Chlorine‐Substituted N‐Heteroacene Analogues Acting as Organic Semiconductors for Solution‐Processed n‐type Organic Field‐Effect Transistors

Abstract

High performance solution processable n-type organic semiconductor is an essential element to realize lowcost, all organic and flexible composite logic circuits. In the design of n-type semiconducting materials, tuning the LUMO level of compounds is a key point. As a strong electron withdrawing unit, the introduction of chlorine atom into the chemical structure can increase the electron affinity of the material and reduce the LUMO energy level. Here, a series chlorine substituted N-heteroacene analogues of 6,7,8,9tetrachloro-4,11-bis(4-((2-ethylhexyl) ,2,3,4,8,9,10,11-octachloro-6,13-bis(4-((2ethylhexyl)oxy)phenyl)quinoxalino[2,3-b]phenazine (8Cl) and 12Cl have been synthesized and characterized. Solutionprocessed organic field-effect transistors (OFETs) based on these four compounds exhibit good electron mobilities of 0.04 cm 2 V À 1 s À 1 , 0.01 cm 2 V À 1 s À 1 , 2 × 10 À 3 cm 2 V À 1 s À 1 and 3 × 10 À 3 cm 2 V À 1 s À 1 , respectively, under ambient conditions. The results suggest that these chlorine substituted π-conjugated N-heteroacene analogues are promising n-type semiconductors in OFET applications.