YIG/SRR结构的磁可调太赫兹左手材料

利用钇铁石榴石(YIG)在外加磁场作用下,等效磁导率为负值和电谐振环结构可以实现负介电常数的性质,组合设计出了一种新型磁可调左手材料.通过理论分析与计算表明,该结构在太赫兹频段范围内实现了左手通带,且左手通带可以随着外加磁场的增大而产生蓝移,达到了磁可调的目的.该结构具有通带性能良好、损耗低、制作方便等优点,在未来太赫兹波功能器件设计中具有广泛的应用前景.     

左手材料设计与制备的研究进展

左手材料是一种介电常数ε和磁导率μ同时为负值的超材料,具有许多非常奇异的电磁学性质.阐述了左手材料的基本概念和性质,介绍了能够同时实现负介电常数和负磁导率的Ω形、S形和树枝等单一结构,综述了利用机械加工法和化学制备法制备的高频段负磁导率材料,以及基于耦合作用的电磁波垂直入射条件下左手材料的设计与制备方法,阐述了超材料负磁导率或左手行为的验证方法,最后展望了左手材料的应用前景.     

氧化锌纳米棒的研究进展

氧化锌具有良好的化学惰性和生物兼容性,也是目前同时具有压电性质和半导体性质的唯一材料.氧化锌纳米棒及其阵列由于具有新奇的物理和化学性质而成为目前研究的热点之一.综述了近年来氧化锌纳米棒的制备方法、合成机理及应用研究等,展望了其广阔的应用前景.     

原子转移自由基聚合法制备聚合物刷

介绍了原子转移自由基聚合法(ATRP)制备聚合物刷(平面刷、球形刷和分子刷)的研究进展及应用前景.聚合物刷子的奇异构象使其具有许多新奇的性质和潜在的应用前景.ATRP是制备具有可控结构的聚合物以及有机/无机杂化材料的一种较好的方法.通过ATRP制备聚合物刷,可以有效地改变聚合物刷的组成和聚合度,从而改变聚合物刷的表面性质,设计出具有新型结构及性能的材料.     

纸质机械运动机构设计研究

目的 实现玩具类产品的机械运动机构的纸质化.结合纸材料的力学特性,探索纸材料应用于机械产品制作的可行性,以及基于纸材料的机械零件结构的设计方法.方法 依据纸材料本身的特性,结合机械运动机构的传动方式,思考纸质机械机构设计的方式,总结出转动副、移动副、齿轮等各类典型机械运动机构纸质化设计方法,在实现运动功能的基础上确保运动零件的力学强度.同时以纸质齿轮设计为例,利用CorelDraw作为二次开发平台开发插件,降低纸质机械机构设计的操作难度.结论 以机械玩具产品为案例,对纸质材料力学特性的机械机构设计方法进行实践,论证了低成本机械玩具创意设计方法的可行性,为机械产品创意设计探索了新的材料选择,也为纸产品创新发展提供了更多的设计概念.     

介孔材料的制备、表征、组装及其应用

介孔材料因具有一系列独特性质而成为近年来材料研究的热点.对介孔材料的制备技术进行了简要介绍并分析了其影响因素,概括了常用的表征方法,进一步系统阐述了介孔材料的组装及应用,并展望了介孔材料研究的发展前景.     

有机/复合相变储能材料研究进展

相变储能材料在相变过程中实现能量的储存或释放,这种材料因具有优良的性能而成为近年来研究的热点.主要介绍了相变材料的分类、性质以及评价标准,着重讨论了有机/复合相变材料的一些常见的制备方法,如原位聚合法、界面聚合法、喷雾干燥法、多孔材料吸附法和溶胶-凝胶法等.概括了相变材料在太阳能利用、建筑材料、空调蓄冷、工业余热回收和军事伪装隐身等方面的应用研究,并提出了相变材料研究的未来发展趋势.     

基于外场调控的智能热控超材料

超材料因其结构可设计性和优异的物理性能成为近年来的研究热点.热学超材料因能针对性设计红外发射率和反射率等热性能而备受关注.近年来热学超材料朝着"智能化"和"多功能"的趋势发展,智能热调控超材料是实现高效热控的重要途径.以相变涂层为主的传统智能热控材料具有精度低、调控幅度小和可设计性差等局限性.超结构设计能使材料实现理想的电磁特性,并通过表面等离激元等不同的损耗机制实现特定波段的完美吸收.在此基础上,引入相变材料或可重构表面实现的智能热控超材料能够快速、精准地实现热性能的大幅调控.智能热控超材料可实现热场、电场、力场和其他外场等多方式调控.合理的超结构设计能够使材料在热场的被动调控下同时实现吸收率和吸收峰峰位稳定调谐.基于电场调控的材料具有更高的调制精度和快速响应能力.生物启迪的力学热控超材料因其设计简单和柔性的优势而有望大面积应用.此外,基于磁、光等其他外场实现热调控也有相关报道.本文归纳了智能热控超材料的研究现状,首先简单介绍了完美吸收和智能热控的相关概念,从结构设计和损耗机理的角度出发,分析了基于不同外场智能热控超材料的调控途径和研究进展,最后总结了智能热控超材料目前面临的挑战并展望其未来的发展方向.     

