Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

Weigang Zhu; Guoping Li; Subhrangsu Mukherjee; Natalia E. Powers-Riggs; Leighton O. Jones; Eliot Gann; R. Joseph Kline; Andrew Herzing; Jenna L. Logsdon; Lucas Flagg; Charlotte L. Stern; Ryan M. Young; Kevin L. Kohlstedt; George C Schatz; Dean M. DeLongchamp; Michael R. Wasielewski; Ferdinand Melkonyan; Antonio Facchetti; Tobin Jay Marks

doi:10.1039/d2ee03883h

Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

Weigang Zhu, Guoping Li, Subhrangsu Mukherjee, Natalia E. Powers-Riggs, Leighton O. Jones, Eliot Gann, R. Joseph Kline, Andrew Herzing, Jenna L. Logsdon, Lucas Flagg, Charlotte L. Stern, Ryan M. Young, Kevin L. Kohlstedt^*, George C Schatz^*, Dean M. DeLongchamp^*, Michael R. Wasielewski^*, Ferdinand Melkonyan^*, Antonio Facchetti^*, Tobin Jay Marks^*

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

Addressing pertinent and perplexing questions regarding why nonfullerene acceptors (NFAs) promote higher power conversion efficiencies (PCEs) than traditional fullerenes and how photoactive bulk heterojunction (BHJ) film morphology, charge photogeneration, and recombination dynamics dictate solar cell performance have stimulated many studies of polymer solar cells (PSCs), yet quantitative relationships remain limited. Better understanding in these areas offers the potential to advance materials design and device engineering, afford higher PCEs, and ultimate commercialization. Here we probe quantitative relationships between BHJ film morphology, charge carrier dynamics, and photovoltaic performance in model binary and ternary blend systems having a wide bandgap donor polymer, a fullerene, and a promising NFA. We show that optimal PC71BM incorporation in a PBDB-TF:ITIC-Th binary system matrix retains the original π-face-on orientation, ITIC-Th crystallinity and BHJ film crystallite dimensions, and reduces film upper surface ITIC-Th segregation. Such morphology changes together simultaneously increase hole (μ_h) and electron (μ_e) mobilities, facilitate light-activated ITIC-Th to PC71BM domain electron delocalization, reduce free charge carrier (FC) bimolecular recombination (BR) within PBDB-TF:ITIC-Th mixed regions, and increase FC extraction pathways viaPBDB-TF:PC71BM pairs. The interplay of these effects yields significantly enhanced inverted cell short-circuit current density (J_SC), fill factor (FF), and PCE. Unexpectedly, we also find that excessive PC71BM in the PBDB-TF:ITIC-Th binary system alters the PBDB-TF orientation to π-edge-on, increases large scale PC71BM-rich aggregations and BHJ upper surface PC71BM composition. These morphology changes increase parasitic decay processes such as intersystem crossing from photoexcited PC71BM, compromising the J_SC, FF, and PCE metrics. ITIC-Th X-ray diffraction reveals a unique sidechain-dominated molecular network with previously unknown sidechain-end group stacking, rationalizing the STEM and GIWAXS results, photophysics, and the high μ_e. DFT computation reveals charge transfer networks within ITIC-Th crystallites, supporting excited-state electron delocalization from ITIC-Th to PC71BM. This structure-property understanding leads to a newly reported NFA blend with PCE near 17%.

