MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Ming Gu,Yue Tian,Cai’e Cui,Ping Huang,Lei Wang,Qiufeng Shi
A novel red-emitting Ba 2 ZrF 8 : Mn 4+ phosphor was prepared by two-step method at low temperature, where critical precursor K 2 MnF 6 was prepared first by the reduction of KMnO 4 using H 2 O2 as reducer. The crystal structure and morphology of the phosphor was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), showing single phase product. Luminescent properties of the phosphor were investigated by photoluminescence spectroscopy (PL) and decay curves. The molar ratio of KMnO 4 : KHF 2 was confirmed to play the key role in improving the luminous efficiency. More importantly, the phosphor exhibits a broadband excitation from 300 to 520 nm due to 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g transition of Mn 4+ , matching well with blue LED chips. Under 465 nm excitation, intense red emission at around 630 nm with high color purity is achieved, suggesting the red-emitting phosphor has great potential for white light-emitting diodes (wLEDs).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Yanfang Wang,Dongliang Chen,Xiong Yin,Peng Xu,Fan Wu,Meng He
Electromagnetic wave absorbing materials that can exhibit effective absorption in a broad bandwidth at a thin thickness are strongly desired due to their widespread applications in electronic devices. In this study, hybrids of MoS2 and reduced graphene oxide (RGO) were prepared and their microwave absorption performance was investigated for the first time. It was found that a thin sample consisting of 10 wt % MoS2/RGO hybrid in the wax matrix exhibited an effective microwave absorption bandwidth of 5.72 GHz at the thickness less than 2.0 mm. The highest reflection loss of −50.9 dB was observed at 11.68 GHz for a sample with a thickness of 2.3 mm. Results obtained in this study indicate that hybrids of MoS2 and RGO are promising microwave absorbing materials, which can exhibit broad effective absorption bandwidth at low filler loading and thin thickness.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Optical Materials
·
2021
·Vol. 9
·期 24
·2101423
·
IF 9.926
Hao Hu,Yingmeng Liu,Zuoxiang Xie,Zewen Xiao,Guangda Niu,Jiang Tang
The luminescent property of 2D perovskite materials promotes their applications in light emitting diodes, phosphor powders, and scintillators. Recently, an interesting extrinsic low-energy broadband luminescence is hotly investigated. However, the understanding of such emissions is still at the early stage. In this study, based on a modified solvent evaporation method, centimeter-size (BDA)PbI 4 (BDA = NH 3 C 4 H 8 NH 3 2+ ) single crystals are grown which, besides the band–band emission, show a large Stokes-shifted broadband luminescence. We find such emission can be effectively excited by sub-gap photons and conclude defects-induced shallow traps are the corresponding luminescence centers. Density functional theory (DFT) calculations indicate that in-plane iodine vacancies can introduce shallow electron traps in the band gap and give rise to the broadband emission.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Xiaoyang Wang,Jianguo Huang,Hao Feng,Jinfeng Li,Zehao Xu,Kaiwen Xiong,Yuantao Zhang
The Snoek limit hinders strong and wideband electromagnetic wave (EMW) absorption, and to meet this challenge, it is essential to obtain an economical and scalable microstructural solution. In this work, we used a SiO 2 -B 2 O 3 -RO-Fe 2 O 3 multicomponent glass system to design microstructures using dendritic Fe 3 O 4 crystal precipitates in the amorphous glass matrix. The flower-like Fe 3 O 4 structures that formed in situ at the grain interface exhibited a significant strengthening effect on EMW absorption performance. The minimum reflection loss (RL) value reached − 61.0 dB at 7.2 GHz when the sample thickness was 3.3 mm, and the effective absorption bandwidth (EAB) was 6.0 GHz (8.6–14.6 GHz), with a sample thickness of 2.4 mm. This approach not only provided a novel strategy for constructing synergistic multiple transmission-absorption mechanisms, but also provided an option for developing inexpensive high-performance EMW-absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 26
·9841-9848
·
IF 8.067
Jindong Cao,Jiawei Lin,Kunjie Liu,Yan Xiong,Na Wang,Shihui He,Xusheng Zhang,Zhongnan Guo,Xin Chen,Jing Zhao,Quanlin Liu
