Conductance Switching and Mechanisms in Single‐Molecule Junctions

Jia, Chuancheng; Wang, Jinying; Yao, Chang‐Jiang; Cao, Yang; Zhong, Yu‐Wu; Liu, Zhongfan; Guo, Xuefeng

doi:10.1002/anie.201304301

Cited by 170 publications

(149 citation statements)

References 32 publications

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“…5−7 An ideal switch requires fast and large changes in electronic conductance, i.e., well-defined ON and OFF states, by a gate electrode. 2 Most molecular switches, with some exhibiting high switching ratios (as high as 300 in an optoelectronic switch 8 ), are based on dramatic conformational changes in the molecule, 2 which is not compatible with the design of complex devices assembled from single-molecular components. 9,10 To overcome these drawbacks, a breakthrough in molecular switching was introduced by Liljeroth et al 10 via hydrogen transfer (H-tautomerization).…”

Section: ■ Introductionmentioning

confidence: 99%

High On/Off Conductance Switching Ratio via H-Tautomerization in Quinone

Tawfik

Cui

Ringer

et al. 2015

J. Chem. Theory Comput.

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Through first-principles electron transport simulations using the nonequilibrium Green's function formalism together with density functional theory, we show that, upon H-tautomerization, a simple derivative of quinone can act as a molecular switch with high ON/OFF ratio, up to 70 at low bias voltage. This switching behavior is explained by the quantum interference effect, where the positional change of hydrogen atoms causes the energies of the transmission channels to overlap. Our results suggest that this molecule could have potential applications as an effective switching device.

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Section: ■ Introductionmentioning

confidence: 99%

High On/Off Conductance Switching Ratio via H-Tautomerization in Quinone

Tawfik

Cui

Ringer

et al. 2015

J. Chem. Theory Comput.

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“…Molecular devices, which are based on 1‐nm‐size single molecules or nanoscale collections of single molecules, provide a promising future for achieving the breakthrough of dimensional miniaturization in the next‐generation electronic devices . A great deal of molecular electronics have been fabricated successfully, including molecular switches, wires, rectifiers, and sensors, however, the molecular device library still possesses enormous potential to be further extended. As the classical temperature‐change devices, heaters have been employed in all walks of life and, therefore, next‐generation molecular heaters with nanometer size are urgently desired to realize the demand of the dimensional miniaturization.…”

Section: Introductionmentioning

confidence: 99%

Ultrahigh Temperature Graphene Molecular Heater

Huang

Liu

Tan

et al. 2018

Adv Materials Inter

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for metal films, [10] which are the basic building blocks of traditional heaters, after reducing the thickness strongly inhibits the realization of molecular heaters. Therefore, it is of great importance to find a satisfactory molecular building block with thicknesses controlled at the atomic level and unique electrical properties to achieve the construction of molecular heater.Graphene, which can be considered as a polycyclic aromatic hydrocarbon molecule with strictly atomic thickness, has been known as an excellent conductor of both heat and electricity. [11] Regarding that the electrothermal conversion of the heater is driven by the collision of charged particles in the electric field, also known as Joule heating, the heat performance is determined by the current flow and the intrinsic resistance of it. The extremely high current density [12] (≈2 × 10 9 A cm −2 ) and thermal conductivity [13] (≈5300 W m −1 K −1 ), as well as relatively low thermal loss, [14] where the convective heat-transfer coefficient is 12.4 W cm −2 °C −1 , of graphene could provide an anticipated heating performance, thus making the graphene molecule a promising building block of the molecular heater. However, the catalytic-growth characteristic of graphene makes it hard for direct growth on insulated substrate, thus the as-fabricated films suffer from the significant drawback of low crystallinity and nonuniformity. [15][16][17] Meanwhile, the transferred graphene is also criticized because of its cracks and residues, which leads to decayed electrical and thermal properties. Therefore, the heat temperature was limited to ≈200 °C in previous graphene-based heaters. [18] Here, graphene molecules with thicknesses controlled at the atomic level were directly grown on ceramic substrates, where the achievement of high-quality and uniform distribution characteristics had been demonstrated successfully. Graphene molecular heater (GMH), which exhibited extremely high heating temperature up to ≈400 °C only at a very low input voltage of 4.3 V, based on 1-nm-thick graphene molecule was first achieved and its heating characteristics were systematically explored, including the Joule heating efficiency, temperature distribution, and heating rate, where all the heating performances exhibit promising characteristics. What's more, the heating temperature of the GMH could be further improved to 600 °C, which was far beyond the oxidation temperature of graphene molecule in the atmosphere, after being encapsulated by hexagon boron nitride (h-BN) molecule. Thus, we believe the as-constructed GMH could further enrich the Although a number of molecular devices have been fabricated successfully, molecular heater still keeps blank. It is of great importance to find a satisfactory molecular building block with thicknesses controlled at the atomic level and outstanding electrical properties to achieve the construction of molecular heater. Graphene, a polycyclic aromatic hydrocarbon molecule with strictly atomic thickness, is known as a superior heat and electricit...

