两种宽谱带蓝光发射材料的制备、表征及光学特性

合成了两种以钙为中心金属离子的有机电致发光材料2-(2-羟基苯基)苯并噻唑钙Ca(BTZ)₂和2-(2-羟基苯基苯并噻唑)-(1,10-邻菲罗啉)合钙Ca(BTZ)₂phen。通过红外光谱、紫外-可见光吸收光谱、循环伏安曲线、原子力显微镜以及光致发光光谱表征了材料的结构、光学带隙、能带结构、成膜性以及光学性能。实验结果表明,在DMSO溶液中,Ca(BTZ)₂的紫外吸收峰主要为290,330,422nm;Ca(BTZ)₂phen的紫外吸收峰主要为292,330,428nm。Ca(BTZ)₂的荧光发射峰为458nm和500nm,色坐标为x=0.2176,y=0.3223;Ca(BTZ)₂phen的荧光发射峰主要为465nm和514nm,色坐标为x=0.2418,y=0.3817。利用真空热蒸镀法可以得到均匀致密的Ca(BTZ)₂phen的薄膜,其粗糙度为1.56。Ca(BTZ)₂薄膜也有望通过旋涂制备。实验发现Ca(BTZ)₂与Ca(BTZ)₂phen的荧光光谱几乎覆盖整个可见光区域,为宽谱带发光材料,有望设计成合理的器件结构实现白光发射。     

Electronic Structure and Electromagnetic Properties for 2D Electromagnetic Functional Materials in Gigahertz Frequency

Two‐dimensional (2D) materials exhibit massive potential for research and development in the scientific world due to the unique electrical, optical, thermal, and mechanical properties. Particularly, they have received intensive attentions in the microwave absorption (MA) and electromagnetic interference (EMI) shielding. Herein, the structure and electronic state of 2D materials are examined systematically, and the origination of electromagnetic (EM) response is shown, including electron transport, dipole relaxation, magnetic resonance, and eddy current. Furthermore, the latest research progress of 2D materials in EM field is introduced, and the application prospect and limitation are highlighted.     

Nanoscale Transition Metal Dichalcogenides: Structures,Properties, and Applications

Transition metal dichalcogenides (TMDs), such as MoS₂, MoSe₂, WS₂, and WSe₂, are layered materials with strong in-plane ionic-covalent bonds and weak out-of-plane van der Waals interactions, enabling formation of various nanostructures, such as nanotubes, nanoribbons, nanoflakes, and fullerene-like nanoparticles. Various remarkable properties have been found recently in these nanostructures, opening up brand new opportunities for their applications in nanoelectronics, optoelectronics, spintronics and structural materials. In this article, we present recent advances in the study of two-dimensional TMDs and their derivatives with special emphasis on structures, morphologies, properties (electronic, magnetic, thermal, mechanical), and applications (transistors, sensors, catalysts, lubricants, and composite materials). In addition, routes for modifying these properties by chemical doping, defect engineering, strain engineering, and electric fields are discussed. Our intent is to present a state-of-the-art view in this fast evolving field, with a balanced theoretical and experimental perspective.     

Toward Quantum Paraelectric,Paraelastic, and Paramagnetic 2D Materials

Quantum fluctuations are known to affect the finite-temperature properties of materials made out of light elements such as hydrogen and helium. More recently, it has also been realized that quantum effects may play a role on structural transformations of ferroic materials containing heavier atoms, provided the energy barrier separating two different phases is small when compared to thermal fluctuations. Herein, 2D ferroelectric and ferroelastic materials are showcased as potential candidates to experience quantum effects on their structural conformation at liquid helium temperatures. A brief literature overview of the path integral molecular dynamics approach, which could be useful for the discovery of quantum paraelectric, paraelastic, and paramagnetic behavior in 2D materials, is also provided.     

TiN/TiB2纳米复合材料的合成与性能

 结合高能球磨和高温高压实验技术,制备了块体TiN/TiB₂纳米复合材料。通过X射线衍射和拉曼光谱对材料的微观结构进行了研究。结果表明,采用金属Ti和六方BN为原料,在球磨过程和高温高压实验过程中,TiN先于TiB₂形成,球磨70 h后有少量的纳米晶TiN开始形成。在高温高压实验中,在样品腔的合成温度低于1 300 ℃时,没有TiB₂出现;当温度达到1 300 ℃后,合成出了TiN和TiB₂的复合材料。对所合成的块状材料的热膨胀性和导电性能进行了测试。     

