High-Performance Organic Field-Effect Transistors Fabricated Based on a Novel Ternary π-Conjugated Copolymer

In this study, we developed a ternary conjugated polymer, IFBT-TT, consisting of centrosymmetric indaceno[1,2-b:5,6-b']dithiophene and thieno[3,2-b]thiophene as the electron-donating units and an asymmetric 5-fluorobenzo[c][1,2,5]thiadiazole as the electron-accepting unit. The target copolymer was synthesized using an acceptor-donor-acceptor (A-D-A) type of macromonomer, which gave the target copolymer a precisely defined D1-A-D2-A architecture. Theoretical simulation revealed that the IFBT-TT features C-H···N and F···S nonbonding interactions, leading to a highly rigid and planar molecular backbone. Although the spin-cast IFBT-TT films exhibited an amorphous morphology lacking in ordered structures, the fabricated field-effect transistors presented remarkable p-type transport properties with high mobility of up to 5.0 cm² V^-1 s^-1 and excellent ambient stability. These observations highlight that the integration of a three-component D1-A-D2-A-type backbone framework is an effective molecular design strategy for high-mobility conjugated polymers.