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“…Photoinduced charge transport in heterostructures is the core of most detectors, [1,2] sensors, [3,4] photoswitches, [5][6][7] and photovoltaic devices. [8][9][10][11] By effectively controlling charge transport at the heterointerface, specific functions can be realized, and the operating efficiencies can be improved in these devices.…”

Section: Introductionmentioning

confidence: 99%

High‐Efficiency Photovoltaic Conversion at Selective Electron Tunneling Heterointerfaces

Jia

Guan

et al. 2017

Adv Elect Materials

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particular, highly efficient photogenerated electron-hole pair separation, transport, and collection at the heterointerface are the key to achieve high photon-to-current conversion efficiency for photovoltaic devices. [12][13][14][15] Therefore, interface engineering was widely applied to control the photoinduced charge transport processes at the heterointerface for improving the performance of photovoltaic devices. [16][17][18][19] Recently, we discovered an ipsilateral selective electron tunneling (ISET) mechanism, which can be used to effectively separate photoinduced electron-hole pair at the heterointerface. [20,21] Specifically, when photoactive materials are assembled on the outside surface of single-layer graphene (SLG)/TiO 2 , Schottky diode, photoexcited electrons, as well as holes produced from the photoactive materials transport along the same direction to SLG, whereas only electron can further inject into the TiO 2 layer, thus realizing photogenerated electron-hole pair separation at the Schottky interface. With acridine orange (AO) dye as a model photoactive material, ≈86.8% photocarriers separation/collection efficiency was realized at the AO/SLG/ TiO 2 interface. Therefore, such an ISET effect at the heterointerface has great potential to be applied for efficient photovoltaic conversion.Due to a highly photoactive and unique amphiphilic structure, Z907 ruthenium molecules were widely used as the dye sensitizer in all-solid-state dye-sensitized solar cells. [22] In this work, Z907 molecules were chosen as the photoactive material to construct a Z907/SLG/TiO 2 ternary interface. As shown in Figure 1a, the photoexcited electrons in Z907 molecules are expected to tunnel across SLG and ballistically inject into the conductance band (CB) of the TiO 2 semiconductor layer, while photoexcited holes in Z907 molecules can only transport to the SLG semimetal layer. After that, the electron and hole are collected by the TiO 2 layer and the SLG layer, respectively, and further transport to the outside circuit for photoelectric conversion. Based on such an ISET mechanism, the electron transparency of the graphene layer is crucial for the high-efficiency photovoltaic conversion in ISET-based photovoltaic devices. Considering the fact that the electron transparency decreases with increasing the thickness of graphene, [23] single-layer graphene was chosen to construct the ISET-based heterointerface. With such an ISET-based heterointerface, we investigated the photoinduced carrier dynamic processes and photoelectric conversion performances at the heterointerface.Effectively controlling photoinduced charge transport at the heterointerface is of crucial importance for improving the performance of photovoltaic devices. On the basis of an ipsilateral selective electron tunneling (ISET) mechanism, here this study investigates photoinduced charge transport and photovoltaic conversion at a simplified dye/single-layer graphene (SLG)/TiO 2 ternary interface. With an amphiphilic Z907 molecule as the model dye, the photoexcit...

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Conductance Switching and Mechanisms in Single‐Molecule Junctions

Cited by 170 publications

References 32 publications

High On/Off Conductance Switching Ratio via H-Tautomerization in Quinone

High On/Off Conductance Switching Ratio via H-Tautomerization in Quinone

Ultrahigh Temperature Graphene Molecular Heater

High‐Efficiency Photovoltaic Conversion at Selective Electron Tunneling Heterointerfaces

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