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Synthesis and optical properties of highly efficient Na3KMg7（PO4）6:Eu2+ blue phosphor for full-spectrum white-light-emitting diodes:The role of Li2CO3 flux

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Journal of Rare Earths 2024年第7期42卷 1217-1223页

作者： Zihao Wang Sisi Liang Chenyang Zhan Kunyuan Xu Jie Hu Dejian Chen Liping Song Haomiao Zhu School of Physics and Materials Science Nanchang University Ganjiang Innovation Academy Chinese Academy of Sciences CAS Key laboratory of Design and Assembly of Functional nanostructures and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of Sciences Xiamen Key laboratory of Rare Earth Photoelectric Functional Materials Xiamen Research Center of Rare Earth MaterialsHaixi InstituteChinese Academy of Sciences

Full-spectrum phosphor-converted white-light-emitting diodes（pc-WLED） are emerging as a mainstream technology in semiconductor lighting.Nevertheless,high-performance blue phosphor which can be excited efficiently by a 400 nm NUV diode chip is still lacking.Herein,we present a blue-emitting Na3KMg7（PO4）6:Eu2+phosphor synthesized by the solid-reaction method.Particularly,we find that the using of Li2CO3as flux can significantly improve the crystal quality and thus the emission efficiency of the phosphor.Meanwhile,the excitation peak of the phosphor shifts from 365 to 400 nm,which is pivotal for efficient NUV（400 nm） diode chip excitation.The practical Eu2+concentration is also enhanced by using Li2CO3as flux,and the absorption efficiency is greatly increased.This phosphor exhibits superior PL the rmal stability,na mely retains 94% integrated photoluminescence intensity at 150℃of that at 25℃.As a result,the optimized phosphor shows an emission band peaked at 437 nm with a bandwidth of 40 nm and a high external photoluminescence quantum yield of 51.7%.Finally,a pc-WLED was fabricated by using NKMPO:Eu2+blue,Sr2SiO4:Eu2+green,CaAlSiN3:Eu2+red phosphors,and a400 nm NUV diode chip.It shows a high color rendering index of Ra=96.4 and a correlated color temperature of 4358 K.These results prove that NKMPO:Eu2+is a promising blue phosphor for fullspectrum WLED based on NUV diode chips.

关键词： Blue phosphor Eu2+ Full-spectrum white LEDs Na3KMg7(PO4)6 Rare earths

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Three-dimensional nanoscale vortex line visualization and chiral nanostructure fabrication of tightly focused multi-vortex beams via direct laser writing

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Photonics Research 2024年第1期12卷 70-77页

作者： MENGDI LUO JISEN WEN PENGCHENG MA QIUYUAN SUN XIANMENG XIA GANGYAO ZHAN ZHENYAO YANG LIANG XU DAZHAO ZHU CUIFANG KUANG XU LIU Research Center for Intelligent Chips and Devices Zhejiang LabHangzhou 311100China State Key laboratory of Extreme Photonics and Instrumentation College of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou 311200China

optical singularity is pivotal in nature and has attracted wide interest from many disciplines nowadays,including optical communication,quantum optics,and biomedical imaging.Visualizing vortex lines formed by phase singularities and fabricating chiral nanostructures using the evolution of vortex lines are of great significance.In this paper,we introduce a promising method based on two-photon polymerization direct laser writing(2PP-DLW)to record the morphology of vortex lines generated by tightly focused multi-vortex beams(MVBs)at the nanoscale.Due to Gouy phase,the singularities of the MVBs rotate around the optical axis and move towards each other when approaching the focal plane.The propagation dynamics of vortex lines are recorded by 2PP-DLW,which explicitly exhibits the evolution of the phase singularities.Additionally,the MVBs are employed to fabricate stable three-dimensional chiral nanostructures due to the spiral-forward property of the vortex line.Because of the obvious chiral features of the manufactured nanostructures,a strong vortical dichroism is observed when excited by the light carrying orbital angular momentum.A number of applications can be envisioned with these chiral nanostructures,such as optical sensing,chiral separation,and information storage.

