共查询到20条相似文献，搜索用时 0 毫秒
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Lian Hu Huizhen Wu Bingpo Zhang Lingxiao Du Tianning Xu Yongyue Chen Yong Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(15):3099-3109
We explore a strongly interacting QDs/Ag plasmonic coupling structure that enables multiple approaches to manipulate light emission from QDs. Group II–VI semiconductor QDs with unique surface states (SSs) impressively modify the plasmonic character of the contiguous Ag nanostructures whereby the localized plasmons (LPs) in the Ag nanostructures can effectively extract the non‐radiative SSs of the QDs to radiatively emit via SS–LP resonance. The SS–LP coupling is demonstrated to be readily tunable through surface‐state engineering both during QD synthesis and in the post‐synthesis stage. The combination of surface‐state engineering and band‐tailoring engineering allows us to precisely control the luminescence color of the QDs and enables the realization of white‐light emission with single‐size QDs. Being a versatile metal, the Ag in our optical device functions in multiple ways: as a support for the LPs, for optical reflection, and for electrical conduction. Two application examples of the QDs/Ag plasmon coupler for optical devices are given, an Ag microcavity + plasmon‐coupling structure and a new QD light‐emitting diode. The new QDs/Ag plasmon coupler opens exciting possibilities in developing novel light sources and biomarker detectors. 相似文献
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Junyong Park Sanghoon Yoon Kisuk Kang Seokwoo Jeon 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(18):1981-1985
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Seok Min Yoon Hyun Jae Song Hee Cheul Choi 《Advanced materials (Deerfield Beach, Fla.)》2010,22(19):2164-2167
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Knowledge of the phase behavior of polyfluorene solutions and gels has expanded tremendously in recent years. The relationship between the structure formation and photophysics is known at the quantitative level. The factors which we understand control these relationships include virtually all important materials parameters such as solvent quality, side chain branching, side chain length, molecular weight, thermal history and myriad functionalizations. This review describes advances in controlling structure and photophysical properties in polyfluorene solutions and gels. It discusses the demarcation lines between solutions, gels, and macrophase separation in conjugated polymers and reviews essential solid state properties needed for understanding of solutions. It gives an insight into polyfluorene and polyfluorene beta phase in solutions and gels and describes all the structural levels in solvent matrices, ranging from intramolecular structures to the diverse aggregate classes and network structures and agglomerates of these units. It goes on to describe the kinetics and thermodynamics of these structures. It details the manifold molecular parameters used in their control and continues with the molecular confinement and touches on permanently cross‐linked networks. Particular focus is placed on the experimental results of archetypical polyfluorenes and solvent matrices and connection between structure and photonics. A connection is also made to the mean field type theories of hairy‐rod like polymers. This altogether allows generalizations and provides a guideline for materials scientists, synthetic chemists and device engineers as well, for this important class of semiconductor, luminescent polymers. 相似文献
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《Advanced Materials Interfaces》2017,4(20)
To improve the figure of merit (ZT ) of thermoelectric (TE) materials, the decoupling of the power factor and thermal conductivity, which are mutually dependent on each other in the traditional TE materials, is desired. The chalcogenides are one of the typical TE materials. When the chalcogenide TE materials are made from nanostructures, large interface density would apparently result in a low thermal conductivity. Additionally, the power factor of the chalcogenide TE materials can also be improved by some modification of their electronic structures. The bottom‐up solution‐processed synthesis to prepare the nanostructured chalcogenide TE materials is versatile, simple, low‐cost, and compatible with the scale‐up manufacture and printed flexible electronics. In this progress report, first, the techniques used to improve the ZT of chalcogenides with nanostructures are summarized. Subsequently, the chemical strategies to enhance the ZT are summarized. Finally, the interface and microstructure engineering concepts are concluded, which are crucial to improvement of the ZT of the chalcogenide TE materials from the solution‐processed nanostructures. 相似文献
