Electro-optical circuits based on light-sensing ambipolar organic field-effect transistors

The author reports on light-sensing ambipolar organic field-effect transistors (LS-OFETs) based on blends of[6,6]-phenyl-C61-butyric acid methyl ester and poly [2-methoxy-5-(3′,7′-dimethyloctyloxy)]-p-phenylene vinylene. By carefully tuning the ambipolar transport character of the LS-OFETs, their photoresponsivity can be controlled and optimized. By combining LS-OFETs with ordinary unipolar organic transistors, fabrication of electro-optical switches and logic circuits, such as NOT and OR gates, is demonstrated. This is the only report of organic electro-optical circuits in which signal processing involves the use of both optical and electrical input signals. Such circuits could one day be explored in optical sensor array applications.