关键词： vortex chiral singularity

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Deformable Catalytic Material Derived from Mechanical Flexibility for Hydrogen Evolution Reaction

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Nano-Micro Letters 2024年第2期16卷 287-311页

作者： Fengshun Wang Lingbin Xie Ning Sun Ting Zhi Mengyang Zhang Yang Liu Zhongzhong Luo Lanhua Yi Qiang Zhao Longlu Wang College of Electronic and optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts&Telecommunications(NJUPT)9 WenyuanNanjing 210023People’s Republic of China Key laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education School of ChemistryXiangtan UniversityXiangtan 411105People’s Republic of China State Key laboratory of Organic Electronics and Information Displays&Jiangsu Key laboratory for Biosensors Institute of Advanced Materials(IAM)&Institute of Flexible Electronics(Future Technology)Nanjing University of Posts&Telecommunications9 WenyuanNanjing 210023People’s Republic of China

Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions,especially electrocatalytic hydrogen evolution reaction(HER).In recent years,deformable catalysts for HER have made great progress and would become a research hotspot.The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration.The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties.Here,firstly,we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process.Secondly,a series of strategies to design highly active catalysts based on the mechanical flexibility of lowdimensional nanomaterials were summarized.Last but not least,we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts,which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.

关键词： Deformable catalytic material Micro-nanostructures evolution Mechanical flexibility Hydrogen evolution reaction

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Biomimetic leaf structures for ultra-thin electromagnetic wave absorption

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Nano Research 2024年第5期17卷 4507-4516页

作者： Shikun Hou Ying Wang Feng Gao Fei Jin Benfeng Zhu Qiong Wu Hongliang Ge Zhihai Cao Hua Yang Magnetism Key laboratory of Zhejiang Province&College of optical and Electronic Technology China Jiliang UniversityHangzhou 310018China Department of Materials Science and Engineering Guangdong Technion-Israel Institute of TechnologyShantou 515063China Key laboratory of Advanced Textile Materials and Manufacturing Technology and Engineering Research Center for Eco-Dyeing&Finishing of Textiles Ministry of EducationZhejiang Sci-Tech UniversityHangzhou 310018China

Ultra-thin electromagnetic wave(EMW)absorbers present challenging demands on EMW absorption performance.Drawing inspiration from heather leaf structures,this study introduces an innovative design strategy for EMW absorbing material,proposing biomimetic leaf SnO_(2) structures(bio-SnO_(2))on carbon fabric(CF).By employing leaf-shaped SnS2 as precursors,biomimetic leaf SnO_(2) nanostructures are constructed on CF surface after a simple thermal treatment,resulting in bio-SnO_(2)@CF composite.Experimental results indicate that bio-SnO_(2)@CF exhibits an exceptional minimum reflection loss of-54.8 dB at an incredibly thin thickness of 1.2 mm.Radar cross section(RCS)simulations further validate the outstanding EMW attenuation ability of bio-SnO_(2)@CF,attaining a maximum RCS reduction value of 16.9 dBm^(2) at an incident wave angle ofθ=0°.This novel research showcases the biomimetic structural design strategy and its remarkable function in enhancing the EMW absorbing performance at ultra-thin absorber thickness.

