Dual-gate low-voltage organic transistor for pressure sensing (original) (raw)
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Pressure sensing by flexible, organic, field effect transistors
Applied Physics Letters, 2006
A mechanical sensor based on a pentacene field effect transistor has been fabricated. The pressure dependence of the output current has been investigated by applying a mechanical stimulus by means of a pressurized air flow. Experimental results show a reversible current dependence on pressure. Data analysis suggests that variations of threshold voltage, mobility and contact resistance are responsible for current variations. Thanks to the flexibility of the substrate and the low cost of the technology, this device opens the way for flexible mechanical sensors that can be used in a variety of innovative applications such as e-textiles and robotic interfaces.
Strain Sensitivity and Transport Properties in Organic Field-Effect Transistors
IEEE Electron Device Letters, 2012
We present the electromechanical characterization of organic field-effect transistors (OFETs) fabricated with different organic semiconductors. Pentacene-and poly(3-hexylthiophene-2,5-diyl) (P3HT)-based OFETs have been investigated as strain sensors, and a clear correlation between the structural and morphological properties of the active layer with the device sensitivity has been observed. The highly disordered structure of polymeric films, as P3HT, confirmed by morphological and structural investigations, gives rise to a dramatic reduction of the device response to mechanical stimuli. Nevertheless, an unambiguous, fast, and reproducible response has been obtained also for this material, which, being solution processible, represents a valuable solution for the fabrication of low-cost pressure sensors for a variety of innovative applications.
Low voltage active pressure sensor based on polymer space-charge-limited transistor
Applied Physics Letters, 2009
Low voltage active pressure sensor is realized by vertically stacking a pressure sensitive rubber on a polymer space-charge-limited transistor. The sensor can be turned on and off by modulating the metal-grid base voltage within the range of 3 V. The output current is irrelevant to the pressure as the sensor is off. As the sensor is turned on, the output current values can be used to monitor the pressure. Reversible pressure sensing characteristics is observed below the pressure of 7.11 psi. The response time of the sensor to the pressure is as short as 22 ms.
Advanced Materials Interfaces, 2019
Flexible pressure sensors are increasingly impacting a wide variety of novel applications such as wearable health care sensors, in vivo monitoring, and even artificial skin. As a fundamental device component, organic field‐effect transistors (OFETs) are of great interest due to their inherent advantages related to low‐cost solution fabrication processes and compatibility with plastic substrates. During OFET fabrication, it is almost impossible to avoid the water traces in the organic semiconductor (OSC) active layer, especially when ambient solution processing techniques are employed. Water exhibits a strong influence on the electrical performance in OFETs, such as hysteresis and nonideal transfer characteristics. Here, it is shown that the presence of water in OSCs also results in pressure‐sensitive devices caused by the modification of the water dipole alignment. This exciting phenomenon is exploited in a novel OFET, namely, hydrogel‐based electrolyte‐gated organic field‐effect tr...
Sensors
Organic Field-Effect Transistors (OFETs) are attracting a rising interest for the development of novel kinds of sensing platforms. In this paper, we report about a peculiar sensor device structure, namely Organic Charge-Modulated Field-Effect Transistor (OCMFET), capable of operating at low voltages and entirely fabricated with large-area techniques, i.e., inkjet printing and chemical vapor deposition, that can be easily upscaled to an industrial size. Device fabrication is described, and statistical characterization of the basic electronic parameters is reported. As an effective benchmark for the application of large-area fabricated OCMFET to the biomedical field, its combination with pyroelectric materials and compressible capacitors is discussed, in order to employ the proposed device as a temperature pressure sensor. The obtained sensors are capable to operate in conditions which are relevant in the biomedical field (temperature in the range of 18.5–50 °C, pressure in the range ...
2010
Here we report on the fabrication and detailed characterization of flexible low-voltage organic thin-film transistors directly integrated with pyro- and piezoelectric sensors. The functional layer of the capacitive sensors is a ferroelectric fluoropolymer. The transistors on the other hand are based on a high-k nanocomposite gate dielectric and on pentacene as the organic semiconductor and can be operated well below 5V. It is shown, that the transistors can be fabricated on the fluororpolymer layer. Since the control of parameter spread is a very important topic in large area electronics, it was attempted to investigate the homogeneity of a significant set of devices by individual assessment of the layer composition and thickness, the pentacene morphology, the actual geometry and the electrical parameters. It turned out that starting from the measured device parameters such as layer thickness, capacitance, channel dimension, grain size and threshold voltage, the drain current can be...
Organic Thin-Film Transistors as Gas Sensors: A Review
Materials, 2020
Organic thin-film transistors (OTFTs) are miniaturized devices based upon the electronic responses of organic semiconductors. In comparison to their conventional inorganic counterparts, organic semiconductors are cheaper, can undergo reversible doping processes and may have electronic properties chiefly modulated by molecular engineering approaches. More recently, OTFTs have been designed as gas sensor devices, displaying remarkable performance for the detection of important target analytes, such as ammonia, nitrogen dioxide, hydrogen sulfide and volatile organic compounds (VOCs). The present manuscript provides a comprehensive review on the working principle of OTFTs for gas sensing, with concise descriptions of devices’ architectures and parameter extraction based upon a constant charge carrier mobility model. Then, it moves on with methods of device fabrication and physicochemical descriptions of the main organic semiconductors recently applied to gas sensors (i.e., since 2015 bu...