“…20,27,28 Two popular approaches include, for example, (1) block copolymers where a conjugated electrondonating block is covalently linked to a nonconjugated flexible block with an electron acceptor as side chains, 7,23,24 and (2) donor/acceptor block copolymers where D/A-conjugated blocks are separated by nonconjugated bridge units (B). 7,10,11,[16][17][18][19][20][21][22] We have been working on the second approach and have earlier developed a (DBAB) n type block copolymer earlier (shown in Scheme 1,top), where D is a conjugated donor block, A is a conjugated acceptor block, and B is a nonconjugated and flexible bridge chain. 7,10,11,[16][17][18][19][20][21][22] However, as Scheme 1 shows, the (DBAB) n type block copolymer could suffer from poor solid-state phase separation when the sizes of the donor or acceptor blocks are not uniform.…”