Tb3+和Na2WO4共掺杂SiO2材料的制备及其发光性质

通过溶胶-凝胶技术制备了稀土离子Tb3 和Na2WO4共掺杂的SiO2材料,利用DTA-TG,IR,XRD等测试手段研究了材料的结构。材料属于非晶态,800℃退火后Tb3 和Na2WO4共掺杂样品的主要结构为SiO2的网状结构。通过三维荧光光谱,荧光激发光谱和发射光谱,分析探讨了Na2WO4对掺稀土离子的SiO2体系发光性质的影响。结果显示,在230nm激发下,样品显示Tb3 的5D4—7Fj(j=4,5,6)和5D3—7Fj(j=4,5,6)发射光谱,在紫外灯的照射下,发射均匀的蓝绿色荧光,说明样品掺杂均匀且分散性较好。Na2WO4的掺入,并不影响Tb3 在SiO2基质中的发射峰的主要位置,但对发光强度有很大的影响,敏化了5D4—7F6蓝色跃迁而猝灭了5D4—7F5绿色跃迁,使材料发射蓝绿色荧光。文章通过所得的能级图,对样品的跃迁机理进行了分析。     

Preparation,Properties and Applications of Chitosan-Based Biocomposites/Blend Materials: A Review

Taking inspiration from many published chitosan (Cs)-based biocomposites, this article is written to highlight the significant effect of reinforcing and/or blending Cs polymer with the different constituents to increase various properties (mechanical, hydrophilic, thermal, adsorption ability and stability) of Cs without sacrificing any of its positive properties. It is concluded that the properties of Cs biocomposites with a synthetic constituent have contributed to its rigidity since only mechanical interaction occurred at the interfacial region. Instead of physical interactions, the addition of an organic constituent also promoted the chemical interactions at the interfacial region of the Cs biocomposites. This consequently produced Cs biocomposites with synthetic constituents with relatively low strength and stiffness but high resistance to fracture, whereas the ones with an organic constituent have high strength and stiffness but are very brittle. This review also screens the current applications of Cs-based biocomposites in the field of drug delivery, tissue engineering, antibacterial, food packaging, biomedical, metal adsorption and dye removal.     

In-plane optical anisotropy of two-dimensional VOCl single crystal with weak interlayer interaction

Transition-metal oxyhalides $MOX$ ($M = {\rm Fe}$, Cr, V; $O ={\rm oxygen}$, $X= {\rm F}$, Cl, Br, I), an emerging type of two-dimensional (2D) van der Waals materials, have been both theoretically and experimentally demonstrated to possess unique electronic and magnetic properties. However, the intrinsic in-plane anisotropic properties of 2D VOCl still lacks in-depth research, especially optical anisotropy. Herein, a systematic Raman spectroscopic study is performed on VOCl single-crystal with different incident laser polarization at various temperatures. The polarized-dependent Raman scattering spectra reveal that the ${{ A}}_{{\rm g}}$ mode of VOCl show a 2-lobed shape in parallel polarization configuration while a 4-lobed shape in vertical configuration. In addition, the temperature-dependent and thickness-dependent Raman scattering spectra confirm a relatively weak van der Waals interaction between each layers among VOCl single crystal. These findings might provide better understanding on the in-plane anisotropic phenomenon in VOCl layers, thus will accelate further application of 2D single crystals for nanoscale angle-dependent optoelectronics.     

Review of Raman spectroscopy of two-dimensional magnetic van der Waals materials

Ultrathin van der Waals (vdW) magnets provide a possibility to access magnetic ordering in the two-dimensional (2D) limit, which are expected to be applied in the spintronic devices. Raman spectroscopy is a powerful characterization method to investigate the spin-related properties in 2D vdW magnets, including magnon and spin-lattice interaction, which are hardly accessible by other optical methods. In this paper, the recent progress of various magnetic properties in 2D vdW magnets studied by Raman spectroscopy is reviewed, including the magnetic transition, spin-wave, spin-lattice interaction, symmetry tuning induced by spin ordering, and nonreciprocal magneto-phonon Raman scattering.     

Recent Research on One-Dimensional Silicon-Based Semiconductor Nanomaterials: Synthesis,Structures, Properties and Applications

The field of silicon nanowires (SiNWs) and silicon-based 1D nanostructured heterostructures represent one of the most important research subjects within the nanomaterials family. A series of synthesis approaches of SiNWs and silicon-based 1D nanostructured heterostructures have been developed, and have garnered the greatest attention in the past decades for a variety of applications. This article provides an overview on recent research on the synthesis, properties and applications of SiNWs, silicon nanotubes (SiNTs) and complex silicon-based 1D nanostructures.     

