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1.
Abstract

Fullerenes are made by the intersection of twelve pentagonal nanocones. This note deals with an innovative isomeric mechanism, based on a sequence of Stone-Wales rotations, for moving the pentagonal face on the cusp of the nanocone. The modified nanocone is the seed for creating new fullerenes with different symmetry and size. Present results may help to model fullerene formation and, on the pure algorithmic side, may contribute to evolve the computer tools that generate fullerenes. This mechanism may also find application in mimicking the behaviors of biological systems that, like many viruses, are also describable in terms of spherical cages tiled by polygons.  相似文献   
2.
A low‐cost oil bath synthetic route is presented to produce uniform and highly crystalline layered cobalt hydroxide nanocones (NCs) intercalated with dodecyl sulfate anions (C12H25OSO3?, DS?). A new exfoliating procedure, by gradually unravelling/unzipping these NCs through heat treatment in formamide‐water binary solution, is developed to prepare unilamellar nanosheets. Moreover, the NCs can be readily modified with various inorganic or organic anions via a conventional anion‐exchange process at ambient temperature. The exchanged product, for example, NO3?–intercalated NCs, can be more easily and rapidly transformed into cobalt oxides (e.g., Co3O4 and CoO) than the original DS?–intercalated form while retaining a conical feature. Both the cobalt hydroxide NCs and exfoliated nanosheets are electrochemically redoxable, exhibiting a Faradaic pseudocapacitive behavior. The magnetic measurements further reveal both antiferromagnetic behaviors for transformed Co3O4 and CoO NCs. Their Néel temperature values are lower than those of bulk oxides due to finite size and geometric confinement effect. The peculiar conical feature of NCs with a hollow interior and tunable layer spacing, as well as exfoliated unilamellar nanosheets with all surface area exposed, may show promise for potential applications in electrochemical energy storage and magnetic devices.  相似文献   
3.
A highly tunable design for obtaining double resonance substrates to be used in surface‐enhanced Raman spectroscopy is proposed. Tandem truncated nanocones composed of Au‐SiO2‐Au layers are designed, simulated and fabricated to obtain resonances at laser excitation and Stokes frequencies. Surface‐enhanced Raman scattering experiments are conducted to compare the enhancements obtained from double resonance substrates to those obtained from single resonance gold truncated nanocones. The best enhancement factor obtained using the new design is 3.86 × 107. The resultant tandem structures are named after “Fairy Chimneys” rock formation in Cappadocia, Turkey.  相似文献   
4.
This paper proposes and experimentally demonstrates an a-Si:H random nanocone/PEDOT:PSS/P3HT:PCBM hybrid solar cell to extend the absorption to near infrared and solve the difficulty of carrier transport through organic-inorganic interface. The internal electrical field inside a-Si:H random nanocone force holes move to the anode and electrons move to the cathode. The insertion of a layer of PEDOT:PSS conducting polymer between organic-inorganic interface could cause electrons and holes to partially recombine, thus establishing an electrically connected a-Si:H and P3HT:PCBM bulk heterojunction, which enables carriers transport through organic-inorganic interfaces efficiently. As compared to conventional polymer solar cells, the open-circuit voltage of hybrid solar cells was increased from 0.51 to 0.78 V. Additionally, the power conversion efficiency was increased from 1.73% to 2.22%, which demonstrates approximately 28% enhancement, indicating that the hybrid structure could largely increase the efficiency of polymer solar cells.  相似文献   
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In this work, we report a simple one-step growth process to synthesize a novel and distinct carbon nanostructure, called a carbon nanofiber bundle-ended nanocone (CNFNC) structure, by using microwave plasma chemical vapor deposition (MPCVD) method with CH4 and H2 as source gases and Fe catalyst. The nanostructures and their properties after each processing step were characterized by FESEM, HRTEM, ED, AES, and Raman spectroscopy. The preliminary results have demonstrated that the CNFNC structures exhibit excellent field emission properties. The results also show that the favored conditions to form the CNFNC structures include a combination of lower CH4/H2 flow ratio, higher substrate negative bias, and proper working pressure and deposition time. The possible growth mechanism of the CNFNC structures is proposed.  相似文献   
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将商用CdS粉在真空炉中通过简单的热蒸发获得了大量高纯的CdS锥状纳米结构.扫描电子显微镜(SEM)、透射电子显微镜(TEM)观察和X射线衍射谱(XRD)的分析表明:CdS纳米锥状晶体为六角硫镉矿晶体结构,其形状为典型的纳米锥,晶格常数为a=0.413 nm,c=0.671 nm,沿着[0001]方向生长.CdS纳米锥的长度是20 μm到50 μm,直径从~100 nm减少到~20 nm.本文还详细研究了CdS纳米锥晶体的拉曼特性及其在激光辐射下的室温光致发光行为,探讨了绿光(波长为~512 nm)发射的机制.结果表明,这种CdS纳米锥可能用于新颖的光学器件.  相似文献   
9.
Artificial photonic synapses with morphologically controlled photoreception, allowing for area-dependent tunable light reception as well as information storage and learning, have potential for application in emerging photo-interactive neuro-computing technologies. Herein, an artificially intelligent (AI) photonic synapse with area-density-tunable perovskite nano-cone arrays templated in a self-assembled block copolymer (BCP) is presented, which is based on a field effect transistor with a floating gate of photoreceptive perovskite crystal arrays preferentially synthesized in a micro-phase-segregated BCP film. These arrays are capable of electric charge (de)trapping and photo-excited charge generation, and they exhibit versatile synaptic functions of the nervous system, including paired-pulse facilitation and long-term potentiation, with excellent reliability. The area-density variable perovskite floating gate developed by off-centered spin coating process allows for emulating the human retina with a position-dependent spatial distribution of cones. 60 × 12 arrays of the developed synapse devices exhibit position-dependent dual functions of receptor and synapse. They are AI and exhibit a pattern recognition accuracy up to ≈90% when examined using the Modified National Institute of Standards and Technology handwritten digit pattern recognition test.  相似文献   
10.
Exploring self‐assembled nanostructures with controllable architectures has been a central theme in nanoscience and nanotechnology because of the tantalizing perspective of directly integrating such bottom‐up nanostructures into functional devices. Here, the growth of kinked single‐crystal In2O3 nanostructures consisting of a nanocone base and a nanowire tip with an epitaxial and defect‐free transition is demonstrated for the first time. By tailoring the growth conditions, a reliable switching of the growth direction from [111] to [110] or [112] is observed when the Au catalyst nanoparticles at the apexes of the nanocones shrink below ≈100 nm. The natural formation of kinked nanoarchitectures at constant growth pressures is related to the size‐dependent free energy that changes for different orientations of the nanowires. The results suggest that the mechanism of forming such kinked nanocone–nanowire nanostructures in well‐controlled growth environment may be universal for a wide range of functional materials.  相似文献   
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