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991.
Near‐Infrared Photodetectors Based on MoTe2/Graphene Heterostructure with High Responsivity and Flexibility 下载免费PDF全文
Wenzhi Yu Shaojuan Li Yupeng Zhang Weiliang Ma Tian Sun Jian Yuan Kai Fu Qiaoliang Bao 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(24)
2D transition metal dichalcogenides (TMDCs) have attracted considerable attention due to their impressively high performance in optoelectronic devices. However, efficient infrared (IR) photodetection has been significantly hampered because the absorption wavelength range of most TMDCs lies in the visible spectrum. In this regard, semiconducting 2D MoTe2 can be an alternative choice owing to its smaller band gap ≈1 eV from bulk to monolayer and high carrier mobility. Here, a MoTe2/graphene heterostructure photodetector is demonstrated for efficient near‐infrared (NIR) light detection. The devices achieve a high responsivity of ≈970.82 A W?1 (at 1064 nm) and broadband photodetection (visible‐1064 nm). Because of the effective photogating effect induced by electrons trapped in the localized states of MoTe2, the devices demonstrate an extremely high photoconductive gain of 4.69 × 108 and detectivity of 1.55 × 1011 cm Hz1/2 W?1. Moreover, flexible devices based on the MoTe2/graphene heterostructure on flexible substrate also retains a good photodetection ability after thousands of times bending test (1.2% tensile strain), with a high responsivity of ≈60 A W?1 at 1064 nm at V DS = 1 V, which provides a promising platform for highly efficient, flexible, and low cost broadband NIR photodetectors. 相似文献
992.
Rational Design and Synthesis of Extremely Efficient Macroporous CoSe2–CNT Composite Microspheres for Hydrogen Evolution Reaction 下载免费PDF全文
Jin Koo Kim Gi Dae Park Jung Hyun Kim Seung‐Keun Park Yun Chan Kang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
Uniquely structured CoSe2–carbon nanotube (CNT) composite microspheres with optimized morphology for the hydrogen‐evolution reaction (HER) are prepared by spray pyrolysis and subsequent selenization. The ultrafine CoSe2 nanocrystals uniformly decorate the entire macroporous CNT backbone in CoSe2–CNT composite microspheres. The macroporous CNT backbone strongly improves the electrocatalytic activity of CoSe2 by improving the electrical conductivity and minimizing the growth of CoSe2 nanocrystals during the synthesis process. In addition, the macroporous structure resulting from the CNT backbone improves the electrocatalytic activity of the CoSe2–CNT microspheres by increasing the removal rate of generated H2 and minimizing the polarization of the electrode during HER. The CoSe2–CNT composite microspheres demonstrate excellent catalytic activity for HER in an acidic medium (10 mA cm?2 at an overpotential of ≈174 mV). The bare CoSe2 powders exhibit moderate HER activity, with an overpotential of 226 mV at 10 mA cm?2. The Tafel slopes for the CoSe2–CNT composite and bare CoSe2 powders are 37.8 and 58.9 mV dec?1, respectively. The CoSe2–CNT composite microspheres have a slightly larger Tafel slope than that of commercial carbon‐supported platinum nanoparticles, which is 30.2 mV dec–1. 相似文献
993.
Healing Effect of Controlled Anti‐Electromigration on Conventional and High‐Tc Superconducting Nanowires 下载免费PDF全文
Xavier D. A. Baumans Joseph Lombardo Jérémy Brisbois Gorky Shaw Vyacheslav S. Zharinov Ge He Heshan Yu Jie Yuan Beiyi Zhu Kui Jin Roman B. G. Kramer Joris Van de Vondel Alejandro V. Silhanek 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(26)
The electromigration process has the potential capability to move atoms one by one when properly controlled. It is therefore an appealing tool to tune the cross section of monoatomic compounds with ultimate resolution or, in the case of polyatomic compounds, to change the stoichiometry with the same atomic precision. As demonstrated here, a combination of electromigration and anti‐electromigration can be used to reversibly displace atoms with a high degree of control. This enables a fine adjustment of the superconducting properties of Al weak links, whereas in Nb the diffusion of atoms leads to a more irreversible process. In a superconductor with a complex unit cell (La2?x Cex CuO4), the electromigration process acts selectively on the oxygen atoms with no apparent modification of the structure. This allows to adjust the doping of this compound and switch from a superconducting to an insulating state in a nearly reversible fashion. In addition, the conditions needed to replace feedback controlled electromigration by a simpler technique of electropulsing are discussed. These findings have a direct practical application as a method to explore the dependence of the characteristic parameters on the exact oxygen content and pave the way for a reversible control of local properties of nanowires. 相似文献
994.
