1
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Schulz T, Marian CM. Simulating the full spin manifold of triplet-pair states in a series of covalently linked TIPS-pentacenes. J Comput Chem 2024. [PMID: 39139132 DOI: 10.1002/jcc.27475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/17/2024] [Accepted: 07/24/2024] [Indexed: 08/15/2024]
Abstract
Combined density functional theory and multireference configuration interaction methods have been used to elucidate singlet fission (SF) pathways and mechanisms in three regioisomers of side-on linked pentacene dimers. In addition to the optically bright singlets (S1 $$ {}_1 $$ and S2 $$ {}_2 $$ ) and singly excited triplets (T1 $$ {}_1 $$ and T2 $$ {}_2 $$ ), the full spin manifold of multiexcitonic triplet-pair states (1 $$ {}^1 $$ ME,3 $$ {}^3 $$ ME,5 $$ {}^5 $$ ME) has been considered. In the ortho- and para-regioisomers, the1 $$ {}^1 $$ ME and S1 $$ {}_1 $$ potentials intersect upon geometry relaxation of the S1 $$ {}_1 $$ excitation. In the meta-regioisomer, the crossing occurs upon delocalization of the optically bright excitation. The energetic accessibility of these conical intersections and the absence of low-lying charge-transfer states suggests a direct SF mechanism, assisted by charge-resonance effects in the1 $$ {}^1 $$ ME state. While the5 $$ {}^5 $$ ME state does not appear to play a role in the SF mechanism of the ortho- and para-regioisomers, its participation in the disentanglement of the triplet pair is conceivable in the meta-regioisomer.
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Affiliation(s)
- Timo Schulz
- Institute of Theoretical and Computational Chemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christel M Marian
- Institute of Theoretical and Computational Chemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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2
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Yang Y, Su W, Wang H, Bao X, Liu X, Bo Z, Zhang W. Promotion of Fast and Efficient Singlet Fission Process of PDI Dimers by Selenium Substitution. J Phys Chem B 2024; 128:7219-7226. [PMID: 39007639 DOI: 10.1021/acs.jpcb.4c01744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Singlet fission (SF) is a triplet generation mechanism capable of turning a singlet exciton into two triplet excitons. It has the potential to enhance the power conversion efficiency of single-junction solar cells. Perylene diimides (PDIs) are a class of dye molecules with photovoltaic properties and are beginning to receive more and more attention due to their potential for SF. Here, we report a selenium-substituted PDI dimer, Se-PDI-II, and we studied its SF mechanism by using steady-state, transient absorption, and time-resolved photoluminescence spectroscopy. Compared with the unsubstituted dimer PDI-II, we found that the introduction of selenium atoms can suppress excimer emission during the SF process, showing much higher SF efficiency and triplet yield.
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Affiliation(s)
- Yubo Yang
- School of Physics and Astronomy, Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - Wenli Su
- School of Physics and Astronomy, Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - Hang Wang
- College of Textiles & Clothing, State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China
| | - Xiaotian Bao
- School of Physics and Astronomy, Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhishan Bo
- College of Textiles & Clothing, State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China
| | - Wenkai Zhang
- School of Physics and Astronomy, Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
- Key Laboratory of Multiscale Spin Physics, Ministry of Education, Beijing Normal University, Beijing 100875, China
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3
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Lin LC, Dill RD, Thorley KJ, Parkin SR, Anthony JE, Johnson JC, Damrauer NH. Revealing the Singlet Fission Mechanism for a Silane-Bridged Thienotetracene Dimer. J Phys Chem A 2024; 128:3982-3992. [PMID: 38717589 PMCID: PMC11129308 DOI: 10.1021/acs.jpca.4c01463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/24/2024]
Abstract
Tetraceno[2,3-b]thiophene is regarded as a strong candidate for singlet fission-based solar cell applications due to its mixed characteristics of tetracene and pentacene that balance exothermicity and triplet energy. An electronically weakly coupled tetraceno[2,3-b]thiophene dimer (Et2Si(TIPSTT)2) with a single silicon atom bridge has been synthesized, providing a new platform to investigate the singlet fission mechanism involving the two acene chromophores. We study the excited state dynamics of Et2Si(TIPSTT)2 by monitoring the evolution of multiexciton coupled triplet states, 1TT to 5TT to 3TT to T1 + S0, upon photoexcitation with transient absorption, temperature-dependent transient absorption, and transient/pulsed electron paramagnetic resonance spectroscopies. We find that the photoexcited singlet lifetime is 107 ps, with 90% evolving to form the TT state, and the complicated evolution between the multiexciton states is unraveled, which can be an important reference for future efforts toward tetraceno[2,3-b]thiophene-based singlet fission solar cells.
