum efficiency and luminous efficiency are all gradually decreased. This work effectively offers a scheme for realizing the high color rendering performance of phosphor-converted transparent ceramics in white LEDs/LDs.
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
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhe Xu,Lina Cao,Jingming Chan,Balaji Devakumar,Xiaoyong Huang
Highly efficient broadband blue-emitting phosphors are urgently needed for full-visible-spectrum white light-emitting diodes (WLEDs). Herein, we report a new highly luminescent garnet-type Ca 2 LuHf 2 GaAl 2 O 12 :Ce 3+ (abbreviated as: CLHGAO:Ce 3+ ) blue phosphor enabling full-visible-spectrum LED lighting. These CLHGAO:Ce 3+ phosphors doped with different Ce 3+ concentrations have been prepared by using a high-temperature solid-state reaction approach, and their phase purity, crystal structure, luminescent properties, CIE color coordinates, and quantum efficiency have been systematically studied. Importantly, CLHGAO:Ce 3+ blue phosphors show a broadband excitation spectrum in the 300–450 nm spectral range peaking around 398 nm, matching well with the emission wavelengths of commercial near-ultraviolet LED chips (380–420 nm). Upon 398 nm excitation, the optimal CLHGAO:2%Ce 3+ phosphor sample generates a bright broad blue emission band (emission peak: 472 nm; bandwidth: 84 nm) with high internal quantum efficiency of 79.2% and external quantum efficiency of 55.3%. Notably, the emission intensity of CLHGAO:2%Ce 3+ phosphor is about 1.87 times higher compared to the commercial BaMgAl 10 O 17 :Eu 2+ blue phosphor (emission peak: 451 nm; bandwidth: 53 nm). Finally, a white LED device is fabricated with a 395 nm near-UV LED chip with CLHGAO:2%Ce 3+ blue phosphor and commercial (Ba,Sr) 2 SiO 4 :Eu 2+ green phosphor as well as commercial CaAlSiN 3 :Eu 2+ red phosphor, and the device demonstrates bright warm-white emission with an ultrahigh color rendering index (Ra = 95.1, R9 = 97.8, R12 = 88.4) and low correlated color temperature of 3540 K. These results show that as-developed blue-emitting CLHGAO:Ce 3+ garnet phosphors with superior photoluminescence properties can potentially be used in phosphor-converted full-visible-spectrum WLEDs.
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
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Junhu Cai,Xiang Zhang,Yu Chen,Wenzong Lai,Wenyan Zhang,Zexi Lin,Yun Ye,Sheng Xu,Tailiang Guo,Jiajun Luo,Enguo Chen
Inorganic metal halide perovskite quantum dots (PQDs) have recently emerged as promising candidates for color conversion materials in Micro-LED displays, due to their outstanding color purity, high absorption coefficient, tunable emission wavelength . However the inferior stability and undesirable photoluminescence quantum yield (PLQY) restrict their particle applications. Herein, CsPbX 3 /PMMA (X = Br, I) composites with improved stability and optical performance were successfully prepared by a general and mild in-situ polymerization strategy. The ester carbonyl (C O) group in MMA formed complexes with Pb 2+ , leading to the in-situ thermal polymerization of polymethyl methacrylate (PMMA) under the action of the initiator. The multifunctional PMMA can efficiently passivate halogen vacancies while acting as a barrier against the degradation caused by heat, water, and oxygen. As a result, the PLQYs and stability of PMMA-coated CsPbX 3 PQDs have been significantly improved. When implementing CsPbX 3 /PMMA/PDMS composites as color conversion layers in Micro-LEDs, they achieve an impressive color gamut of 127.23% with excellent stability. We believe our work will stimulate the exploration of perovskite/polymer composites for industrial Micro-LED applications.
