Synthesis of Hybrid Electroactive Materials by Low-Potential Electropolymerization of Gold Nanoparticles Capped with Tailored EDOT-Thiophene Precursor Units

The synthesis of gold nanoparticles (GNPs) capped with alkanethiols with terminal bithiophenic polymerizable groups, consisting of 3,4-ethylenedioxythiophene (EDOT) and 3-alkylsulfanylthiophene, is described. Transmission electron microscopy (TEM) and light diffusion show that these stabilized GNPs have an average size of 2–3 nm with low polydispersity. The electrochemical behavior of C10S-Au is investigated in dichloromethane in the presence of Bu4NPF6. The results show that these capped GNPs undergo straightforward and efficient electropolymerization under potentiodynamic or potentiostatic conditions. TEM images show that the electrodeposited films of the composite material present a very homogeneous structure, in which the size of the GNPs incorporated into the polythiophene matrix is unchanged. Results of cyclic voltammetry and spectroelectrochemistry obtained on polymer films deposited on platinum electrodes and transparent indium tin oxide electrodes, respectively, show that the reversible charging–discharging process and electrochromic behavior typical of poly(thiophenes) are preserved in the hybrid electroactive material

New cyclopropano 70 fullerene derivatives for the photovoltaic application

New cyclopropano 70 fullerenes derivatives were synthesised for photovoltaic (PV) application. The organic PV cells realized with these molecules blended with RR-P3HT polymer provided improved characteristics: 1.5% conversion efficiency (eta%), 9.29 mA/cm2 current density, 0.51 V open circuit voltage and 0.34 fill factor. The IPCE spectrum for P3HT: cyclopropano 70 fullerene cells shows a new peak around 430 nm with 71% external quantum efficiency. This explains the increased current density

Negative Differential Resistance, Memory and Reconfigurable Logic Functions based on Monolayer Devices derived from Gold Nanoparticles Functionalized with Electro-polymerizable Thiophene-EDOT Units

We report on hybrid memristive devices made of a network of gold nanoparticles (10 nm diameter) functionalized by tailored 3,4(ethylenedioxy)thiophene (TEDOT) molecules, deposited between two planar electrodes with nanometer and micrometer gaps (100 nm to 10 um apart), and electropolymerized in situ to form a monolayer film of conjugated polymer with embedded gold nanoparticles (AuNPs). Electrical properties of these films exhibit two interesting behaviors: (i) a NDR (negative differential resistance) behavior with a peak/valley ratio up to 17, and (ii) a memory behavior with an ON/OFF current ratio of about 1E3 to 1E4. A careful study of the switching dynamics and programming voltage window is conducted demonstrating a non-volatile memory. The data retention of the ON and OFF states is stable (tested up to 24h), well controlled by the voltage and preserved when repeating the switching cycles (800 in this study). We demonstrate reconfigurable Boolean functions in multiterminal connected NP molecule devices.Comment: Full manuscript, figures and supporting information, J. Phys. Chem. C, on line, asap (2017

Functionalized Gold Nanoparticles with Electropolymerizable π-Conjugated Systems for a Neuro-inspired Memristive Nanoparticle Organic Synapse-Transistor

Nanoparticle Organic Memory Field-Effect Transistors (NOMFET) are molecule-based devices that exhibit the main behavior of a biological spiking synapse. This behavior is obtained by virtue of the combination of two properties of the NOMFET: the transconductance gain of the transistor and the memory effect due to the presence of nanoparticles (NPs) which are used as nanoscale capacitors to store the electrical charges, and which are embedded into an organic semiconducting layer [1]. Thus, the transconductance of the transistor can be dynamically tuned by the amount of charge in the NPs. In this context, we present here a novel method for the elaboration of NOMFET active materials based on the electrochemical deposition of gold NPs grafted with alkanethiol-terminated π-conjugated precursors combining low oxidation potential and high reactivity. The straightforward electropolymerization of these new precursors leads to the formation of a semiconducting network in which the electronic and transport properties and the charging/discharging speed of the gold NPs can be modulated. Such hybrid material could advantageously replace the pentacene layer generally used in NOMFETs. This novel approach is based on previously demonstrated enhancement of charge-tunneling across monolayers of SAMs of alkanethiol-bithiophenic systems on a planar gold surface after electrochemical conversion into more extended conjugated systems [2]. The synthesis of the precursors and nanoparticles will be described and the morphology and electronic properties of the hybrid electropolymerized films will be discussed with regard to the behavior of the resulting NOMFET-devices. [1] F. Alibart, S. Pleutin, D. Guerin, C. Novembre, S. Lenfant, K. Lmimouni, C. Gamrat, D. Vuillaume, Adv. Funct. Mater. 2010, 20, 330-337. [2] M. Oçafrain, T. K. Tran, P. Blanchard, S. Lenfant, S. Godey, D. Vuillaume, J. Roncali, Adv. Funct. Mater. 2008, 18, 2163-2171

Oligothiophene-derivatized azobenzene as immobilized photoswitchable conjugated systems

Immobilization of an azobenzene-bithiophene compound on a gold surface leads to self-assembled monolayers with photoswitchable electrical properties

Structural Control of the Horizontal Double Fixation of Oligothiophenes on Gold

Quaterthiophenes bearing one (1) or two (2) alkanethiol chains attached at the internal β-position of the outermost thiophene ring through a sulfide linkage have been synthesized. Cyclic voltammetric analysis of their electrochemical behavior in solution suggests that electrooxidation of the doubly substituted oligomer 2 leads to electrodeposition of a poly(disulfide) on the anode surface. Monolayers of 1 or 2 on gold surfaces have been investigated and characterized by cyclic voltammetry, ellipsometry, contact angle measurement, and X-ray photoelectron spectroscopy. The results of these investigations indicate that introduction of two thiol groups in the structure leads to double fixation of the oligothiophene chain with the main axis of the conjugated system oriented parallel to the surface. The effects of single versus double fixation of the quaterthiophene chain on the electrochemical properties and stability of the corresponding monolayers are discussed

Synthesis and Characterization of Gold Nanoparticles Functionalized with Electropolymerizable or Optically Switchable π-Conjugated Systems

International audienc

High on-off conductance switching ratio in light-driven self-assembled molecular devices

Date du colloque : 5-9/01/2010International audienc

OPTOSAM: Surfaces aux propriétés électroniques réversiblement modifiables par stimulation optique

Date du colloque&nbsp;: 10/2008</p