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Affiliation(s)
- Liang-Chun Lin
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Ryan D. Dill
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Karl J. Thorley
- Department
of Chemistry & Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Sean R. Parkin
- Department
of Chemistry & Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - John E. Anthony
- Department
of Chemistry & Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Justin C. Johnson
- National
Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Niels H. Damrauer
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Renewable
and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
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4
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Greißel PM, Schroeder ZW, Thiel D, Ferguson MJ, Clark T, Guldi DM, Tykwinski RR. Controlling Interchromophore Coupling in Diamantane-Linked Pentacene Dimers To Create a "Binary" Pair. J Am Chem Soc 2024; 146:10875-10888. [PMID: 38579119 DOI: 10.1021/jacs.4c01507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
Two isomeric pentacene dimers, each linked by a diamantane spacer, have been synthesized. These dimers are designed to provide experimental evidence to support quantum mechanical calculations, which predict the substitution pattern on the carbon-rich diethynyldiamantane spacer to be decisive in controlling the interpentacene coupling. Intramolecular singlet fission (i-SF) serves as a probe for the existence and strength of the electronic coupling between the two pentacenes, with transient absorption spectroscopy as the method of choice to characterize i-SF. 4,9-Substitution of diamantane provides a pentacene dimer (4,9-dimer) in which the two chromophores are completely decoupled and that, following photoexcitation, deactivates to the ground state analogous to a monomeric pentacene chromophore. Conversely, 1,6-substitution provides a pentacene dimer (1,6-dimer) that exhibits sufficiently strong coupling to drive i-SF, resulting in correlated triplet M(T1T1) yields close to unity and free triplet (T1 + T1) yields of ca. 50%. Thus, the diamantane spacer effectively switches "on" or "off" the coupling between the chromophores, based on the substitution pattern. The binary control of diamantane contrasts other known molecular spacers designed only to modulate the coupling strength between two pentacenes.
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Affiliation(s)
- Phillip M Greißel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Zachary W Schroeder
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Dominik Thiel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Timothy Clark
- Computer Chemistry Center (CCC), Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Nägelsbachstrasse 25, 91052 Erlangen, Germany
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstrasse 3, 91058 Erlangen, Germany
| | - Rik R Tykwinski
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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5
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Kim J, Teo HT, Hong Y, Cha H, Kim W, Chi C, Kim D. Elucidating Singlet-Fission-Born Multiexciton Dynamics via Molecular Engineering: A Dilution Principle Extended to Quintet Triplet Pair. J Am Chem Soc 2024; 146:10833-10846. [PMID: 38578848 DOI: 10.1021/jacs.4c01326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
Multiexciton in singlet exciton fission represents a critical quantum state with significant implications for both solar cell applications and quantum information science. Two distinct fields of interest explore contrasting phenomena associated with the geminate triplet pair: one focusing on the persistence of long-lived correlation and the other emphasizing efficient decorrelation. Despite the pivotal nature of multiexciton processes, a comprehensive understanding of their dependence on the structural and spin properties of materials is currently lacking in experimental realizations. To address this gap in knowledge, molecular engineering was employed to modify the TIPS-tetracene structures, enabling an investigation of the structure-property relationships in spin-related multiexciton processes. In lieu of the time-resolved electron paramagnetic resonance technique, two time-resolved magneto-optical spectroscopies were implemented for quantitative analysis of spin-dependent multiexciton dynamics. The utilization of absorption and fluorescence signals as complementary optical readouts, in the presence of a magnetic field, provided crucial insights into geminate triplet pair dynamics. These insights encompassed the duration of multiexciton correlation and the involvement of the spin state in multiexciton decorrelation. Furthermore, simulations based on our kinetic models suggested a role for quintet dilution in multiexciton dynamics, surpassing the singlet dilution principle established by the Merrifield model. The integration of intricate model structures and time-resolved magneto-optical spectroscopies served to explicitly elucidate the interplay between structural and spin properties in multiexciton processes. This comprehensive approach not only contributes to the fundamental understanding of these processes but also aligns with and reinforces previous experimental studies of solid states and theoretical assessments.
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Affiliation(s)
- Juno Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul 03722, Korea
| | - Hao Ting Teo
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Yongseok Hong
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul 03722, Korea
| | - Hyojung Cha
- Department of Hydrogen and Renewable Energy, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Woojae Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul 03722, Korea
| | - Chunyan Chi
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Dongho Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul 03722, Korea
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6
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Mencaroni L, Elisei F, Marrocchi A, Spalletti A, Carlotti B. Intramolecular Singlet Fission Coupled with Intermolecular Triplet Separation as a Strategy to Achieve High Triplet Yields in Fluorene-Based Small Molecules. J Phys Chem B 2024; 128:3442-3453. [PMID: 38544417 DOI: 10.1021/acs.jpcb.4c00194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
In this work, detailed experimental proof and in-depth analysis of the singlet fission (SF) mechanism, operative in fluorene-based small molecules, are carried out by employing advanced time-resolved spectroscopies with nanosecond and femtosecond resolution. The investigation of the effect of solution concentration and solvent viscosity together with temperature and excitation wavelength demonstrates INTRAmolecular formation of the correlated triplet pair followed by INTERmolecular independent triplet separation via a "super-diffusional" triplet-triplet transfer process. This unconventional INTRA- to INTERmolecular SF may be considered an "ideal" mechanism. Indeed, intramolecular formation of the correlated triplet pair is here interestingly proved for small molecules rather than large multichromophoric systems, allowing easy synthesis and processability while maintaining good control over the SF process. On the other hand, the intermolecular triplet separation may be exploited to achieve high triplet quantum yields in these new SF small molecules.
