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

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 (mu(h)) and electrons (mu(e)) in OHJTs is consistent with that of mu(uni) in their unique OFETs. The mu(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 mu(e). The layers of the p-type materials films are responsible for the occasions of the highest mu(h) and mu(e) emerging.

Automated summary

This study fabricated organic heterojunction transistors (OHJTs) with different isomers as p-type semiconductors and investigated their influence on the transistor performance. The analysis of the properties of the isomer films revealed that the film thickness plays a crucial role in determining the highest field-effect mobilities.