Block copolymers for opto-electronics

Design, synthesis, and characterization of a novel c‐donor‐nc‐bridge‐c‐acceptor type block copolymer for optoelectronic applications

“…Block copolymers are known to self‐assemble into a variety of BONS type morphologies at nanoscale, making it an attractive candidate for solar cell applications. There have been a number of efforts on the development of various block copolymer systems containing conjugated donor and acceptor blocks, since chemically different donor and acceptor blocks may undergo phase separation on the nanometer scale . When two different conjugated blocks are covalently connected directly, charge separated states appear not stable .…”

“…When two different conjugated blocks are covalently connected directly, charge separated states appear not stable . Two popular approaches include, for example, (1) block copolymers where a conjugated electron‐donating block is covalently linked to a nonconjugated flexible block with an electron acceptor as side chains, and (2) donor/acceptor block copolymers where D/A‐ conjugated blocks are separated by nonconjugated bridge units ( B ) …”

“…We have been working on the second approach and have earlier developed a ( DBAB ) n type block copolymer earlier (shown in Scheme , top), where D is a conjugated donor block, A is a conjugated acceptor block, and B is a nonconjugated and flexible bridge chain . However, as Scheme 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.…”

“…There have been a number of efforts on the development of various block copolymer systems containing conjugated donor and acceptor blocks, since chemically different donor and acceptor blocks may undergo phase separation on the nanometer scale. 7,10,11,[16][17][18][19][20][21][22][23][24][25][26][27][28] When two different conjugated blocks are covalently connected directly, charge separated states appear not stable. 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).…”

“…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.…”