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Affiliation(s)
- Letizia Mencaroni
- Department of Chemistry, Biology and Biotechnology and CEMIN, University of Perugia, via dell'Elce di sotto n.8, Perugia 06123, Italy
| | - Fausto Elisei
- Department of Chemistry, Biology and Biotechnology and CEMIN, University of Perugia, via dell'Elce di sotto n.8, Perugia 06123, Italy
| | - Assunta Marrocchi
- Department of Chemistry, Biology and Biotechnology and CEMIN, University of Perugia, via dell'Elce di sotto n.8, Perugia 06123, Italy
| | - Anna Spalletti
- Department of Chemistry, Biology and Biotechnology and CEMIN, University of Perugia, via dell'Elce di sotto n.8, Perugia 06123, Italy
| | - Benedetta Carlotti
- Department of Chemistry, Biology and Biotechnology and CEMIN, University of Perugia, via dell'Elce di sotto n.8, Perugia 06123, Italy
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7
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Greißel PM, Thiel D, Gotfredsen H, Chen L, Krug M, Papadopoulos I, Miskolzie M, Torres T, Clark T, Brøndsted Nielsen M, Tykwinski RR, Guldi DM. Intramolecular Triplet Diffusion Facilitates Triplet Dissociation in a Pentacene Hexamer. Angew Chem Int Ed Engl 2024; 63:e202315064. [PMID: 38092707 DOI: 10.1002/anie.202315064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Indexed: 01/26/2024]
Abstract
Triplet dynamics in singlet fission depend strongly on the strength of the electronic coupling. Covalent systems in solution offer precise control over such couplings. Nonetheless, efficient free triplet generation remains elusive in most systems, as the intermediate triplet pair 1 (T1 T1 ) is prone to triplet-triplet annihilation due to its spatial confinement. In the solid state, entropically driven triplet diffusion assists in the spatial separation of triplets, resulting in higher yields of free triplets. Control over electronic coupling in the solid state is, however, challenging given its sensitivity to molecular packing. We have thus developed a hexameric system (HexPnc) to enable solid-state-like triplet diffusion at the molecular scale. This system is realized by covalently tethering three pentacene dimers to a central subphthalocyanine scaffold. Transient absorption spectroscopy, complemented by theoretical structural optimizations and steady-state spectroscopy, reveals that triplet diffusion is indeed facilitated due to intramolecular cluster formation. The yield of free triplets in HexPnc is increased by a factor of up to 14 compared to the corresponding dimeric reference (DiPnc). Thus, HexPnc establishes crucial design aspects for achieving efficient triplet dissociation in strongly coupled systems by providing avenues for diffusive separation of 1 (T1 T1 ), while, concomitantly, retaining strong interchromophore coupling which preserves rapid formation of 1 (T1 T1 ).
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Affiliation(s)
- Phillip M Greißel
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Dominik Thiel
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Henrik Gotfredsen
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
- Current address: Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, OX1 3TA, UK
| | - Lan Chen
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Marcel Krug
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
- Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Mark Miskolzie
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Tomás Torres
- Department of Organic Chemistry, Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
- IMDEA Nanociencia, C/Faraday 9, Cantoblanco, 28049, Madrid, Spain
| | - Timothy Clark
- Department of Chemistry and Pharmacy &, Computer-Chemie-Center (CCC), Friedrich-Alexander-University Erlangen-Nuremberg, Nägelsbachstraße 25, 91052, Erlangen, Germany
| | - Mogens Brøndsted Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Rik R Tykwinski
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
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8
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Reid OG, Johnson JC, Eaves JD, Damrauer NH, Anthony JE. Molecular Control of Triplet-Pair Spin Polarization and Its Optoelectronic Magnetic Resonance Probes. Acc Chem Res 2024; 57:59-69. [PMID: 38103045 PMCID: PMC10765369 DOI: 10.1021/acs.accounts.3c00556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023]
Abstract
ConspectusPreparing and manipulating pure magnetic states in molecular systems are the key initial requirements for harnessing the power of synthetic chemistry to drive practical quantum sensing and computing technologies. One route for achieving the requisite higher spin states in organic systems exploits the phenomenon of singlet fission, which produces pairs of triplet excited states from initially photoexcited singlets in molecular assemblies with multiple chromophores. The resulting spin states are characterized by total spin (quintet, triplet, or singlet) and its projection onto a specified molecular or magnetic field axis. These excited states are typically highly polarized but exhibit an impure spin population pattern. Herein, we report the prediction and experimental verification of molecular design rules that drive the population of a single pure magnetic state and describe the progress toward its experimental realization.A vital feature of this work is the close partnership among theory, chemical synthesis, and spectroscopy. We begin by presenting our theoretical framework for understanding spin manifold interconversion in singlet fission systems. This theory makes specific testable predictions about the intermolecular structure and orientation relative to an external magnetic field that should lead to pure magnetic state preparation and provides a powerful tool for interpreting magnetic spectra. We then test these predictions through detailed magnetic spectroscopy experiments on a series of new molecular architectures that meet one or more of the identified structural criteria. Many of these architectures rely on the synthesis of molecules with features unique to this effort: rigid bridges between chromophores in dimers, heteroacenes with tailored singlet/triplet-pair energy level matching, or side-group engineering to produce specific crystal structures. The spin evolution of these systems is revealed through our application and development of several magnetic resonance methods, each of which has different sensitivities and relevance in environments relevant to quantum applications.Our theoretical predictions prove to be remarkably consistent with our experimental results, though experimentally meeting all the structural prescriptions demanded by theory for true pure-state preparation remains a challenge. Our magnetic spectra agree with our model of triplet-pair behavior, including funneling of the population to the ms = 0 magnetic sublevel of the quintet under specified conditions in dimers and crystals, showing that this phenomenon is subject to control through molecular design. Moreover, our demonstration of novel and/or highly sensitive detection mechanisms of spin states in singlet fission systems, including photoluminescence (PL), photoinduced absorption (PA), and magnetoconductance (MC), points the way toward both a deeper understanding of how these systems evolve and technologically feasible routes toward experiments at the single-molecule quantum limit that are desirable for computational applications.
