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Alqahtani O, Hosseini SM, Ferron T, Murcia V, McAfee T, Vixie K, Huang F, Armin A, Shoaee S, Collins BA. Evidence That Sharp Interfaces Suppress Recombination in Thick Organic Solar Cells. ACS Appl Mater Interfaces 2021; 13:56394-56403. [PMID: 34787408 DOI: 10.1021/acsami.1c15570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Commercialization and scale-up of organic solar cells (OSCs) using industrial solution printing require maintaining maximum performance at active-layer thicknesses >400 nm─a characteristic still not generally achieved in non-fullerene acceptor OSCs. NT812/PC71BM is a rare system, whose performance increases up to these thicknesses due to highly suppressed charge recombination relative to the classic Langevin model. The suppression in this system, however, uniquely depends on device processing, pointing toward the role of nanomorphology. We investigate the morphological origins of this suppressed recombination by combining results from a suite of X-ray techniques. We are surprised to find that while all investigated devices are composed of pure, similarly aggregated nanodomains, Langevin reduction factors can still be tuned from ∼2 to >1000. This indicates that pure aggregated phases are insufficient for non-Langevin (reduced) recombination. Instead, we find that large well-ordered conduits and, in particular, sharp interfaces between domains appear to help to keep opposite charges separated and percolation pathways clear for enhanced charge collection in thick active layers. To our knowledge, this is the first quantitative study to isolate the donor/acceptor interfacial width correlated with non-Langevin charge recombination. This new structure-property relationship will be key to successful commercialization of printed OSCs at scale.
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Affiliation(s)
- Obaid Alqahtani
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, United States
- Department of Physics, Prince Sattam Bin Abdulaziz University, Alkharj 11942, KSA
| | - Seyed Mehrdad Hosseini
- Optoelectronics of Organic Semiconductors Institute, University of Potsdam, Potsdam-Golm 14476, Germany
| | - Thomas Ferron
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
| | - Victor Murcia
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, United States
| | - Terry McAfee
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kevin Vixie
- Department of Mathematics, Washington State University, Pullman, Washington 99164, United States
| | - Fei Huang
- Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China
| | - Ardalan Armin
- Department of Physics, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, U.K
| | - Safa Shoaee
- Optoelectronics of Organic Semiconductors Institute, University of Potsdam, Potsdam-Golm 14476, Germany
| | - Brian A Collins
- Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164, United States
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, United States
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