2,5-Bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4-(2H,5H)-dione-Based Donor-Acceptor Alternating Copolymer Bearing 5,5′-Di (thiophen-2-yl)-2,2′-biselenophene Exhibiting 1.5 cm2.V-1.s-1 Hole Mobility in Thin-Film Transistors

A novel diketopyrrolopyrrole-based pi-conjugated copolymer P(DPP-alt-DTBSe), 5, and a known copolymer P(DPP-alt-QT), 4, have been synthesized in 80-90% yield using the Stille coupling reaction. The molecular weights of 4 and 5 are 58 781 and 19 271 g/mol, respectively, with polydispersity values of 3.25-3.35. A relatively small band gap of 1.32-1.39 eV and excellent solubility in organic solvents were achieved in the two polymers. Thin-film transistors made of 5 exhibit outstanding performance (e.g., mu > 1.0-1.5 cm(2).V(-1)s(-1), I-on/I-off > 10(5)-10(6)) with a conventional n-octyltrichlorosilane-SiO2 gate dielectric.