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The first example of inkjet-printed, electrolyte-gated organic field-effect transistors, fabricated on flexible polyimide substrates is presented. The inter-digitated source and drain electrodes, and the coplanar gate electrodes, are inkjet-printed using a homemade gold nanoparticle ink. A semiconducting ink based on the p-type, organic semiconductor poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b] thiophene)] (DPP-DTT) is formulated and inkjet-printed onto the channel. The performances of inkjet-printed, coplanar devices are compared to those of transistors whose gate electrode consists in a metallic wire inserted in the electrolyte. Printed transistors show excellent electrical properties with field-effect mobility as high as 0.04 cm(2) V-1 s(-1). The electrical behavior of inkjet-printed, coplanar devices is also modeled using the Nernst-Planck-Poisson (NPP) equations, where the output and transfer curves are calculated based on the charge and potential distribution inside the device. Good quantitative agreement between the simulation and experiments is achieved, outlining the attainable use of NPP simulations as predictive tools for device design and optimization. To demonstrate an example of application, printed transistors are functionalized for the detection of complementary DNA strands. This study opens an avenue for the next generation of low-cost, flexible sensors and circuits, both through experimental studies and device modeling. Funding Agencies|French National Research Agency (Agence Nationale de la Recherche) [ANR-17-CE08-0025]; Swedish Research Council [2017-04474]

Driven by the development of new functional inks, inkjet-printed electronics has achieved several milestones upon moving from the integration of simple electronic elements (e.g., temperature and pressure sensors, RFID antennas, etc.) to high-tech applications (e.g. in optoelectronics, energy storage and harvesting, medical diagnosis). Currently, inkjet printing techniques are limited by spatial resolution higher than several micrometers, which sets a redhibitorythreshold for miniaturization and for many applications that require the controlled organization of constituents at the nanometer scale. In this Review, we present the physico-chemical concepts and the equipment constraints underpinning the resolution limit of inkjet printing and describe the contributions from molecular, supramolecular, and nanomaterials-based approaches for their circumvention. Based on these considerations, we propose future trajectories for improving inkjet-printing resolution that will be driven and supported by breakthroughs coming from chemistry. Please check all text carefully as extensive language polishing was necessary. Title ok? Yes.

International audience; We studied the morphology of linear particle deposits obtained by inkjet-printing of silica nanoparticle suspension in drying condition where contact line depinning occurs. We show that this evaporation mode can be obtained by adjusting the particle concentration in different solvents. For isolated drops, deposited manually or by inkjet printing, drying induces the formation of two concentric rings in which particles self-assemble into a monolayer. For fused drops, our main result is that stable rivulets could be formed by drop overlap leading, after drying, to the formation of three parallel lines composed of a self-assembled particle monolayer. The three lines are of homogeneous thickness with two very thin outer lines ( 1 µm width) and a wider central line ( 20 µm width). We reveal how the width of the resulting lines is influenced by drop spacing in a predictable manner for a large experimental window knowing the drop size.

We demonstrate that electrolyte-gated organic field-effect transistors (EGOFETs) can detect extremely minute modifications in the composition of the electrochemical double layers forming at the channel/electrolyte and gate/electrolyte interfaces, thus permitting real-time monitoring of alkylthiols self-assembling on a gold surface. We used this property to assay the enzymatic activity of acetylcholinesterase which, in the presence of its substrate (acetylthiocholine), produces thiocholine. Keywords: Electrochemical double layer, EGOFET, Alkylthiol, Acetylcholinesterase

International audience; We studied the dependence of solid deposit shape obtained by free drying of sessile drops on the particles concentration and Derjaguin-Landau-Verwey-Overbeek (DLVO) particle/substrate interaction. In contrast to previous contributions using pH as a control parameter of interactions, we investigated an unprecedentedly wide range of concentrations and particle/substrate DLVO forces by modifying the nature of the substrate and particles as well as their size and surface chemistry whereas long-distance repulsive interactions between particles were maintained for most of the drying time. Our main result is that the different shapes of deposits obtained by modifying the particle concentration are the same in the different regimes of concentration regardless of particle/substrate interaction in the studied range of DLVO forces and particle concentrations. The second result is that, contrary to expectations, the dominant morphology of dry patterns at low particle concentration always shows a dot-like pattern for all the studied systems.

