Boosting Contact Electrification by Amorphous Polyvinyl Alcohol Endowing Improved Contact Adhesion and Electrochemical Capacitance.

Ion conductive hydrogels are relevant components in wearable, biocompatible, and biodegradable electronics. Polyvinyl-alcohol (PVA) homopolymer is often the favored choice for integration into supercapacitors and energy harvesters as in sustainable triboelectric nanogenerators (TENGs). However, to further improve hydrogel-based TENGs, a deeper understanding of the impact of their composition and structure on devices performance is necessary.

Evaluating Toxicity of Chemicals using a Zebrafish Vibration Startle Response Screening System.

We developed a simple screening system for the evaluation of neuromuscular and general toxicity in zebrafish embryos. The modular system consists of electrodynamic transducers above which tissue culture dishes with embryos can be placed. Multiple such loudspeaker-tissue culture dish pairs can be combined.

2D Materials-Based Electrochemical Triboelectric Nanogenerators.

The integration of 2D materials in triboelectric nanogenerators (TENGs) is known to increase the mechanical-to-electrical power conversion efficiency. 2D materials are used in TENGs with multiple roles as triboelectric material, charge-trapping fillers, or as electrodes. Here, novel TENGs based on few-layers graphene (FLG) electrodes and stable gel electrolytes composed of liquid phase exfoliated 2D-transition metal dichalcogenides and polyvinyl alcohol are developed.

Intrinsically distinct hole and electron transport in conjugated polymers controlled by intra and intermolecular interactions.

It is still a matter of controversy whether the relative difference in hole and electron transport in solution-processed organic semiconductors is either due to intrinsic properties linked to chemical and solid-state structure or to extrinsic factors, as device architecture. We here isolate the intrinsic factors affecting either electron or hole transport within the same film microstructure of a model copolymer semiconductor. Relatively, holes predominantly bleach inter-chain interactions with H-type electronic coupling character, while electrons' relaxation more strongly involves intra-chain interactions with J-type character.

Uniaxial Alignment of Conjugated Polymer Films for High-Performance Organic Field-Effect Transistors.

Polymer semiconductors have been experiencing a remarkable improvement in electronic and optoelectronic properties, which are largely related to the recent development of a vast library of high-performance, donor-acceptor copolymers showing alternation of chemical moieties with different electronic affinities along their backbones. Such steady improvement is making conjugated polymers even more appealing for large-area and flexible electronic applications, from distributed and portable electronics to healthcare devices, where cost-effective manufacturing, light weight, and ease of integration represent key benefits. Recently, a strong boost to charge carrier mobility in polymer-based field-effect transistors, consistently achieving the range from 1.

Transparent and Highly Responsive Phototransistors Based on a Solution-Processed, Nanometers-Thick Active Layer, Embedding a High-Mobility Electron-Transporting Polymer and a Hole-Trapping Molecule.

Organic materials are suitable for light sensing devices showing unique features such as low cost, large area, and flexibility. Moreover, transparent photodetectors are interesting for smart interfaces, windows, and display-integrated electronics. The ease of depositing ultrathin organic films with simple techniques enables low light absorbing active layers, resulting in the realization of transparent devices.

Live cell imaging shows hepatocyte growth factor-induced Met dimerization.

The canonical model of receptor tyrosine kinase (RTK) activation assumes that ligand-induced dimerization of inactive receptor monomers is a prerequisite for autophosphorylation. For several RTK families, recent results of fluorescence microscopy provided evidence for preformed receptor dimers that may or may not require ligand binding for kinase activity. Here we report, for the first time, the application of advanced quantitative fluorescence microscopy techniques to study changes in the oligomerization state of the RTK Met in response to stimulation by its endogenous ligand hepatocyte growth factor (HGF).

Macroscopic and high-throughput printing of aligned nanostructured polymer semiconductors for MHz large-area electronics.

High-mobility semiconducting polymers offer the opportunity to develop flexible and large-area electronics for several applications, including wearable, portable and distributed sensors, monitoring and actuating devices. An enabler of this technology is a scalable printing process achieving uniform electrical performances over large area. As opposed to the deposition of highly crystalline films, orientational alignment of polymer chains, albeit commonly achieved by non-scalable/slow bulk alignment schemes, is a more robust approach towards large-area electronics.

Electronic transport regimes through an alkoxythiolated diphenyl-2,2'-bithiophene-based molecular junction diodes: critical assessment of the thermal dependence.

The detailed understanding of electronic transport through a single molecule or an ensemble of self-assembled molecules embedded between two metallic leads is still a matter of controversy. Multiple factors influence the charge transport in the molecular junction, with particular attention to be given to the band states of the electrodes, molecular orbital energies, bias potential and importantly molecule-electrode electronic coupling. Moreover it is not trivial to disentangle molecular contributions from other possible conduction pathways directly coupling the opposite electrodes.

Photoactive molecular junctions based on self-assembled monolayers of indoline dyes.

We demonstrate the feasibility of a photodetector based on an ensemble molecular junction, where a self-assembled monolayer of an organic donor-acceptor dye is directly sandwiched between two electrodes. In such a device, upon photoexcitation and generation of a charge-transfer state on the molecule, charges are dissociated and directly collected at the electrodes without the need of transport through a bulk phase, as in usual photodetectors. We show that the device can work in photovoltaic regime and the spectral response can be tuned by varying the light absorbing dye.