有机室温磷光材料在生物医学中的应用

近年来,纯有机室温磷光(RTP)材料由于具有长的激发态寿命、大的Stokes位移、丰富的激发态性质等特点而备受研究者的广泛关注.相较于重金属配合物或无机磷光材料,有机磷光材料的原料来源广、成本低、合成条件温和,兼具质轻、柔性、可大面积制备等诸多优势,室温磷光材料在数据加密、传感、有机电致发光、生物成像等领域展现出良好的应用前景.有机磷光材料具有长寿命发光和三线态发射的特征,利用时间分辨技术能有效扣除生物组织自身的背景荧光干扰,极大地提高生物传感和成像的灵敏度与信噪比,并通过与三线态氧气的TTA过程,有望实现这类材料在光动力抗癌与抗菌等生物领域的应用.而且纯有机磷光材料不存在重金属元素的毒性问题.因此,纯有机磷光材料在生物成像、癌症治疗等生物领域实现很好的应用.本文总结了近年来有机室温磷光在生物应用中的研究进展,包括生物成像、生物传感、光动力抗癌、抗菌等.最后,提出该领域尚待解决的问题并展望未来前景.     

金属间化合物Mg2Si的研究进展

金属间化合物Mg2Si作为高强轻质结构材料以及半导体热电材料均很有发展前途.综述了Mg2Si的基本性质、制备工艺和应用,着重阐述了Mg2Si制备及其作为增强相的研究进展,指出了存在的问题以及今后的研究方向.     

2D Ruddlesden–Popper Perovskites for Optoelectronics

Conventional 3D organic–inorganic halide perovskites have recently undergone unprecedented rapid development. Yet, their inherent instabilities over moisture, light, and heat remain a crucial challenge prior to the realization of commercialization. By contrast, the emerging 2D Ruddlesden?Popper‐type perovskites have recently attracted increasing attention owing to their great environmental stability. However, the research of 2D perovskites is just in their infancy. In comparison to 3D analogues, they are natural quantum wells with a much larger exciton binding energy. Moreover, their inner structural, dielectric, optical, and excitonic properties remain to be largely explored, limiting further applications. This review begins with an introduction to 2D perovskites, along with a detailed comparison to 3D counterparts. Then, a discussion of the organic spacer cation engineering of 2D perovskites is presented. Next, quasi‐2D perovskites that fall between 3D and 2D perovskites are reviewed and compared. The unique excitonic properties, electron–phonon coupling, and polarons of 2D perovskites are then be revealed. A range of their (opto)electronic applications is highlighted in each section. Finally, a summary is given, and the strategies toward structural design, growth control, and photophysics studies of 2D perovskites for high‐performance electronic devices are rationalized.     

Efficient Room‐Temperature Phosphorescence from Organic–Inorganic Hybrid Perovskites by Molecular Engineering

Solution‐processed organic–inorganic hybrid perovskites are promising emitters for next‐generation optoelectronic devices. Multiple‐colored, bright light emission is achieved by tuning their composition and structures. However, there is very little research on exploring optically active organic cations for hybrid perovskites. Here, unique room‐temperature phosphorescence from hybrid perovskites is reported by employing novel organic cations. Efficient room‐temperature phosphorescence is activated by designing a mixed‐cation perovskite system to suppress nonradiative recombination. Multiple‐colored phosphorescence is achieved by molecular design. Moreover, the emission lifetime can be tuned by varying the perovskite composition to achieve persistent luminescence. Efficient room‐temperature phosphorescence is demonstrated in hybrid perovskites that originates from the triplet states of the organic cations, opening a new dimension to the further development of perovskite emitters with novel functional organic cations for versatile display applications.     

Two‐Dimensional Materials for Halide Perovskite‐Based Optoelectronic Devices

Halide perovskites have high light absorption coefficients, long charge carrier diffusion lengths, intense photoluminescence, and slow rates of non‐radiative charge recombination. Thus, they are attractive photoactive materials for developing high‐performance optoelectronic devices. These devices are also cheap and easy to be fabricated. To realize the optimal performances of halide perovskite‐based optoelectronic devices (HPODs), perovskite photoactive layers should work effectively with other functional materials such as electrodes, interfacial layers and encapsulating films. Conventional two‐dimensional (2D) materials are promising candidates for this purpose because of their unique structures and/or interesting optoelectronic properties. Here, we comprehensively summarize the recent advancements in the applications of conventional 2D materials for halide perovskite‐based photodetectors, solar cells and light‐emitting diodes. The examples of these 2D materials are graphene and its derivatives, mono‐ and few‐layer transition metal dichalcogenides (TMDs), graphdiyne and metal nanosheets, etc. The research related to 2D nanostructured perovskites and 2D Ruddlesden–Popper perovskites as efficient and stable photoactive layers is also outlined. The syntheses, functions and working mechanisms of relevant 2D materials are introduced, and the challenges to achieving practical applications of HPODs using 2D materials are also discussed.     

