TY - JOUR
T1 - Ultrafast Kinetics of Chlorinated Polymer Donors
T2 - A Faster Excitonic Dissociation Path
AU - Yan, Lihe
AU - Liang, Zezhou
AU - Si, Jinhai
AU - Gong, Pingping
AU - Wang, Yufei
AU - Liu, Xingpeng
AU - Tong, Junfeng
AU - Li, Jianfeng
AU - Hou, Xun
N1 - Publisher Copyright:
©
PY - 2022/2/9
Y1 - 2022/2/9
N2 - Halogen-substituted donor/acceptor materials are widely regarded as a promising strategy toward improved power-conversion efficiencies (PCEs) in polymer solar cells (PSCs). A chlorinated polymer donor, PClBTA-PS, and its non-chlorinated analogue, PBTA-PS, are synthesized. The PClBTA-PS-based devices show significant enhancements in terms of open-circuit voltage (VOC = 0.82 V) and fill factor (FF = 76.20%). In addition, a PCE of 13.20% is obtained, which is significantly higher than that for the PBTA-PS-based devices (PCE = 7.63%). Grazing incident wide-angle X-ray scattering shows that the chlorinated polymer enables better π-πstacking in both pure and blend films. DFT and TD-DFT calculations as well as ultrafast photophysics measurements indicate that chlorinated PClBTA-PS has a smaller bonding energy and a longer spontaneous-emission lifetime. The results also reveal that the charge-transfer-state excitons in PClBTA-PS:IT4Cl blend films split into the charge-separated (CS) state via a faster dissociation path, which produces a higher yield of the CS state. Overall, this study provides a deeper understanding of how a halogen-substituted polymer can improve PSCs in the future.
AB - Halogen-substituted donor/acceptor materials are widely regarded as a promising strategy toward improved power-conversion efficiencies (PCEs) in polymer solar cells (PSCs). A chlorinated polymer donor, PClBTA-PS, and its non-chlorinated analogue, PBTA-PS, are synthesized. The PClBTA-PS-based devices show significant enhancements in terms of open-circuit voltage (VOC = 0.82 V) and fill factor (FF = 76.20%). In addition, a PCE of 13.20% is obtained, which is significantly higher than that for the PBTA-PS-based devices (PCE = 7.63%). Grazing incident wide-angle X-ray scattering shows that the chlorinated polymer enables better π-πstacking in both pure and blend films. DFT and TD-DFT calculations as well as ultrafast photophysics measurements indicate that chlorinated PClBTA-PS has a smaller bonding energy and a longer spontaneous-emission lifetime. The results also reveal that the charge-transfer-state excitons in PClBTA-PS:IT4Cl blend films split into the charge-separated (CS) state via a faster dissociation path, which produces a higher yield of the CS state. Overall, this study provides a deeper understanding of how a halogen-substituted polymer can improve PSCs in the future.
KW - density functional theory
KW - excitonic dissociation path
KW - femtosecond time-resolved transient absorption (fs-TA) spectroscopy
KW - halogen-substitution
KW - polymer solar cells
UR - https://www.scopus.com/pages/publications/85124171414
U2 - 10.1021/acsami.1c24348
DO - 10.1021/acsami.1c24348
M3 - 文章
C2 - 35081710
AN - SCOPUS:85124171414
SN - 1944-8244
VL - 14
SP - 6945
EP - 6957
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 5
ER -