钴掺杂MoSe2共生长中氢气的作用分析及磁电特性研究

采用原位共生长化学气相沉积法,以Co3O4、MoO3、Se粉末为前驱物,710℃下在SiO2衬底上生长掺钴MoSe2纳米薄片,分析讨论氢气含量对其生长及调节机理的影响.表面形貌分析表明,氢气的引入促进了成核所需的氧硒金属化合物以及横向生长中需要的CoMoSe化合物分子的生成;AFM(Atomic Force Microscope)结果表明氢气有利于生长单层二维超薄掺钴MoSe2.随着Co3O4前驱物用量的增加,样品的拉曼和PL(Photoluminescence)谱图分别表现出红移和蓝移现象,带隙实现从1.52—1.57 eV的调制.XPS(X-ray photoelectron spectroscopy)结果分析得到Co的元素组分比为4.4%.通过SQUID-VSM(Superconducting QUantum Interference Device)和器件电学测试分析了样品的磁电特性,结果表明Co掺入后MoSe2由抗磁性变为软磁性;背栅FETs器件的阈值电压比纯MoSe2向正向偏移5 V且关态电流更低;为超薄二维材料磁电特性研究及应用拓展提供了基础探索.     

Theory,preparation, properties and catalysis application in 2D graphynes-based materials

Carbon has three hybridization forms of sp⁻, sp²⁻ and sp³⁻, and the combination of different forms can obtain different kinds of carbon allotropes, such as diamond, carbon nanotubes, fullerene, graphynes (GYs) and graphdiyne (GDY). Among them, the GDY molecule is a single-layer two-dimensional (2D) planar structure material with highly π-conjugation formed by sp⁻ and sp²⁻ hybridization. GDY has a carbon atom ring composed of benzene ring and acetylene, which makes GDY have a uniformly distributed pore structure. In addition, GDY planar material have some slight wrinkles, which makes GDY have better self-stability than other 2D planar materials. The excellent properties of GDY make it attract the attention of researchers. Therefore, GDY is widely used in chemical catalysis, electronics, communications, clean energy and composite materials. This paper summarizes the recent progress of GDY research, including structure, preparation, properties and application of GDY in the field of catalysts.     

Review on Tin (II) Sulfide (SnS) Material: Synthesis,Properties, and Applications

Tin (II) sulphide (SnS), a direct band gap semiconductor compound, has recently received great attention due to its unique properties. Because of low cost, absence of toxicity, and good abundance in nature, it is becoming a candidate for future multifunctional devices particularly for light conversion applications. Although the current efficiencies are low, the cost-per-Watt is becoming competitive. At room temperature, SnS exhibits stable low-symmetric, double-layered orthorhombic crystal structure, having a = 0.4329, b = 1.1192, and c = 0.3984 nm as lattice parameters. These layer-structured materials are of interest in various device applications due to the arrangement of structural lattice with cations and anions. The layers of cations are separated only by van der Waals forces that provide intrinsically chemically inert surface without dangling bonds and surface density of states. As a result, there is no Fermi level pinning at the surface of the semiconductor. This fact leads to considerably high chemical and environmental stability. Further, the electrical and optical properties of SnS can be easily tailored by modifying the growth conditions or doping with suitable dopants without disturbing its crystal structure.

In the last few decades, SnS has been synthesized and studied in the form of single-crystals and thin-films. Most of the SnS single-crystals have been synthesized by Bridgeman technique, whereas thin films have been developed using different physical as well as chemical deposition techniques. The synthesis or development of SnS structures in different forms including single-crystals and thin films, and their unique properties are reviewed here. The observed physical and chemical properties of SnS emphasize that this material could has novel applications in optoelectronics including solar cell devices, sensors, batteries, and also in biomedical sciences. These aspects are also discussed.     

二(2-苯基-8-羟基喹啉)锌和喹啉锌的合成和荧光性质

合成了一种新型二(2-苯基-8-羟基喹啉)锌配合物。利用元素分析、红外吸收光谱等方法表征了结构,并对比研究了二(2-苯基-8-羟基喹啉)锌和喹啉锌的荧光性质,前者的激发光谱在465nm处出现了较强的吸收,并且发射峰位置发生了明显的红移,由喹啉锌的495nm移至2-苯基-8-羟基喹啉锌和喹啉锌的521nm处。对有关的吸收峰的归属进行了讨论,初步认为苯环的取代增加了有机配体π-π键的共轭程度,使HOMO-LUMO之间能隙变小,引起发射峰红移。     

Microfluidic Synthesis of Semiconductor Materials: Toward Accelerated Materials Development in Flow