International audience; We studied the assembly of nanoparticles (NPs) with oppositely charged linear and periodic copolymers (CPs), alternating ionic and polar sequences, in the dilute range of polymer concentration. For the first time, we considered CPs displaying a contour length much higher than the gold NP (AuNP) perimeter. We assumed that such CPs will enable the collection of a finite number of NPs into linear nanostructures with a gain of colloidal stability and a better structural control compared to electrostatic complexes obtained with homopolyelectrolytes. As a case study, we synthesized anionic AuNPs and CPs consisting of alternated cationic poly-l-lysine (PLL) blocks and polar sequences of poly(ethylene glycol) (PEG). We showed that complexation of AuNPs with CPs is quite similar to that observed with homo PLL. In that respect, finite size nanometric clusters, of less than 30 NPs, are formed outside the electroneutrality domain and a fast phase separation occurs at the electroneutrality. Nevertheless, the presence of PEG blocks allowed us to highlight some specific effects. First, the global charge of the positively charged clusters was found to be always lower for CP-based clusters than for homo PLL with a dependence of the charge with the number and the mass of the PEG blocks. Second, in spite of this effect which should have promoted the formation of a dense structure, the fractal dimension characterizing the structure of the clusters in bulk was found to be always below 1.8. Finally, we showed that PEG blocks influence the interparticle distance by disfavoring plasmon delocalization when the clusters are dispersed in water and collapse around the NPs when the clusters are deposited on the substrate.

International audience; We demonstrate the fabrication, by exclusive means of inkjet-printing, of capacitive relative humidity sensors on flexible, plastic substrate. These sensors can be successfully used for the measurement of relative-humidity in both air and common soil. We also show that the same technique may be used for the fabrication of the same type of sensors on the surface of the leaves of Elaegnus Ebbingei (silverberry).Our results demonstrate the suitability of leaves as substrate for printed electronics and pave the way to the next generation of sensors to be used in fields such as agriculture and flower farming.

Among organic thin film transistors (OTFTs), Organic Electrochemical Transistors (OECTs) have been extensively used for cell monitoring while Electrolyte-Gated Organic Field-Effect Transistors (EGOFETs) have never been described for that kind of application. However, EGOFETs are well adapted for this use because, as well as OECTs, they can operate directly in aqueous solutions such as cells culture media, but they offer much a higher on/off ratio which could lead to better sensitivity. As a proof of concept, we propose herein to monitor the photosynthetic activity of a cyanobacterium (Anabaena flos-aquae) contained within an EGOFET's electrolyte.

accepte le 3 septembre 2020; International audience; We have investigated charge transfers between donor (D) and acceptor (A) species at their excited state in a light-assisted STM setup (LA-STM). Through an all-solution process, we have elaborated supramolecular architectures deposited on the Au(111) surface and made of 2D islands of PC71BM (electron acceptor) on top of a single layer of the polymer PTB7 (electron donor). The STM junction under modulated laser irradiation exhibits a strong background of photothermal signal attributed both to vertical and lateral expansion of the tip. However, from the analysis of di↵erential images obtained at opposite voltages, we have been able to detect additional photocurrent peaks located at the PTB7/PC71BM interfaces, providing evidence for active charge transfer between D/A species at their excited state. We discuss this phenomenon in the framework of a charge transport model at interfaces in organic electronics systems.

Surface Enhanced Raman Scattering (SERS) has been widely praised for its extreme sensitivity but has not so far been put to use in routine analytical applications, with the accessible scale of measurements a limiting factor. We report here on a frugal implementation of SERS dedicated to the quantitative detection of Zn2+ in water, Zn being an element that can serve as an indicator of contamination by heavy metals in aquatic bodies. The method consists in randomly aggregating simple silver colloids in the analyte solution in the presence of a complexometric indicator of Zn2+, recording the SERS spectrum with a portable Raman spectrometer and analysing the data using multivariate calibration models. The frugality of the sensing procedure enables us to acquire a dataset much larger than conventionally done in the field of SERS, which in turn allows for an in-depth statistical analysis of the analytical performances that matter to end-users. In pure water, the proposed sensor is sensitive and accurate in the 160–2230 nM range, with a trueness of 96% and a precision of 4%. Although its limit of detection is one order of magnitude higher than those of golden standard techniques for quantifying metals, its sensitivity range matches Zn levels that are relevant to the health of aquatic bodies. Moreover, its frugality positions it as an interesting alternative to monitor water quality. Critically, the combination of the simple procedure for sample preparation, abundant SERS material and affordable portable instrument paves the way for a realistic deployment to the water site, with each Zn reading three to five times cheaper than through conventional techniques. It could therefore complement current monitoring methods in a bid to solve the pressing needs for large scale water quality data.

