Systematic Merging of Nonfullerene Acceptor π-Extension and Tetrafluorination Strategies Affords Polymer Solar Cells with >16% Efficiency.

Autor:	Li G; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Zhang X; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.; State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 610054, P.R. China., Jones LO; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Alzola JM; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Mukherjee S; Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Feng LW; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Zhu W; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.; Tianjin Key Laboratory of Molecular Optoelectronic Sciences (TJ-MOS), Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, China., Stern CL; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Huang W; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Yu J; State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 610054, P.R. China., Sangwan VK; Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States., DeLongchamp DM; Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Kohlstedt KL; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Wasielewski MR; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Hersam MC; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.; Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States., Schatz GC; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States., Facchetti A; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.; Flexterra Corporation, 8025 Lamon Avenue, Skokie, Illinois 60077, United States., Marks TJ; Department of Chemistry, the Center for Light Energy Activated Redox Processes (LEAP), and the Materials Research Center (MRC), Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.; Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Jazyk:	angličtina
Zdroj:	Journal of the American Chemical Society [J Am Chem Soc] 2021 Apr 28; Vol. 143 (16), pp. 6123-6139. Date of Electronic Publication: 2021 Apr 13.
DOI:	10.1021/jacs.1c00211
Abstrakt:	The end-capping group (EG) is the essential electron-withdrawing component of nonfullerene acceptors (NFAs) in bulk heterojunction (BHJ) organic solar cells (OSCs). To systematically probe the impact of two frequent EG functionalization strategies, π-extension and halogenation, in A-DAD-A type NFAs, we synthesized and characterized four such NFAs: BT-BIC , LIC , L4F , and BO-L4F . To assess the relative importance of these strategies, we contrast these NFAs with the baseline acceptors, Y5 and Y6 . Up to 16.6% power conversion efficiency (PCE) in binary inverted OSCs with BT-BO - L4F combining π-extension and halogenation was achieved. When these two factors are combined, the effect on optical absorption is cumulative. Single-crystal π-π stacking distances are similar for the EG strategies of π-extension. Increasing the alkyl substituent length from BT-L4F to BT-BO-L4F significantly alters the packing motif and eliminates the EG core interactions of BT-L4F . Electronic structure computations reveal some of the largest NFA π-π electronic couplings observed to date, 103.8 meV in BT-L4F and 47.5 meV in BT-BO-L4F . Computed electronic reorganization energies, 132 and 133 meV for BT-L4F and BT-BO-L4F , respectively, are also lower than Y6 (150 meV). BHJ blends show preferential π-face-on orientation, and both fluorination and π-extension increase NFA crystallinity. Femto/nanosecond transient absorption spectroscopy (fs/nsTA) and integrated photocurrent device analysis (IPDA) indicate that π-extension modifies the phase separation to enhance film ordering and carrier mobility, while fluorination suppresses unimolecular recombination. This systematic study highlights the synergistic effects of NFA π-extension and fluorination in affording efficient OSCs and provides insights into designing next-generation materials.
Databáze:	MEDLINE
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