All-organic and fully-printed semitransparent photodetectors based on narrow bandgap conjugated molecules.

All-organic, fully-printed and semitransparent photodetectors with a broad wavelength band response, based on a ternary blend comprising narrow band-gap small molecules, are demonstrated. The ternary blend with a semiconducting polymer allows for the optimal printing of small molecules, suppressing strong phase segregation, and uncontrolled crystallization. The insertion of a suitable interlayer enables the adoption of polymer, transparent, top and bottom printed electrodes, thus making light detection possible from both device sides.

Internalization of Met requires the co-receptor CD44v6 and its link to ERM proteins.

Receptor Tyrosine Kinases (RTKs) are involved in many cellular processes and play a major role in the control of cell fate. For these reasons, RTK activation is maintained under tight control. Met is an essential RTK that induces proliferation, differentiation, migration, survival and branching morphogenesis.

Recombination dynamics of charge pairs in a push-pull polyfluorene-derivative.

We investigate the properties of long-lived species in F8BT films through time-resolved photoluminescence (PL) measurements at room temperature and 10 K. The kinetics consist of an initial exponential decay (τ = 2.26 ns) followed by a weak power-law decay (I(t) [proportionality] t(-1)) up to at least 1 ms, both of which depend weakly on temperature.

c-Met recruits ICAM-1 as a coreceptor to compensate for the loss of CD44 in Cd44 null mice.

CD44 isoforms act as coreceptors for the receptor tyrosine kinases c-Met and VEGFR-2. However, Cd44 knockout mice do not show overt phenotypes, in contrast to Met and Vegfr-2 knockout mice. We hypothesized that CD44 is being compensated for by another factor in Cd44 null mice.

Conjugated zwitterionic polyelectrolyte as the charge injection layer for high-performance polymer light-emitting diodes.

A new zwitterionic conjugated polyelectrolyte without free counterions has been used as an electron injection material in polymer light-emitting diodes. Both the efficiency and maximum brightness were considerably improved in comparison with standard Ca cathode devices. The devices showed very fast response times, indicating that the improved performance is, in addition to hole blocking, due to dipoles at the cathode interface, which facilitate electron injection.

Self-assembly of alkoxy-substituted bis(hydrazone)-based organic ligands and of a metallosupramolecular grid on graphite.

Self-assembly of a bis(hydrazone) chelating ligand functionalized with octadecyloxy substituents is described, as well as the reproducible thermally activated self-assembly of its metallosupramolecular cationic Co(II) [2x2] grid-type complex, on a highly oriented pyrolitic graphite (HOPG) substrate. Scanning tunnelling microscopy measurements at the solid/liquid interface reveal that the grid units of the annealed films are oriented edge-on to the basal plane of the HOPG, which indicates that the influence of the octadecyl chains is not sufficient to tie the grids into a face-on orientation. To gain a detailed understanding of the self-assembly behaviour of the grid on HOPG, the results for the grid itself have been compared to those of its constituent ligands.

Azobenzenes as light-controlled molecular electronic switches in nanoscale metal-molecule-metal junctions.

Conductance switching associated with the photoisomerization of azobenzene-based (Azo) molecules was observed in nanoscopic metal-molecule-metal junctions. The junctions were formed by using a conducting atomic force microscope (C-AFM) approach, where a metallic AFM tip was used to electrically contact a gold-supported Azo self-assembled monolayer. The measured 30-fold increase in conductance is consistent with the expected decrease in tunneling barrier length resulting from the conformational change of the Azo molecule.

Haploinsufficiency of c-Met in cd44-/- mice identifies a collaboration of CD44 and c-Met in vivo.

Recent evidence has shown that the activation of receptor tyrosine kinases is not only dependent on binding of their ligands but in addition requires adhesion molecules as coreceptors. We have identified CD44v6 as a coreceptor for c-Met in several tumor and primary cells. The CD44v6 ectodomain is required for c-Met activation, whereas the cytoplasmic tail recruits ERM proteins and the cytoskeleton into a signalosome complex.

Cooperative light-induced molecular movements of highly ordered azobenzene self-assembled monolayers.

Photochromic systems can convert light energy into mechanical energy, thus they can be used as building blocks for the fabrication of prototypes of molecular devices that are based on the photomechanical effect. Hitherto a controlled photochromic switch on surfaces has been achieved either on isolated chromophores or within assemblies of randomly arranged molecules. Here we show by scanning tunneling microscopy imaging the photochemical switching of a new terminally thiolated azobiphenyl rigid rod molecule.

Hepatocyte growth factor-induced Ras activation requires ERM proteins linked to both CD44v6 and F-actin.

In several types of cells, the activation of the receptor tyrosine kinase c-Met by its ligand hepatocyte growth factor (HGF) requires the coreceptor CD44v6. The CD44 extracellular domain is necessary for c-Met autophosphorylation, whereas the intracellular domain is required for signal transduction. We have already shown that the CD44 cytoplasmic tail recruits ezrin, radixin and moesin (ERM) proteins to the complex of CD44v6, c-Met, and HGF.