Metalated porphyrins have been described to bind nucleic acids. Additionally, cobalt porphyrins present catalytic properties towards oxygen reduction. In this work, a carboxylic acid-functionalized cobalt porphyrin was physisorbed on reduced graphene oxide, then immobilized on glassy carbon electrodes. The carboxylic groups were used to covalently graft amino-terminated oligonucleotide probes which are complementary to a short microRNA target. It was shown that the catalytic oxygen electroreduction on cobalt porphyrin increases upon hybridization of miRNA strand (“signal-on” response). Current changes are amplified compared to non-catalytic amperometric system. Apart from oxygen, no added reagent is necessary. A limit of detection in the sub-nanomolar range was reached. This approach has never been described in the literature.

Through an all-solution process, we elaborate a host–guest system based on the self-assembly of a porphyrin derivative entrapped in a PTCDI–melamine porous network on Au(111). In contrast to the unpatterned molecular assembly, complementary STM and surface IR spectroscopy show that the host template modifies the packing and the tilt angle of porphyrin nanodomains.

International audience; Acetylacetonato-platina[6]- and -platina[7]helicenes have been prepared from 2-pyridyl-substituted benzophenanthrene ligands by following a two-step cycloplatination reaction. The photophysical properties (UV-visible absorption and emission behavior) and chiroptical properties (circular dichroism and molar rotation) of the resolved enantiomers have been measured. These metallahelicenes constitute a novel family of easily accessible helicene derivatives that exhibit large and tuneable chiroptical properties that can be rationalized theoretically and compared to the parent [6]- and [7]carbohelicenes. Furthermore, they are red phosphors at room temperature and their large chiroptical properties can be modulated by oxidation of the metal center to Pt(IV). Hetero- and homochiral diastereomeric bis(metallahelicene)s that possess a rare Pt(III)-Pt(III) scaffold bridged by benzoato ligands have also been prepared. It is shown that the heterochiral (P,M)-bis(Pt(III)-[6]helicene) 9a(1) can isomerize into the homochiral (P,P)- and (M,M)-bis(Pt(III)-[6]helicene) 9a(2). Spectral assignments and an analysis of the optical rotation of these systems were made with the help of time-dependent density functional theory. The calculations highlight the contributions of the metal centers to the chiroptical properties. For 9a(1) and 9a(2), σ-π conjugation between the helicenes and the Pt-Pt moiety may contribute strongly to the optical rotation and electronic circular dichroism.

A variety of chiral Lambda-type and X-type oligothiophenes (MDC 1-10) was synthesized and studied by means of UV-vis and CD spectroscopy in order to model the chiral interchain interactions of conjugated polymers with optically Active side chains in both neutral and oxidized state. It was found that, within the class of chiral Lambda-type oligothiophenes, the interchain chiral exciton coupling was only present when using an electronwithdrawing imine linkage between the oligothiophene and the chiral unit (MDC 7-9). Together with the observed decrease in g-value (dissymmetry factor for absorption) by extending the oligothiophene moiety, these linkage and elongation restrictions impose crucial drawbacks on chiral Lambda-type oligothiophenes as study model in both neutral and oxidized state. Therefore, a new chiral X-type oligothiophene (MDC 10) was developed that combines chiral exciton coupling in neutral state with the additional ability of oxidation. ispartof: Chemistry of Materials vol:20 issue:6 pages:2133-2143 status: published

Oligothiophene-Bodipy-based donor-acceptor systems for light harvesting have been synthesized and characterized. Absorption, excitation, and emission spectra indicate a tuneable and efficient resonance energy transfer from quaterthiophene as donor to mono- and bis-Bodipy as acceptors. This shows that engineering tuneable light harvesting systems is possible based on the combination of oligothiophenes with one or two Bodipy(s).

The synthesis of a new series of Lambda-type, D-Pi-A regioregular oligothiophenes is described. The simultaneous presence of the chiral centers and the Lambda-type structure disfavored the formation of centro-symmetrical dimeric assemblies. Hence, enhanced first hyperpolarizabilities betaHRS were measured in comparison with those of the corresponding monomers.