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Affiliation(s)
- Obadiah G. Reid
- National
Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
| | - Justin C. Johnson
- National
Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
| | - Joel D. Eaves
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Niels H. Damrauer
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - John E. Anthony
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
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9
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Wang K, Chen X, Xu J, Peng S, Wu D, Xia J. Recent Advance in the Development of Singlet-Fission-Capable Polymeric Materials. Macromol Rapid Commun 2024; 45:e2300241. [PMID: 37548255 DOI: 10.1002/marc.202300241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/24/2023] [Indexed: 08/08/2023]
Abstract
Singlet fission (SF) is a spin-allowed process in which a higher-energy singlet exciton is converted into two lower-energy triplet excitons via a triplet pair intermediate state. Implementing SF in photovoltaic devices holds the potential to exceed the Shockley-Queisser limit of conventional single-junction solar cells. Although great progress has been made in exploiting the underlying mechanism of SF over the past decades, the scope of materials capable of SF, particularly polymeric materials, remains poor. SF-capable polymer is one of the most potential candidates in the implementation of SF into devices due to their distinct superiorities in flexibility, solution processability and self-assembly behavior. Notably, recent advancements have demonstrated high-performance SF in isolated donor-acceptor (D-A) copolymer chains. This review provides an overview of recent progress in the development of SF-capable polymeric materials, with a significant focus on elucidating the mechanisms of SF in polymers and optimizing the design strategies for SF-capable polymers. Additionally, the paper discusses the challenges encountered in this field and presents future perspectives. It is expected that this comprehensive review will offer valuable insights into the design of novel SF-capable polymeric materials, further advancing the potential for SF implementation in photovoltaic devices.
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Affiliation(s)
- Kangwei Wang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan, 430070, China
| | - Xingyu Chen
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
| | - Jingwen Xu
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
| | - Shaoqian Peng
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan, 430070, China
| | - Di Wu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan, 430070, China
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, China
| | - Jianlong Xia
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan, 430070, China
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, China
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10
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Hou Y, Papadopoulos I, Bo Y, Wollny AS, Ferguson MJ, Mai LA, Tykwinski RR, Guldi DM. Catalyzing Singlet Fission by Transition Metals: Second versus Third Row Effects. PRECISION CHEMISTRY 2023; 1:555-564. [PMID: 38037593 PMCID: PMC10685717 DOI: 10.1021/prechem.3c00082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 12/02/2023]
Abstract
The synthesis and characterization of platinum(II) and palladium(II) complexes bearing two (dimers Pt(Lpc)2Cl2 and Pd(Lpc)2Cl2), one (monomers Pt(Lpc)(Lref)Cl2 and Pd(Lpc)(Lref)Cl2), or no (reference compounds Pt(Lref)2Cl2 and Pd(Lref)2Cl2) pentacene-based pyridyl ligands are presented. Photophysical properties of the dimers are probed by means of steady-state and time-resolved transient absorption measurements in comparison to the monomer and model compounds. Our results document that despite enhanced spin-orbit coupling from the presence of heavy atoms, intramolecular singlet fission (iSF) is not challenged by intersystem crossing. iSF thus yields correlated triplet pairs and even uncorrelated triplet excited states upon decoherence. Importantly, significant separation of the two pentacenyl groups facilitates decoupling of the two chromophores. Furthermore, the mechanism of iSF is altered depending on the respective metal center, that is, Pt(II) versus Pd(II). The dimer based on Pt(II), Pt(Lpc)2Cl2, exhibits a direct pathway for the iSF and forms a correlated triplet pair with singlet-quintet spin-mixing within 10 ns in variable solvents. On the other hand, the dimer based on Pd(II), Pd(Lpc)2Cl2, leads to charge transfer mixing during the population of the correlated triplet pair that is dependent on solvent polarity. Moreover, Pd(Lpc)2Cl2 gives rise to a stable equilibrium between singlet and quintet correlated triplet pairs with lifetimes of up to 170 ns. Inherent differences in the size and polarizability, when contrasting platinum(II) with palladium(II), are the most likely rationale for the underlying trends.