关键词： biomimetic leaf structures electromagnetic wave absorption ultra-thin thickness

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发射峰为875 nm的高热稳定性立方相Sc(PO_(3))_(3):Cr^(3+)荧光粉

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Science China Materials 2024年第3期67卷 931-938页

作者：刘乐聂文东吴会杰张景荣梁思思朱浩淼 CAS Key laboratory of Design and Assembly of Functional nanostructures Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China Xiamen Key laboratory of Rare Earth Photoelectric Functional Materials Xiamen Research Center of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen 361021China

近红外(NIR)荧光粉转换型发光二极管(pc-LED)具有尺寸小、效率高以及光谱易于调节的特点,在特种照明、传感、微型近红外光谱仪等各领域有很好的应用前景.目前,已报道的发射波长超过850 nm的近红外荧光粉的荧光热稳定性较差.在本项研究中... 详细信息

近红外(NIR)荧光粉转换型发光二极管(pc-LED)具有尺寸小、效率高以及光谱易于调节的特点,在特种照明、传感、微型近红外光谱仪等各领域有很好的应用前景.目前,已报道的发射波长超过850 nm的近红外荧光粉的荧光热稳定性较差.在本项研究中,我们合成了一种立方相结构的Sc(PO_(3))_(3):xCr^(3+)(x=0,1,5,10,12,14,16,18 at%)荧光粉,其具有725–1150 nm的宽发射带,发射峰为875 nm,与之前报道的发射峰超过850 nm的荧光粉相比,其表现出优异的热稳定性,在423 K下,5 at%样品的积分发光强度保留了室温下的73.4%.通过对比研究立方相和单斜相Sc(PO_(3))_(3):Cr^(3+)荧光粉变温X射线衍射,发现立方相荧光粉优异的荧光热稳定性可能归因于高温下较小的键长和键角变化.利用该荧光粉制备的NIR pc-LED在150 mA电流驱动下,产生了26.62 mW的NIR辐射功率.驱动电流为10 mA时,最高电光转换效率为11.87%.这项工作为开发具有优异荧光热稳定性的Cr^(3+)离子掺杂近红外荧光粉提供了思路.

关键词： near infrared phosphor pc-LEDs broadband emission Sc(PO_(3))_(3) luminescent materials

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Optimization of transverse unidirectional scattering by morphology modification of irregular V-shaped silicon nanoantennas

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Optoelectronics Letters 2024年

作者： ZENG Ming ZHAO Feng WANG Xianghui School of Electrical Engineering and Automation Tianjin University Institute of Modern Optics Tianjin Key laboratory of Micro-scale optical Information Science and Technology Nankai University

A scheme based on irregular V-shaped silicon nanoantennas is proposed to optimize transverse unidirectional scattering under plane wave irradiation. Traditional methods of designing regular shapes offer fewer parameters and higher search efficiency. However， due to the limitations of regular shapes， it is challenging to meet high-precision design requirements. Irregular shape design allows for a broader range of adjustments， but the complexity of shape parameters leads to lower search efficiency and a higher likelihood of converging to local optima. This paper proposes an irregular fine-tuning scheme for regular V-shaped silicon nanoscale antennas that combines the advantages of both approaches. Firstly， the regular V-shaped nanoantenna is tuned to generate transverse unidirectional scattering and then transformed into a binary image. Subsequently， the kernel geometry is fixed while the morphology is modified by a surface contour method to form irregular V-shapes. Finally， those irregular V-shapes are input into a pre-trained predictor cascaded by Bayesian optimization and the nanoantenna’s shape is progressively updated by minimizing the mean squared error between the target scattering and the predicted scattering of irregular nanostructures. The results demonstrate that the optimized irregular V-shaped nanoantennas exhibit perfecter transverse directional scattering and the scattering tail in the opposite direction is greatly shrunk， the mean square error of its scattering compared to the ideal unidirectional scattering has decreased by approximately 29% after optimization. Our findings can promote all-dielectric nanoantennas with specific directional scattering in integrated nanophotonics circuits and sensors.

