Showing papers by "Jérémie Grisolia published in 2016"
TL;DR: A new class of highly sensitive nano-electro-mechanical systems based on freestanding monolayered gold NP membranes is evidences, which are attributed to the exponential dependence of the tunnel electron transport in 2D NP arrays on the strain-induced length variation of the interparticle junctions.
Abstract: The electro-mechanical sensing properties of freestanding monolayered membranes of dodecanethiol coated 7 nm gold nanoparticles (NPs) are investigated using AFM force spectroscopy and conductive AFM simultaneously. The electrical resistance of the NP membranes increases sensitively with the point-load force applied in the center of the membranes using an AFM tip. Numerical simulations of electronic conduction in a hexagonally close-packed two-dimensional (2D) array of NPs under point load-deformation are carried out on the basis of electronic transport measurements at low temperatures and strain modeling of the NP membranes by finite element analysis. These simulations, supporting AFM-based electro-mechanical measurements, attribute the high strain sensitivity of the monolayered NP membranes to the exponential dependence of the tunnel electron transport in 2D NP arrays on the strain-induced length variation of the interparticle junctions. This work thus evidences a new class of highly sensitive nano-electro-mechanical systems based on freestanding monolayered gold NP membranes.
18 citations
TL;DR: This report reports on photo-current generation in freestanding monolayered gold nanoparticle membranes excited by using a focused laser beam, which is attributed to a combination of trap state dynamics and bolometric effects in a nanocomposite medium yielding a temperature rise of 40 K.
Abstract: We report on photo-current generation in freestanding monolayered gold nanoparticle membranes excited by using a focused laser beam. The absence of a substrate leads to a 50% increase of the photo-current at the surface plasmon resonance. This current is attributed to a combination of trap state dynamics and bolometric effects in a nanocomposite medium yielding a temperature rise of 40 K.
12 citations
TL;DR: In this article, the strong impact of humidity on the performances of gold colloidal nanoparticle (NP)-based resistive strain gauges is quantified and investigated by coupling electro-mechanical and in situ small-angle X-ray scattering measurements.
Abstract: The strong impact of humidity over the performances of gold colloidal nanoparticle (NP)-based resistive strain gauges is quantified and investigated by coupling electro-mechanical and in situ small-angle X-ray scattering measurements. When the relative humidity increases from 0% to 60%, the electrical resistance at rest of the NP-based sensors increases by 40%, and their sensitivity increases by 50%. This is accompanied by a rise of about 1% to 2% in the center-to-center distance between neighboring NPs and by an increase of the compactness of the NP assembly, possible evidence of a reorganization of the NPs. An encapsulation solution, based on alternating polymer and alumina layers, stabilizes the performances of the NP-based strain gauges for strains up to 0.4%. This approach could be extended to other flexible NP-based devices.
12 citations
TL;DR: This work is a sample case of contact electromechanics at scales ranging from the device scale down to the individual ligand molecule, where the vacuum tunneling mechanism is favored over the conduction by coherent molecular states, which is a decision-making aid for the choice of ligand in applications.
Abstract: Nanoparticle assemblies with thiol-terminated alkyl chains are studied by conducting atomic force microscopy (c-AFM) regarding their use as strain gauges for touch-sensitive panels. Current–force spectroscopy is used as a characterization tool complementary to the macroscopic setup since it allows a bias to be applied to a limited number of junctions, overcoming the Coulomb blockade energy and focusing on the contact electromechanics and the transport mechanism across the ligand. First, transition voltage spectroscopy is applied with varying force to target the underlying tunneling mechanism by observing whether the transition between the ohmic and exponential current–voltage behavior is force-dependent. Secondly, current–force spectroscopy in the ohmic range below the transition voltage is performed. The current–force behavior of the AFM probe in contact with a nanoparticle multilayer is associated with the spread of force and current within the nanoparticle lattice and at the level of adjacent particles by detailed contact mechanics treatment. The result is twofold: concerning the architecture of sensors, this work is a sample case of contact electromechanics at scales ranging from the device scale down to the individual ligand molecule. Regarding transport across the molecule, the vacuum tunneling mechanism is favored over the conduction by coherent molecular states, which is a decision-making aid for the choice of ligand in applications.
2 citations
01 Oct 2016
TL;DR: In this paper, the authors present their teaching experience in short practical training programs adapted for secondary and university students where they confront their theoretical background to real life, i.e. by elaborating and testing their own micro/nano-system for a specified functionality.
Abstract: In the last two decades, the teaching of microelectronics and nanotechnologies has become more and more challenging. First, numerous fundamental sciences converge, which implies the introduction of more and complex theoretical concepts, from simple electronic to quantum mechanics, as well as from chemistry, biology, medicine, … Here, we present our teaching experience in short practical training programs adapted for secondary and university students where they confront their theoretical background to real life, i.e. by elaborating and testing their own micro/nano-system for a specified functionality.
1 citations