Photolithographic Patterning of Organic Semiconductors for Organic Field-Effect Transistors

Over the past 25 years, three major photolithography strategies have been employed for patterning organic semiconductors in organic field-effect transistors (OFETs): modified photolithography (MPL), orthogonal photolithography (OPL), and direct photolithography (DPL). This Review examines key studies to highlight the strengths and weaknesses of each strategy. Two DPL methods, in particular, show great promise: organic azide/diazirine cross-linkers (Z-cross-linkers) and UV-cross-linkable organic semiconducting blends (X-blends). These methods not only simplify the photolithography process significantly but also enhance the chemical and physical resistance of patterned organic semiconductors against photolithographic chemicals and tandem solution-depositions. Consequently, these advancements enable the fabrication of organic integrated circuits entirely through solution processes. In conclusion, photolithography of organic semiconductors serves a dual purpose: it facilitates the patterning of active layers for OFETs and acts as an enabling technology for fabricating sophisticated and cost-effective organic integrated circuits.