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Affiliation(s)
- Yuxuan Hou
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Ilias Papadopoulos
- Department
of Chemistry and Pharmacy & Interdisciplinary Center for Molecular
Materials (ICMM), Friedrich-Alexander-University
Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Yifan Bo
- Department
of Chemistry and Pharmacy & Interdisciplinary Center for Molecular
Materials (ICMM), Friedrich-Alexander-University
Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Anna-Sophie Wollny
- Department
of Chemistry and Pharmacy & Interdisciplinary Center for Molecular
Materials (ICMM), Friedrich-Alexander-University
Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Michael J. Ferguson
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Lukas A. Mai
- Department
of Chemistry and Pharmacy & Interdisciplinary Center for Molecular
Materials (ICMM), Friedrich-Alexander-University
Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Rik R. Tykwinski
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Dirk M. Guldi
- Department
of Chemistry and Pharmacy & Interdisciplinary Center for Molecular
Materials (ICMM), Friedrich-Alexander-University
Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
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11
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Bo Y, Hou Y, Thiel D, Weiß R, Clark T, Ferguson MJ, Tykwinski RR, Guldi DM. Tetracene Dimers: A Platform for Intramolecular Down- and Up-conversion. J Am Chem Soc 2023; 145:18260-18275. [PMID: 37531628 DOI: 10.1021/jacs.3c02417] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
Photon energy conversion can be accomplished in many different ways, including the two opposing manners, down-conversion (i.e., singlet fission, SF) and up-conversion (i.e., triplet-triplet annihilation up-conversion, TTA-UC). Both processes have the potential to help overcome the detailed balance limit of single-junction solar cells. Tetracene, in which the energies of the lowest singlet excited state and twice the triplet excited state are comparable, exhibits both down- and up-conversion. Here, we have designed meta-diethynylphenylene- and 1,3-diethynyladamantyl-linked tetracene dimers, which feature different electronic coupling, to characterize the interplay between intramolecular SF (intra-SF) and intramolecular TTA-UC (intra-TTA-UC) via steady-state and time-resolved absorption and fluorescence spectroscopy. Furthermore, we have used Pd-phthalocyanine as a sensitizer to enable intra-TTA-UC in the two dimers via indirect photoexcitation in the near-infrared part of the solar spectrum. The work is rounded off by temperature-dependent measurements, which outline key aspects of how thermal effects impact intra-SF and intra-TTA-UC in different dimers.
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Affiliation(s)
- Yifan Bo
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
| | - Yuxuan Hou
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Dominik Thiel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
| | - René Weiß
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
| | - Timothy Clark
- Department of Chemistry and Pharmacy & Computer-Chemie-Center (CCC), Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstr. 25, 91052 Erlangen, Germany
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Rik R Tykwinski
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
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12
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Mencaroni L, Alebardi M, Elisei F, Škorić I, Spalletti A, Carlotti B. Unveiling the double triplet nature of the 2Ag state in conjugated stilbenoid compounds to achieve efficient singlet fission. Phys Chem Chem Phys 2023; 25:21089-21099. [PMID: 37527269 DOI: 10.1039/d3cp02805d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
In this investigation, the excited-state evolution in a series of all-trans stilbenoid compounds, displaying a low-lying dark singlet state of 2Ag-like symmetry nearly degenerate with the bright 1Bu state, was unveiled by employing advanced ultrafast spectroscopies while probing the effect of solvent polarizability. Together with the dual emission, femtosecond transient absorption and broadband fluorescence up-conversion disclosed the double nature of the 2Ag-like state showing both singlet features, a lifetime typical of a singlet and the ability to emit, and a triplet character, exhibiting a triplet-like absorption spectrum. The ultrafast formation (in hundreds of femtoseconds) from the non-relaxed upper singlet state led to the identification of 2Ag as the correlated triplet pair of singlet fission. The spectral difference obtained by comparison of transient absorption peaks of the 2Ag (1TT) and the triplet states was found to be in remarkable agreement with the observed triplet yield and the 1(TT) separation rate constant. Indeed, this spectral shift provided an experimental method to gain qualitative insight into the ease of separation of the 1(TT) and the relative SF efficiency. The highly conjugated polyene-like structures enable the ultrafast formation of the double triplet, but then the large binding energy prevents the triplet separation and thus the effective completion of singlet fission. Even though thermodynamically feasible for all the investigated stilbenoids according to TD-DFT calculations, singlet fission resulted to occur efficiently in the case of 1-(pyridyl-4-ylethenyl)-4-(p-nitrostyryl)benzene and nitro-styrylfuran with the triplet yield reaching 120% and 140%, respectively, triggered by their greatly enhanced intramolecular charge transfer character relative to the other compounds in the series.
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Affiliation(s)
- Letizia Mencaroni
- Department of Chemistry, Biology and Biotechnology, University of Perugia, via elce di sotto 8, 06123 Perugia, Italy.
| | - Martina Alebardi
- Department of Chemistry, Biology and Biotechnology, University of Perugia, via elce di sotto 8, 06123 Perugia, Italy.
| | - Fausto Elisei
- Department of Chemistry, Biology and Biotechnology, University of Perugia, via elce di sotto 8, 06123 Perugia, Italy.
| | - Irena Škorić
- Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, 10000 Zagreb, Croatia
| | - Anna Spalletti
- Department of Chemistry, Biology and Biotechnology, University of Perugia, via elce di sotto 8, 06123 Perugia, Italy.
| | - Benedetta Carlotti
- Department of Chemistry, Biology and Biotechnology, University of Perugia, via elce di sotto 8, 06123 Perugia, Italy.
