Bias‐Stable Fullerene‐Based n‐Type Organic Transistors Using Ionic Liquid as a Stabilizer

Despite decades of extensive efforts in the engineering and molecular design of organic semiconductors (OSCs), the transistor performance and stability of n-type OSCs remain lower than those of their p-type counterparts. In recent years, incorporating ionic liquids (ILs) into electronic and optoelectronic devices has enabled exceptional performance and environmental stability through doping, film crystallization processes, and energetic alignment because of their unique physicochemical properties. This paper reports on bias-stable n-type organic field-effect transistors (OFETs) based on an n-type fullerene-based semiconductor ([6,6]-phenyl-C-61-butyric acid methyl ester (PCBM)) with a solid-state IL additive. The optimized PCBM-IL OFETs exhibits a more than fivefold increase in electron mobility, excellent continuous bias-stress stability for over 1 h, and a remarkable increase in current output under ambient conditions due to synergistic PCBM-IL interactions and robust interfacial properties, which reduces resistance and minimized interface traps.