Original language	English (US)
Pages (from-to)	1234-1250
Number of pages	17
Journal	Energy and Environmental Science
Volume	16
Issue number	3
DOIs	https://doi.org/10.1039/d2ee03883h
State	Published - Feb 7 2023

Funding

This research was supported in part by the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001059 (W. Z. single crystal growth, devices, microscopy, GIXRD; L. O. J., K. L. K., G. C. S. theory; J. L. L., N. E. P.-R., R. M. Y., M. R. W. fs/ns TA; T. J. M., A. F., W. Z. project discussions). This work was also supported by the US Department of Commerce, National Institute of Standards and Technology as part of the Center for Hierarchical Materials Design Award 70NANB10H005 (F. S. M. materials synthesis and characterization) and 70NANB19H005; the U.S. Office of Naval Research Contract #N00014-20-1-2116 (G. L., materials synthesis, T. J. M., A. F., project direction); and the Qatar National Research Foundation grant NPRP12S-0304-190227/02-484761 (G. L. material synthesis, solar cell fabrication). This work made use of the EPIC, Keck-II, and/or SPID facilities of Northwestern's NUANCE Center, which received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205). Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory Part of this research was undertaken on the Soft X-ray Spectroscopy beamline at the Australian Synchrotron, part of ANSTO. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of the 11-BM (CMS) beamline of the National Synchrotron Light Source II, operated by Brookhaven National Laboratory is supported by the DOE Office of Science under Contract No. DE-SC0012704. RSoXS data were acquired at the Advanced Light Source, which was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the DOE under Contract DE-AC02-05CH11231. Beamline support at beamline 11.0.1.2 was provided by A. L. D. Kilcoyne and C. Wang. W. Zhu thanks the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (KFJJ202001, Unconventional Organic Nonlinear Optical Hybrid Materials and Devices) for partial financial support. The authors thank Prof. B. Savoie of Purdue University for valuable discussions. Certain commercial equipment, instruments, materials or software are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by NIST, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. W. Zhu sincerely thanks S. Li for the support in completing this manuscript.

ASJC Scopus subject areas

Environmental Chemistry
Renewable Energy, Sustainability and the Environment
Nuclear Energy and Engineering
Pollution

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1039/d2ee03883h

Cite this

Zhu, W., Li, G., Mukherjee, S., Powers-Riggs, N. E., Jones, L. O., Gann, E., Kline, R. J., Herzing, A., Logsdon, J. L., Flagg, L., Stern, C. L., Young, R. M., Kohlstedt, K. L., Schatz, G. C., DeLongchamp, D. M., Wasielewski, M. R., Melkonyan, F., Facchetti, A., & Marks, T. J. (2023). Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends. Energy and Environmental Science, 16(3), 1234-1250. https://doi.org/10.1039/d2ee03883h

@article{cae8719888ab4642b757072155a4c45e,

title = "Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends",

abstract = "Addressing pertinent and perplexing questions regarding why nonfullerene acceptors (NFAs) promote higher power conversion efficiencies (PCEs) than traditional fullerenes and how photoactive bulk heterojunction (BHJ) film morphology, charge photogeneration, and recombination dynamics dictate solar cell performance have stimulated many studies of polymer solar cells (PSCs), yet quantitative relationships remain limited. Better understanding in these areas offers the potential to advance materials design and device engineering, afford higher PCEs, and ultimate commercialization. Here we probe quantitative relationships between BHJ film morphology, charge carrier dynamics, and photovoltaic performance in model binary and ternary blend systems having a wide bandgap donor polymer, a fullerene, and a promising NFA. We show that optimal PC71BM incorporation in a PBDB-TF:ITIC-Th binary system matrix retains the original π-face-on orientation, ITIC-Th crystallinity and BHJ film crystallite dimensions, and reduces film upper surface ITIC-Th segregation. Such morphology changes together simultaneously increase hole (μh) and electron (μe) mobilities, facilitate light-activated ITIC-Th to PC71BM domain electron delocalization, reduce free charge carrier (FC) bimolecular recombination (BR) within PBDB-TF:ITIC-Th mixed regions, and increase FC extraction pathways viaPBDB-TF:PC71BM pairs. The interplay of these effects yields significantly enhanced inverted cell short-circuit current density (JSC), fill factor (FF), and PCE. Unexpectedly, we also find that excessive PC71BM in the PBDB-TF:ITIC-Th binary system alters the PBDB-TF orientation to π-edge-on, increases large scale PC71BM-rich aggregations and BHJ upper surface PC71BM composition. These morphology changes increase parasitic decay processes such as intersystem crossing from photoexcited PC71BM, compromising the JSC, FF, and PCE metrics. ITIC-Th X-ray diffraction reveals a unique sidechain-dominated molecular network with previously unknown sidechain-end group stacking, rationalizing the STEM and GIWAXS results, photophysics, and the high μe. DFT computation reveals charge transfer networks within ITIC-Th crystallites, supporting excited-state electron delocalization from ITIC-Th to PC71BM. This structure-property understanding leads to a newly reported NFA blend with PCE near 17%.",

