Textile electronic circuits Fibrous transistors

Textile electronic circuits based on organic fibrous transistors... 

The transistor as a component of the e-textile plays a crucial role in the textile electronic circuit. The existing fibrous transistors can be divided into two categories wire thin film transistors (WTFTs Lee and Subramanian, 2003 Maccioni et al., 2006 Locci et al., 2007) and wire electrochemical transistors (WECTs Hamedi et al., 2007 De Rossi, 2007 Tao et al., 2011). WTFT, also called WFET, is based on the field-effect transistor (FET) technology and WECT is based on electrochemical technology. With the help of these transistors, the textile electronic circuit can be achieved without loss of mechanical properties such as flexibility or softness. 

This chapter reviews the current status of the fibrous transistor development and textile electronic circuit. It covers semiconducting materials, fibrous transistors, and textile electronic circuits. Section 25.2 will discuss the materials employed in semiconductor manufacturing, especially in fibrous transistors. Section 25.3 will present traditional and fibrous transistors. Textile electronic circuits are discussed in Section 25.4. The different methodologies of use will be compared. And finally, the conclusion and perspectives will be discussed. 

Tao, X., Koncar, V., Dufour, C., 2012. Realization of fibrous electrochemical transistors and textile electronic circuits. I actualite chimique 360—361, 65—68. 

Textile electronics is another exciting area of apphcation. Fibrous diodes and transistors have already been developed in different laboratories. Flexible sensors and actuators (textile displays, heating fabrics) will in the future be part of our clothes, car interiors and home textiles. Therefore, flexible textile-based electronic circuits will be fully integrated to fabrics and connected to databases and servers making possible new ways to utilize clothing and other textiles. 

Transistors as the basic and crucial component for electronic circuits have been vigorously studied since 1947. The essential function of a transistor comes from its ability to control a larger signal by an apphed small signal between one pair of its terminals. This property makes the transistor as an amplifier or switch. According to the mechanism of the generation of carriers in the channel, transistors can be divided into three categories bipolar junction transistor, field-effect transistor, and electrochemical transistor. In electronic textile applications, the EET and ECT are employed to realize fibrous transistors. 

When Lee and Subramanian invented the first fibrous transistor (Lee and Subramanian, 2003), they did not use it to develop a textile circuit. The reason may be in the rigidity, stability, and reproductivity of the fibrous transistor. The wire was in aluminum. It was difficult to insert it into woven fabric as a normal textile filament. Moreover, its evaporated semiconductor and source-drain electrodes were delicate. They would be easily destroyed during the assembly process. Besides, the source-drain electrodes were only in one side of the wire. The alignment with other conductive yams was a problem in the source-drain position. Even if this kind of fibrous transistor was ameliorated by using stainless wire as gate and depositing the source-drain around the whole wire (Lee and Subramanian, 2005 Maccioni et al., 2006), there still was no laboratory prototype of a fibrous transistor-based electronic circuit published. Because the deposition should be carried out in vacuum, it became impossible to exploit series manufacturing for... 

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