Electron deficient dicyanovinylene-ladder-type pentaphenylene derivative for n-type Organic Field Effect Transistors

International audienceA bridged pentaphenylene derivative functionalized with dicyanovinylene units LPP([double bond, length as m-dash]C(CN)2)2 has been designed, synthesized and characterized. The optical and electrochemical properties have been carefully studied through a combined experimental and theoretical approach and compared with those of two pentaphenylene derivatives bearing methylenes (LPP) or carbonyl (LPP([double bond, length as m-dash]O)2) on the bridgeheads. LPP([double bond, length as m-dash]C(CN)2)2 which possesses a very low LUMO level, ca. −4.02 eV, has been successfully used as an active layer in n-channel OFETs using the epoxy based photoresist SU-8 as a gate insulator. LPP([double bond, length as m-dash]C(CN)2)2 based n-channel OFETs show low voltage functioning (low gate-source and drain-source voltages), high ratio between the on and the off currents (2 × 105), interesting subthreshold swing (S = 1) and excellent stability under electrical stress and in a nitrogen atmosphere. More importantly, we have also shown that LPP([double bond, length as m-dash]C(CN)2)2 based n-channel OFETs present an excellent environmental stability. This work is to the best of our knowledge the first report on bridged pentaphenylene-based semiconductors in n-type OFETs and highlights the potential of such type of material to provide air stable OFETs

The Use of a Water Soluble Flexible Substrate to Embed Electronics in Additively Manufactured Objects: From Tattoo to Water Transfer Printed Electronics

The integration of electronics into the process flow of the additive manufacturing of 3D objects is demonstrated using water soluble films as a temporary flexible substrate. Three process variants are detailed to evaluate their capabilities to meet the additive manufacturing requirements. One of them, called water transfer printing, shows the best ability to fabricate electronics onto 3D additively manufactured objects. Moreover, a curved capacitive touchpad hidden by color films is successfully transferred onto the 3D objects, showing a potential application of this technology to fabricate fully additively manufactured discrete or even hidden electronic devices

Initiation à la technologie d'impression jet d'encre: Réalisation de jauges de P2 contraintes organiques sur papier

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Large Area Freestanding Au Nanoporous Ultrathin Films Transfer Printed on Bendable Substrates and 3D Surfaces for Flexible Electronics

International audienceConductive films based on metal nanomaterials have been studied as electrical interconnects for flexible electronics. Among them, freestanding ultrathin films are flexible, making them ideal candidates for integration onto 3D surfaces with complex shapes. Nevertheless, obtaining self-supported films of a few tens of nm with an area of several cm(2) without breaking them is difficult. The solution proposed in this work is to get the films floating on the water surface before transferring them to 3D flexible surfaces by a water transfer printing process. Herein, we report the fabrication of stable and homogeneous Au nanoporous films with a thickness range of 6-60 nm and a floating surface area of several tens of cm(2) on the water surface. The process combines Au and Cu magnetron sputtering deposition, Cu dealloying, and etching in acid vapor. We show that the transfer of such ultrathin films with a large area from the water surface onto the surface of flat flexible substrates or 3D surfaces is possible, maintaining conformability without significant electrical conductivity degradation. The thinnest films have a sheet resistance of about 10 Omega/square with a transparency of about 50% at 550 nm. Because of their specific nanostructuration consisting of nanopores and interconnected nanoligaments, these films transferred to flexible flat surfaces can withstand bending for at least 3000 cycles with a curvature radius of 1 mm. Moreover, we show that a transfer of a design to a complex curved surface of 3D objects is possible using a 6 nm layer, whose role is to keep the geometry of the design during the transfer process

TP Eurodots : Silicium microcristallin et Semiconducteur organique : Quel matériau pour l'électronique flexible ?

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Substrate-Free Transfer of Silicon- and Metallic-Based Strain Sensors on Textile and in Composite Material for Structural Health Monitoring

International audienceNew technologies to integrate electronics and sensors on or into objects can support the growth of embedded electronics. The method proposed in this paper has the huge advantage of being substrate-free and applicable to a wide range of target materials such as fiber-based composites, widely used in manufacturing, and for which monitoring applications such as fatigue, cracks, and deformation detection are crucial. Here, sensors are first fabricated on a donor substrate using standard microelectronic processes and then transferred to the host material by direct transfer printing. Results show the viability of composites instrumented by strain gauges. Indeed, dynamic and static measurements highlight that the deformations can be detected with high sensitivity both on the surface and at various points in the depth of the composite material. Thanks to this technology, for the first time, a substrate-free piezoresistive n-doped silicon strain sensor is transferred into a composite material and characterized as a function of strain applied on it. It is shown that the transfer process does not alter the electrical behavior of the sensors that are five times more sensitive than extensively used metallic ones. An application designed for monitoring the deformation of a rudder foil with a classic NACA profile in real time is presented

Organic and Metallic Sensors on Complex 3-D Object Using an Original Method: Water Transfer Printing

International audienceSensors need to intimately wrap objects that we want to monitor, track, or supervise. By way of example, adding a strain gauge, some temperature or humidity sensors directly on 3-D objects, leads to improved structural health monitoring, protects materials from overheating, and sustaining a comfortable humidity level. In this letter, we present a conformal and substrate-free transfer of sensors to complex 3-D objects using water transfer printing (WTP) concept. Herein, the sensors are screen-printed using carbon and silver inks. To determine if the WTP process affects sensors performances, we compare the sensitivities obtained from transferred sensors with those directly screen-printed on polyethylene terephthalate (PET) substrate. Three types of sensors are studied to highlight WTP capabilities, paving the way for multisensor platforms. Obtained results highlight that transferred carbon strain gauges are more sensitive than screen-printed sensors. Therefore, their corresponding linear gauge factors were calculated as 18 and 15, respectively. Temperature sensitivity of carbon and silver-based sensors increases after WTP process. For silver temperature sensors, the corresponding sensitivities are 0.24%/°C for the screen-printed sensor and 0.28%/°C for the transferred one. Moreover, the WTP process demonstrated no significant impact on the transfer of carbon humidity sensor. © 2017 IEEE

Détection de protéines liées au métabolisme du fer par SGFET, transistor à grille suspendue

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