Organic electrochemical transistor

Sammanfattning: Conducting polymers entered the research field in late 70's and investigations regarding printable electronics started a decade later. In this thesis printable organic electrochemical transistors (OECT) will be treated. Conjugated polymers can be switched between a high conducting and low conducting state in electrochemical cells. Here in our work, poly(3,4-ethylenedioxythiophene) (PE DOT) is used as the conducting and electrochemical active material. The electrochemical transistors presented can have both a bi-stable and dynamic functionality. Operating voltages is below 2V and on/off ratios are typically 5000, but 105 have been reached. The device is all-organic and has been realised with common printing techniques such as with screen printing. The bi-stable transistor in combination with an electrochemical electrochromic (EC) display forms a smart pixel circuitry. By combining several of these smart pixels an actively addressed cross-point matrix display is achieved. This results in an all-organic active matrix display that can be printed on paper. One important feature of organic electrochemical devices is that both ions and electrons can be used as charge (signal) carriers. This is of particular interest and importance for chemical sensors. By combination of Nation®, which is a protonconducting electrolyte that changes its conductivity upon exposure to humidity, and the OECT a humidity sensor is achieved. Here the OECT acts as the transducer, converting ion signals into an electronic signal.