Very Low Band Gap Thiadiazoloquinoxaline Donor-Acceptor Polymers as Multi-tool Conjugated Polymers

Here we report on the synthesis of two novel very low band gap (VLG) donor-acceptor polymers (E-g <= 1 eV) and an oligomer based on the thiadiazoloquinoxaline acceptor. Both polymers demonstrate decent ambipolar mobilities, with P1 showing the best performance of similar to 10(-2) cm(2) V-1 s(-1) for p- and n-type operation. These polymers are among the lowest band gap polymers (less than or similar to 0.7 eV) reported, with a neutral lambda(max) = 1476 nm (P2), which is the farthest red-shifted lambda(max) reported to date for a soluble processable polymer. Very little has been done to characterize the electrochromic aspects of VLG polymers; interestingly, these polymers actually show a bleaching of their neutral absorptions in the near-infrared region and have an electrochromic contrast up to 30% at a switching speed of 3 s.