共查询到20条相似文献,搜索用时 10 毫秒
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Kamatchi Jothiramalingam Sankaran Manekkathodi Afsal Shiu‐Cheng Lou Huang‐Chin Chen Chulung Chen Chi‐Young Lee Lih‐Juann Chen Nyan‐Hwa Tai I‐Nan Lin 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(1):179-185
Enhanced electron field emission (EFE) behavior of a core–shell heterostructure, where ZnO nanorods (ZNRs) form the core and ultrananocrystalline diamond needles (UNCDNs) form the shell, is reported. EFE properties of ZNR‐UNCDN core–shell heterostructures show a high emission current density of 5.5 mA cm?2 at an applied field of 4.25 V μm?1, and a low turn‐on field of 2.08 V μm?1 compared to the 1.67 mA cm?2 emission current density (at an applied field of 28.7 V μm?1) and 16.6 V μm?1 turn‐on field for bare ZNRs. Such an enhancement in the field emission originates from the unique materials combination, resulting in good electron transport from ZNRs to UNCDNs and efficient field emission of electrons from the UNCDNs. The potential application of these materials is demonstrated by the plasma illumination measurements that lowering the threshold voltage by 160 V confirms the role of ZNR‐UNCDN core–shell heterostructures in the enhancement of electron emission. 相似文献
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Low Temperature Direct of Graphene onto Metal Nano‐Spindt Tip with Applications in Electron Emission
Angel T. T. Koh Yuan Mei Foong Zamri Yusop Masaki Tanemura Daniel H. C. Chua 《Advanced Materials Interfaces》2014,1(5)
Graphene has been known for its superior electronic properties ever since its discovery in 2004. The high aspect ratio and ballistic transport properties exhibited by this one‐dimensional material are especially useful for electron emission applications. However, they are typically grown horizontally and excess efforts, such as the use of transfer techniques, is required to orientate them before effective electron emission from the graphene edges can occur. These transfer techniques have been shown to lead to additional defects to the as‐grown graphene structure, thereby degrading its properties. Here, we present an approach to directly fabricate graphene onto metal nano‐sized spindt tips (or nanocones) using the solid‐state transformation of carbon deposited from a pulsed laser system at low temperature. Besides providing a layer of chemical and mechanical protection for the metal nanocones, the graphene‐on‐metal nanocones gave enhanced emission properties compared to bare metal nanocones. This was due to the reduction of effective field emission tunneling barrier, which was a result of graphene‐metal charge transfer interactions. Controlling the metal nanocones density was also an important factor in determining the field emission performance, as electron screening from neighboring cones should be minimized. 相似文献
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Raising the Working Temperature of a Triboelectric Nanogenerator by Quenching Down Electron Thermionic Emission in Contact‐Electrification 下载免费PDF全文
Cheng Xu Aurelia Chi Wang Haiyang Zou Binbin Zhang Chunli Zhang Yunlong Zi Lun Pan Peihong Wang Peizhong Feng Zhiqun Lin Zhong Lin Wang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)
As previously demonstrated, contact‐electrification (CE) is strongly dependent on temperature, however the highest temperature in which a triboelectric nanogenerator (TENG) can still function is unknown. Here, by designing and preparing a rotating free‐standing mode Ti/SiO2 TENG, the relationship between CE and temperature is revealed. It is found that the dominant deterring factor of CE at high temperatures is the electron thermionic emission. Although it is normally difficult for CE to occur at temperatures higher than 583 K, the working temperature of the rotating TENG can be raised to 673 K when thermionic emission is prevented by direct physical contact of the two materials via preannealing. The surface states model is proposed for explaining the experimental phenomenon. Moreover, the developed electron cloud‐potential well model accounts for the CE mechanism with temperature effects for all types of materials. The model indicates that besides thermionic emission of electrons, the atomic thermal vibration also influences CE. This study is fundamentally important for understanding triboelectrification, which will impact the design and improve the TENG for practical applications in a high temperature environment. 相似文献
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Nanofiber‐Directed Anisotropic Self‐Assembly of CdSe–CdS Quantum Rods for Linearly Polarized Light Emission Evidenced by Quantum Rod Orientation Microscopy 下载免费PDF全文
Arkajyoti Chakrabarty Guillaume Raffy Mitasree Maity Leire Gartzia‐Rivero Samuel Marre Cyril Aymonier Uday Maitra André Del Guerzo 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(37)
Hybrid soft materials composed of CdSe–CdS nanorods or “quantum rods” (QRs) and the fluorescent 2,3‐didecyloxyanthracene (DDOA) low molecular weight organogelator are obtained through self‐assembly. Spectroscopy, microscopy, and rheology studies show that the QRs and DDOA coassemble, thereby stabilizing the organogels. Depending on the QR load and excitation wavelength, single nanofibers (NFs) of the hybrid gel display either sharp polarized red luminescence (under green excitation), or dual perpendicularly polarized blue and red emissions (under UV excitation). Transmission electron microscopy, microspectroscopy, and quantum rod orientation microscopy (QROM) reveal that QRs align along the organogel NFs with order parameters reaching 76% and 87%. This paves the way for obtaining surfaces of QR/NF assemblies yielding sharp red linearly polarized emission. In addition, this work demonstrates that QRs can be used more generally to probe nanostructured soft materials, even nonemissive ones. QROM allows to establish maps of the orientation of single QRs dispersed onto or within a gel network by measuring the polarization of the emission of the individual QRs. As occurs within this work in which QRs and NFs interact, the orientation of each QR reveals information on the underlying nanostructure (such as surface striation, bundle formation, and helicity). 相似文献
