Abstract
All-conjugated block copolymers bring together hole- and electron-conductive polymers and can be used as the active layer of solution-processed photovoltaic devices, but it remains unclear how molecular structure, morphology, and electronic properties influence performance. Here, the role of the chemical linker is investigated through analysis of two donor-linker-acceptor block copolymers that differ in the chemistry of the linking group. Device studies show that power conversion efficiencies differ by a factor of 40 between the two polymers, and ultrafast transient absorption measurements reveal charge separation only in block copolymers that contain a wide bandgap monomer at the donor-acceptor interface. Optical measurements reveal the formation of a low-energy excited state when donor and acceptor blocks are directly linked without this wide bandgap monomer. For both samples studied, it is found that the rate of charge recombination in these systems is faster than in polymer-polymer and polymer-fullerene blends. This work demonstrates that the linking group chemistry influences charge separation in all-conjugated block copolymer systems, and further improvement of photovoltaic performance may be possible through optimization of the linking group. These results also suggest that all-conjugated block copolymers can be used as model systems for the donor-acceptor interface in bulk heterojunction blends
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5578-5585 |
| Number of pages | 8 |
| Journal | Advanced Functional Materials |
| Volume | 25 |
| Issue number | 35 |
| DOIs | |
| State | Published - Sep 1 2015 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics
- Electrochemistry
Cite this
}
Linking Group Influences Charge Separation and Recombination in All-Conjugated Block Copolymer Photovoltaics. / Mok, Jorge W.; Lin, Yen Hao; Yager, Kevin G.; Mohite, Aditya D.; Nie, Wanyi; Darling, Seth B.; Lee, Youngmin; Gomez, Enrique Daniel; Gosztola, David; Schaller, Richard D.; Verduzco, Rafael.
In: Advanced Functional Materials, Vol. 25, No. 35, 01.09.2015, p. 5578-5585.Research output: Contribution to journal › Article
TY - JOUR
T1 - Linking Group Influences Charge Separation and Recombination in All-Conjugated Block Copolymer Photovoltaics
AU - Mok, Jorge W.
AU - Lin, Yen Hao
AU - Yager, Kevin G.
AU - Mohite, Aditya D.
AU - Nie, Wanyi
AU - Darling, Seth B.
AU - Lee, Youngmin
AU - Gomez, Enrique Daniel
AU - Gosztola, David
AU - Schaller, Richard D.
AU - Verduzco, Rafael
PY - 2015/9/1
Y1 - 2015/9/1
N2 - All-conjugated block copolymers bring together hole- and electron-conductive polymers and can be used as the active layer of solution-processed photovoltaic devices, but it remains unclear how molecular structure, morphology, and electronic properties influence performance. Here, the role of the chemical linker is investigated through analysis of two donor-linker-acceptor block copolymers that differ in the chemistry of the linking group. Device studies show that power conversion efficiencies differ by a factor of 40 between the two polymers, and ultrafast transient absorption measurements reveal charge separation only in block copolymers that contain a wide bandgap monomer at the donor-acceptor interface. Optical measurements reveal the formation of a low-energy excited state when donor and acceptor blocks are directly linked without this wide bandgap monomer. For both samples studied, it is found that the rate of charge recombination in these systems is faster than in polymer-polymer and polymer-fullerene blends. This work demonstrates that the linking group chemistry influences charge separation in all-conjugated block copolymer systems, and further improvement of photovoltaic performance may be possible through optimization of the linking group. These results also suggest that all-conjugated block copolymers can be used as model systems for the donor-acceptor interface in bulk heterojunction blends
AB - All-conjugated block copolymers bring together hole- and electron-conductive polymers and can be used as the active layer of solution-processed photovoltaic devices, but it remains unclear how molecular structure, morphology, and electronic properties influence performance. Here, the role of the chemical linker is investigated through analysis of two donor-linker-acceptor block copolymers that differ in the chemistry of the linking group. Device studies show that power conversion efficiencies differ by a factor of 40 between the two polymers, and ultrafast transient absorption measurements reveal charge separation only in block copolymers that contain a wide bandgap monomer at the donor-acceptor interface. Optical measurements reveal the formation of a low-energy excited state when donor and acceptor blocks are directly linked without this wide bandgap monomer. For both samples studied, it is found that the rate of charge recombination in these systems is faster than in polymer-polymer and polymer-fullerene blends. This work demonstrates that the linking group chemistry influences charge separation in all-conjugated block copolymer systems, and further improvement of photovoltaic performance may be possible through optimization of the linking group. These results also suggest that all-conjugated block copolymers can be used as model systems for the donor-acceptor interface in bulk heterojunction blends
UR - http://www.scopus.com/inward/record.url?scp=84941748026&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84941748026&partnerID=8YFLogxK
U2 - 10.1002/adfm.201502623
DO - 10.1002/adfm.201502623
M3 - Article
AN - SCOPUS:84941748026
VL - 25
SP - 5578
EP - 5585
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
IS - 35
ER -