Double Exposure Method: a Novel Photolithographic Process to Fabricate Flexible Organic Field-Effect Transistors and Circuits

A novel process called double exposure method has for the first time been developed to utilize common organic materials as insulating layers at low annealing temperature in the process of photolithography. In this method, organic dielectric layer will not dissolve in the final lift-off step by using developer to replace traditional acetone. Bottom-gate bottom-contact (BGBC) OFETs are fabricated on the flexible PET substrates with polystyrene (PS) and pentacene as dielectric layer and semiconductor layer, respectively. Transistors with mobility of 0.36 cm(2) V-1 s(-1) and logic inverter with gain of 9 on the plastic substrates have been fabricated, demonstrating the potential appliction of double exposure method in flexible organic electronics.