1,721,026 research outputs found
Soft Lithography Fabrication of Fully Flexible and Transparent all Organic FETs for Large Area Application
No full textProducing smart sensing films by means of organic field effect transistors
No full textWe have fabricated the first example of totally flexible field effect device for chemical detection based on an organic field effect transistor (OFET) made by pentacene films grown on flexible plastic structures. The ion sensitivity is achieved by employing a thin Mylar foil as gate dielectric. A sensitivity of the device to the pH of the electrolyte solution has been observed A similar structure can be used also for detecting mechanical deformations on flexible surfaces. Thanks to the flexibility of the substrate and the low cost of the employed technology, these devices open the way for the production of flexible chemical and strain gauge sensors that can be employed in a variety of innovative applications such as wearable electronics, e-textiles, new man-machine interfaces
Flexible organic thin-film transistors for pH monitoring
No full textA novel freestanding flexible device based on an Organic Field Effect Transistor (OFET), able to detect pH changes in chemical solutions thanks to a functionalized loating-gate, was realized and successfully tested. The device is assembled on a lexible film (Mylar), which acts at the same time as gate insulator and as mechanical support for the whole structure. On one side of the foil a control gate and drain/source contacts are photolithographically patterned, and a pentacene active layer deposited; on the opposite side a gold floating gate is defined. The sensor performs the detection of the chemical species placed over the probe area by detecting the associated electric charge: the structure, basically, works as a loating-gate transistor whose threshold voltage is modulated by the surface charge due to the solution under investigation. By properly functionalizing the loating gate surface, sensitivity to different species and the detection of different reactions can be achieved, with the same sensor. In this work we present its application as ion-sensitive device. pH sensitivity is achieved by functionalizing the sensing surface with thio-aminic groups as such groups protonate proportionally to the concentration of H3 O+ ions in the solution. Such a structure does not require a counter-electrode as the OFET is biased through a control gate. Moreover, the working mechanism is independent of the choice of semiconductor, gate or dielectric material, since the OFET is insulated from the solution. The application as DNA sensor is currently under investigation as wel
Organic-based inverters: Basic concepts, materials, novel architectures and applications
No full textWhile organic materials have demonstrated industry-leading performances in a wide array of electronic applications (including OLEDs and OPVs), their use for integration into electronic circuits has been so far limited, in spite of their potential for portable, flexible, light-weight, low-cost applications. However, recent advances in organic (semi)conductors and novel designs in organic field-effect transistors and hybrid systems have reaffirmed the potential of organic logic circuits. This review article provides an overview of organic-based inverter operation and considers all aspects of such circuits including their active layer, processing methods, hybrid organic/inorganic inverters, novel architectures and potential applications. This journal i
Towards the textile transistor: Assembly and characterization of an organic field effect transistor with a cylindrical geometry
No full textQuesto lavoro è stato selezionato per la pubblicazione nel volume del 16/10/2006 del Virtual Journal of Nanoscale Science & Technology, pubblicato dall’American Institute of Physics e dall’American Physical Societ
Organic-based sensor for chemical detection in aqueous solution
No full textWe present a flexible, pentacene-based field-effect device, for the detection of chemical species in aqueous solution. The sensor consists in a double-gate transistor, where the detection is achieved by exploiting the charge sensing capabilities of the floating-gate terminal. To provide the pH -sensitivity, the floating gate is functionalized with thioamine groups as such groups protonize proportionally to the concentration of H3O+ ions in solution. With respect to the existing organic-based devices for pH monitoring, our sensor does not require a counterelectrode and the organic semiconductor is not affected by the contact with the monitored solutio
Investigation on different organic semiconductor/organic dielectric interfaces in pentacenebased thin-film transistors
No full textOrganic Thin-Film Transistors (O1'FTs) in top-contact configuration and Metal- Insulator-Semiconductor (MIS) structures with different organic dielectrics as the gate insulator have been fabricated using the same organic semiconductor layer, pentacene, in order to investigate the changes in the electrical behavior by varying the interface properties. A gold bottom gate electrode was sputtered on a glass substrate whereas gold source and drain were thermally evaporated onto the pentacene layer. Several organic dielectrics have been tested as insulating layers, namely poly(vinyl alcohol) (PVA), polyvinyl alcohol cross-linked with ammonium dichromate (c.l. PVA) poly (4-vinyl phenol) (PVP), poly(dimethylsiloxane) (PDMS) and poly(methylsilsesquioxane) (pMSSQ). The interesting differences found by varying the interface confirm that the chemical-physical interaction between semiconductor and dielectric is crucial for the conduction mechanisms of the charge carriers
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