The conductance of single-molecule junctions may be governed by the structure molecule in gap or way it bonds with leads, and information contained a Raman spectrum is ideal for examining both. Here we demonstrate that molecule-to-surface bonding characterized during electron transport 'fishing-mode' tip-enhanced spectroscopy (FM-TERS). This technique allows mutually verifiable signals contributions to acquired simultaneously at room temperature. Density functional theory calculations reveal...

The study of the oxygen reduction reaction (ORR) at high-index Pt(hkl) single crystal surfaces has received considerable interest due to their well-ordered, typical atomic structures and superior catalytic activities. However, it is difficult obtain direct spectral evidence ORR intermediates during processes, especially surfaces. Herein, in situ Raman spectroscopy been employed investigate processes containing [011̅] zone—i.e., Pt(211) Pt(311). Through control isotope substitution...

Abstract It is vital to understand the oxygen reduction reaction (ORR) mechanism at molecular level for rational design and synthesis of high activity fuel‐cell catalysts. Surface enhanced Raman spectroscopy (SERS) a powerful technique capable detecting bond vibrations surface species in low wavenumber range, however, using it probe practical nanocatalysts remains extremely challenging. Herein, shell‐isolated nanoparticle‐enhanced (SHINERS) was used investigate ORR processes on bimetallic Pt...

We measured single-molecule conductances for three different redox systems self-assembled onto gold by the STMBJ method and compared them with electrochemical heterogeneous rate constants determined ultrafast voltammetry. It was observed that fast indeed give higher conductance. Monotonous dependency of conductance on potential reveals large molecular fluctuations prevent levels to lie in between Fermi electrodes nanogap configuration. Electronic coupling factors both experimental approaches...

The ability to control over the quantum interference (QI) effect in single molecular junctions is attractive application of electronics. Herein we report that QI meta-benzene based molecule with dihydrobenzo[ b]thiophene as anchoring group ( meta-BT) can be controlled by manipulating electrode potential electrolyte while redox state does not change. More than 2 orders magnitude conductance change observed for meta-BT ranging from <10-6.0 10-3.3 G0 varying potential, upper value even larger...

Abstract Deciphering charge transport through multichannel pathways in single‐molecule junctions is of high importance to construct nanoscale electronic devices and deepen insight into biological redox processes. Herein, we report two tailor‐made folded wires featuring intramolecular π–π stacking interactions. The scanning tunneling microscope (STM) based break‐junction technique theoretical calculations show that through‐bond through‐space conjugations are integrated one wire, allowing for...

Abstract The success of different heterogeneous strategies organometallic catalysts has been demonstrated to achieve high selectivity and activity in photo/electrocatalysis. However, yielding their catalytic mechanisms at complex molecule‐electrode electrochemical interfaces remains a great challenge. Herein, shell‐isolated nanoparticle‐enhanced Raman spectroscopy is employed elucidate the dynamic process, interfacial structure, intermediates copper hydroxide‐2‐2′ bipyridine on Au electrode...

Single-molecule conductance of three sulphur-functionalized organometallic wires with two ruthenium(II) centres spaced by 1,3-butadiyne was firstly investigated using an electrochemically assisted-mechanically controllable break junction (EC-MCBJ) approach. It is demonstrated that single-molecular these diruthenium(II) incorporated systems significantly higher than oligo(phenylene-ethynylene) (OPE) having comparable lengths and exhibits weaker length dependence. The improvement in molecules...

Abstract Heterogeneous metal interfaces play a key role in determining the mechanism and performance of catalysts. However, situ characterization such at molecular level is challenging. Herein, two model interfaces, Pd Pt overlayers on Au single crystals, were constructed. The electronic structures these as well effects crystallographic orientation them analyzed by shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS) using phenyl isocyanide (PIC) probe molecule. A clear red...

Through-bond conjugated molecules are the major frameworks for traditional molecular wires, while through-space units rarely utilized and studied although they have shown unique conducting potential. Herein, we present novel single-molecule wires built on hexaphenylbenzene. Their conductance, measured by scanning tunneling microscopy based break-junction technique, increases with improvement of conjugation finally reaches a remarkable value (12.28 nS) which greatly exceeds that conventional...

Abstract Clarifying interfacial electronic effects on molecular adsorption is significant in many chemical and biochemical processes. Here, we used STM breaking junction shell‐isolated nanoparticle‐enhanced Raman spectroscopy to probe electron transport geometries of 4,4′‐bipyridine (4,4′‐BPY) at Au(111). Modifying the surface with 1‐butyl‐3‐methylimidazolium cation‐containing ionic liquids (ILs) decreases density stabilizes a vertical orientation pyridine through nitrogen atom σ‐bond...