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三维声子晶体中的布里渊克莱因空间和半旋转空间（英文）

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Science Bulletin 2024年第13期 2050-2058页

作者：朱震霄杨林运吴吉恩孟岩郗翔颜贝陈景明陆久阳黄学勤邓伟胤尚策沈平杨怡豪陈红胜向柯鑫刘癸庚刘正猷高振 State Key laboratory of optical Fiber and Cable Manufacture Technology Department of Electronic and Electrical Engineering Southern University of Science and Technology School of Physics and Optoelectronics South China University of Technology Key laboratory of Artificial Micro-and nanostructures of Ministry of Education and School of Physics and Technology Wuhan University King Abdullah University of Science and Technology (KAUST) Physical Science and Engineering Division (PSE) Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation ZJU-Hangzhou Global Science and Technology Innovation CenterCollege of Information Science and Electronic Engineering ZJU-UIUC Institute Zhejiang University Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Institute for Advanced Studies Wuhan University

The Bloch band theory and Brillouin zone（BZ） that characterize wave-like behaviors in periodic mediums are two cornerstones of contemporary physics, ranging from condensed matter to topological physics.Recent theoretical breakthrough revealed that, under the projective symmetry algebra enforced by artificial gauge fields, the usual two-dimensional（2D） BZ（orientable Brillouin two-torus） can be fundamentally modified to a non-orientable Brillouin Klein bottle with radically distinct manifold topology.However, the physical consequence of artificial gauge fields on the more general three-dimensional（3D） BZ（orientable Brillouin three-torus） was so far missing. Here, we theoretically discovered and experimentally observed that the fundamental domain and topology of the usual 3D BZ can be reduced to a non-orientable Brillouin Klein space or an orientable Brillouin half-turn space in a 3D acoustic crystal with artificial gauge fields. We experimentally identify peculiar 3D momentum-space non-symmorphic screw rotation and glide reflection symmetries in the measured band structures. Moreover, we experimentally demonstrate a novel stacked weak Klein bottle insulator featuring a nonzero Z2topological invariant and self-collimated topological surface states at two opposite surfaces related by a nonlocal twist, radically distinct from all previous 3D topological insulators. Our discovery not only fundamentally modifies the fundamental domain and topology of 3D BZ, but also opens the door towards a wealth of previously overlooked momentum-space multidimensional manifold topologies and novel gaugesymmetry-enriched topological physics and robust acoustic wave manipulations beyond the existing paradigms.

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Tantalum pentoxide:a new material platform for high-performance dielectric metasurface optics in the ultraviolet and visible region

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Light(Science & Applications) 2024年第1期13卷 142-152页

作者： Cheng Zhang Lu Chen Zhelin Lin Junyeob Song Danyan Wang Moxin Li Okan Koksal Zi Wang Grisha Spektor David Carlson Henri J.Lezec Wenqi Zhu Scott Papp Amit Agrawal School of optical and Electronic Information&Wuhan National laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhanHubei 430074China National Institute of Standards and Technology GaithersburgMD 20899USA University of Maryland College ParkMD 20742USA National Institute of Standards and Technology BoulderCO 80305USA

Dielectric metasurfaces,composed of planar arrays of subwavelength dielectric structures that collectively mimic the operation of conventional bulk optical elements,have revolutionized the field of optics by their potential in constructing high-efficiency and multi-functional optoelectronic systems on chip.The performance of a dielectric metasurface is largely determined by its constituent material,which is highly desired to have a high refractive index,low optical loss and wide bandgap,and at the same time,be fabrication friendly.Here,we present a new material platform based on tantalum pentoxide(Ta2O5)for implementing high-performance dielectric metasurface optics over the ultraviolet and visible spectral region.This wide-bandgap dielectric,exhibiting a high refractive index exceeding 2.1 and negligible extinction coefficient across a broad spectrum,can be easily deposited over large areas with good quality using straightforward physical vapor deposition,and patterned into high-aspect-ratio subwavelength nanostructures through commonly-available fluorine-gas-based reactive ion etching.We implement a series of highefficiency ultraviolet and visible metasurfaces with representative light-field modulation functionalities including polarization-independent high-numerical-aperture lensing,spin-selective hologram projection,and vivid structural color generation,and the devices exhibit operational efficiencies up to 80%.Our work overcomes limitations faced by scalability of commonly-employed metasurface dielectrics and their operation into the visible and ultraviolet spectral range,and provides a novel route towards realization of high-performance,robust and foundry-manufacturable metasurface optics.

