Fabrication and characterization of thin-film field-effect transistors with alkyl-phenyl[n]phenacenes (n = 4-6)

Alkyl-phenyl[n]phenacenes (n = 4-6) are newly synthesized molecules, in which two types of alkyl substituents, decyl and tetradecyl groups, are added to the benzene core frameworks, [n]phenacenes. These include: 2-decyl-8-phenyl[4]phenacene (PhC10-CHR), 3-tetradecyl-8-phenyl[4]phenacene (PhC14-CHR), 3-decyl-10-phenyl[5]phenacene (PhC10-PIC), 3-tetradecyl-10-phenyl[5]phenacene (PhC14-PIC), 2-decyl-10-phenyl[6]phenacene (PhC10-FUL), and 2-tetradecyl-10-phenyl[6]phenacene (PhC14-FUL). [4]phenacene, [5]phenacene, and [6]phenacene are named “chrycene,” “picene,” and “fulminene,” respectively. In this study, field-effect transistors (FETs) using thin films of the above molecules were fabricated with SiO₂ and ZrO₂ gate dielectrics, and their p-channel transport properties were fully investigated to clarify whether these molecules are available for FET devices. Among these molecules, the PhC10-PIC thin-film FET with ZrO₂ provides a higher field-effect mobility (μ) compared with other molecules, which can reach up to 1.66 cm² V⁻¹ s⁻¹. This paper discusses a design strategy for phenacene-type molecules for high-performance thin-film FET.