Negative Differential Resistance in Phenylene Ethynylene Oligomers

Cornil, Jérôme; Karzazi, Y.; Jl, Brédas

doi:10.1021/ja017475q

Cited by 128 publications

(84 citation statements)

References 15 publications

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“…[25] Recently, we have demonstrated from the results of semiempirical calculations performed on the three-ring phenylene ethynylene oligomer that the rotation of the central ring by 90 can lead to an NDR signature, as a result of resonant tunneling processes occurring through the twisted ring for a very limited range of applied electric field. [26] In this contribution, we illustrate that the same mechanism applies for three-ring phenylene oligomers substituted by electroactive substituents on the central ring, for which an NDR behavior has been observed experimentally; [12,13] we also show that the resonant tunneling processes are activated as soon as the central ring is significantly twisted with respect to the plane defined by the other two rings. This picture contrasts with the initial idea that the NDR peak observed for molecule 1b is associated to an abrupt conformational change (most probably a rotation of the central substituted ring induced by the interaction between the permanent dipole moment of the molecule and the electric field).…”

Section: Introductionsupporting

confidence: 61%

Resonant Tunneling Processes along Conjugated Molecular Wires: A Quantum‐Chemical Description

Karzazi

Cornil

Brédas

2002

Adv Funct Materials

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Molecular electronics research is a very active area in the field of nanotechnology. It is now well established that individual or self‐assembled molecules can behave as nanoscopic switches in transistor and diode configurations. Molecular wires inserted into nanopores and contacted by two metallic electrodes can also be used as active elements for the fabrication of resonant tunneling diodes (RTDs). The RTD current/voltage (I/V) characteristics can display a negative differential resistance (NDR) behavior (i.e., a negative slope in the I/V curve) for reasons that are not yet fully understood. Here we describe a possible mechanism at the quantum‐chemical level that is based on conformational effects and accounts for the experimental observation of strong NDR signatures in substituted phenylene ethynylene oligomers. The occurrence of a peak current in the I/V curves is rationalized by analyzing the evolution of the one‐electron structure of the molecular wires upon application of a static electric field aligned along the molecular axis (the field simulates the driving voltage applied between the two electrodes in the RTD devices). The results of our calculations provide a general basis to develop strategies for the design of molecular wires displaying an NDR behavior.

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Section: Introductionsupporting

confidence: 61%

Resonant Tunneling Processes along Conjugated Molecular Wires: A Quantum‐Chemical Description

Karzazi

Cornil

Brédas

2002

Adv Funct Materials

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“…Some groups experimentally and theoretically observed NDR in many physical systems such as oligo (phenylene ethynylene) (OPE) molecular devices with semiconductor electrodes [20], doped and squashed C 60 molecular device [21], porphyry molecular junctions modulated with side groups, CNTs or heterojunctions with the metal electrodes [22]. Possible mechanisms have been proposed to explain the NDR behavior, such as the variation of the coupling between the molecular orbital and the incident states from the electrodes at different bias voltages [20], the channel conduction being suppressed at a certain bias [22], the resonant and off resonant electronic tunneling mechanism [25], the biasinduced alignment of molecular orbitals [26], side group effects [27], and the splitting of the molecular orbitals [28]. In spite of a number of studies about NDR in various kinds of molecular devices, the origin for NDR is still under intense debate due to their structural complexity.…”

Section: Introductionmentioning

confidence: 99%

Negative differential resistance behavior of silicon monatomic chain encapsulated in carbon nanotubes

Zhang¹,

Wang²,

Zhao³

2012

Computational Materials Science

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a b s t r a c tUsing nonequilibrium Green's functions in combination with density-functional theory (DFT), we investigated the electronic transport properties of the silicon monatomic chains (SiMCs) with different geometries which were induced by the encapsulation of the carbon nanotubes (CNTs). The encapsulated SiMCs, which were put inside (5,5), (6,6), (7,7) and (8,8) hydrogenated armchair CNTs, were coupled to two Au (1 0 0) nanoscale electrodes. The electronic transport property of an isolated finite SiMC was also studied to serve as a reference to our calculations. As the diameter of CNTs increases, the geometry structures of SiMCs changed. Calculated results show that the current-voltage (I-V) characteristics depend sensitively on the geometry structures of SiMCs and can be controlled by the size-selective encapsulation. Negative differential resistance (NDR) phenomena were observed within certain bias voltage ranges. A detailed analysis of the origin of NDR was carried out with the transmission spectrum, the spatial distribution of frontier molecular orbitals and the molecular projected self-consistent Hamiltonian (MPSH) states taken into consideration. These results indicated that the size-selective encapsulation of SiMCs in CNTs can become a possible candidate for designing the silicon-based nanoelectronic devices.

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“…Based on such studies, Seminario et al proposed that charging of the molecule and subsequent localization/delocalization of molecular orbitals is the microscopic mechanism behind NDR, 8,9 while Cornil et al have found that bias-induced alignment of molecular orbitals on the first and last phenyl rings of twisted TW's can lead to NDR. 10 In this paper we present the first studies of the electrical properties of functionalized TW's covalently bound to gold surfaces. Most prominent previous studies of related systems include the IV characteristics of a functionalized benzene ring 13 and a bare TW.…”

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confidence: 99%

Conductance switching in a molecular device: The role of side groups and intermolecular interactions

2003

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We report first-principles studies of electronic transport in monolayers of Tour wires functionalized with different side groups. An analysis of the scattering states and transmission eigenchannels suggests that the functionalization does not strongly affect the resonances responsible for current flow through the monolayer. However, functionalization has a significant effect on the interactions within the monolayer, so that monolayers with NO2 side groups exhibit local minima associated with twisted conformations of the molecules. We use our results to interpret observations of negative differential resistance and molecular memory in monolayers of NO2 functionalized molecules in terms of a twisting of the central ring induced by an applied bias potential.

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Negative Differential Resistance in Phenylene Ethynylene Oligomers

Cited by 128 publications

References 15 publications

Resonant Tunneling Processes along Conjugated Molecular Wires: A Quantum‐Chemical Description

Resonant Tunneling Processes along Conjugated Molecular Wires: A Quantum‐Chemical Description

Negative differential resistance behavior of silicon monatomic chain encapsulated in carbon nanotubes

Conductance switching in a molecular device: The role of side groups and intermolecular interactions

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