Multi‐Selenophene Incorporated Thiazole Imide‐Based n‐Type Polymers for High‐Performance Organic Thermoelectrics
Yongchun Li, Wenchang Wu, Yimei Wang, Enmin Huang, Sang Young Jeong, Han Young Woo, Xugang Guo, Kui Feng
Abstract
Abstract Developing polymers with high electrical conductivity ( σ ) after n‐doping is a great challenge for the advance of the field of organic thermoelectrics (OTEs). Herein, we report a series of thiazole imide‐based n‐type polymers by gradually increasing selenophene content in polymeric backbone. Thanks to the strong intramolecular noncovalent N⋅⋅⋅S interaction and enhanced intermolecular Se⋅⋅⋅Se interaction, with the increase of selenophene content, the polymers show gradually lowered LUMOs, more planar backbone, and improved film crystallinity versus the selenophene‐free analogue. Consequently, polymer PDTzSI−Se with the highest selenophene content achieves a champion σ of 164.0 S cm −1 and a power factor of 49.0 μW m −1 K −2 in the series when applied in OTEs after n‐doping. The σ value is the highest one for n‐type donor‐acceptor OTE materials reported to date. Our work indicates that selenophene substitution is a powerful strategy for developing high‐performance n‐type OTE materials and selenophene incorporated thiazole imides offer an excellent platform in enabling n‐type polymers with high backbone coplanarity, deep‐lying LUMO and enhanced mobility/conductivity.