| 초록 |
Imide-functionalized π-conjugated polymers are highly promising semiconductors in the field of organic electronics. Semiconducting polymers derived from naphthalene diimide (NDI) and perylene diimide (PDI) are the “benchmark materials” in organic thin-film transistor (OTFT) and all-polymer solar cell (all-PSC) field. We report here a series of novel imide-functionalized ladder-type bithiophene imide derivatives (BTIn, n = 1-5) with up to 5 imide groups and 15 rings. The homopolymers show tunable FMO levels and film morphologies. Novel imide-functionalized thiazoles were also synthesized, enabling the access of all-acceptor homopolymers, which exhibit unipolar n-type transport in OTFTs with the highest electron mobilities (μes) > 3 cm2 V−1 s−1. Notably, these polymers do not show undesirable kink in transistor curves, thus avoiding mobility overestimation. The deep-lying polymer FMOs led to suppressed Ioffs of 10−10-10−11 A, thus remarkable Ion/Ioffs of 107-108 achieved, while maintaining a large μe of 1.6 cm2 V−1 s−1. Besides all-acceptor homopolymers, these novel imide-functionalized arenes were incorporated to donor-acceptor and donor-acceptor-acceptor copolymers, which also showed unipolar n-type transport with substantial μes > 1 cm2 V−1 s−1. When used as acceptor materials, the all-PSCs exhibited power conversion efficiencies (PCEs) of > 9%, the highest value except NDI-based polymer acceptors. When used as the donor materialss, and the non-fullerene small molecule-based solar cells showed PCEs > 13%. |
