Effect of Bond-Length Alternation in Molecular Wires

Abstract

Current-voltage (I-V) characteristics for metal-molecule-metal junctions formed from three classes of molecules measured with a simple crossed-wire molecular electronics test-bed are reported. Junction conductance as a function of molecular structure is consistent with I-V characteristics calculated from extended Hückel theory coupled with a Green's function approach, and can be understood on the basis of bond-length alternation.

Amine-linked single-molecule circuits: systematic trends across molecular families

“…Measurements of the conductance through oligophenylenes and carotanoids of different length also showed exponential dependence on molecule length, but with a smaller decay constant as expected [23,24]. Comparison of the conductance through alkanes to that through prototypical molecular wires with extended pi electron states (oligophenyleneethynylene, OPV and oligophenylenevinylene, OPV) showed substantially higher conductance through the conjugated molecules and a rational dependence on the HOMO-LUMO gap [23,[25][26][27]. In a series of asymmetric junctions formed with oligophenyl and acene monothiols, systematic changes in conductance with electrode Fermi level alignment were observed [28].…”

Nanogap Electrodes

“…There are mainly two approaches for wiring molecules between electrodes. One method is to make top-contact junctions, which includes scanning probe microscopy (scanning tunneling microscopy (STM) and conducting atomic force microscopy (AFM)), [11][12][13][14][15][16][17][18][19][20][21][22] cross wire junctions, [23][24][25] mercury drop electrodes [26,27] and thermally deposited metal films. [6] All devices manufactured by this kind of method can be categorized as 'prototype devices', which are very useful for fundamental investigations and have already provided many important results.…”

“…[6] All devices manufactured by this kind of method can be categorized as 'prototype devices', which are very useful for fundamental investigations and have already provided many important results. [4][5][6][7][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] However, these devices are far from practical applications, as we can not imagine a nanometer device carrying a huge scanning probe microscopy (SPM) system or other systems. The other way utilizes nanogap electrodes [28][29][30][31][32] to form metal/molecule/metal devices.…”

Crystal structure of 2,5-diethoxy-1,4-bis[2-(quinoline)ethenyl]benzene, C32H28N2O2

“…The oligo(phenylene vinylene) and its derivatives (OPVs) are one kind of highly conjugated linear molecules, attracting increasing interest in the elds of nonliear optic [1], solid state opto-electronics [2] and molecular devices [3]. A large number of OPVs with large two-photon absorption sections (nonliear optical properties) were synthesized and investigated by changing the donor/acceptor(D/A) strength, conjugation length [4], for their potential applications in two-photon uorescence imaging, optical power limiting, two-photon up-conversion lasing, three-dimensional optical data storage, 3D microfabrication, and photodynamic therapy [5].…”