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

A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.

/pdf/ultrasensitive-photodetectors-based-on-monolayer-mos2-2ytu9i2qtp.pdf

Ultrasensitive photodetectors based on monolayer MoS2.

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Materials with good flexibility and high conductivity that can provide electromagnetic interference (EMI) shielding with minimal thickness are highly desirable, especially if they can be easily processed into films. Two-dimensional metal carbides and nitrides, known as MXenes, combine metallic conductivity and hydrophilic surfaces. Here, we demonstrate the potential of several MXenes and their polymer composites for EMI shielding. A 45-micrometer-thick Ti3C2Tx film exhibited EMI shielding effectiveness of 92 decibels (>50 decibels for a 2.5-micrometer film), which is the highest among synthetic materials of comparable thickness produced to date. This performance originates from the excellent electrical conductivity of Ti3C2Tx films (4600 Siemens per centimeter) and multiple internal reflections from Ti3C2Tx flakes in free-standing films. The mechanical flexibility and easy coating capability offered by MXenes and their composites enable them to shield surfaces of any shape while providing high EMI shielding efficiency.

Electromagnetic interference shielding with 2D transition metal carbides (MXenes)

Graphene and other two-dimensional materials, such as transition metal dichalcogenides, have rapidly established themselves as intriguing building blocks for optoelectronic applications, with a strong focus on various photodetection platforms The versatility of these material systems enables their application in areas including ultrafast and ultrasensitive detection of light in the ultraviolet, visible, infrared and terahertz frequency ranges These detectors can be integrated with other photonic components based on the same material, as well as with silicon photonic and electronic technologies Here, we provide an overview and evaluation of state-of-the-art photodetectors based on graphene, other two-dimensional materials, and hybrid systems based on the combination of different two-dimensional crystals or of two-dimensional crystals and other (nano)materials, such as plasmonic nanoparticles, semiconductors, quantum dots, or their integration with (silicon) waveguides

http://www-g.eng.cam.ac.uk/nms/publications/pdf/nnano.2014.215.pdf

Photodetectors based on graphene, other two-dimensional materials and hybrid systems

Fine Characteristics Tailoring of Organic and Inorganic Nanowires Using Focused Electron-Beam Irradiation†

We present the confocal Raman spectra of isolated single poly(3-methylthiophene) (P3MT) nanotubes fabricated by the electrochemical polymerization method. A complete polymerization to the level of individual nanotubes has been confirmed by the clear observation of all characteristic Raman modes from each P3MT nanotube. A high-resolution confocal microscope combined with an atomic force microscope enabled us to detect subtle differences in spectra taken at different locations of the nanotube, which are attributed to fluctuation of the conjugation length distribution and the doping level.

Confocal Raman spectroscopy of single poly(3-methylthiophene) nanotubes

Functionalized CdSe/ZnS quantum dots (QDs) were attached to the surface of Au nanowire (NW) Analysis of optical absorption spectra disclosed surface plasmon bands of Au NWs at 562 and 627 nm and showing an overlap with the QD absorption band Micro Raman spectra (λex = 514 nm) of the QDs/Au single NW exhibited surface enhanced Raman scattering (SERS) peaks at 180, 205, and 277 cm−1, corresponding to surface, longitudinal, and transverse optical phonon modes, respectively From time-resolved fluorescence spectra, the exciton lifetime of QDs decreased after hybridization with Au NW due to the energy transfer, supporting the SERS effect

Surface enhanced Raman scattering effect of CdSe/ZnS quantum dots hybridized with Au nanowire

Local absorption spectra and absorption coefficients were obtained from organic rubrene single nanoplates. Absorption along the b-axis was higher than along the a-axis for polarized illumination on an ab-faced single-crystal rubrene nanoplate, and the lowest crystal transition peak (∼530 nm) relatively increased in size with an increasing incidence angle due to the anisotropic absorption strength along the crystal axes. Rubrene thin films grown by organic molecular beam deposition displayed microscopically varying absorption spectra; the relative peak height of the M-polarized band and the overall absorption strength were strongest with polarized illumination along the c-axis.

Anisotropic optical absorption of organic rubrene single nanoplates and thin films studied by μ-mapping absorption spectroscopy

Layered transition metal dichalcogenides, such as MoS2, WSe2 and WS2, are exciting two-dimensional (2D) materials because they possess tunable optical and electrical properties that depend on the number of layers. In this study, the nanoscale photoluminescence (PL) characteristics of the p-type WSe2 monolayer, and WSe2 layers hybridized with the fluorescent dye Cy3 attached to probe-DNA (Cy3/p-DNA), have been investigated as a function of the concentration of Cy3/DNA by using high-resolution laser confocal microscopy. With increasing concentration of Cy3/p-DNA, the measured PL intensity decreases and its peak is red-shifted, suggesting that the WSe2 layer has been p-type doped with Cy3/p-DNA. Then, the PL intensity of the WSe2/Cy3/p-DNA hybrid system increases and the peak is blue-shifted through hybridization with relatively small amounts of target-DNA (t-DNA) (50-100 nM). This effect originates from charge and energy transfer from the Cy3/DNA to the WSe2. For t-DNA detection, our systems using p-type WSe2 have the merit in terms of the increase of PL intensity. The p-type WSe2 monolayers can be a promising nanoscale 2D material for sensitive optical bio-sensing based on the doping and de-doping responses to biomaterials.

https://iopscience.iop.org/article/10.1088/1361-6528/aa8889/pdf

Jinsoo Joo

Papers

Fine Characteristics Tailoring of Organic and Inorganic Nanowires Using Focused Electron-Beam Irradiation†

Confocal Raman spectroscopy of single poly(3-methylthiophene) nanotubes

Surface enhanced Raman scattering effect of CdSe/ZnS quantum dots hybridized with Au nanowire

Anisotropic optical absorption of organic rubrene single nanoplates and thin films studied by μ-mapping absorption spectroscopy

Sensitive optical bio-sensing of p-type WSe2 hybridized with fluorescent dye attached DNA by doping and de-doping effects.