Search results for "Self-assembled monolayers"
showing 10 items of 10 documents
Influence of alkylphosphonic acid grafting on the electronic and magnetic properties of La2/3Sr1/3MnO3 surfaces
2015
Self-assembled monolayers (SAMs) are highly promising materials for molecular engineering of electronic and spintronics devices thanks to their surface functionalization properties. In this direction, alkylphosphonic acids have been used to functionalize the most common ferromagnetic electrode in organic spintronics: La2/3Sr1/3MnO3 (LSMO). However, a study on the influence of SAMs grafting on LSMO electronic and magnetic properties is still missing. In this letter, we probe the influence of alkylphosphonic acids-based SAMs on the electronic and magnetic properties of the LSMO surface using different spectroscopies. We observe by X-ray photoemission and X-ray absorption that the grafting of …
Carboxylic derivatives of spin-crossover complexes in switchable materials and surfaces
2022
Los compuestos de transición de espín (SCO, de las siglas en inglés spin-crossover) son un ejemplo perfecto de biestabilidad molecular. La transición entre sus estados de alto y bajo espín (HS y LS, de las siglas en inglés, High Spin y Low Spin, respectivamente) se puede controlar mediante estímulos externos como la temperatura, presión, luz, por nombrar unos pocos. Esto los convierte en compuestos muy interesantes para aplicaciones tales como espintrónica, almacenamiento de memoria y dispositivos conmutables. El interés científico en este tipo de moléculas y la búsqueda de aplicaciones ha ido creciendo a lo largo de los años. Para ello, la deposición de dichos compuestos es el primer paso …
Electrochemistry of methylene blue at an alkanethiol modified electrode
2012
International audience; Gold surfaces were derivatized with decanethiol. The electrochemistry of methylene blue at these modified electrodes was investigated in function of the gold cleaning process and compared with the results obtained at a bare gold electrode. Cyclic voltammetry at low methylene blue concentrations (c(MB) <= 16 mu M) yielded surface behavior data. The properties of the film vary with the electrode pretreatment. Without electrochemical cleaning step, the standard potential at a gold electrode modified with 1-decanethiol is nearly the same as on a bare gold electrode. On the other hand, when the electrode is electrochemically cleaned before adsorption of the alkanethiols, …
Regenerable ZnO/GaAs Bulk Acoustic Wave Biosensor for Detection of Escherichia coli in “Complex” Biological Medium
2021
A regenerable bulk acoustic wave (BAW) biosensor is developed for the rapid, label-free and selective detection of Escherichia coli in liquid media. The geometry of the biosensor consists of a GaAs membrane coated with a thin film of piezoelectric ZnO on its top surface. A pair of electrodes deposited on the ZnO film allows the generation of BAWs by lateral field excitation. The back surface of the membrane is functionalized with alkanethiol self-assembled monolayers and antibodies against E. coli. The antibody immobilization was investigated as a function of the concentration of antibody suspensions, their pH and incubation time, designed to optimize the immunocapture of bacteria. The perf…
Spectroscopic and Theoretical Study of the Grafting Modes of Phosphonic Acids on ZnO Nanorods
2013
Metal oxides are versatile substrates for the design of a wide range of SAM-based organic-inorganic materials among which ZnO nanostructures modified with phosphonic SAM are promising semiconducting systems for applications in technological fields such as biosensing, photonics, and field-effect transistors (FET). Despite previous studies reported on various successful grafting approaches, issues regarding preferred anchoring modes of phosphonic acids and the role of a second reactive group (i.e., a carboxylic group) are still a matter of controversial interpretations. This paper reports on an experimental and theoretical study on the functionalization of ZnO nanorods with monofunctional alk…
Electrogeneration of Diiodoaurate in Dimethylsulfoxide on Gold Substrate and Localized Patterning
2016
International audience; A localized etching of gold surface by scanning electrochemical microscope technique is presented where a dimethylsulfoxide-based electrolyte charged with iodine is used. The electrogenerated triiodide ion at the platinum ultramicroelectrode tip (feedback mode) acts as an oxidant for gold surface. The effects of electrode diameter and the bias time have been investigated. The approach curve method was used to hold the electrode tip close to the gold surface. A scanning electron microscope is used to observe the etched gold surfaces where disk-shaped dots are generated. The diameter of these holes depends directly on the Pt electrode diameter and the bias time.
Spontaneous growth of 2D coordination polymers on functionalized ferromagnetic surfaces
2018
2D coordination polymers grow spontaneously on reactive surfaces due to surface oxidation. The growth process is observed in real time.
A metal-responsive interdigitated bilayer for selective quantification of mercury( ii ) traces by surface plasmon resonance
2016
Reusable surface plasmon resonance chips allowing the quantitative and selective detection of mercury(II) ions in water at the 0.01 nM level are reported. The surface-modified gold sensor consists of a rarefied self-assembled monolayer of octanethiol topped with a Langmuir–Blodgett monolayer of an amphiphilic and highly-specific chelator. The interdigitated architecture confers to the bilayer a high packing density, surface coverage, and binding-group accessibility.
Modulating the luminance of organic light-emitting diodes via optical stimulation of a photochromic molecular monolayer at transparent oxide electrode
2020
Nanoscale 12(9), 5444-5451 (2020). doi:10.1039/D0NR00724B
Trimesic acid on Cu in ethanol: Potential-dependent transition from 2-D adsorbate to 3-D metal-organic framework
2017
We report the potential-dependent interactions of trimesic acid with Cu surfaces in EtOH. CV experiments and electrochemical surface-enhanced Raman spectroscopy show the presence of an adsorbed trimesic acid layer on Cu at potentials lower than 0 V vs Cu. The BTC coverage increases as the potential increases, reaching a maximum at 0 V. Based on molecular dynamics simulations, we report adsorption geometries and possible structures of the organic adlayer. We find that, depending on the crystal facet, trimesic acid adsorbs either flat or with one or two of the carboxyl groups facing the metal surface. At higher coverages, a multi-layer forms that is composed mostly of flat-lying trimesic acid…