关键词： dielectric optics ultraviolet

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In situ photoelectric biosensing based on ultranarrowband near-infrared plasmonic hot electron photodetection

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Advanced Photonics 2024年第2期6卷 81-89页

作者： Xianghong Nan Wenduo Lai Jie Peng Haiquan Wang Bojun Chen Huifan He Zekang Mo Zikun Xia Ning Tan Zhong Liu Long Wen Dan Gao Qin Chen Jinan University College of Physics&Optoelectronic EngineeringInstitute of NanophotonicsGuangdong Provincial Key Laboratory of Nanophotonic ManipulationGuangzhouChina Tsinghua University Shenzhen International Graduate SchoolState Key Laboratory of Chemical OncogenomicsShenzhenChina Jinan University College of Life Science and TechnologyGuangzhouChina

Narrowband photodetection is an important measurement technique for material analysis and sensing,for example,nondispersive infrared sensing technique.Both photoactive material engineering and nanophotonic filtering schemes have been explored to realize wavelength-selective photodetection,while most devices have a responsive bandwidth larger than 2%of the operating wavelength,limiting sensing performance.Near-infrared photodetection with a bandwidth of less than 0.2%of the operating wavelength was demonstrated experimentally in Au/Si Schottky nanojunctions.A minimum linewidth of photoelectric response down to 2.6 nm was obtained at a wavelength of 1550 nm by carefully tailing the absorptive and radiative loss in the nanostructures.Multiple functions were achieved on chip with the corrugated Au film,including narrowband resonance,light harvesting for sensing and photodetection,and electrodes for hot electron emission.Benefiting from such a unity integration with in situ photoelectric conversion of the optical sensing signal and the ultranarrowband resonance,self-contained on-chip biosensing via simple intensity interrogation was demonstrated with a limit of detection down to 0.0047%in concentration for glucose solution and 150 ng∕m L for rabbit IgG.Promising potential of this technique is expected for the applications in on-site sensing,spectroscopy,spectral imaging,etc.

关键词： plasmonics hot electron sensor photodetector spectroscopy

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Experimental study on effects of gas flow rate on soot characteristics in diffusion flames coupled with plasma

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Science China(Technological Sciences) 2024年第2期67卷 475-485页

作者： QI DanDan CHEN MingXiao TU Xin LIU Dong MIIT Key laboratory of Thermal Control of Electronic Equipment School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China Advanced Combustion laboratory School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Electrical Engineering and Electronics University of LiverpoolLiverpool L693GJUK

This study examined the evolution of morphology and nanostructure of soot particles from the plasma-flame interaction for various gas flow rates.The current study used both optical diagnostic and sampling methods to explore the soot production and combustion characteristics.Soot particles were characterized at the same positions downstream from the flame zone by thermophoretic sampling and transmission electron microscopy.Moreover,X-ray diffraction analysis,and thermogravimetric analysis were performed to study the nanostructure and oxidation reactivity of soot.A reduction in soot concentration was found with the plasma addition,which illustrated an inhibition effect of plasma on soot emission.The increased gas flow rate promoted soot concentration since a growing number of carbons participated in the combustion process.Depending on the gas flow rate(carbon content)variation and plasma activation,either liquid-like soot material with irregularly shaped protrusions or chain-like structure,or a mixture of both,were generated from the diffusion flames.The soot produced by plasma-flame interaction also demonstrated a high correlation between nanostructure and reactivity.The soot from lower carbon content with plasma activation had a shorter fringe length and larger fringe tortuosity related to higher oxidation reactivity.On the contrary,soot from the highest carbon content without plasma-flame interaction exhibited prevalent fullerene-like nanostructures with evident large or small shells and also had a higher carbonization degree resulting in lower oxidation reactivity.

关键词： soot characteristics gas flow rate plasma diffusion flames

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