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Gaspar H, Figueira F, Strutyński K, Melle-Franco M, Ivanou D, Tomé JPC, Pereira CM, Pereira L, Mendes A, Viana JC, Bernardo G. PffBT4T-2OD Based Solar Cells with Aryl-Substituted N-Methyl-Fulleropyrrolidine Acceptors. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E4100. [PMID: 31817967 PMCID: PMC6947311 DOI: 10.3390/ma12244100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 11/20/2019] [Accepted: 12/05/2019] [Indexed: 01/06/2023]
Abstract
Novel C60 and C70 N-methyl-fulleropyrrolidine derivatives, containing both electron withdrawing and electron donating substituent groups, were synthesized by the well-known Prato reaction. The corresponding highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels were determined by cyclic voltammetry, from the onset oxidation and reduction potentials, respectively. Some of the novel fullerenes have higher LUMO levels than the standards PC61BM and PC71BM. When tested in PffBT4T-2OD based polymer solar cells, with the standard architecture ITO/PEDOT:PSS/Active-Layer/Ca/Al, these fullerenes do not bring about any efficiency improvements compared to the standard PC71BM system, however they show how the electronic nature of the different substituents strongly affects the efficiency of the corresponding organic photovoltaic (OPV) devices. The functionalization of C70 yields a mixture of regioisomers and density functional theory (DFT) calculations show that these have systematically different electronic properties. This electronic inhomogeneity is likely responsible for the lower performance observed in devices containing C70 derivatives. These results help to understand how new fullerene acceptors can affect the performance of OPV devices.
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Affiliation(s)
- Hugo Gaspar
- IPC/i3N—Institute for Polymers and Composites, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal; (H.G.); (J.C.V.)
| | - Flávio Figueira
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal;
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (K.S.); (M.M.-F.)
| | - Karol Strutyński
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (K.S.); (M.M.-F.)
| | - Manuel Melle-Franco
- CICECO—Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (K.S.); (M.M.-F.)
| | - Dzmitry Ivanou
- LEPABE, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; (D.I.); (A.M.)
| | - João P. C. Tomé
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal;
- CQE and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Carlos M. Pereira
- CIQUP, Department of Chemistry and Biochemistry, University of Porto, Rua do Campo Alegre, w/n, 4169-007 Porto, Portugal;
| | - Luiz Pereira
- Department of Physics and i3N—Institute for Nanostructures, Nanomodelling and Nanofabrication, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Adélio Mendes
- LEPABE, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; (D.I.); (A.M.)
| | - Júlio C. Viana
- IPC/i3N—Institute for Polymers and Composites, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal; (H.G.); (J.C.V.)
| | - Gabriel Bernardo
- LEPABE, Department of Chemical Engineering, University of Porto, 4200-465 Porto, Portugal; (D.I.); (A.M.)
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Umeyama T, Imahori H. Isomer Effects of Fullerene Derivatives on Organic Photovoltaics and Perovskite Solar Cells. Acc Chem Res 2019; 52:2046-2055. [PMID: 31318521 DOI: 10.1021/acs.accounts.9b00159] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Solar energy conversion is one of the most important issues for creating and maintaining a future sustainable society. In this regard, photovoltaic technologies have attracted much attention because of their potential to solve energy and environmental issues. In particular, thin-film solar cells, such as organic photovoltaics (OPVs) and perovskite solar cells (PSCs), are highly promising owing to their flexibility, light weight, and low-cost production. One of the most important factors used to evaluate solar-cell performance is the power conversion efficiency (PCE), which is the ratio of the output electric power divided by the input light power. The PCEs of PSCs have become comparable to those of multicrystalline silicon solar cells in a laboratory level, but the PCEs of OPVs have yet to catch up with them and still need to be improved. The insufficient durability of PSCs and OPVs is also a challenge that needs to be addressed. Fullerene derivatives have been utilized as electron acceptors and electron-transport materials in OPVs and PSCs. However, the use of fullerene derivatives requires attention to their isomers if they are multiadducts or even monoadducts produced from fullerenes with low symmetry. Their nonuniform structures and electronic properties may exert a negative effect on photovoltaic properties. However, most researchers in the field of OPVs and PSCs have been unaware of the importance of the isomerism. Even the most prevalent, high-performance fullerene acceptor, [6,6]-phenyl-C71-butyric acid methyl ester ([70]PCBM), has been used as an isomer mixture. In this Account, we summarize recent studies on the effects of isomer separation of fullerene derivatives on the device performances of OPVs and PSCs. Largely, fullerene derivatives containing various isomers are categorized into [60]fullerene bisadducts, [70]fullerene bisadducts, and [70]fullerene monoadducts. In all cases, the difference in isomerism was found to have a large impact on PCEs. The miscibility with polymer donors and film-forming property of fullerene derivatives were affected by the isomer separations, which exert the most potent influence on device performances. Although the disorders in energy levels among isomers are not definitely influencing on photovoltaic properties of isomer mixtures, the molecular packing structures of fullerene derivatives make a significant effect on their photovoltaic properties. Notably, isomerically pure fullerene derivatives often-but not always-exhibit higher PCEs than the isomer mixture. The search for the best isomers of fullerene derivatives and their optimal compositional ratios, which extensively depend on their roles and the combined materials, will be an indispensable step to achieving consistently higher device performances for OPVs and PSCs.
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Affiliation(s)
- Tomokazu Umeyama
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hiroshi Imahori
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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Tukhbatullina AA, Khamitov EM, Sabirov DS. Distributed polarizability of fullerene [2+1]-adducts C60X (n = 1 and 2) with symmetric addends X = CH2 and O: A fresh view on the effect of positional isomerism. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2018.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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He FG, Li ZJ, Yang WW, Gao X. Synthesis of (MeO) 2Bn 2C 70: Regiochemistry of 2-fold Additions to C 70 with Addends That Are Preferential for Ortho Addition and Capable of Para Addition. J Org Chem 2018; 83:13716-13725. [PMID: 30352153 DOI: 10.1021/acs.joc.8b01977] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Three C70 tetraadducts, 2,10-(MeO)2-5,9-Bn2C70 (6), 1,56-Bn2-2,57-(MeO)2C70 (7, 2 o'clock isomer), and 1,41-Bn2-2,58-(MeO)2C70 (8, 12 o'clock isomer), were obtained from the reaction of C70 with MeO- and BnBr (benzyl bromide). The structures of 6-8 were resolved via single-crystal X-ray diffraction and spectroscopic characterizations. Computational calculations on the electrophilic Fukui functions fk+, the stability of reaction intermediates, and activation barriers for the key processes of the reaction were performed to rationalize the regioselectivity of the reaction. A conversion of the 5 and 12 o'clock intermediates to the 2 o'clock intermediate was proposed to account for the regioselectivity related to the 2-fold additions at the two distinctive polar regions of C70. Electrochemical study showed a similar electron deficiency for the 2 and 12 o'clock isomers, while the 2,5,9,10-tetraadduct was more electron deficient with respect to the 2 and 12 o'clock isomers.
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Affiliation(s)
- Fa-Gui He
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Chinese Academy of Sciences , 5625 Renmin Street , Changchun , Jilin 130022 , China
| | - Zong-Jun Li
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Chinese Academy of Sciences , 5625 Renmin Street , Changchun , Jilin 130022 , China
| | - Wei-Wei Yang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Chinese Academy of Sciences , 5625 Renmin Street , Changchun , Jilin 130022 , China
| | - Xiang Gao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Chinese Academy of Sciences , 5625 Renmin Street , Changchun , Jilin 130022 , China
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