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Takimiya K Shinamura S Osaka I Miyazaki E 《Advanced materials (Deerfield Beach, Fla.)》2011,23(38):4347-4370
Thienoacenes consist of fused thiophene rings in a ladder-type molecular structure and have been intensively studied as potential organic semiconductors for organic field-effect transistors (OFETs) in the last decade. They are reviewed here. Despite their simple and similar molecular structures, the hitherto reported properties of thienoacene-based OFETs are rather diverse. This Review focuses on four classes of thienoacenes, which are classified in terms of their chemical structures, and elucidates the molecular electronic structure of each class. The packing structures of thienoacenes and the thus-estimated solid-state electronic structures are correlated to their carrier transport properties in OFET devices. With this perspective of the molecular structures of thienoacenes and their carrier transport properties in OFET devices, the structure-property relationships in thienoacene-based organic semiconductors are discussed. The discussion provides insight into new molecular design strategies for the development of superior organic semiconductors. 相似文献
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A new route to self-assembled nanocomposite thermoelectric materials is proposed. High-energy mechanical alloying brings materials into a nonequilibrium intermediate state, such as a solid solution with an extended solubility. The large driving force for the transformation to the equilibrium state leads to nanometer-scale microstructure formation, which is ideal for reducing lattice thermal conductivity. 相似文献
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Liang Z Tang Q Mao R Liu D Xu J Miao Q 《Advanced materials (Deerfield Beach, Fla.)》2011,23(46):5514-5518
An exploratory study on novel silylethynylated N-heteropentacenes, which have their N atoms on the terminal rings of the pentacene backbone, is reported. This study leads to both p- and n-channel organic thin-film transistors with high field-effect mobility and also reveals that the position of the N atoms plays an important role in tuning the structures and properties of organic semiconductors based on N-heteropentacenes. 相似文献
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Xingang Zhao Deepa Madan Yan Cheng Jiawang Zhou Hui Li Susanna M. Thon Arthur E. Bragg Mallory E. DeCoster Patrick E. Hopkins Howard E. Katz 《Advanced materials (Deerfield Beach, Fla.)》2017,29(34)
Air‐stable and soluble tetrabutylammonium fluoride (TBAF) is demonstrated as an efficient n‐type dopant for the conjugated polymer ClBDPPV. Electron transfer from F? anions to the π‐electron‐deficient ClBDPPV through anion–π electronic interactions is strongly corroborated by the combined results of electron spin resonance, UV–vis–NIR, and ultraviolet photoelectron spectroscopy. Doping of ClBDPPV with 25 mol% TBAF boosts electrical conductivity to up to 0.62 S cm?1, among the highest conductivities that have been reported for solution‐processed n‐type conjugated polymers, with a thermoelectric power factor of 0.63 µW m?1 K?2 in air. Importantly, the Seebeck coefficient agrees with recently published correlations to conductivity. Moreover, the F?‐doped ClBDPPV shows significant air stability, maintaining the conductivity of over 0.1 S cm?1 in a thick film after exposure to air for one week, to the best of our knowledge the first report of an air‐stable solution‐processable n‐doped conductive polymer with this level of conductivity. The result shows that using solution‐processable small‐anion salts such as TBAF as an n‐dopant of organic conjugated polymers possessing lower LUMO (lowest unoccupied molecular orbital), less than ?4.2 eV) can open new opportunities toward high‐performance air‐stable solution‐processable n‐type thermoelectric (TE) conjugated polymers. 相似文献
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Nanomorphology Effects in Semiconductors with Native Ferromagnetism: Hierarchical Europium (II) Oxide Tubes Prepared via a Topotactic Nanostructure Transition 
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下载免费PDF全文 Bastian Trepka Philipp Erler Severin Selzer Tom Kollek Klaus Boldt Mikhail Fonin Ulrich Nowak Daniel Wolf Axel Lubk Sebastian Polarz 《Advanced materials (Deerfield Beach, Fla.)》2018,30(1)