author = "Weigang Zhu and Guoping Li and Subhrangsu Mukherjee and Powers-Riggs, {Natalia E.} and Jones, {Leighton O.} and Eliot Gann and Kline, {R. Joseph} and Andrew Herzing and Logsdon, {Jenna L.} and Lucas Flagg and Stern, {Charlotte L.} and Young, {Ryan M.} and Kohlstedt, {Kevin L.} and Schatz, {George C} and DeLongchamp, {Dean M.} and Wasielewski, {Michael R.} and Ferdinand Melkonyan and Antonio Facchetti and Marks, {Tobin Jay}",

note = "Funding Information: This research was supported in part by the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001059 (W. Z. single crystal growth, devices, microscopy, GIXRD; L. O. J., K. L. K., G. C. S. theory; J. L. L., N. E. P.-R., R. M. Y., M. R. W. fs/ns TA; T. J. M., A. F., W. Z. project discussions). This work was also supported by the US Department of Commerce, National Institute of Standards and Technology as part of the Center for Hierarchical Materials Design Award 70NANB10H005 (F. S. M. materials synthesis and characterization) and 70NANB19H005; the U.S. Office of Naval Research Contract #N00014-20-1-2116 (G. L., materials synthesis, T. J. M., A. F., project direction); and the Qatar National Research Foundation grant NPRP12S-0304-190227/02-484761 (G. L. material synthesis, solar cell fabrication). This work made use of the EPIC, Keck-II, and/or SPID facilities of Northwestern's NUANCE Center, which received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205). Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory Part of this research was undertaken on the Soft X-ray Spectroscopy beamline at the Australian Synchrotron, part of ANSTO. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of the 11-BM (CMS) beamline of the National Synchrotron Light Source II, operated by Brookhaven National Laboratory is supported by the DOE Office of Science under Contract No. DE-SC0012704. RSoXS data were acquired at the Advanced Light Source, which was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the DOE under Contract DE-AC02-05CH11231. Beamline support at beamline 11.0.1.2 was provided by A. L. D. Kilcoyne and C. Wang. W. Zhu thanks the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (KFJJ202001, Unconventional Organic Nonlinear Optical Hybrid Materials and Devices) for partial financial support. The authors thank Prof. B. Savoie of Purdue University for valuable discussions. Certain commercial equipment, instruments, materials or software are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by NIST, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. W. Zhu sincerely thanks S. Li for the support in completing this manuscript. Publisher Copyright: {\textcopyright} 2023 The Royal Society of Chemistry.",

year = "2023",

month = feb,

day = "7",

doi = "10.1039/d2ee03883h",

language = "English (US)",

volume = "16",

pages = "1234--1250",

journal = "Energy and Environmental Science",

issn = "1754-5692",

publisher = "Royal Society of Chemistry",

number = "3",

}

Zhu, W, Li, G, Mukherjee, S, Powers-Riggs, NE, Jones, LO, Gann, E, Kline, RJ, Herzing, A, Logsdon, JL, Flagg, L, Stern, CL, Young, RM, Kohlstedt, KL , Schatz, GC, DeLongchamp, DM, Wasielewski, MR, Melkonyan, F, Facchetti, A & Marks, TJ 2023, 'Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends', Energy and Environmental Science, vol. 16, no. 3, pp. 1234-1250. https://doi.org/10.1039/d2ee03883h

Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends. / Zhu, Weigang; Li, Guoping; Mukherjee, Subhrangsu et al.
In: Energy and Environmental Science, Vol. 16, No. 3, 07.02.2023, p. 1234-1250.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

AU - Zhu, Weigang

AU - Li, Guoping

AU - Mukherjee, Subhrangsu

AU - Powers-Riggs, Natalia E.