As an emerging material, organic–inorganic metal halides (OIMHs) have been widely studied in the field of optoelectronics in recent years. In this work, a series of compounds (TMEDA)3(SbxBi1−x)2Cl12·H2O (0.1 ≤ x ≤ 0.6) (TMEDA = N,N,N′-trimethylethylenediamine) were synthesized. The incorporation of Sb3+ greatly enhanced the photoluminescence quantum yield of (TMEDA)3Bi2Cl12·H2O from 1% to 38%. The variation in the degree of distortion of the inorganic octahedra and the relatively suitable distances between metal ions are considered to be the reasons for the intense emission. (TMEDA)3(SbxBi1−x)2Cl12·H2O (0.1 ≤ x ≤ 0.6) exhibited a yellow phosphorescence emission at 605 nm and 595 nm under excitation at 305 nm and 375 nm, respectively. With the incorporation of Sb3+, changes in the emission intensity under different excitation wavelengths showed different trends. Thus, we attribute the yellow broadband emissions to the triplet emission of Bi3+ and Sb3+. Finally, we combined (TMEDA)3(Sb0.5Bi0.5)2Cl12·H2O with commercial phosphors and a near-ultraviolet light-emitting diode chip to prepare a white-light-emitting diode device, which exhibited a high color-rendering index of 94.4. The aim of our work was to investigate the structural effects of the photoluminescence of Sb3+-doped OIMHs and to further explore ways to improve the Sb3+ emission efficiency in the field of photoluminescence of OIMHs.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2025
·
IF 3.7
Yueyue Wu,Lan Liu,Zifan Li,Jiayi Xie,Zixin Wang,Guo Fang,Keyan Li,Zhenhui Tao,Xin Li,Fei Xiu,Juqing Liu
Graphical With the synergy of Mn 2+ and ODA codecoration, CDs with ultrabroadband and efficient yellow fluorescence in the solid state were synthesized through a simple one-step solvothermal process. These synthetic phosphors exhibit a production yield of 80%, an FWHM of 98 nm, and a solid-state quantum yield up to 62.8%, allowing for high-CRI white LEDs in green and health lighting. Exploiting environment-friendly and efficient phosphors is crucial to constructing high-quality and sustainable white light-emitting devices. Here, we demonstrate a facile and high-yield approach to synthesize Mn 2+ /octadecylamine (ODA)-codecorated carbon dots (CDs) with ultrabroadband and efficient yellow fluorescence in the solid state. The dots are prepared from anhydrous citric acid (CA), 1-ODA, and manganese acetate through a simple one-step hydrothermal process, with a production yield of 80%, a full width at half maxima (FWHM) of 98 nm, and a solid-state quantum yield up to 62.8%. Utilizing the synthetic CDs powder as a phosphor to directly coat on a blue light-emitting chip, the device exhibits warm white emission, with a high color rendering index (CRI) of 88, correlated color temperature (CCT) of 4215 K, and Commission International de l'Éclairage (CIE) coordinates of (0.33, 0.31), endowing great potential applications in green and health lighting.
研究领域:
材料科学
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光学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Tengfei Wang,Qing Pang,Boyu Liu,Hongyu Wang
Titanium dioxide (TiO 2 ), once considered a promising material for microwave absorption, still faces significant challenges in achieving broadband absorption performance. To address this issue, herein, a simple approach is reported for successfully introducing defects and crystalline/amorphous heterostructures onto mesoporous TiO 2 (Meso-am-TiO 2-x ). This study demonstrates the superior microwave absorbing properties of Meso-am-TiO 2-x , particularly in the low-frequency range. A reflection loss of up to −25.7 dB is achieved with a thickness of 4.6 mm, and the effective absorption bandwidth (EAB) value extends to 4.32 GHz. The experimental results indicate that the synergistic effects of the high specific surface area of mesoporous TiO 2 , defects-induced conduction loss, defect-induced dipole polarization loss, and interfacial polarization loss between the crystalline and amorphous heterostructures enhance the microwave absorption properties of Meso-am-TiO 2-x . This study provides insights toward developing innovative low-frequency broadband TiO 2 absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2024
·Vol. 12
·期 7
·4057-4066
·
IF 10.7
Xiao Li,Haowei Zhou,Jinlin Zhang,Xinyue Zhang,Man Li,Jieyan Zhang,Moustafa Adel Darwish,Tao Zhou,Shi-Kuan Sun,Lei Xie,Di Zhou
Carbon materials have been widely recognized as one of the important candidates for superior microwave absorbers, but further enhancement of their properties (especially for a wide bandwidth) is still a great challenge. In this study, we developed a simple soft template-carbonization method to construct special shell-like carbon superstructures used for significant enhancement of microwave absorption. Through an interfacial self-assembly process using ribose as the carbon precursor, a copolymer as the soft template, and sulfuric acid as the catalyst, three microstructurally distinct carbon materials: sphere-like, rod-like, and shell-like carbon superstructures can be prepared by simply adjusting the amount of the structure-guiding agent PSSMA. Owing to the unique semi-hollow cavity structure of the shell-like carbon superstructures, the conductive loss and polarization loss are synergistically regulated, accompanied by the synergistic improvement of their impedance matching and loss capability. As a result, the shell-like carbon superstructures hold excellent electromagnetic wave absorption capability, in which the reflection loss (RL) can reach −49.14 dB and the effective absorption bandwidth (EAB) can reach 8.24 GHz. The relationships between the morphological structure, microscopic loss mechanism, and macroscopic microwave absorption performance are also investigated in detail. In addition, under far-field conditions, the shell-like carbon superstructures are characterized by a high degree of conductivity and polarization loss compared with PEC. Besides, the maximum radar cross-section (RCS) reduction of shell-like carbon superstructures reaches 31.19 dB m2 compared with PEC under far-field conditions, which again verifies that shell-like carbon superstructures can dissipate more electromagnetic waves in real environments. This work provides a reference for the rational construction of new high-performance carbon superstructure microwave absorbers.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
