Molecular junctions made of tungsten-polyoxometalate self-assembled monolayers: Towards polyoxometalate-based molecular electronics devices

Velessiotis, D.; Douvas, Antonios M.; Athanasiou, S.; Nilsson, B.; Petersson, Göran; Södervall, U.; Alestig, G.; Argitis, Panagiotis; Γλέζος, Ν.

doi:10.1016/j.mee.2011.01.039

Cited by 19 publications

(14 citation statements)

References 7 publications

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“…Moreover, it has been observed that the electronic state and conduction mode of an SWNT vary enormously with the type of molecular species adsorbed 17 , 18 . Phosphododecamolybdic acid, (H 3 PMo 12 O 40 ; PMo 12 hereafter), is one of the POMs exhibiting reversible multi-electron redox properties 19 – 21 , electronic versatility 22 , 23 and negative differential resistance (NDR) on highly ordered pyrolytic graphite (HOPG) 24 .…”

Section: Introductionmentioning

confidence: 99%

A molecular neuromorphic network device consisting of single-walled carbon nanotubes complexed with polyoxometalate

et al. 2018

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In contrast to AI hardware, neuromorphic hardware is based on neuroscience, wherein constructing both spiking neurons and their dense and complex networks is essential to obtain intelligent abilities. However, the integration density of present neuromorphic devices is much less than that of human brains. In this report, we present molecular neuromorphic devices, composed of a dynamic and extremely dense network of single-walled carbon nanotubes (SWNTs) complexed with polyoxometalate (POM). We show experimentally that the SWNT/POM network generates spontaneous spikes and noise. We propose electron-cascading models of the network consisting of heterogeneous molecular junctions that yields results in good agreement with the experimental results. Rudimentary learning ability of the network is illustrated by introducing reservoir computing, which utilises spiking dynamics and a certain degree of network complexity. These results indicate the possibility that complex functional networks can be constructed using molecular devices, and contribute to the development of neuromorphic devices.

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Section: Introductionmentioning

confidence: 99%

A molecular neuromorphic network device consisting of single-walled carbon nanotubes complexed with polyoxometalate

et al. 2018

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“…4,5 In addition, they can be directly exploited for fast switching, diode, and memory applications as well as for chemical sensors or biosensors. Our group has already demonstrated, using planar junctions 6,7 as well as vertical junctions and STM measurements, 8 that the redox properties of the inorganic 12tungstophosphoric acid (H 3 PW 12 O 40 ), a member of the polyoxometalate (POM) class can be, in principle, exploited in novel memory structures. In the current work we extensively investigate the transport mechanisms and the charging states of hybrid organic-inorganic capacitor structures which contain POMs as the charge trapping medium.…”

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confidence: 99%

Tungsten polyoxometalate molecules as active nodes for dynamic carrier exchange in hybrid molecular/semiconductor capacitors

Balliou

Douvas

Normand

et al. 2014

Journal of Applied Physics

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Superhydrophobicity on transparent fluorinated ethylene propylene films with nano-protrusion morphology by Ar+ O2 plasma etching: Study of the degradation in hydrophobicity after exposure to the environment Photoresist modifications by plasma vacuum ultraviolet radiation: The role of polymer structure and plasma chemistry J. Vac. Sci. Technol. B 28, 993 (2010); 10.1116/1.3484249Ion beam deposition of tantalum pentoxide thin film at room temperature In this work we study the utilization of molecular transition metal oxides known as polyoxometalates (POMs), in particular the Keggin structure anions of the formula PW 12 O 40 3À , as active nodes for potential switching and/or fast writing memory applications. The active molecules are being integrated in hybrid Metal-Insulator/POM molecules-Semiconductor capacitors, which serve as prototypes allowing investigation of critical performance characteristics towards the design of more sophisticated devices. The charging ability as well as the electronic structure of the molecular layer is probed by means of electrical characterization, namely, capacitance-voltage and current-voltage measurements, as well as transient capacitance measurements, C (t), under step voltage polarization. It is argued that the transient current peaks observed are manifestations of dynamic carrier exchange between the gate electrode and specific molecular levels, while the transient C (t) curves under conditions of molecular charging can supply information for the rate of change of the charge that is being trapped and de-trapped within the molecular layer. Structural characterization via surface and cross sectional scanning electron microscopy as well as atomic force microscopy, spectroscopic ellipsometry, UV and Fourier-transform IR spectroscopies, UPS, and XPS contribute to the extraction of accurate electronic structure characteristics and open the path for the design of new devices with on-demand tuning of their interfacial properties via the controlled preparation of the POM layer. V C 2014 AIP Publishing LLC.

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“…transport properties, and low-cost preparation. [25][26][27] The typical structures of POMs are referred to as Keggin and Dawson types. Unlike PEDOT:PSS, MoO 3 , and conjugated polymers, POMs have definite molecular structures, which can not only ensure the reproducibility of device performance, but also provide an opportunity to investigate the "molecular structureÀphotoelectronic propertyÀdevice performance" relationship.…”

Section: Introductionmentioning

confidence: 99%

Exploring Inorganic Hole Collection Materials from Mixed‐Metal Dawson‐Type Polyoxometalates for Efficient Organic Photovoltaic Devices

Fang

Zhang

et al. 2021

Solar RRL

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Interfacial layer materials play an important role in performance enhancement of organic solar cells (OSCs). Herein, the utilization of mixed‐metal Dawson‐type polyoxometalates, namely P2Mo3W15O62 (POM‐1) and P2Mo9W9O62 (POM‐2), as anode interlayer (AIL) materials, for efficiently collecting holes to boost the photovoltaic efficiency of OSCs, is explored. The increase in molybdenum substitution in the mixed‐metal POMs can lower the conduction band level and increase the reduction potential. Meanwhile, the high work function of POMs helps to remove the energy barrier in the hole collection, which solves the serious problem of Voc loss in OSCs. As a result, OSCs modified by POM‐2 can exhibit superior photovoltaic performance with power conversion efficiency of 14.8%. The results of Mott−Schottky analysis, current density−light intensity dependence, and excitons dissociation probability indicate the efficient hole collection and the depressed charge recombination in the POM‐2‐based OSC device. By means of fabricating OSCs, the effect of the two POM‐based AILs on various photoactive layers is also investigated, and POM‐2 exhibits excellent hole collection capability. Moreover, the advantages of low‐cost and solution‐processable conduct make POM‐2 a promising candidate as the AIL material for future mass production of OSCs.

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Molecular junctions made of tungsten-polyoxometalate self-assembled monolayers: Towards polyoxometalate-based molecular electronics devices

Cited by 19 publications

References 7 publications

A molecular neuromorphic network device consisting of single-walled carbon nanotubes complexed with polyoxometalate

A molecular neuromorphic network device consisting of single-walled carbon nanotubes complexed with polyoxometalate

Tungsten polyoxometalate molecules as active nodes for dynamic carrier exchange in hybrid molecular/semiconductor capacitors

Exploring Inorganic Hole Collection Materials from Mixed‐Metal Dawson‐Type Polyoxometalates for Efficient Organic Photovoltaic Devices

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