The Polymer Society of Korea

Abstract

This study evaluates ambipolar organic thin film transistors (OTFTs) and complementary-like inverters using PTCDI-C₁₃and pentacene bilayers deposited sequentially on a polymer-grafted SiO₂ dielectric. As the underlying layers in semiconductor heterojunction bilayers (HJBs), PTCDI-C₁₃ crystallites with a nominal thickness of 4 monolayers (ML) were deposited and reorganized thermally. Finally, the crystal growth of pentacene was intermediated on the PTCDI-C₁₃ crystallites. Semiconductor HJBs clearly exhibited ambipolar charge-carrier transport, and the ambipolar OTFTs exhibited various hole (m_h) and electron (m_e) mobilities of 0.10-0.75 and 0.013-0.55 cm² V^-1 s^-1, respectively, depending on the p-conjugated structures of the semiconductors. The terrace-like crystal growth of pentacene could be intermediated on the smooth layered crystallites of PTCDI-C₁₃. Complementary-like inverters using two ambipolar OTFTs yielded a high voltage gain of up to 80.