Low-voltage flexible organic transistors based on a water-soluble natural gate dielectric exhibiting high-performance and stability

The use of natural material components in organic devices increases nature friendliness and biodegradability. In this paper, water-soluble natural protein gelatin is explored as a gate dielectric for demonstration of high performance and low voltage (−3 V) operation in flexible organic field-effect transistors (OFETs). The fabricated p-channel devices showed excellent electrical characteristics of maximum field-effect mobility up to 3.0 cm 2 V −1 s −1 , high current on/off ratios, low subthreshold swing, and nearly zero threshold voltage due to the high-quality dielectric semiconductor interface achieved through optimized processes of fabricating flexible OFET devices. These devices exhibited very high operational stability as confirmed by various stability tests including bias-stress, repeatability, electromechanical stability, cyclic stability, and long-term ambient stability. For electromechanical stability, no significant changes in the performance were observed upon application of compressive and tensile strain due to bending. A very high environmental stability with almost unchanged electrical characteristics over 24 weeks was demonstrated. Further, circuit applicability was analyzed by switching characteristics from resistive load inverters. These results indicate gelatin as a promising biodegradable dielectric candidate for low voltage flexible OFETs.