TY - JOUR
T1 - Impact of side-chain fluorination on photovoltaic properties
T2 - Fine tuning of the microstructure and energy levels of 2D-conjugated copolymers
AU - Shin, Jisoo
AU - Kim, Min
AU - Kang, Boseok
AU - Lee, Jaewon
AU - Kim, Heung Gyu
AU - Cho, Kilwon
N1 - Funding Information:
This work was supported by a grant (Code No. 2011-0031628) from the Center for Advanced Soft Electronics under the Global Frontier Research Program of the Ministry of Science, ICT and Future Planning, Korea.
Publisher Copyright:
© The Royal Society of Chemistry 2017.
PY - 2017
Y1 - 2017
N2 - The control of the molecular energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is crucial to the design of highly efficient polymer solar cells (PSCs). In particular, the fine control of the HOMO energy level is vital because it can ensure that polymer solar cell devices have a high open circuit voltage (Voc) and a high short circuit current density (Jsc). We systematically synthesized a series of polymers substituted with different numbers of fluorine (F) atoms in conjugated side chains to fine-tune the HOMO energy levels of the donor polymer, and then optimized the associated solar cell devices by varying the length of the alkyl chain in the conjugated side chains. A series of conjugated side chains with non-fluorinated (0F), mono-fluorinated (1F), and di-fluorinated (2F) alkoxyphenyl groups at the meta position were synthesized and introduced into the donor polymer. The strong electron-withdrawing properties of fluorine were found to reduce the HOMO energy level and yield high Voc values up to 1.01 V. The substitution of the conjugated side chain with fluorine affects not only the energy level of the polymer but also its intermolecular packing and crystallinity due to the resulting intermolecular interactions, and was found to be effective in the control of Jsc and FF. A maximum efficiency of 7.64% was achieved for the polymer with the mono-fluorinated conjugated side chain.
AB - The control of the molecular energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is crucial to the design of highly efficient polymer solar cells (PSCs). In particular, the fine control of the HOMO energy level is vital because it can ensure that polymer solar cell devices have a high open circuit voltage (Voc) and a high short circuit current density (Jsc). We systematically synthesized a series of polymers substituted with different numbers of fluorine (F) atoms in conjugated side chains to fine-tune the HOMO energy levels of the donor polymer, and then optimized the associated solar cell devices by varying the length of the alkyl chain in the conjugated side chains. A series of conjugated side chains with non-fluorinated (0F), mono-fluorinated (1F), and di-fluorinated (2F) alkoxyphenyl groups at the meta position were synthesized and introduced into the donor polymer. The strong electron-withdrawing properties of fluorine were found to reduce the HOMO energy level and yield high Voc values up to 1.01 V. The substitution of the conjugated side chain with fluorine affects not only the energy level of the polymer but also its intermolecular packing and crystallinity due to the resulting intermolecular interactions, and was found to be effective in the control of Jsc and FF. A maximum efficiency of 7.64% was achieved for the polymer with the mono-fluorinated conjugated side chain.
UR - http://www.scopus.com/inward/record.url?scp=85027465516&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85027465516&partnerID=8YFLogxK
U2 - 10.1039/c7ta04098a
DO - 10.1039/c7ta04098a
M3 - Article
AN - SCOPUS:85027465516
SN - 2050-7488
VL - 5
SP - 16702
EP - 16711
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 32
ER -