研究领域:
材料科学
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光学工程
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显示技术
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 1
·382-390
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IF 3.094
Linli Shen,Zelong Zhang,Yi Zhao,Haisheng Yang,Lin Yuan,Ya Chen,Weidong Xiang,Xiaojuan Liang
In this report, a mixed-metal cation-based halide perovskite (HP) CsPb 1− x Ti x Br 3 quantum dots (QDs) were first embedded in the B–Si–Zn glasses using a traditional approach of melt quenching and heat treating. A battery of test results such as photoluminescence, X-ray diffraction, and time-resolved attenuation prove that Ti ions do not destroy the properties of CsPbBr 3 , and they are successfully doped into CsPbBr 3 . At the same time, the doping of Ti ions also reduces the toxicity of lead. By altering the ratio of Pb/Ti, we determined the optimum ratio of CsPb 0.7 Ti 0.3 Br 3 QDs through experimental data. Due to the excellent optical properties and stability of CsPb 0.7 Ti 0.3 Br 3 QDs glass, it was designed to construct the white-light emitting diode device with tunable color coordinate, color rendering index, correlated color temperature, and a high luminous efficiency compared with CsPbBr 3 QDs glass, which may be a promising candidate for the field of lighting and displays.
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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DOI
高影响因子
RSC Advances
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2016
·Vol. 7
·期 2
·914-918
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IF 3.289
Ruixin Xu,Xiaoyuan Guan,Minghui He,Jianwen Yang
Photocaged amines (PCAs) can allow a spatiotemporal control of the highly versatile and widely implemented nucleophile-catalyzed thiol-Michael addition reaction. However, a major challenge with most PCAs is that their relatively low quantum yields easily lead to low photosensitivity, especially under the radiation of light-emitting diodes (LEDs). In this paper, the phototriggered base proliferation (PBP) reaction as a powerful 365 nm LED photoclick tool is presented for the nucleophile-initiated thiol-Michael addition reaction. Compared to the PCA system, the advantages of this approach lie in its enhanced photosensitivity, increased reaction rate and elevated conversion. Finally, due to the persistent interactions of the produced longeval amine, remarkable post conversion was thus initially achieved after irradiation.
研究领域:
有机化学
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光化学
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生物化学
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DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 28
·10292-10301
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IF 8.067
Zixuan Wu,Xinxin Han,Juan Wang,Yayun Zhou,Ke Xing,Sheng Cao,Jialong Zhao,Bingsuo Zou,Ruosheng Zeng
Near-infrared (NIR) phosphor-converted light-emitting diode (pc-LED) is a prospective next-generation light source for smart and broadband NIR spectroscopy. However, the improvement of photoluminescence quantum yield and thermal quenching stability is still a crucial challenge for the pc-LED related broadband NIR phosphors. Herein, a highly efficient and thermally stable broadband NIR emitting fluoride phosphor Cs2KGaF6:Cr3+ is fabricated, which exhibits a full width at half-maximum (FWHM) of 110 nm centered at 782 nm. Notably, the phosphor exhibits an ultra-high internal quantum efficiency (IQE) of 90.2% and excellent thermal stability (I150 °C = 88.7%). The excellent anti-thermal quenching behavior is attributed to the relatively weak electron–phonon coupling effect in Cs2KGaF6:Cr3+ with a small Huang–Rhys factor of 2.17. Based on the prominent luminescent properties of the phosphor, a NIR pc-LED with a high photoelectric conversion efficiency of 22.05% is fabricated by combining the phosphor with a commercial blue LED chip. Moreover, the NIR pc-LED manifests distinguished performances in night vision security inspection, non-destructive testing, intelligent identification and biomedical imaging, indicating extensive application prospects for the as-prepared Cs2KGaF6:Cr3+ phosphor.