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Quasi‐epitaxial Growth of [Ru(bpy)3]2+ by Confinement in Clay Nanoplatelets Yields Polarized Emission 下载免费PDF全文
Daniel A. Kunz Markus J. Leitl Lukas Schade Jasmin Schmid Beate Bojer Ulrich T. Schwarz Geoffrey A. Ozin Hartmut Yersin Josef Breu 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(7):792-796
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Daniel M. Balazs Bartosz M. Matysiak Jamo Momand Artem G. Shulga Maria Ibáñez Maksym V. Kovalenko Bart J. Kooi Maria Antonietta Loi 《Advanced materials (Deerfield Beach, Fla.)》2018,30(38)
Colloidal quantum dots (CQDs) are nanoscale building blocks for bottom‐up fabrication of semiconducting solids with tailorable properties beyond the possibilities of bulk materials. Achieving ordered, macroscopic crystal‐like assemblies has been in the focus of researchers for years, since it would allow exploitation of the quantum‐confinement‐based electronic properties with tunable dimensionality. Lead‐chalcogenide CQDs show especially strong tendencies to self‐organize into 2D superlattices with micrometer‐scale order, making the array fabrication fairly simple. However, most studies concentrate on the fundamentals of the assembly process, and none have investigated the electronic properties and their dependence on the nanoscale structure induced by different ligands. Here, it is discussed how different chemical treatments on the initial superlattices affect the nanostructure, the optical, and the electronic‐transport properties. Transistors with average two‐terminal electron mobilities of 13 cm2 V?1 s?1 and contactless mobility of 24 cm2 V?1 s?1 are obtained for small‐area superlattice field‐effect transistors. Such mobility values are the highest reported for CQD devices wherein the quantum confinement is substantially present and are comparable to those reported for heavy sintering. The considerable mobility with the simultaneous preservation of the optical bandgap displays the vast potential of colloidal QD superlattices for optoelectronic applications. 相似文献
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Metal–Organic Frameworks: A New Class of Lasing Materials: Intrinsic Stimulated Emission from Nonlinear Optically Active Metal–Organic Frameworks (Adv. Mater. 17/2017) 下载免费PDF全文
Raghavender Medishetty Venkatram Nalla Lydia Nemec Sebastian Henke David Mayer Handong Sun Karsten Reuter Roland A. Fischer 《Advanced materials (Deerfield Beach, Fla.)》2017,29(17)
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Direct Observations of the Formation and Redox‐Mediator‐Assisted Decomposition of Li2O2 in a Liquid‐Cell Li–O2 Microbattery by Scanning Transmission Electron Microscopy 下载免费PDF全文
Chuchu Yang Jiuhui Han Pan Liu Chen Hou Gang Huang Takeshi Fujita Akihiko Hirata Mingwei Chen 《Advanced materials (Deerfield Beach, Fla.)》2017,29(41)
Operando scanning transmission electron microscopy observations of cathodic reactions in a liquid‐cell Li–O2 microbattery in the presence of the redox mediator tetrathiafulvalene (TTF) in 1.0 m LiClO4 dissolved dimethyl sulfoxide electrolyte are reported. It is found that the TTF addition does not obviously affect the discharge reaction for the formation of a solid Li2O2 phase. The coarsening of Li2O2 nanoparticles occurs via both conventional Ostwald ripening and nonclassical crystallization by particle attachment. During charging, the oxidation reaction at significantly reduced charge potentials mainly takes place at Li2O2/electrolyte interfaces and has obvious correspondence with the oxidized TTF+ distributions in the electric fields of the charged electrode. This study provides direct evidence that TTF truly plays a role in promoting the decomposition of Li2O2 as a soluble charge‐transfer agent between the electrode and the Li2O2. 相似文献
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Photoacoustic Imaging: Bright Aggregation‐Induced‐Emission Dots for Targeted Synergetic NIR‐II Fluorescence and NIR‐I Photoacoustic Imaging of Orthotopic Brain Tumors (Adv. Mater. 29/2018) 下载免费PDF全文
Zonghai Sheng Bing Guo Dehong Hu Shidang Xu Wenbo Wu Weng Heng Liew Kui Yao Jingying Jiang Chengbo Liu Hairong Zheng Bin Liu 《Advanced materials (Deerfield Beach, Fla.)》2018,30(29)
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Rare earth co-permeation of (NH4)3[CrMo6O24H6]•7H2O was reported and the conductivity of (NH4)3[CrMo6O24H6] was improved by 6.734×109 times. X-ray fluorescence spectrometry (XRF), thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) have been used to character (NH4)3[CrMo6 O24H6] •7H2O and permeated sample. Experimental results showed that Nd could be permeated into the body of this sample and the XRD patterns showed great difference between (NH4)3[CrMo6O24H6] •7H2O and permeated sample. The structure of (NH4)3[CrMo6O24H6] •7H2O was destroyed and new compound MoN perhaps formed. 相似文献