Air‐Stable n‐Type Organic Field‐Effect Transistors Based on Carbonyl‐Bridged Bithiazole Derivatives

Abstract An electronegative conjugated compound composed of a newly designed carbonyl‐bridged bithiazole unit and trifluoroacetyl terminal groups is synthesized as a candidate for air‐stable n‐type organic field‐effect transistor (OFET) materials. Cyclic voltammetry measurements reveal that carbonyl‐bridging contributes both to lowering the lowest unoccupied molecular orbital energy level and to stabilizing the anionic species. X‐ray crystallographic analysis of the compound shows a planar molecular geometry and a dense molecular packing, which is advantageous to electron transport. Through these appropriate electrochemical properties and structures for n‐type semiconductor materials, OFET devices based on this compound show electron mobilities as high as 0.06 cm² V⁻¹ s⁻¹ with on/off ratios of 10⁶ and threshold voltages of 20 V under vacuum conditions. Furthermore, these devices show the same order of electron mobility under ambient conditions.