Influence of hydrophobic nanogrooved gate dielectric surfaces on mobility and operational stability of polymer-based organic field-effect transistors

Abstract

We have fabricated arrays of bottom-gate/top-contact type organic field-effect transistors (OFETs) having active layers of poly(2,5-bis(3-hexadecylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT-C16) and poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4b′]dithiophen-2-yl)-alt-[1,2,5]thiadiazolo[3,4-c]pyridine] (PCDTPT). The change in the field-effect mobility and the bias-stress stability by introducing nanogroove structures on the gate dielectric surface was investigated. Anisotropic charge transport and alignment-induced mobility enhancement were clearly observed for both semiconducting polymers. Under the same bias stress conditions, the electrical stability was evaluated and compared. The electrical stabilities of pBTTT-C16 OFETs were found to be higher than those of PCDTPT OFETs, independent of the presence of nanogroove structures on the gate dielectric surfaces.