Organic Heterojunction Transistors Based on DEP‐DTT Isomers and PTCDI‐CH₂C₃F₇

Abstract Organic heterojunction transistors (OHJTs) are fabricated with three isomers, DEP‐bb‐DTT, DEP‐bt‐DTT, and DEP‐tt‐DTT as p‐type semiconductors, and PTCDI‐CH₂C₃F₇ as n‐type semiconductor. All the OHJTs present n‐channel and ambipolar operating modes in turn with the thickness (t) of the isomers films increasing. The properties of p‐type semiconductors directly affect the performances of OHJTs. The amplitude variation of the highest field‐effect mobilities for holes (μ_h) and electrons (μ_e) in OHJTs is consistent with that of μ_uni in their unique OFETs. The μ_e in DEP‐bb‐DTT/PTCDI‐CH₂C₃F₇ OHJTs present flipped V‐shaped behaviors, while they show the upright and inverted V‐shaped combination patterns in DEP‐bt‐DTT/PTCDI‐CH₂C₃F₇ and DEP‐tt‐DTT/PTCDI‐CH₂C₃F₇ OHJTs. By analyzing these p‐type isomers pristine and annealed films, a transformation from monolayer to bilayer occurring in the initial growth course of the DEP‐bt‐DTT and DEP‐tt‐DTT films is discovered and responsible for the variation tendencies of μ_e. The layers of the p‐type materials films are responsible for the occasions of the highest μ_h and μ_e emerging.