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13
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Tait CE, Krzyaniak MD, Stoll S. Computational tools for the simulation and analysis of spin-polarized EPR spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 349:107410. [PMID: 36870248 DOI: 10.1016/j.jmr.2023.107410] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/10/2023] [Accepted: 02/18/2023] [Indexed: 06/18/2023]
Abstract
The EPR spectra of paramagnetic species induced by photoexcitation typically exhibit enhanced absorptive and emissive features resulting from sublevel populations that differ from thermal equilibrium. The populations and the resulting spin polarization of the spectra are dictated by the selectivity of the photophysical process generating the observed state. Simulation of the spin-polarized EPR spectra is crucial in the characterization of both the dynamics of formation of the photoexcited state as well as its electronic and structural properties. EasySpin, the simulation toolbox for EPR spectroscopy, now includes extended support for the simulation of the EPR spectra of spin-polarized states of arbitrary spin multiplicity and formed by a variety of different mechanisms, including photoexcited triplet states populated by intersystem crossing, charge recombination or spin polarization transfer, spin-correlated radical pairs created by photoinduced electron transfer, triplet pairs formed by singlet fission and multiplet states arising from photoexcitation in systems containing chromophores and stable radicals. In this paper, we highlight EasySpin's capabilities for the simulation of spin-polarized EPR spectra on the basis of illustrative examples from the literature in a variety of fields ranging across chemistry, biology, material science and quantum information science.
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Affiliation(s)
- Claudia E Tait
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom.
| | - Matthew D Krzyaniak
- Department of Chemistry, Center for Molecular Quantum Transduction and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston 60208, IL, United States
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, 98195, WA, United States
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14
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Dill RD, Joshi G, Thorley KJ, Anthony JE, Fluegel B, Johnson JC, Reid OG. Near-Infrared Absorption Features of Triplet-Pair States Assigned by Photoinduced-Absorption-Detected Magnetic Resonance. J Phys Chem Lett 2023; 14:2387-2394. [PMID: 36848633 PMCID: PMC10009807 DOI: 10.1021/acs.jpclett.2c03665] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
Singlet fission proceeds through a manifold of triplet-pair states that are exceedingly difficult to distinguish spectroscopically. Here, we introduce a new implementation of photoinduced-absorption-detected magnetic resonance (PADMR) and use it to understand the excited-state absorption spectrum of a tri-2-pentylsilylethynyl pentadithiophene (TSPS-PDT) film. These experiments allow us to directly correlate magnetic transitions driven by RF with electronic transitions in the visible and near-infrared spectrum with high sensitivity. We find that the new near-infrared excited-state transitions that arise in thin films of TSPS-PDT are correlated with the magnetic transitions of T1, not 5TT. Thus, we assign these features to the excited-state absorption of 1TT, which is depleted when T1 states are driven to a spin configuration that forbids subsequent fusion. These results clarify the disputed origin of triplet-associated near-infrared absorption features in singlet-fission materials and demonstrate an incisive general purpose tool for studying the evolution of high-spin excited states.
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Affiliation(s)
- Ryan D. Dill
- University
of Colorado Boulder, Department of Chemistry, Boulder, Colorado 80309, United States
| | - Gajadhar Joshi
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Karl J. Thorley
- University
of Kentucky Center for Applied Energy Research, Lexington, Kentucky 40511, United States
| | - John E. Anthony
- University
of Kentucky Center for Applied Energy Research, Lexington, Kentucky 40511, United States
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Brian Fluegel
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Justin C. Johnson
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, University
of Colorado, Boulder, Colorado 80309, United States
| | - Obadiah G. Reid
- National
Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, University
of Colorado, Boulder, Colorado 80309, United States
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15
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Dill RD, Smyser KE, Rugg BK, Damrauer NH, Eaves JD. Entangled spin-polarized excitons from singlet fission in a rigid dimer. Nat Commun 2023; 14:1180. [PMID: 36859382 PMCID: PMC9977721 DOI: 10.1038/s41467-023-36529-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/31/2023] [Indexed: 03/03/2023] Open
Abstract
Singlet fission, a process that splits a singlet exciton into a biexciton, has promise in quantum information. We report time-resolved electron paramagnetic resonance measurements on a conformationally well-defined acene dimer molecule, TIPS-BP1', designed to exhibit strongly state-selective relaxation to specific magnetic spin sublevels. The resulting optically pumped spin polarization is a nearly pure initial state from the ensemble. The long-lived spin coherences modulate the signal intrinsically, allowing a measurement scheme that substantially removes noise and uncertainty in the magnetic resonance spectra. A nonadiabatic transition theory with a minimal number of spectroscopic parameters allows the quantitative assignment and interpretation of the spectra. In this work, we show that the rigid dimer TIPS-BP1' supports persistent spin coherences at temperatures far higher than those used in conventional superconducting quantum hardware.