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
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2021
·
IF 9.811
Yaxin Xu,Xingchen Chai,Wantian Yang,Jiarui Hu,Junnian Chen,Yunbin He
Lead-free zero-dimensional (0D) hybrid bismuth halide perovskites have aroused great interest due to their promising emission properties and good chemical stability. Herein, we report the design and synthesis of mixed-cation-phase 0D guanidinium–formamidinium bismuth chloride, [C(NH2)3]2[CH(NH2)2]3Bi2Cl11 (denoted as Gua2FA3Bi2Cl11), where an individual corner-sharing [Bi2Cl11]5– dimer is completely isolated and surrounded by the mixed Gua+ and FA+ organic cations. The corner-sharing connectivity mode in Gua2FA3Bi2Cl11 differs from that in pristine Gua3BiCl6, featuring an isolated [BiCl6]3– unit. Importantly, Gua2FA3Bi2Cl11 yields remarkable broadband emission spanning from 350 to 750 nm, different from the pristine Gua3BiCl6, showing distinct narrowband emission. Further investigation of photophysical properties reveals that the broadband emission has contributions from both free excitons and self-trapped excitons. Moreover, Gua2FA3Bi2Cl11 not only exhibits excellent photostability under continuous high-power UV lamp irradiation during 70 min but also is humidity stable for over 6 months under ambient conditions. This finding presents a novel molecular engineering strategy for the development of eco-friendly and stable 0D perovskite broadband emitters.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 8
·1692-1700
·
IF 7.779
Decai Huang,Xianguo He,Jingrong Zhang,Jie Hu,Sisi Liang,Dejian Chen,Kunyuan Xu,Haomiao Zhu
In recent years, near-infrared phosphor-converted light emitting diodes (NIR pc-LEDs) have been emerging as a promising compact and efficient NIR light source for a variety of applications such as sensing, bioimaging and food analysis. However, the development of broadband NIR phosphors with both high emission efficiency and excellent photoluminescence (PL) thermal stability is still facing a great challenge. Herein, a blue light excitable AlP3O9:Cr3+ phosphor with a broadband NIR emission covering 650–1000 nm is presented. In particular, in situ variable-temperature XRD measurements demonstrate that the AlP3O9:Cr3+ phosphor shows a near zero thermal expansion in the temperature range of 300–423 K, which is beneficial for achieving good PL thermal stability. The experiment shows that ∼91% of the PL intensity is retained at 423 K compared to that at room temperature, verifying our hypothesis. An efficient NIR pc-LED is fabricated by using the AlP3O9:Cr3+ phosphor and commercial blue diode chips, generating a NIR radiant flux of 29.5 mW at 60 mA drive current. Finally, the NIR pc-LED was successfully used as the light source for identifying spoiled eggs based on the NIR spectroscopic technique. This work provides a strategy to achieve high performance NIR phosphor systems.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
RARE METALS
·
2023
·Vol. 42
·期 11
·3787-3796
·
IF 8.8
Peng Chao-Yue,Wang Bo,Yuan Li-Fang,Hu Kai-Ge,Chen Geng,Wu Hao-Yi,Hu Yi-Hua,Jin Ya-Hong
Broadband near-infrared (NIR) light sources play a critical role in widespread applications such as advanced spectroscopy analysis and nondestructive testing. One of the most promising techniques is the fabrication of broadband NIR phosphor-converted light emitting diode (pc-LED). However, the purposeful design of a tunable ultra-broadband NIR-emitting phosphor in a single host is still a challenge. In this work, Ga 2 GeO 5 with two sites of six-coordinated [Ga1O 6 ] and five-coordinated [Ga2O 5 ] is chosen to host Cr 3+ , successfully producing tunable broadband NIR luminescence (680–1350 nm). It can be tuned largely from 828 to 970 nm with the full-width at half maximum (FWHM) varied from 208 to 258 nm just by simply adjusting the Cr 3+ -doping content. The tailoring of the Cr 3+ NIR spectral emission is ascertained to the site occupation preference and competition. The encapsulation of a prototype of NIR pc-LED with an output power of 29.5 mW@390 mA is conducted for the implementation of night-vision application. This work provides a novel broadband NIR phosphor by Cr 3+ -doping in both the six- and five-coordination field, meanwhile, further demonstrating the feasibility of discovering new host material with more than one crystallographic site for Cr 3+ to trigger tunable broadband NIR emission. Graphical abstract
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）