Hybrid Lead Halide Perovskites for Ultrasensitive Photoactive Switching in Terahertz Metamaterial Devices

The recent meteoric rise in the field of photovoltaics with the discovery of highly efficient solar‐cell devices is inspired by solution‐processed organic–inorganic lead halide perovskites that exhibit unprecedented light‐to‐electricity conversion efficiencies. The stunning performance of perovskites is attributed to their strong photoresponsive properties that are thoroughly utilized in designing excellent perovskite solar cells, light‐emitting diodes, infrared lasers, and ultrafast photodetectors. However, optoelectronic application of halide perovskites in realizing highly efficient subwavelength photonic devices has remained a challenge. Here, the remarkable photoconductivity of organic–inorganic lead halide perovskites is exploited to demonstrate a hybrid perovskite–metamaterial device that shows extremely low power photoswitching of the metamaterial resonances in the terahertz part of the electromagnetic spectrum. Furthermore, a signature of a coupled phonon–metamaterial resonance is observed at higher pump powers, where the Fano resonance amplitude is extremely weak. In addition, a low threshold, dynamic control of the highly confined electric field intensity is also observed in the system, which could tremendously benefit the new generation of subwavelength photonic devices as active sensors, low threshold optically controlled lasers, and active nonlinear devices with enhanced functionalities in the infrared, optical, and the terahertz parts of the electromagnetic spectrum.     

Merits and Challenges of Ruddlesden–Popper Soft Halide Perovskites in Electro‐Optics and Optoelectronics

Following the rejuvenation of 3D organic–inorganic hybrid perovskites, like CH₃NH₃PbI₃, (quasi)‐2D Ruddlesden–Popper soft halide perovskites R₂A_n?1Pb_nX_3n+1 have recently become another focus in the optoelectronic and photovoltaic device community. Although quasi‐2D perovskites were first introduced to stabilize optoelectronic/photovoltaic devices against moisture, more interesting properties and device applications, such as solar cells, light‐emitting diodes, white‐light emitters, lasers, and polaritonic emission, have followed. While delicate engineering design has pushed the performance of various devices forward remarkably, understanding of the fundamental properties, especially the charge‐transfer process, electron–phonon interactions, and the growth mechanism in (quasi)‐2D halide perovskites, remains limited and even controversial. Here, after reviewing the current understanding and the nexus between optoelectronic/photovoltaic properties of 2D and 3D halide perovskites, the growth mechanisms, charge‐transfer processes, vibrational properties, and electron–phonon interactions of soft halide perovskites, mainly in quasi‐2D systems, are discussed. It is suggested that single‐crystal‐based studies are needed to deepen the understanding of the aforementioned fundamental properties, and will eventually contribute to device performance.     

Ultrathin Ruddlesden–Popper Perovskite Heterojunction for Sensitive Photodetection

Thanks to their unique optical and electric properties, 2D materials have attracted a lot of interest for optoelectronic applications. Here, the emerging 2D materials, organic–inorganic hybrid perovskites with van der Waals interlayer interaction (Ruddlesden–Popper perovskites), are synthesized and characterized. Photodetectors based on the few‐layer Ruddlesden–Popper perovskite show good photoresponsivity as well as good detectivity. In order to further improve the photoresponse performance, 2D MoS₂ is chosen to construct the perovskite–MoS₂ heterojunction. The performance of the hybrid photodetector is largely improved with 6 and 2 orders of magnitude enhancement for photoresponsivity (10⁴ A W^?1) and detectivity (4 × 10¹⁰ Jones), respectively, which demonstrates the facile charge separation at the interface between perovskite and MoS₂. Furthermore, the contribution of back gate tuning is proved with a greatly reduced dark current. The results demonstrated here will open up a new field for the investigation of 2D perovskites for optoelectronic applications.     