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Affiliation(s)
- Ryan D. Dill
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Kori E. Smyser
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Brandon K. Rugg
- grid.419357.d0000 0001 2199 3636National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Niels H. Damrauer
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA ,grid.266190.a0000000096214564Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80309 USA
| | - Joel D. Eaves
- grid.266190.a0000000096214564Department of Chemistry, University of Colorado Boulder, Boulder, CO 80309 USA ,grid.266190.a0000000096214564Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO 80309 USA
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16
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Yago T, Tashiro M, Hasegawa K, Gohdo M, Tsuchiya S, Ikoma T, Wakasa M. Triplet-Triplet Annihilation via the Triplet Channel in Crystalline 9,10-Diphenylanthracene. J Phys Chem Lett 2022; 13:8768-8774. [PMID: 36102694 DOI: 10.1021/acs.jpclett.2c01839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Delayed fluorescence resulting from triplet-triplet annihilation in crystalline 9,10-diphenylanthracene was observed by means of steady-state fluorescence measurements under magnetic fields of ≤10 T. At five specific magnetic fields, four peaks and one dip in the magnetic field dependence of fluorescence intensity were observed, proving that exchange-coupled triplet pairs were generated in the course of triplet-triplet annihilation. The dip was in the opposite direction predicted for singlet channel triplet-triplet annihilation. Further analysis using the stochastic Liouville equation confirmed that the closest exchange-coupled triplet pair in crystalline 9,10-diphenylanthracene is quenched via both triplet channel and singlet channel triplet-triplet annihilation.
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Affiliation(s)
- Tomoaki Yago
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama 338-8570, Japan
| | - Manami Tashiro
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama 338-8570, Japan
| | - Kiichi Hasegawa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama 338-8570, Japan
| | - Masao Gohdo
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibarakai, Osaka 567-0047, Japan
| | - Syuta Tsuchiya
- Graduate School of Science and Technology, Niigata University, 2-8050, Ikarashi, Nishi-Ku, Niigata 950-2181, Japan
| | - Tadaaki Ikoma
- Graduate School of Science and Technology, Niigata University, 2-8050, Ikarashi, Nishi-Ku, Niigata 950-2181, Japan
| | - Masanobu Wakasa
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-ohkubo, Sakura-ku, Saitama 338-8570, Japan
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17
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Feng Y, Das PJ, Young RM, Brown PJ, Hornick JE, Weber JA, Seale JSW, Stern CL, Wasielewski MR, Stoddart JF. Alkoxy-Substituted Quadrupolar Fluorescent Dyes. J Am Chem Soc 2022; 144:16841-16854. [PMID: 36083184 DOI: 10.1021/jacs.2c04906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polar and polarizable π-conjugated organic molecules containing push-pull chromophores have been investigated extensively in the past. Identifying unique backbones and building blocks for fluorescent dyes is a timely exercise. Here, we report the synthesis and characterization of a series of fluorescent dyes containing quadrupolar A-D-A constitutions (where A = acceptor and D = donor), which exhibit fluorescence emission at a variety of different wavelengths. We have investigated the effects of different electron-withdrawing groups, located at both termini of a para-terphenylene backbone, by steady-state UV/vis and fluorescence spectroscopy. Pyridine and substituted pyridinium units are also introduced during the construction of the quadrupolar backbones. Depending on the quadrupolarity, fluorescence emission wavelengths cover from 380 to 557 nm. Time-resolved absorption and emission spectroscopy reveal that the photophysical properties of those quadrupolar dyes result from intramolecular charge transfer. One of the dyes we have investigated is a symmetrical box-like tetracationic cyclophane. Its water-soluble tetrachloride, which is non-cytotoxic to cells up to a loading concentration of 1 μM, has been employed in live-cell imaging. When taken up by cells, the tetrachloride emits a green fluorescence emission without any hint of photobleaching or disruption of normal cell behavior. We envision that our design strategy of modifying molecules through the functionalization of the quadrupolar building blocks as chromophores will lead to future generations of fluorescent dyes in which these A-D-A constitutional fragments are incorporated into more complex molecules and polymers for broader photophysical and biological applications.
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Affiliation(s)
- Yuanning Feng
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Partha Jyoti Das
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Ryan M Young
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, United States
| | - Paige J Brown
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, United States
| | - Jessica E Hornick
- Chemistry for Life Processes Institutes, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Department of Molecular Biosciences, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Jacob A Weber
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - James S W Seale
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Charlotte L Stern
- Integrated Molecular Structure Education and Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Michael R Wasielewski
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208, United States
| | - J Fraser Stoddart
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,School of Chemistry, University of New South Wales, Sydney 2052, New South Wales, Australia.,Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.,ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
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18
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Parallel triplet formation pathways in a singlet fission material. Nat Commun 2022; 13:5244. [PMID: 36068233 PMCID: PMC9448805 DOI: 10.1038/s41467-022-32844-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 08/18/2022] [Indexed: 11/08/2022] Open
Abstract
Harvesting long-lived free triplets in high yields by utilizing organic singlet fission materials can be the cornerstone for increasing photovoltaic efficiencies potentially. However, except for polyacenes, which are the most studied systems in the singlet fission field, spin-entangled correlated triplet pairs and free triplets born through singlet fission are relatively poorly characterized. By utilizing transient absorption and photoluminescence spectroscopy in supramolecular aggregate thin films consisting of Hamilton-receptor-substituted diketopyrrolopyrrole derivatives, we show that photoexcitation gives rise to the formation of spin-0 correlated triplet pair 1(TT) from the lower Frenkel exciton state. The existence of 1(TT) is proved through faint Herzberg-Teller emission that is enabled by vibronic coupling and correlated with an artifact-free triplet-state photoinduced absorption in the near-infrared. Surprisingly, transient electron paramagnetic resonance reveals that long-lived triplets are produced through classical intersystem crossing instead of 1(TT) dissociation, with the two pathways in competition. Moreover, comparison of the triplet-formation dynamics in J-like and H-like thin films with the same energetics reveals that spin-orbit coupling mediated intersystem crossing persists in both. However, 1(TT) only forms in the J-like film, pinpointing the huge impact of intermolecular coupling geometry on singlet fission dynamics.
