Dipyridyl‐Fused Quinoxalineimide (DPQI): A Strong Electron‐Withdrawing Building Block for n‐Type Polymer Semiconductors

Abstract

Exploration of new electron‐withdrawing building blocks plays a key role in the development of n‐type organic semiconductors. Herein, a strong electron‐withdrawing building block, dipyridyl‐fused quinoxalineimide (DPQI), was successfully designed and synthesized. Single‐crystal structure reveals that DPQI molecule possesses a completely planar backbone, which is beneficial for charge transport. For comparison, dibenzo‐fused quinoxalineimide (DBQI) was also synthesized. The frontier molecular orbital (FMO) energy levels downshift with the incorporation of nitrogen atoms onto the p‐conjugated backbone of quinoxalineimide. Two acceptor‐acceptor (or all‐acceptor) polymers P(BTI‐DBQI) and P(BTI‐DPQI) based on DBQI and DPQI were synthesized, respectively. Two polymers exhibit deep lowest‐unoccupied molecular orbital (LUMO) levels (~‐3.5 eV). Additionally, P(BTI‐DPQI) exhibits unipolar n‐type charge transport with μe of 1.4×10‐4 cm2 V‐1 s‐1 in the organic field‐effect transistors (OFET), which render them highly attractive for developing n‐type semiconductors device. This work demonstrates that DPQI is a promising building block for constructing n‐type polymer semiconductors.