π-Extended Poly(benzimidazoanthradiisoquinolinedione) Ladder-type Conjugated Polymer
Qiang He, Teck Lip Dexter Tam, Tingting Lin, Sheau Wei Chien, Ming Lin, Hong Meng, Wei Huang, Jianwei Xu
Abstract
Since the 1960s, poly(benzobisimidazobenzophenathrolinedione) (BBL) has been the only n-type ladder-type conjugated polymer (LCP) that is utilized in thin film electronic devices. Its high electrochemical and thermal stabilities make it a promising candidate for organic electrochemical transistors (OECTs) and thermoelectrics (OTEs) applications. Here we report the synthesis and characterization of a new π-extended poly(benzimidazoanthradiisoquinolinedione) (BAL). The tetrachlorinated BAL (Cl4-BAL) is fully soluble in methanesulfonic acid (MSA) and can be spin-coated into good quality thin films, enabling the fabrication and characterization of OTEs. Doping of Cl4-BAL films using our in-house benzyl viologen radical cation (BV●+) n-dopant shows better electrical air-stability as compared to BBL due to its very low LUMO value (−4.83 eV), making it a promising material toward air-stable n-doped conducting polymers.