Semiconductors with native ferromagnetism barely exist and defined nanostructures are almost unknown. This lack impedes the exploration of a new class of materials characterized by a direct combination of effects on the electronic system caused by quantum confinement effects with magnetism. A good example is EuO for which currently no reliable routes for nanoparticle synthesis can be established. Bottom‐up approaches applicable to other oxides fail because of the labile oxidation state +II. Instead of targeting a direct synthesis, the two steps—“structure control” and “chemical transformation”—are separated. The generation of a transitional, hybrid nanophase is followed by its conversion into EuO under full conservation of all morphological features. Hierarchical EuO materials are now accessible in the shape of oriented nanodisks stacked to tubular particles. Magnetically, the coupling of either vortex or onion states has been found. An unexpected temperature dependence is governed by thermally activated transitions between these states. 相似文献
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Fangliang Gao Lei Wen Zhenzhu Xu Jinglei Han Yuefeng Yu Shuguang Zhang Guoqiang Li 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(21)
The effects of the growth parameters on the uniformity and the aspect ratio of InN nanowires grown on Si(111) substrates have been studied systematically, and a modified quasi‐equilibrium model is proposed. The growth temperature is of great importance for both the nucleation of the nanowires and the migration of In and N atoms, thus affecting the uniformity of the InN nanowires. In order to improve the uniformity of the InN nanowires, both traditional substrate nitridation and pre‐In‐droplet deposition have been implemented. It is found that the substrate nitridation is favorable for the nucleation of InN nanowires. However, the initial In atoms adhered to the substrate are insufficient to sustain the uniform growth of the InN nanowires. We have found that the initial In droplet on the substrate is not only advantageous for the nucleation of the InN nanowire, but also favorable for the In atom equilibrium between the initial In droplets and the direct In flux. Therefore, InN nanowires with a uniform aspect ratio and optimal diameter can be achieved. The results reported herein provide meaningful insights to understanding the growth kinetics during the InN nanowires growth, and open up great possibilities of developing high‐performance group III‐nitride‐based devices. 相似文献
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Jason A. McNulty T. Thao Tran P. Shiv Halasyamani Shane J. McCartan Ian MacLaren Alexandra S. Gibbs Felicia J. Y. Lim Patrick W. Turner J. Marty Gregg Philip Lightfoot Finlay D. Morrison 《Advanced materials (Deerfield Beach, Fla.)》2019,31(40)
Since the observation that the properties of ferroic domain walls (DWs) can differ significantly from the bulk materials in which they are formed, it has been realized that domain wall engineering offers exciting new opportunities for nanoelectronics and nanodevice architectures. Here, a novel improper ferroelectric, CsNbW2O9, with the hexagonal tungsten bronze structure, is reported. Powder neutron diffraction and symmetry mode analysis indicate that the improper transition (TC = 1100 K) involves unit cell tripling, reminiscent of the hexagonal rare earth manganites. However, in contrast to the manganites, the symmetry breaking in CsNbW2O9 is electronically driven (i.e., purely displacive) via the second‐order Jahn–Teller effect in contrast to the geometrically driven tilt mechanism of the manganites. Nevertheless CsNbW2O9 displays the same kinds of domain microstructure as those found in the manganites, such as the characteristic six‐domain “cloverleaf” vertices and DW sections with polar discontinuities. The discovery of a completely new material system, with domain patterns already known to generate interesting functionality in the manganites, is important for the emerging field of DW nanoelectronics. 相似文献
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Tao Jiang Wei Tang Xiangyu Chen Chang Bao Han Long Lin Yunlong Zi Zhong Lin Wang 《Advanced Materials Technologies》2016,1(1)
Triboelectric nanogenerators (TENGs) have emerged as a highly effective and easily scalable technology for harvesting mechanical energy. Recently, standards and figure‐of‐merits have been defined to quantify the performance of TENGs. In this work, the figure‐of‐merits of rolling‐friction‐based TENGs are investigated through a theoretical model based on the rolling freestanding mode, including the conductor‐to‐dielectric and dielectric‐to‐dielectric cases. By combining finite‐element simulations and semi‐analytical derivations, the basic properties and resistive load output characteristics of rolling TENGs are calculated for various structural parameters, such as the electrode gap or rod diameter. The average output power is optimized by maximizing the structural figure‐of‐merit, which depends on the structural parameters. The results gained in this work could provide useful guidance for optimizing the performance of rolling‐friction‐based TENGs toward practical self‐powered systems. 相似文献