During the past decade, the chemistry of BINAP, BINAM, and BINOL derivatives experienced an important development due to multiple applications in catalysis, metallo-supramolecular chemistry and material science. Consequently, the need to develop functionalized binaphthyl derivatives became crucial. In this context, we were interested in preparing 2,2′-dimethoxy-1,1′-binaphthyl-3,3′-diacetic acid species. The latter were efficiently prepared using a modified Arndt–Eistert reaction that afforded the expected chiral diacid in good yield. Compared to the method we described earlier, this new strategy allows the preparation of the target homologated diacid chloride in a very efficient manner, limiting wastes and tedious column chromatographies.

We demonstrate the capability to build zero and one-dimensional electroactive molecular nanostructures ordered over a macroscopic scale and stable under ambient conditions. To realize these arrays, we use the selective grafting of functionalized thiols (juglon and terthiophene based) on a self-organized metallic template. The nanoscale patterning of the molecular conductance is demonstrated and analyzed by scanning tunneling spectroscopy. Finally, the influence of the nanostructuring on electro-chemical properties is measured, paving the way to an all-bottom-up fabrication of nanostructured templates for nanosciences. (C) 2013 AIP Publishing LLC.

With their rich electronic, vibrational, rotational and hyperfine structure, molecular systems have the potential to play a decisive role in precision tests of fundamental physics. For example, electroweak nuclear interactions should cause small energy differences between the two enantiomers of chiral molecules, a signature of parity symmetry breaking. Enantioenriched oxorhenium(VII) complexes S-(-)- and R-(+)-3 bearing a chiral 2-methyl-1-thio-propanol ligand have been prepared as potential candidates for probing molecular parity violation effects via high resolution laser spectroscopy of the Re=O stretching. Although the rhenium atom is not a stereogenic centre in itself, experimental vibrational circular dichroism (VCD) spectra revealed a surrounding chiral environment, evidenced by the Re=O bond stretching mode signal. The calculated VCD spectrum of the R enantiomer confirmed the position of the sulfur atom cis to the methyl, as observed in the solid-state X-ray crystallographic structure, and showed the presence of two conformers of comparable stability. Relativistic quantum chemistry calculations indicate that the vibrational shift between enantiomers due to parity violation is above the target sensitivity of an ultra-high resolution infrared spectroscopy experiment under active preparation., Comment: 9 pages, 8 figures

The intent of this tutorial review is to cover the recent progress accomplished in iron and manganese porphyrin-catalyzed enantioselective epoxidation of terminal olefins. The literature is covered up to the beginning of 2005. In the first part of the manuscript, we will present the results obtained with simple catalysts in the early eighties, before describing the pickets and strapped series reported more recently. We will also place a special emphasis on the biomimetic approach that oriented most of this research throughout the years. As a conclusion, we will demonstrate that easy-to-prepare porphyrin catalysts should play an important role in the future and should compete with other well-known, successful systems. Among those, the popular titanium tartrate-catalyzed Sharpless-Katsuki asymmetric epoxidation allows the conversion of allylic alcohols to chiral epoxides with high enantiomeric excesses and high conversion. We will also cite the chiral metallosalen complexes independently reported by Jacobsen and Katsuki in 1990. Using manganese-salens, cis-1,2-disubstituted, trisubstituted and some tetrasubstituted olefins are efficiently epoxidized with high enantiomeric excess. However, they suffer from two major drawbacks. They often require low temperature for the epoxidation of monosubstituted (57% ee for styrene at 5 degrees C; 80% at -78 degrees C). More importantly, they proceed with low turnover numbers, TON (TON approximately 40 for styrene). More recently, a new approach involving metal-free chiral dioxiranes was also reported. In some cases, they constitute an interesting alternative to the more common systems previously discussed. Compared to the three pre-cited systems, chiral metalloporphyrins allow the enantioselective epoxidation of unfunctionalized terminal olefins with high enantiomeric excess (97% ee for styrene) and impressive turnover numbers (16000) when PhIO is used as oxidant. These results highlight the remarkable potential of porphyrin-based catalysts.

Parity violation (PV) effects in chiral molecules have so far never been experimentally observed. To take this challenge up, a consortium of physicists, chemists, theoreticians and spectroscopists has been established and aims at measuring PV energy differences between two enantiomers by using high-resolution laser spectroscopy. In this article, we present our common strategy to reach this goal, the progress accomplished in the diverse areas, and point out directions for future PV observations. The work of Andr\'e Collet on bromochlorofluoromethane enantiomers, their synthesis and their chiral recognition by cryptophanes made feasible the first generation of experiments presented in this paper., Comment: 30 pages, 11 figures