The nature of molecule-electrode interface is critical for the integration atomically precise molecules as functional components into circuits. Herein, we demonstrate that electric field localized metal cations in outer Helmholtz plane can modulate interfacial Au-carboxyl contacts, realizing a reversible single-molecule switch. STM break junction and I-V measurements show electrochemical gating aliphatic aromatic carboxylic acids have conductance ON/OFF behavior electrolyte solution...

Nitrobenzene is currently the most widely used explosive substance, and known for its high toxicity mutagenicity. It can cause severe environmental water pollution, posing a risk to public health. Among various explosives analysis methods, surface-enhanced Raman spectroscopy (SERS) has advantages of fast speed, low detection cost, easy operation, become one promising analytical methods. Here, we present portable reliable sol-based SERS method trace amounts 2,4,6-trinitrotoluene (TNT) in...

Constructing single-molecule parallel circuits with multiple conduction channels is an effective strategy to improve the conductance of a single molecular junction, but rarely reported. We present novel through-space conjugated circuit (f-4Ph-4SMe) comprised pair closely parallelly aligned p-quaterphenyl chains tethered by vinyl bridge and end-capped four SMe anchoring groups. Scanning-tunneling-microscopy-based break junction (STM-BJ) transmission calculations demonstrate that f-4Ph-4SMe...

Enhancing the gating performance of single-molecule conductance is significant for realizing molecular transistors. Herein, we report a new strategy to improve electrochemical efficiency with fused structures consisting heterocyclic rings furan, thiophene, or selenophene. One order magnitude ratio achieved within potential window 1.2 V selenophene-based molecule, which significantly greater than that other and benzene ring molecules. This caused by different electronic molecules transmission...

The STM break junction (STM-BJ) and mechanically controllable (MCBJ) are the two most widely applied techniques to fabricate atomic-size nanowires for conductance measurement. However, drawbacks of mechanical crashing between electrodes same material in these hamper its capability application view variety metals as well environment perform measurements. In this paper, we present an electrochemical strategy STM-BJ by establishing a chemically well-defined metallic contact through...

We present the first in situ surface Raman spectra of hydrogen on rhodium under electrochemical conditions using gold-core rhodium-shell (Au@Rh) nanoparticles for SERS or silica-shell (Au@SiO(2)) SHINERS. The advantage SHINERS lies versatility to study single crystal surfaces such as H-Rh(111) system.

In this work, the single molecule conductance of alkanedicarboxylic acid (HOOC–(CH2)n–COOH, n = 1–5) binding to Cu and Ag electrodes is systematically studied by using electrochemical jump-to-contact scanning tunneling microscopy break junction approach (ECSTM-BJ). The results show that depends on molecular length electrode materials, which give a decay constant βN 0.95 ± 0.02 per (−CH2) unit for 0.71 0.03 electrodes. contact shows order Gn=0,Cu > Gn=0,Ag. These differences can be attributed...

We very recently reported a new spectroscopic application for expanding the versatility of surface Raman called “shell-isolated nanoparticle-enhanced spectroscopy” or “SHINERS”. The most important and difficult part SHINERS experiment is effective transfer strong electromagnetic field from gold core through isolating silica alumina shell to probed surface. For this it essential that chemically inert dielectric be ultrathin (2–5 nm) yet pinhole-free. Herein we describe experimental...

The triplex DNA has received much interest due to its various applications in gene regulation, molecular switch, and sensor development. However, realizing a highly selective recognition using fluorescence probe specific only for the topology is still great challenge. Herein, we found that relative structural analogues of natural robinetin, myricetin, quercetin, kaempferol, morin, rutin, baicalin, luteolin, naringenin, genistein, chrysin, galangin, isorhamnetin, several synthetic flavonoids,...

Some physicochemical intrigues for which transient electrochemistry was necessary to solve the problem are summarized in this feature article. First, we highlight main constraints be aware of access low time scales, and particularly focus on effects stray capacitances. Then, electron transfer rate constant measured redox molecules a self-assembled monolayer configuration is compared conductance through same systems, but at single molecule level. This evidences strong conformational changes...

We have determined the conductance of alkane-linked ferrocene molecules with carboxylic acid anchoring groups using STM break junction technique, and three sets values were found, i.e. high (HC), medium (MC) low (LC) values. The enhancing effect incorporated on electron transport in saturated alkane molecular wires is demonstrated by increased molecules, attributed to reduction tunneling barrier HOMO-LUMO gap induced insertion ferrocene. Furthermore, electron-withdrawing carbonyl group...