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Optical characterization of Peierls instability of zigzag-edge phosphorene nanoribbons
摘要： It has been demonstrated that the bare zigzag-edge phosphorene nanoribbons (zPNRs) were regularly believed as metals. However, some first-principle work [EPL108, 47005 (2014); PRB94, 075422 (2016)] suggested that zPNRs could be Peierls-gapped semiconductor due to the edge-reconstructions. In this work, we study the optical characterization of edge-Peierls-instability (EPI) in zPNRs based on the tight-binding calculations. Responding to EPI, an additional infrared absorption can be observed in the polarized-optical-conductivity-spectrum which is resonant to the Peierls gap. This new peak could be either singlet or doublet, which is determined by the ribbons embracing even- or odd-number zigzag chains. Moreover, it is unraveled that the opening of the Peierls gap is intimately related to the formation of the isolated edge-state subbands near the Fermi level.
关键词： Optical conductivity spectrum,Peierls instability,Tight-binding calculations,Zigzag-edge phosphorene nanoribbons
更新于2025-09-19 17:15:36
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[Communications in Computer and Information Science] VLSI Design and Test Volume 892 (22nd International Symposium, VDAT 2018, Madurai, India, June 28-30, 2018, Revised Selected Papers) || Performance Analysis of Graphene Based Optical Interconnect at Nanoscale Technology
摘要： In the modern technology era, interconnect is the key element for designing integrated circuits that provides on-chip and off-chip communication path for various systems. The primary challenges for modeling interconnect are reduced propagation delay, power dissipation, and its power delay product at advanced technology. This paper critically addresses the performance of optical interconnects using equivalent electrical model that comprises of different composite materials. Using industry standard HSPICE, the propagation delay and power dissipation characteristics of graphene nanoribbon have been compared with other composite materials. It has been observed that the propagation delay for graphene nanoribbon can be improved by 99.91% as compared to other composite materials. The power delay product of the proposed graphene based interconnect model is 59.73% lesser compared to other composite materials at 22 nm technology node.
关键词： Power delay product (PDP),Graphene nanoribbons,Propagation delay,Optical interconnect,Power dissipation
更新于2025-09-19 17:15:36
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Plasmonic Gas Sensing with Graphene Nanoribbons
摘要： The main challenge to exploiting plasmons for gas vibrational mode sensing is the extremely weak infrared absorption of gas species. In this work, we explore the possibility of trapping free-gas molecules via surface adsorption, optical, or electrostatic fields to enhance gas-plasmon interactions and to increase plasmon-sensing ability. We discuss the relative strengths of these trapping forces and find gas adsorption in a typical nanoribbon array plasmonic setup produces measurable dips in optical extinction of magnitude 0.1% for a gas concentration of about the parts per thousand level.
关键词： Optical extinction,Infrared absorption,Graphene nanoribbons,Gas-plasmon interactions,Plasmonic gas sensing
更新于2025-09-19 17:13:59
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High-performance counter electrode based on nitrogen-doped porous carbon nanoribbons for quantum dot-sensitized solar cells
摘要： Nitrogen-doped porous carbon nanoribbons (NPCNs) are facilely prepared by carbonization of polypyrrole (PPy) nanotubes followed by a chemical activation process. NPCN counter electrodes are subsequently fabricated by depositing NPCNs onto Ti mesh for quantum dot-sensitized solar cells (QDSCs). Electrochemical tests are carried out to evaluate the electrocatalytic performance of obtained NPCN electrode. The data of electrochemical tests suggest that the NPCN electrode has a superior electrocatalytic ability towards polysulfide (S2?/Sn2?) electrolyte regeneration reaction and displays a high stability in polysulfide electrolyte. The excellent electrocatalytic performance of NPCN electrode can be ascribed to their large surface area, 2D porous nanoribbon morphology, abundant nitrogen atom doping, which provides electrocatalytic active sites and facilitates the electrolyte diffusion. Consequently, a power conversion efficiency of 3.27% is obtained by using NPCN electrode as the counter electrode for QDSC. This efficiency is close to the QDSC assembled with commonly used PbS electrode (4.0%).
关键词： nitrogen doping,porous carbon nanoribbons,quantum dots,counter electrode,solar cells
更新于2025-09-19 17:13:59
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The detection of sub-terahertz radiation using graphene-layer and graphene-nanoribbon FETs with asymmetric contacts
摘要： We report on the detection of sub-terahertz radiation using single layer graphene and graphene-nanoribbon FETs with asymmetric contacts (one is the Schottky contact and one – the Ohmic contact). We found that cutting graphene into ribbons a hundred nanometers wide leads to a decrease of the response to sub-THz radiation. We show that suppression of the response in the graphene nanoribbons devices can be explained by unusual properties of the Schottky barrier on graphene-vanadium interface.