Controlled synthesis of semiconductor nano/microparticles has attracted substantial attention for use in numerous applications from photovoltaics to photocatalysis and bioimaging due to the breadth of available physicochemical and optoelectronic properties. Microfluidic material synthesis strategies have recently been demonstrated as an effective technique for rapid development, controlled synthesis, and continuous manufacturing of solution-processed semiconductor nano/microparticles, due to enhanced parametric control enabling precise tuning of material properties, size, and morphologies. In this review, the basics of microfluidic material synthesis approaches complemented with recent advances in the flow fabrication of metal oxide, chalcogenide, and perovskite semiconductor particles are discussed. Furthermore, advancements in artificial intelligence (AI)-driven materials–space exploration and accelerated formulation optimization using modular microfluidic reactors are outlined. Finally, future directions for the fabrication of semiconducting materials in flow and the implementation of AI with automated microfluidic reactors for accelerated material discovery and development are presented.     

Recent Advances in Spatial Self-Phase Modulation with 2D Materials and its Applications

In recent years, spatial self-phase modulation (SSPM) with two-dimensional (2D) materials has attracted the attention of many researchers as an emerging and ubiquitous nonlinear optical effect. In this review, the state of the art of 2D material-based SSPM is summarized. SSPM measures or tunes the nonlinearity of 2D materials, and it is also an effective approach to study the band structure of 2D materials. Several modified forms of SSPM, such as high-order, white-light-excited, vector field excited, and optically nonlinearly enhanced SSPM are also presented. Subsequently, the physical origin of the SSPM formation mechanism is compared and analyzed. Furthermore, the applications of SSPM with 2D materials, including passive photonic devices, generation of Bessel beams, and identifying the mode of the orbital angular momentum, are listed. Finally, several urgent problems of the SSPM with 2D materials, potential applications, and prospects for future development are presented.     

Eu~(3+)掺杂的Na_2YMg_2(VO_4)_3荧光粉制备和发光特性

采用溶胶-凝胶法制备了Na2Y1-xMg2(VO4)3∶x Eu~(3+)(x=0.15~0.75)系列自激活荧光粉。用XRD、SEM、光致发光光谱和荧光衰减曲线分别对其结构、形貌和发光性能进行表征。XRD结果显示样品为纯石榴石结构,其中Eu~(3+)取代Y~(3+);SEM照片显示样品为粒径大小在0.3~1μm范围内不规则的光滑球状颗粒;光谱分析表明,Na2YMg2(VO4)3作为自激活发光基质可以被200~400 nm紫外光有效激发,发出源于VO_4~(3-)电荷迁移跃迁的波长范围为400~700 nm的宽谱带绿光。掺杂Eu~(3+)后,在340 nm紫外光激发下同时出现了VO_4~(3-)的电荷迁移带和Eu~(3+)的特征光谱。不同浓度Eu~(3+)掺杂的光谱和荧光衰减曲线表明,存在VO_4~(3-)和Eu~(3+)之间的能量传递。     

A Review of Selenium (Se) Nanoparticles: From Synthesis to Applications

Selenium is an essential trace element that plays a crucial role in various physiological activities, exerting a significant impact on human health. Selenium deficiency can lead to the development of several diseases, while excessive doses can be toxic. In recent years, there is a growing interest in elemental selenium nanoparticles (SeNPs) due to their good biocompatibility, low toxicity, and high antioxidant activity, making them suitable for numerous applications. The quest for enhancing efficacy and reducing toxicity has driven extensive research on SeNPs. This review aims to provide a comprehensive summary of the recent advancements made in the synthesis, characterization, properties, and applications of SeNPs. Moreover, the challenges associated with SeNPs research, as well as the future trends in the field, are thoroughly discussed. This review aims to provide an insight into the current state of research on SeNPs and highlight areas that require further exploration and development.     

Hyperbranched Polyimide-Silica Hybrid Materials: Synthesis,Structure, Dynamics,and Gas Transport Properties

A series of organic–inorganic hybrid materials were prepared from a hyperbranched polyimide precursor (hyperbranched polyamic acid), tetramethoxysilane, and/or 3-glycidyloxypropyl-trimethoxysilane via a sol-gel process. The hyperbranched polyimide-silica hybrids, whose polyimide moieties were based on commercially available monomers 4,4′,4^″-triaminotriphenylmethane and 4,4′-oxydiphthalic anhydride taken in molar ratio 1:1, contained from 10 to 30 wt% silica. Their morphology and dynamics were characterized by using scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, laser-interferometric creep rate spectroscopy, and wide-angle X-ray diffraction. Attention was also focused on the relation between morphology/dynamics and gas transport properties of these materials.