TY - JOUR
T1 - Reduced Nonradiative Recombination Energy Loss Enabled Efficient Polymer Solar Cells via Tuning Alkyl Chain Positions on Pendent Benzene Units of Polymers
AU - Bi, Xiaoman
AU - Wu, Ziang
AU - Zhang, Tao
AU - An, Cunbin
AU - Xu, Ye
AU - Ma, Kangqiao
AU - Li, Sunsun
AU - Zhang, Shaoqing
AU - Yao, Huifeng
AU - Xu, Bowei
AU - Woo, Han Young
AU - Cao, Shaokui
AU - Hou, Jianhui
N1 - Funding Information:
We greatly thank the financial support from the National Natural Science Foundation of China (Grant nos 51703228, 51673201, and 21835006), Beijing National Laboratory for Molecular Sciences (BNLMS-CXXM-201903), and postdoctoral research grant in Henan Province (1902018). H.Y. Woo gratefully acknowledges the funding of the National Research Foundation (NRF) of Korea (2012M3A6A7055540 and 2019R1A6A1A11044070).
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/5/27
Y1 - 2020/5/27
N2 - Nonradiative recombination energy loss (Î"E3) plays a key role in enhancing device efficiencies for polymer solar cells (PSCs). Until now, there is no clear resolution for reducing Î"E3 via molecular design. Herein, we report two conjugated polymers, PBDB-P-p and PBDB-P-m, which are integrated from benzo[1,2-b:4,5-b′]dithiophene with alkylthio chain substituted at para-or meta-position on pendent benzene and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione. Both the polymers have different temperature-dependent aggregation properties but similar molecular energy levels. When BO-4Cl was used as an acceptor to fabricate PSCs, the device of PBDB-P-p:BO-4Cl displayed a maximal power conversion efficiency (PCE) of 13.83%, while the best device of PBDB-P-m:BO-4Cl exhibited a higher PCE of 14.12%. The close JSCs and fill factors in both PSCs are attributed to their formation of effective nanoscale phase separation as confirmed by atomic force microscopy measurements. We find that the PBDB-P-m-based device has 1 order of magnitude higher electroluminescence quantum efficiency (EQEEL) than in the PBDB-P-p-based one, which could arise from the relatively weak aggregation in the PBDB-P-m-based film. Thus, the PBDB-P-m-based device has a remarkably enhanced VOC of 0.86 V in contrast to 0.80 V in the PBDB-P-p-based device. This study offers a feasible structural optimization way on the alkylthio side chain substitute position on the conjugated polymer to enhance VOC by reducing nonradiative recombination energy loss in the resulting PSCs.
AB - Nonradiative recombination energy loss (Î"E3) plays a key role in enhancing device efficiencies for polymer solar cells (PSCs). Until now, there is no clear resolution for reducing Î"E3 via molecular design. Herein, we report two conjugated polymers, PBDB-P-p and PBDB-P-m, which are integrated from benzo[1,2-b:4,5-b′]dithiophene with alkylthio chain substituted at para-or meta-position on pendent benzene and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione. Both the polymers have different temperature-dependent aggregation properties but similar molecular energy levels. When BO-4Cl was used as an acceptor to fabricate PSCs, the device of PBDB-P-p:BO-4Cl displayed a maximal power conversion efficiency (PCE) of 13.83%, while the best device of PBDB-P-m:BO-4Cl exhibited a higher PCE of 14.12%. The close JSCs and fill factors in both PSCs are attributed to their formation of effective nanoscale phase separation as confirmed by atomic force microscopy measurements. We find that the PBDB-P-m-based device has 1 order of magnitude higher electroluminescence quantum efficiency (EQEEL) than in the PBDB-P-p-based one, which could arise from the relatively weak aggregation in the PBDB-P-m-based film. Thus, the PBDB-P-m-based device has a remarkably enhanced VOC of 0.86 V in contrast to 0.80 V in the PBDB-P-p-based device. This study offers a feasible structural optimization way on the alkylthio side chain substitute position on the conjugated polymer to enhance VOC by reducing nonradiative recombination energy loss in the resulting PSCs.
KW - alkylthio-substituted position
KW - nonradiative recombination energy loss
KW - open-circuit voltage
KW - polymer donor
KW - polymer solar cells
UR - http://www.scopus.com/inward/record.url?scp=85085586358&partnerID=8YFLogxK
U2 - 10.1021/acsami.0c04397
DO - 10.1021/acsami.0c04397
M3 - Article
C2 - 32367720
AN - SCOPUS:85085586358
SN - 1944-8244
VL - 12
SP - 24184
EP - 24191
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 21
ER -