AU - Jones, Leighton O.

AU - Gann, Eliot

AU - Kline, R. Joseph

AU - Herzing, Andrew

AU - Logsdon, Jenna L.

AU - Flagg, Lucas

AU - Stern, Charlotte L.

AU - Young, Ryan M.

AU - Kohlstedt, Kevin L.

AU - Schatz, George C

AU - DeLongchamp, Dean M.

AU - Wasielewski, Michael R.

AU - Melkonyan, Ferdinand

AU - Facchetti, Antonio

AU - Marks, Tobin Jay

N1 - Funding Information: This research was supported in part by the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001059 (W. Z. single crystal growth, devices, microscopy, GIXRD; L. O. J., K. L. K., G. C. S. theory; J. L. L., N. E. P.-R., R. M. Y., M. R. W. fs/ns TA; T. J. M., A. F., W. Z. project discussions). This work was also supported by the US Department of Commerce, National Institute of Standards and Technology as part of the Center for Hierarchical Materials Design Award 70NANB10H005 (F. S. M. materials synthesis and characterization) and 70NANB19H005; the U.S. Office of Naval Research Contract #N00014-20-1-2116 (G. L., materials synthesis, T. J. M., A. F., project direction); and the Qatar National Research Foundation grant NPRP12S-0304-190227/02-484761 (G. L. material synthesis, solar cell fabrication). This work made use of the EPIC, Keck-II, and/or SPID facilities of Northwestern's NUANCE Center, which received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205). Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory Part of this research was undertaken on the Soft X-ray Spectroscopy beamline at the Australian Synchrotron, part of ANSTO. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. Use of the 11-BM (CMS) beamline of the National Synchrotron Light Source II, operated by Brookhaven National Laboratory is supported by the DOE Office of Science under Contract No. DE-SC0012704. RSoXS data were acquired at the Advanced Light Source, which was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the DOE under Contract DE-AC02-05CH11231. Beamline support at beamline 11.0.1.2 was provided by A. L. D. Kilcoyne and C. Wang. W. Zhu thanks the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (KFJJ202001, Unconventional Organic Nonlinear Optical Hybrid Materials and Devices) for partial financial support. The authors thank Prof. B. Savoie of Purdue University for valuable discussions. Certain commercial equipment, instruments, materials or software are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by NIST, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose. W. Zhu sincerely thanks S. Li for the support in completing this manuscript. Publisher Copyright: © 2023 The Royal Society of Chemistry.

