Cyano-Functionalized Thienylthiazole Imide-Based n-Type Polymers for High-Performance Organic Electronics

Designing and synthesizing building blocks with strong electron deficiency, planar backbone, and good solubility remains a great challenge in developing n-type polymers with high electron mobility and efficient n-doping capability. Here, we report a novel cyano-functionalized thienylthiazole imide (TzICN), designed by integrating three potent electron-withdrawing functionalities: imide, thiazole, and cyano groups. TzICN features a low-lying lowest unoccupied molecular orbital (LUMO) level, highly planar backbone, compact framework, and excellent solubility, heralding it as a versatile building block for high-performance n-type polymers. Using TzICN, we synthesize an acceptor–acceptor type polymer, PTzICN-BTI, which exhibits a significantly suppressed LUMO level of −3.95 eV, enhanced intramolecular S···C noncovalent interactions, and improved microstructural order compared to its noncyanated counterpart. These characteristics enable PTzICN-BTI to achieve a high electron mobility of 1.32 cm2 V–1 s–1 in thin-film transistors. Furthermore, PTzICN-BTI demonstrates exceptional n-dopability, delivering a remarkable conductivity of 105.1 S cm–1 and power factor of 50.9 μW m–1 K–2 without any postdeposition thermal treatment or doping activation, both of which are among the highest values for n-doped polymers without annealing. This study highlights the power of integrating imide, thiazole, and cyano functionalities within a single building block, offering a powerful strategy for developing high-performance n-type polymers.