Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

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Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.

Ultrathin two-dimensional nanosheets of layered transition metal dichalcogenides (TMDs) are fundamentally and technologically intriguing. In contrast to the graphene sheet, they are chemically versatile. Mono- or few-layered TMDs - obtained either through exfoliation of bulk materials or bottom-up syntheses - are direct-gap semiconductors whose bandgap energy, as well as carrier type (n- or p-type), varies between compounds depending on their composition, structure and dimensionality. In this Review, we describe how the tunable electronic structure of TMDs makes them attractive for a variety of applications. They have been investigated as chemically active electrocatalysts for hydrogen evolution and hydrosulfurization, as well as electrically active materials in opto-electronics. Their morphologies and properties are also useful for energy storage applications such as electrodes for Li-ion batteries and supercapacitors.

http://nanotubes.rutgers.edu/PDFs/nchem_TMDs_2013.pdf

The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets

Polymer/layered silicate nanocomposites: a review from preparation to processing

If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS2, WS2, MoSe2, MoTe2, TaSe2, NbSe2, NiTe2, BN, and Bi2Te3 can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS2 and MoS2 effectively reinforce polymers, whereas WS2/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.

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Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials

Research Development on Sodium-Ion Batteries

The insertion of conjugated polymers in layered host materials and other structurally organized environments is a topic of considerable interest because the resulting organic/inorganic nanostructures can possess novel electrical, structural, and mechanical properties. Such systems can potentially show hybrid properties synergistically derived from both the host and the guest. The authors have reported that the redox intercalative polymerization (RIP) of pyrrole, thophene, and aniline to the corresponding conjugated polymers in V[sub 2]O[sub 5][center dot]nH[sub 2]O and FeOCl produces well-ordered compounds with enhanced electrical properties. This process works only with suitably oxidizing hosts and can be applied to other hosts to the extent that they can accept electrons at a low enough potential. Therefore, non-oxidizing hosts are not suitable for RIP. To broaden the scope of these new hybrid materials to other layered systems, one must use other synthetic methodologies for introducing polymers in non-oxidizing hosts. Here, the authors report the encapsulation of polyaniline (PANI) in MoS[sub 2], giving rise to a novel nanoscale molecular composite with unusual charge-transport properties. Transition-metal dichalcogenides have been extensively investigated for their interesting electrical properties and their application as cathode materials for rechargeable high-energy-density lithium batteries. 12 refs., 2 figs.

New Intercalation Compounds of Conjugated Polymers. Encapsulation of Polyaniline in MoS2

Intercalation of polypyrrole into graphite oxide

Herein we report on the intercalation of polyaniline, poly(2-ethylaniline), and poly(2-propylaniline) into graphite oxide. This was achieved by taking advantage of the exfoliation/reconstruction properties of the layered host. The resulting intercalates were characterized by powder X-ray diffraction and thermogravimetric analysis.

Encapsulation of polyanilines into graphite oxide.

A general approach for the encapsulation of a variety of saturated polymers between the layers of MoS2 giving electrically conductive lamellar compounds is reported.

Rabin Bissessur

Papers

New Intercalation Compounds of Conjugated Polymers. Encapsulation of Polyaniline in MoS2

Intercalation of polypyrrole into graphite oxide

Encapsulation of polyanilines into graphite oxide.

Encapsulation of polymers into MoS2 and metal to insulator transition in metastable MoS2

Intercalation of solid polymer electrolytes into graphite oxide