关键词： detector,THz region,graphene,terahertz radiation,graphene nanoribbons,optoelectronics
更新于2025-09-16 10:30:52
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Transport in armchair graphene nanoribbons and in ordinary waveguides
摘要： We study dc and ac transport along armchair graphene nanoribbons using the k (cid:1) p spectrum and eigenfunctions and general linear-response expressions for the conductivities. Then, we contrast the results with those for transport along ordinary waveguides. In all cases, we assess the influence of elastic scattering by impurities, describe it quantitatively with a Drude-type contribution to the current previously not reported, and evaluate the corresponding relaxation time for long- and short-range impurity potentials. We show that this contribution dominates the response at very low frequencies. In both cases, the conductivities increase with the electron density and show cusps when new subbands start being occupied. As functions of the frequency, the conductivities in armchair graphene nanoribbons exhibit a much richer peak structure than in ordinary waveguides: in the former, intraband and interband transitions are allowed, whereas in the latter, only the intraband ones occur. This difference can be traced to that between the corresponding spectra and eigenfunctions.
关键词： transport,elastic scattering,armchair graphene nanoribbons,intraband and interband transitions,conductivities,relaxation time,Drude-type contribution
更新于2025-09-11 14:15:04
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Exploration of Interfacial Porphine Coupling Schemes and Hybrid Systems by Bond-Resolved Scanning Probe Microscopy
摘要： The templated synthesis of porphyrin-based oligomers and heterosystems is of considerable interest for materials with tunable electronic gaps, photovoltaics, or sensing device elements. In this work, temperature-induced dehydrogenative coupling between unsubstituted free-base porphine units and their attachment to graphene nanoribbons on a well-defined Ag(111) support are scrutinized by bond-resolved scanning probe microscopy techniques. The detailed inspection of covalently fused porphine dimers obtained by in vacuo on-surface synthesis clearly reveals atomistic details of coupling motifs, whereby also putative reaction intermediates are identified. Moreover, the covalent attachment of porphines at preferred locations of atomically precise armchair-type graphene nanoribbons is demonstrated.
关键词： porphyrins,graphene nanoribbons,scanning probe microscopy,surface chemistry,C–C coupling
更新于2025-09-10 09:29:36
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Electric and optical properties modulations of armchair silicene nanoribbons by transverse electric fields
摘要： Under the influence of the external transverse electric fields, the effective mass and optical properties of armchair-edge silicene nanoribbons (ASiNRs) are investigated using the first-principles based on density functional theory (DFT). The results show that, comparing without the external transverse electric fields, the band gaps decrease monotonously, and the effective masses of the electrons and holes change non-monotonously with the absolute value of the electric fields, respectively. The total density of states (DOS) shows that, under the external electric fields, 9-ASiNR exhibits p-type semiconductor characters. Because of the obvious difference of the imaginary parts between the//x and//y directions, 9-ASiNR shows an optical anisotropy. In//x direction, the peaks of the dielectric function have evident red shift which are all associated with the electrons transition between Si 3p orbit and Si 3p, 3s orbits.
关键词： Electrics field,Optical properties,First-principles,Silicene nanoribbons,Electric properties
更新于2025-09-10 09:29:36
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Electrospinning Construction of Flexible Composite Nanoribbons with Color-Tunable Fluorescence
摘要： Herein, we describe the innovative one-dimensional nanomaterials, electrospun composite nanoribbons (width 10.119 ± 0.186 μm) containing complexes of Eu(TTA)3(TPPO)2 and Tb(BA)3phen in a matrix of polymethylmethacrylate (PMMA). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and fluorescence spectroscopy were used to characterize the final products. The novel luminescent composite nanoribbons exhibit green, orange and red fluorescence emission peaks at 490, 545, 592, and 615 nm, which are ascribed to the 5D4 → 7F6 (490 nm) and 5D4 → 7F5 (545 nm) energy transitions of Tb3+ ions, and the 5D0 → 7F1 (592 nm), 5D0 → 7F2 (615 nm) transitions of Eu3+ ions, respectively. It is observed that the doping percentage and the chosen excitation wavelength could be used to tune the emission color of the samples. The color-tunable luminescent composite nanoribbons have potential applications in the fields of display panels, lasers and bioimaging.
关键词： fluorescence,electrospinning,composite nanoribbons,rare earth complexes,tunable color
更新于2025-09-10 09:29:36
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Exploration of Interfacial Porphine Coupling Schemes and Hybrid Systems by Bond-Resolved Scanning Probe Microscopy
摘要： The templated synthesis of porphyrin-based oligomers and heterosystems is of considerable interest for materials with tunable electronic gaps, photovoltaics, or sensing device elements. In this work, temperature-induced dehydrogenative coupling between unsubstituted free-base porphine units and their attachment to graphene nanoribbons on a well-defined Ag(111) support are scrutinized by bond-resolved scanning probe microscopy techniques. The detailed inspection of covalently fused porphine dimers obtained by in vacuo on-surface synthesis clearly reveals atomistic details of coupling motifs, whereby also putative reaction intermediates are identified. Moreover, the covalent attachment of porphines at preferred locations of atomically precise armchair-type graphene nanoribbons is demonstrated.
关键词： porphyrins,graphene nanoribbons,scanning probe microscopy,surface chemistry,C–C coupling
更新于2025-09-10 09:29:36