TY - JOUR
T1 - To Fluorinate or Not to Fluorinate in Organic Solar Cells
T2 - Achieving a Higher PCE of 15.2% when the Donor Polymer is Halogen-Free
AU - Wu, Jianglin
AU - Liao, Chuang Yi
AU - Chen, Yao
AU - Jacobberger, Robert M.
AU - Huang, Wei
AU - Zheng, Ding
AU - Tsai, Kuen Wei
AU - Li, Wei Long
AU - Lu, Zhiyun
AU - Huang, Yan
AU - Wasielewski, Michael R.
AU - Chang, Yi Ming
AU - Marks, Tobin J.
AU - Facchetti, Antonio
N1 - Funding Information:
This work was supported in part by the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under award DE-SC0001059 (J.W.: photovoltaic device fabrication and measurement; R.M.J. and M.R.W.: fs-ns TA; Y.C., W.H, D.Z., T.J.M., and A.F.: project advising), the Office of Naval Research Contract N00014-20-1-2116, AFOSR grant FA9550-18-1-0320 (J.W.: photovoltaic device fabrication and measurement), and Flexterra Corporation; and the Institute for Sustainability and Energy at Northwestern (ISEN). Use of the Advanced Photon Source, an Office of Science User Facility operated by the US DOE Office of Science by Argonne National Laboratory, was supported by the US DOE under contract DE-AC02-06CH11357. Y.H., Z.L., and J.W. acknowledge the financial support for this work from the National Natural Science Foundation of China (project no. 21875148). This work made use of the GIANTFab core facility at Northwestern University. GIANTFab is supported by the Institute for Sustainability and Energy at Northwestern and the Office of the Vice President for Research at Northwestern. J.W. thanks the joint-Ph.D. program supported by the China Scholarship Council (No. 201906240142) for a fellowship.
Funding Information:
This work was supported in part by the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under award DE‐SC0001059 (J.W.: photovoltaic device fabrication and measurement; R.M.J. and M.R.W.: fs‐ns TA; Y.C., W.H, D.Z., T.J.M., and A.F.: project advising), the Office of Naval Research Contract N00014‐20‐1‐2116, AFOSR grant FA9550‐18‐1‐0320 (J.W.: photovoltaic device fabrication and measurement), and Flexterra Corporation; and the Institute for Sustainability and Energy at Northwestern (ISEN). Use of the Advanced Photon Source, an Office of Science User Facility operated by the US DOE Office of Science by Argonne National Laboratory, was supported by the US DOE under contract DE‐AC02‐06CH11357. Y.H., Z.L., and J.W. acknowledge the financial support for this work from the National Natural Science Foundation of China (project no. 21875148). This work made use of the GIANTFab core facility at Northwestern University. GIANTFab is supported by the Institute for Sustainability and Energy at Northwestern and the Office of the Vice President for Research at Northwestern. J.W. thanks the joint‐Ph.D. program supported by the China Scholarship Council (No. 201906240142) for a fellowship.
Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2021/12/16
Y1 - 2021/12/16
N2 - Fluorination of the donor and/or acceptor blocks of photoactive semiconducting polymers is a leading strategy to enhance organic solar cell (OSC) performance. Here, the effects are investigated in OSCs using fluorine-free (TPD-3) and fluorinated (TPD-3F) donor polymers, paired with the nonfullerene acceptor Y6. Interestingly and unexpectedly, fluorination negatively affects performance, and fluorine-free TPD-3:Y6 OSCs exhibit a far higher power conversion efficiency (PCE = 14.5%) than in the fluorine-containing TPD-3F:Y6 blends (PCE = 11.5%). Transmission electron microscopy (TEM) analysis indicates that the TPD-3F:Y6 blends have larger phase domain sizes than TPD-3:Y6, which reduces exciton dissociation efficiency to 81% for TPD-3F:Y6 versus 93% for TPD-3:Y6. Additionally, grazing incidence wide-angle X-ray scattering (GIWAXS) reveals that the TPD-3F:Y6 blends are less textured than those of TPD-3:Y6, while space-charge limited currents reveal lower and unbalanced hole/electron mobility in TPD-3F:Y6 versus TPD-3:Y6 blends. Charge recombination dynamic, transient absorption, and donor–acceptor miscibility assays additionally support this picture. Furthermore, conventional architecture TPD-3:Y6 OSCs deliver a PCE of 15.2%, among the highest to date for halogen-free polymer donor OSCs. Finally, a large-area (20.4 cm2) TPD-3:Y6 blend module exhibits an outstanding PCE of 9.31%, one of the highest to date for modules of area >20 cm2.
AB - Fluorination of the donor and/or acceptor blocks of photoactive semiconducting polymers is a leading strategy to enhance organic solar cell (OSC) performance. Here, the effects are investigated in OSCs using fluorine-free (TPD-3) and fluorinated (TPD-3F) donor polymers, paired with the nonfullerene acceptor Y6. Interestingly and unexpectedly, fluorination negatively affects performance, and fluorine-free TPD-3:Y6 OSCs exhibit a far higher power conversion efficiency (PCE = 14.5%) than in the fluorine-containing TPD-3F:Y6 blends (PCE = 11.5%). Transmission electron microscopy (TEM) analysis indicates that the TPD-3F:Y6 blends have larger phase domain sizes than TPD-3:Y6, which reduces exciton dissociation efficiency to 81% for TPD-3F:Y6 versus 93% for TPD-3:Y6. Additionally, grazing incidence wide-angle X-ray scattering (GIWAXS) reveals that the TPD-3F:Y6 blends are less textured than those of TPD-3:Y6, while space-charge limited currents reveal lower and unbalanced hole/electron mobility in TPD-3F:Y6 versus TPD-3:Y6 blends. Charge recombination dynamic, transient absorption, and donor–acceptor miscibility assays additionally support this picture. Furthermore, conventional architecture TPD-3:Y6 OSCs deliver a PCE of 15.2%, among the highest to date for halogen-free polymer donor OSCs. Finally, a large-area (20.4 cm2) TPD-3:Y6 blend module exhibits an outstanding PCE of 9.31%, one of the highest to date for modules of area >20 cm2.
KW - blend morphology
KW - bulk heterojunction blend
KW - fluorination effects
KW - organic solar cells
KW - thieno[3,4-c]pyrrole-4,6-dione
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U2 - 10.1002/aenm.202102648
DO - 10.1002/aenm.202102648
M3 - Article
AN - SCOPUS:85118506269
SN - 1614-6832
VL - 11
JO - Advanced Energy Materials
JF - Advanced Energy Materials
IS - 47
M1 - 2102648
ER -
