Carrier Mobility and Luminescence Properties of a One-Step Synthesized π-Extended Diketopyrrolopyrrole Derivative

This study demonstrates the one-step synthesis of 4,5,11,12-tetrapentyl-7H,14H-thieno[3,2-g]thieno[3',2':7,8]indolizino[2,1-a]indolizine-7,14-dione (BIPI) from 6-dodecyne and 3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione via Ru-catalyzed CH-NH activation, reported by Gońka et al. in 2019. The synthesized BIPI exhibited intense luminescence and broad absorption up to 600 nm owing to the substantial overlap between the HOMO and LUMO orbitals. The high planarity achieved through cyclization further enabled the fabrication of organic field-effect transistors using the vacuum deposition method, demonstrating a hole mobility of μ_h = 1.6 × 10^-2 cm²/(V s). Band calculations using Quantum ESPRESSO with the crystal structure of BIPI revealed the increase in valence band dispersion and movement of holes along the columnar direction. The ideal carrier mobility is calculated by the charge transfer rate.