Dispensing-printed graphene plus CNT for source/drain electrodes in organic thin-film transistors

Abstract

Graphene and multi-walled carbon nanotubes (CNTs) have emerged as promising materials in advanced electronics, particularly for use in composite inks. Although screen printing is widely utilized for depositing such materials because of its cost-effectiveness and rapid processing, its limitations, such as lack of selectivity and suboptimal ink utilization, necessitate alternative approaches. This study explores a precision dispensing system for depositing graphene and CNT (Gr + CNT) composite ink as source/drain (S/D) electrodes in organic thin-film transistors (OTFTs). The dispensing printing method produced S/D electrodes with excellent electrical conductivity, pattern fidelity, and adhesion. The Gr + CNT electrodes exhibited a thickness of approximately 7.8 mu m and a trapezoidal edge with an 11.5 degrees incline that facilitates efficient charge injection and extraction. Furthermore, n-type and p-type OTFTs with a bottom-gate bottom-contact architecture were fabricated using these optimized electrodes, achieving mobilities of 0.07 cm2V(-)1 s(-)1 and 0.20 cm2V(-)1 s(-)1, respectively.