A Novel and Facile Route to Synthesize Atomic‐Layered MoS2 Film for Large‐Area Electronics 下载免费PDF全文
Stephen Boandoh Soo Ho Choi Ji‐Hoon Park So Young Park Seungho Bang Mun Seok Jeong Joo Song Lee Hyeong Jin Kim Woochul Yang Jae‐Young Choi Soo Min Kim Ki Kang Kim 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(39)
High‐quality and large‐area molybdenum disulfide (MoS2) thin film is highly desirable for applications in large‐area electronics. However, there remains a challenge in attaining MoS2 film of reasonable crystallinity due to the absence of appropriate choice and control of precursors, as well as choice of suitable growth substrates. Herein, a novel and facile route is reported for synthesizing few‐layered MoS2 film with new precursors via chemical vapor deposition. Prior to growth, an aqueous solution of sodium molybdate as the molybdenum precursor is spun onto the growth substrate and dimethyl disulfide as the liquid sulfur precursor is supplied with a bubbling system during growth. To supplement the limiting effect of Mo (sodium molybdate), a supplementary Mo is supplied by dissolving molybdenum hexacarbonyl (Mo(CO)6) in the liquid sulfur precursor delivered by the bubbler. By precisely controlling the amounts of precursors and hydrogen flow, full coverage of MoS2 film is readily achievable in 20 min. Large‐area MoS2 field effect transistors (FETs) fabricated with a conventional photolithography have a carrier mobility as high as 18.9 cm2 V?1 s?1, which is the highest reported for bottom‐gated MoS2‐FETs fabricated via photolithography with an on/off ratio of ≈105 at room temperature. 相似文献
995.
Photonic Reactions Leading to Fluorescence in a Polymeric System Induced by the Photothermal Effect of Magnetite Nanoparticles Using a 780 nm Multiphoton Laser 下载免费PDF全文
Bum Chul Park Hee‐Dae Kim June Park Yu Jin Kim Young Keun Kim 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(37)
Recently, polymer‐coated magnetite (Fe3O4) nanoparticles (NPs) are extensively studied for applications in therapeutics or diagnostics using photothermal effect. Therefore, it is essential to understand the interactions between Fe3O4 NPs and polymers when optical stimuli are applied. Herein, the photonic reactions of Fe3O4 NPs and polymer composites upon application of a 780 nm multiphoton laser are analyzed. The photonic reactions produce unique results including fluorescence from conformationally changed polymer and low‐temperature phase transformation of Fe3O4 NPs. Typically, π‐conjugated chains are formed, inducing fluorescence through a series of main and side‐chain cleavage reactions of polymers with the aliphatic chain. In addition, fluorescence is detected in the cellular system by photonic reactions between Fe3O4 NPs and biomolecules. After multiphoton laser irradiation, light emission is detected near the intracellular Fe3O4 NPs, and a stronger intensity is observed in large‐sized NPs. 相似文献
996.