PY - 2023/2/7

Y1 - 2023/2/7

N2 - Addressing pertinent and perplexing questions regarding why nonfullerene acceptors (NFAs) promote higher power conversion efficiencies (PCEs) than traditional fullerenes and how photoactive bulk heterojunction (BHJ) film morphology, charge photogeneration, and recombination dynamics dictate solar cell performance have stimulated many studies of polymer solar cells (PSCs), yet quantitative relationships remain limited. Better understanding in these areas offers the potential to advance materials design and device engineering, afford higher PCEs, and ultimate commercialization. Here we probe quantitative relationships between BHJ film morphology, charge carrier dynamics, and photovoltaic performance in model binary and ternary blend systems having a wide bandgap donor polymer, a fullerene, and a promising NFA. We show that optimal PC71BM incorporation in a PBDB-TF:ITIC-Th binary system matrix retains the original π-face-on orientation, ITIC-Th crystallinity and BHJ film crystallite dimensions, and reduces film upper surface ITIC-Th segregation. Such morphology changes together simultaneously increase hole (μh) and electron (μe) mobilities, facilitate light-activated ITIC-Th to PC71BM domain electron delocalization, reduce free charge carrier (FC) bimolecular recombination (BR) within PBDB-TF:ITIC-Th mixed regions, and increase FC extraction pathways viaPBDB-TF:PC71BM pairs. The interplay of these effects yields significantly enhanced inverted cell short-circuit current density (JSC), fill factor (FF), and PCE. Unexpectedly, we also find that excessive PC71BM in the PBDB-TF:ITIC-Th binary system alters the PBDB-TF orientation to π-edge-on, increases large scale PC71BM-rich aggregations and BHJ upper surface PC71BM composition. These morphology changes increase parasitic decay processes such as intersystem crossing from photoexcited PC71BM, compromising the JSC, FF, and PCE metrics. ITIC-Th X-ray diffraction reveals a unique sidechain-dominated molecular network with previously unknown sidechain-end group stacking, rationalizing the STEM and GIWAXS results, photophysics, and the high μe. DFT computation reveals charge transfer networks within ITIC-Th crystallites, supporting excited-state electron delocalization from ITIC-Th to PC71BM. This structure-property understanding leads to a newly reported NFA blend with PCE near 17%.

AB - Addressing pertinent and perplexing questions regarding why nonfullerene acceptors (NFAs) promote higher power conversion efficiencies (PCEs) than traditional fullerenes and how photoactive bulk heterojunction (BHJ) film morphology, charge photogeneration, and recombination dynamics dictate solar cell performance have stimulated many studies of polymer solar cells (PSCs), yet quantitative relationships remain limited. Better understanding in these areas offers the potential to advance materials design and device engineering, afford higher PCEs, and ultimate commercialization. Here we probe quantitative relationships between BHJ film morphology, charge carrier dynamics, and photovoltaic performance in model binary and ternary blend systems having a wide bandgap donor polymer, a fullerene, and a promising NFA. We show that optimal PC71BM incorporation in a PBDB-TF:ITIC-Th binary system matrix retains the original π-face-on orientation, ITIC-Th crystallinity and BHJ film crystallite dimensions, and reduces film upper surface ITIC-Th segregation. Such morphology changes together simultaneously increase hole (μh) and electron (μe) mobilities, facilitate light-activated ITIC-Th to PC71BM domain electron delocalization, reduce free charge carrier (FC) bimolecular recombination (BR) within PBDB-TF:ITIC-Th mixed regions, and increase FC extraction pathways viaPBDB-TF:PC71BM pairs. The interplay of these effects yields significantly enhanced inverted cell short-circuit current density (JSC), fill factor (FF), and PCE. Unexpectedly, we also find that excessive PC71BM in the PBDB-TF:ITIC-Th binary system alters the PBDB-TF orientation to π-edge-on, increases large scale PC71BM-rich aggregations and BHJ upper surface PC71BM composition. These morphology changes increase parasitic decay processes such as intersystem crossing from photoexcited PC71BM, compromising the JSC, FF, and PCE metrics. ITIC-Th X-ray diffraction reveals a unique sidechain-dominated molecular network with previously unknown sidechain-end group stacking, rationalizing the STEM and GIWAXS results, photophysics, and the high μe. DFT computation reveals charge transfer networks within ITIC-Th crystallites, supporting excited-state electron delocalization from ITIC-Th to PC71BM. This structure-property understanding leads to a newly reported NFA blend with PCE near 17%.

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DO - 10.1039/d2ee03883h

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JO - Energy and Environmental Science

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Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

Abstract

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CCDC 2181313: Experimental Crystal Structure Determination

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Quantitative relationships between film morphology, charge carrier dynamics, and photovoltaic performance in bulk-heterojunction binary vs. ternary acceptor blends

Abstract

Funding

ASJC Scopus subject areas

UN SDGs

Access to Document

Other files and links

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Datasets

CCDC 2181313: Experimental Crystal Structure Determination

Cite this