Flexible Quasi-2D Perovskite/IGZO Phototransistors for Ultrasensitive and Broadband Photodetection

Organic–inorganic hybrid perovskites (PVKs) have recently emerged as attractive materials for photodetectors. However, the poor stability and low electrical conductivity still restrict their practical utilization. Owing to the quantum-well feature of two-dimensional (2D) Ruddlesden–Popper PVKs (2D PVKs), a promising quasi-2D PVK/indium gallium zinc oxide (IGZO) heterostructure phototransistor can be designed. By using a simple ligand-exchange spin-coating method, quasi-2D PVK fabricated on flexible substrates exhibits a desirable type-II energy band alignment, which facilitates effective spatial separation of photoexcited carriers. The device exhibits excellent photoresponsivity values of >10⁵ A W⁻¹ at 457 nm, and broadband photoresponse (457–1064 nm). By operating the device in the depletion regime, the specific detectivity is found to be 5.1 × 10¹⁶ Jones, which is the record high value among all PVK-based photodetectors reported to date. Due to the resistive hopping barrier in the quasi-2D PVK, the device can also work as an optoelectronic memory for near-infrared information storage. More importantly, the easy manufacturing process is highly beneficial, enabling large-scale and uniform quasi-2D PVK/IGZO hybrid films for detector arrays with outstanding ambient and operation stabilities. All these findings demonstrate the device architecture here provides a rational avenue to the design of next-generation flexible photodetectors with unprecedented sensitivity.     

Hybridizing Plasmonic Materials with 2D‐Transition Metal Dichalcogenides toward Functional Applications

Recently, 2D transition metal dichalcogenides (TMDs) have become intriguing materials in the versatile field of photonics and optoelectronics because of their strong light–matter interaction that stems from the atomic layer thickness, broadband optical response, controllable optoelectronic properties, and high nonlinearity, as well as compatibility. Nevertheless, the low optical cross‐section of 2D‐TMDs inhibits the light–matter interaction, resulting in lower quantum yield. Therefore, hybridizing the 2D‐TMDs with plasmonic nanomaterials has become one of the promising strategies to boost the optical absorption of thin 2D‐TMDs. The appeal of plasmonics is based on their capability to localize and enhance the electromagnetic field and increase the optical path length of light by scattering and injecting hot electrons to TMDs. In this regard, recent achievements with respect to hybridization of the plasmonic effect in 2D‐TMDs systems and its augmented optical and optoelectronic properties are reviewed. The phenomenon of plasmon‐enhanced interaction in 2D‐TMDs is briefly described and state‐of‐the‐art hybrid device applications are comprehensively discussed. Finally, an outlook on future applications of these hybrid devices is provided.     

Fluorinated 2D Lead Iodide Perovskite Ferroelectrics

Hybrid perovskite materials are famous for their great application potential in photovoltaics and optoelectronics. Among them, lead‐iodide‐based perovskites receive great attention because of their good optical absorption ability and excellent electrical transport properties. Although many believe the ferroelectric photovoltaic effect (FEPV) plays a crucial role for the high conversion efficiency, the ferroelectricity in CH₃NH₃PbI₃ is still under debate, and obtaining ferroelectric lead iodide perovskites is still challenging. In order to avoid the randomness and blindness in the conventional method of searching for perovskite ferroelectrics, a design strategy of fluorine modification is developed. As a demonstration, a nonpolar lead iodide perovskite is modified and a new 2D fluorinated layered hybrid perovskite material of (4,4‐difluorocyclohexylammonium)₂PbI₄, 1 , is obtained, which possesses clear ferroelectricity with controllable spontaneous polarization. The direct bandgap of 2.38 eV with strong photoluminescence also guarantees the direct observation of polarization‐induced FEPV. More importantly, the 2D structure and fluorination are also expected to achieve both good stability and charge transport properties. 1 is not only a 2D fluorinated lead iodide perovskite with confirmed ferroelectricity, but also a great platform for studying the effect of ferroelectricity and FEPV in the context of lead halide perovskite solar cells and other optoelectronic applications.     

One‐Dimensional Dielectric/Metallic Hybrid Materials for Photonic Applications

Explorations of 1D nanostructures have led to great progress in the area of nanophotonics in the past decades. Based on either dielectric or metallic materials, a variety of 1D photonic devices have been developed, such as nanolasers, waveguides, optical switches, and routers. What's interesting is that these dielectric systems enjoy low propagation losses and usually possess active optical performance, but they have a diffraction‐limited field confinement. Alternatively, metallic systems can guide light on deep subwavelength scales, but they suffer from high metallic absorption and can work as passive devices only. Thus, the idea to construct a hybrid system that combines the merits of both dielectric and metallic materials was proposed. To date, unprecedented optical properties have been achieved in various 1D hybrid systems, which manifest great potential for functional nanophotonic devices. Here, the focus is on recent advances in 1D dielectric/metallic hybrid systems, with a special emphasis on novel structure design, rational fabrication techniques, unique performance, as well as their wide application in photonic components. Gaining a better understanding of hybrid systems would benefit the design of nanophotonic components aimed at optical information processing.