研究领域:
材料科学
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光学工程
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电子工程
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DOI
高影响因子
JOURNAL OF LUMINESCENCE
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2021
·
IF 3.599
Jianxu Wang,Jiang Guo,Qiuyi Lv,Zhijiang Ma,Xuyao Feng,Yuhiu Lu,Jing Gao,Wensheng Chen,Bin Deng,Ruijin Yu
A series of novel orange-red emitting tungstate phosphors, Ca 3 La 2 W 2 O 12 (CLWO): x Sm 3+ (0.005 ≤ x ≤ 0.30) were successfully prepared through the solid-state method at high temperature. The space group is hexagonal R 3 ‾ m . Under 600 nm monitoring, a large charge transfer band from 250 to 340 nm composed of the electron transition of O 2- –Sm 3+ and O 2- –W 6+ and represented the strongest excitation at 300 nm. CLWO:Sm 3+ emitted orange-red light at 600 nm ( 4 G 5/2 – 6 H 7/2 ) under the strongest excitation of 300 nm. The intensity ratio of the electric-dipole and magnetic-dipole of all the samples were bigger than 1. With the Sm 3+ -doped concentration increasing, the upward tendency of ratio values originated from the increased degree of lattice distortion . The calculated R c (21.32 Å) and Q (3.78) represented the dipole–dipole interaction to account for the concentration quenching. With the temperature changing from 300 to 400 K, the chromaticity coordinates of samples just have a tiny difference (Δ x = 1.02 × 10 −4 , Δ y = 1.01 × 10 −4 ). The thermal activation energy was calculated to be 0.42 eV and T 0.5 > 480 K. The color purity of all the phosphors reached 98.9%. Ultimately, a white light-emitting diode (w-LED) was fabricated by coating trichromatic (red, blue, and green) phosphors on a near-ultraviolet chip. The fabricated w-LED revealed a high color rendering index (R a = 91, R 9 = 41) and a good chromaticity coordinate (0.320, 0.363) in the white area. Thus, these orange-red phosphors CLWO:Sm 3+ with high thermal stability and high color purity can be potentially used in w-LED applications.
研究领域:
材料科学
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光学
✓ 已验证
DOI
高影响因子
Small
·
2024
·
IF 13
Hanqi Wei,Qihua Yang,Guihua Li,Xuan Liu,Junben Huang,Chujie Wang,Xiaoming Li,Gemei Cai
As one type of recent emerging lead-free perovskites, Cs 2 ZrCl 6 nanocrystals are widely concerned, benefiting from the eminent designability, high X-ray cutoff efficiency, and favorable stability. Improving the luminescence performance of Cs 2 ZrCl 6 nanocrystals has great importance to cater for practical applications. In view of the surface defects frequently formed by the liquid phase method, the particle morphology and surface quality of this material are expected to be regulated if certain intervention is made in the synthesis process. In the work, differing from normal cell lattice modulation based on the ion doping, the grain size and surface morphology of Cs 2 ZrCl 6 nanocrystals are optimized via adding a certain amount of InCl 3 to the synthetic solution. The surface defects are restored to inhibit the defect-induced non-radiative transition, resulting in the improvement of the luminescence properties. Moreover, a flexible Cs 2 ZrCl 6 @polydimethylsiloxane film with excellent heat, water, and bending resistance and a light-emitting diode (LED) device are fabricated, exhibiting excellent application potential for X-ray imaging and blue LED.
研究领域:
材料科学
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光学工程
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医学影像
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产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Yukun Li,Zhaohua Luo,Yongfu Liu,Zehua Liu,Svenja Hanson,Hui Lin,Pan Hu,Peng Sun,Jun Jiang
In the high-power white light LEDs/LDs area, obtaining phosphor-converted materials with high thermal stability and high luminous emittance with proper blue/yellow light ratio has been the main challenge in recent years. In this study, a group of (Ce x Y 1-x ) 3 (Sc y Al 1-y ) 5 O 12 transparent ceramics with high optical quality were proposed to rise to that challenge. Their spectra were regulated by incorporating Sc 3+ , showing blue shifted emission bands (peak position from 554 nm–538 nm), blue shifted excitation bands (462–445 nm) and narrowed full width at half maxima (120–112 nm). Significantly, the prepared Ce:YScAG transparent ceramics (TC) exhibited decent thermal quenching performance with the photoluminescence intensity at 150 °C maintaining 88.7% of its original value at room temperature. The Sc incorporation impacted the atoms’ occupation and distance, crystal field splitting and energy band structure . Under remote LD excitation mode, the luminous efficiency of the prepared Ce:YScAG TC can achieve 164.8 lm/W. And even if the Ce 3+ doping reaches 2.0 at%, the LE can still maintain 117.8 lm/W, exhibiting decent concentration quenching characteristic. Consequently, Ce:YScAG TCs have great potential as promising phosphor-converted materials in future high-power LED and LD white lighting.