Surface Energy and Surface Stability of Ag Nanocrystals at Elevated Temperatures and Their Dominance in Sublimation‐Induced Shape Evolution 下载免费PDF全文
Long‐Bing He Lei Zhang Xiao‐Dong Tan Lu‐Ping Tang Tao Xu Yi‐Long Zhou Zhan‐Yong Ren Yun Wang Chun‐Yu Teng Li‐Tao Sun Jian‐Feng Nie 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
The surface energy and surface stability of Ag nanocrystals (NCs) are under debate because the measurable values of the surface energy are very inconsistent, and the indices of the observed thermally stable surfaces are apparently in conflict. To clarify this issue, a transmission electron microscope is used to investigate these problems in situ with elaborately designed carbon‐shell‐capsulated Ag NCs. It is demonstrated that the {111} surfaces are still thermally stable at elevated temperatures, and the victory of the formation of {110} surfaces over {111} surfaces on the Ag NCs during sublimation is due to the special crystal geometry. It is found that the Ag NCs behave as quasiliquids during sublimation, and the cubic NCs represent a featured shape evolution, which is codetermined by both the wetting equilibrium at the Ag–C interface and the relaxation of the system surface energy. Small Ag NCs (≈10 nm) no longer maintain the wetting equilibrium observed in larger Ag NCs, and the crystal orientations of ultrafine Ag NCs (≈6 nm) can rotate to achieve further shape relaxation. Using sublimation kinetics, the mean surface energy of Ag NCs at 1073 K is calculated to be 1.1–1.3 J m?2. 相似文献
997.
Jin‐Xuan Fan Di‐Wei Zheng Wen‐Wen Mei Si Chen Si‐Yi Chen Si‐Xue Cheng Xian‐Zheng Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(48)
As a characteristic trait of most tumor types, metastasis is the major cause of the death of patients. In this study, a photothermal agent based on gold nanorod is coated with metal (Gd3+)‐organic (polyphenol) network to realize combination therapy for metastatic tumors. This nanotheranostic system significantly enhances antitumor therapeutic effects in vitro and in vivo with the combination of photothermal therapy (PTT) and chemotherapy, also can remarkably prevent the invasion and metastasis due to the presence of polyphenol. After the treatment, an 81% decrease in primary tumor volumes and a 58% decrease in lung metastasis are observed. In addition, the good performance in magnetic resonance imaging, computerized tomography, and photothermal imaging of the nanotheranostic system can realize image‐guided therapy. The multifunctional nanotheranostic system will find a great potential in diagnosis and treatment integration in tumor treatments, and broaden the applications of PTT treatment. 相似文献
998.
Drug Delivery: One‐Step Microfluidic Synthesis of Nanocomplex with Tunable Rigidity and Acid‐Switchable Surface Charge for Overcoming Drug Resistance (Small 9/2017) 下载免费PDF全文
999.
Solar Cells: Multidimensional Anodized Titanium Foam Photoelectrode for Efficient Utilization of Photons in Mesoscopic Solar Cells (Small 34/2017) 下载免费PDF全文
1000.
Multicolor Photo‐Crosslinkable AIEgens toward Compact Nanodots for Subcellular Imaging and STED Nanoscopy 下载免费PDF全文
Xiaofeng Fang Xuanze Chen Rongqin Li Zhihe Liu Haobin Chen Zezhou Sun Bo Ju Yifei Liu Sean Xiao‐An Zhang Dan Ding Yujie Sun Changfeng Wu 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(41)
Aggregation induced emission (AIE) has attracted considerable interest for the development of fluorescence probes. However, controlling the bioconjugation and cellular labeling of AIE dots is a challenging problem. Here, this study reports a general approach for preparing small and bioconjugated AIE dots for specific labeling of cellular targets. The strategy is based on the synthesis of oxetane‐substituted AIEgens to generate compact and ultrastable AIE dots via photo‐crosslinking. A small amount of polymer enriched with oxetane groups is cocondensed with most of the AIEgens to functionalize the nanodot surface for subsequent streptavidin bioconjugation. Due to their small sizes, good stability, and surface functionalization, the cell‐surface markers and subcellular structures are specifically labeled by the AIE dot bioconjugates. Remarkably, stimulated emission depletion imaging with AIE dots is achieved for the first time, and the spatial resolution is significantly enhanced to ≈95 nm. This study provides a general approach for small functional molecules for preparing small sized and ultrastable nanodots. 相似文献