Bis-Diketopyrrolopyrrole and Carbazole-Based Terpolymer for High Performance Organic Field-Effect Transistors and Infra-Red Photodiodes

Carbazoles constitute one of the most widely used donor moieties for organic semiconductors due to their excellent hole transport and high environmental stability. However, they are seldomly used in recent high performance donor–acceptor (D–A) copolymers. In the present study, a planar regular terpolymer, PCbisDPP, composed of carbazole and thiophene flanked bis-diketopyrrolopyrrole (bis-DPP) for application as an active layer for high-performance organic devices is reported. Organic field-effect transistors with PCbisDPP as the active layer exhibit field-effect mobility up to 1.48 cm² v⁻¹ s⁻¹, which to the best of the current knowledge corresponds to the highest hole mobility reported to date for carbazole-based D–A polymers. The high mobility is achieved via a tailored polymer-design resulting in high crystallinity and a strong aggregating property without sacrificing solubility. PCbisDPP is applied as an active donor material in organic photodiode with fullerene derivative PC₆₁BM as an acceptor in a bulk heterojunction blend. Binary additive combinations (tetralin: 1,8-diiodooxtane (3:3) v/v%) utilization achieves an impressive performance with an external quantum efficiency of 80%, an average responsivity of 309.1 mA W⁻¹, and specific detectivity of 4.73 × 10¹¹ Jones in the near infra-red light region (730 nm) utilizing a simple single layer organic photodiode structure as ITO/PEDOT:PSS/PCbisDPP:PC₆₁BM/LiF/Al.