研究领域:
材料科学
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光学工程
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产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2023
·
IF 6.2
Pengyu Su,Yuehao Huang,Yadong Li,Chenguo Hu,Wenbing Shi
With quick development of optoelectronic devices, lead halide perovskite nanocrystals (PNCs) have been extensively researched due to their excellent optoelectronic and luminescent properties. However, the water-induced low stability seriously restricts their applications. In this study, CsPbBr 3 PNCs/polymer composite films are prepared based on even dispersion of PNCs and ultraviolet (UV)-induced chemical crosslinking of methyl methacrylate (MMA) monomers and vinyl silicone oil (VT-PDMS) oligomers . The optimized polymer/PNCs composite film exhibits high photoluminescence quantum yield (PLQY) of 82% comparable to common PNCs, as well as high surface hydrophobicity . This film shows high photoluminescence (PL) intensity (90% of original value) after air aging for 60 days. Its high surface hydrophobicity is attributed to use of VT-PDMS oligomers bearing Si element with low surface energy. Light-emitting-diode (LED) device is constructed employing this optimized composite film, and its color coordinates (0.343, 0.334) is rather close to that of standard white light. Specifically, high PL and surface hydrophobic properties of specimens are simultaneously achieved. The importance of this work can lie in a mild rapid preparation of hydrophobic CsPbBr 3 PNCs/polymer nanocomposites with stable white-light emission for commercial LED devices.
研究领域:
材料科学
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光学工程
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 28
·期 7
·5615-5622
·
IF 1.798
Chu Yang,Hao Haixia,Xie Hongde,Chen Cuili,Cai Peiqing,Seo Hyo Jin
In this work, we report the preparation of lanthanide (Eu 3+ , Tb 3+ )-complex-grafted copolymer of methyl methacrylate and maleic anhydride films. The lanthanide complex with three amino groups was used to react with poly(methyl methacrylate-co-maleic anhydride) (P(MMA-MAH)) via the amidation method. Fourier transform infrared (FT-IR), Transmission electron microscope (TEM), Scanning electron microscope (SEM), Thermogravimetric analysis (TGA) were employed to characterize those polymers. Luminescent properties were evaluated through conducting Photoluminescence (PL) excitation spectra, emission spectra and fluorescence decay curves measurements. The infrared analysis reveals the amidation between amino groups and anhydride rings. The comparatively uniform morphology can be observed in the images of TEM and SEM. These polymers can emit intense characteristic lights including red light from Eu 3+ ions and green light from Tb 3+ ions under 294 nm excitation. The lifetimes of polymers are short (about 1 ms). Meanwhile, these luminescent polymers exhibit high thermal stability (T 5 > 200 °C). We also stimulate a lamp to illustrate the possible application. All these approved interesting results suggest that they hold significant promising applications as luminous layers for optoelectronic devices.
研究领域:
材料科学
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光学
·
化学
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产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Jianmei Pan,Yahai Zhang,Yi Guan,Yingnan Yan,Hua Tang,Xianglong Liu,Mengdi Wang,Xiangxin Wei
The development of hydrogen (H 2 ) production photocatalyst with low cost, non-precious metal and high-activity for commercial application is a long-term target and challenge. In this work, novel silicon carbide (SiC) nanofibers/graphitic carbon nitride (g-C 3 N 4 ) nanosheets (SiC/CNNS) decorated via multipurpose nickel (Ni) nanoparticles were prepared by an easy heat treatment followed by hydrothermal method. The tight Ni interface layers as cocatalyst and electron transfer mediator can significantly enhance the H 2 production property over SiC/CNNS nanoheterojunctions under light-emitting diode (LED) illumination. The optimal Ni/SiC/CNNS with a mass fraction of 10% Ni loading shows the most superior H 2 -generation rate of 6183 μmol g −1 h −1 , which is approximately 53, 3 and 227 times compared to CNNS, 10 %Ni/CNNS and SiC/CNNS, respectively. The metallic Ni nanoparticles play the leading and multifunctional roles in improving photocatalytic activity, including collecting the photo-generated electrons efficiently, transferring and separating the charge carriers rapidly, facilitating the H 2 -production kinetics and decreasing the overpotentials of surface reactions for H 2 -production. It is highly expected that the multipurpose and non-precious metal cocatalyst to form tight interface layers can supply a simple and universal strategy to design high-efficiency cocatalyst-semiconductor–semiconductor photocatalysts for H 2 production.
研究领域:
材料科学
·
能源化学
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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）