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19
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Triplet-pair spin signatures from macroscopically aligned heteroacenes in an oriented single crystal. Proc Natl Acad Sci U S A 2022; 119:e2201879119. [PMID: 35858318 PMCID: PMC9303990 DOI: 10.1073/pnas.2201879119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The photo-driven process of singlet fission generates coupled triplet pairs (TT) with fundamentally intriguing and potentially useful properties. The quintet 5TT0 sublevel is particularly interesting for quantum information because it is highly entangled, is addressable with microwave pulses, and could be detected using optical techniques. Previous theoretical work on a model Hamiltonian and nonadiabatic transition theory, called the JDE model, has determined that this sublevel can be selectively populated if certain conditions are met. Among the most challenging, the molecules within the dimer undergoing singlet fission must have their principal magnetic axes parallel to one another and to an applied Zeeman field. Here, we present time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy of a single crystal sample of a tetracenethiophene compound featuring arrays of dimers aligned in this manner, which were mounted so that the orientation of the field relative to the molecular axes could be controlled. The observed spin sublevel populations in the paired TT and unpaired (T+T) triplets are consistent with predictions from the JDE model, including preferential 5TT0 formation at z ‖ B0, with one caveat-two 5TT spin sublevels have little to no population. This may be due to crossings between the 5TT and 3TT manifolds in the field range investigated by TR-EPR, consistent with the intertriplet exchange energy determined by monitoring photoluminescence at varying magnetic fields.
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20
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21
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Yablon LM, Sanders SN, Miyazaki K, Kumarasamy E, He G, Choi B, Ananth N, Sfeir MY, Campos LM. Singlet fission and triplet pair recombination in bipentacenes with a twist. MATERIALS HORIZONS 2022; 9:462-470. [PMID: 34846410 DOI: 10.1039/d1mh01201k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We investigate triplet pair dynamics in pentacene dimers that have varying degrees of coplanarity (pentacene-pentacene twist angle). The fine-tuning of the twist angle was achieved by alternating connectivity at the 1-position or 2-positions of pentacene. This mix-and-match connectivity leads to tunable twist angles between the two covalently linked pentacenes. These twisted dimers allow us to investigate the subtle effects that the dihedral angle between the covalently linked pentacenes imparts on singlet fission and triplet pair recombination dynamics. We observe that as the dihedral angle between the two bonded pentacenes is increased, the rates of singlet fission decrease, while the accompanying decrease in triplet recombination rates is stark. Temperature-dependent transient optical studies combined with theoretical calculations show that the triplet pair recombination proceeds primarily through a direct multiexciton internal conversion process. Calculations further show that the significant decrease in recombination rates can be directly attributed to a corresponding decrease in the magnitude of the nonadiabatic coupling between the singlet multiexcitonic state and the ground state. These results highlight the importance of the twist angle in designing systems that exhibit rapid singlet fission, while maintaining long triplet pair lifetimes in pentacene dimers.
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Affiliation(s)
- Lauren M Yablon
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Ken Miyazaki
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
| | - Elango Kumarasamy
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, USA.
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA
| | - Bonnie Choi
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Nandini Ananth
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, USA.
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
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22
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Wang L, Cai W, Sun J, Wu Y, Zhang B, Tian X, Guo S, Liang W, Fu H, Yao J. H-Type-like Aggregation-Accelerated Singlet Fission Process in Dipyrrolonaphthyridinedione Thin Film: The Role of Charge Transfer/Excimer Mixed Intermediate State. J Phys Chem Lett 2021; 12:12276-12282. [PMID: 34931841 DOI: 10.1021/acs.jpclett.1c03265] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Through the combination of transient spectroscopy and theoretical simulations, an accelerated singlet fission (SF) process was evidently observed in the strongly coupled H-type-like aggregation thin films of a dipyrrolonaphthyridinedione skeleton. Results elucidate that in this H-type-like aggregation, the substantially stabilized charge transfer (CT) state is close in energy with singlet and excimer states, resulting in a CT/excimer mixed state, which could drive excited-state population escaping from excimer trap and promote an ultrafast and highly efficient SF process. Our results not only enrich the limited capacity of SF materials but also contribute to an in-depth understanding of SF dynamics in H-type aggregation, which is of fundamental importance for designing new SF sensitizers and implementing practical SF applications.
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Affiliation(s)
- Long Wang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Wanlin Cai
- Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jing Sun
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yuling Wu
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Bin Zhang
- Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiangbin Tian
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Shaoting Guo
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - WanZhen Liang
- Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Jiannian Yao
- Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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23
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Bossanyi DG, Sasaki Y, Wang S, Chekulaev D, Kimizuka N, Yanai N, Clark J. Spin Statistics for Triplet-Triplet Annihilation Upconversion: Exchange Coupling, Intermolecular Orientation, and Reverse Intersystem Crossing. JACS AU 2021; 1:2188-2201. [PMID: 34977890 PMCID: PMC8715495 DOI: 10.1021/jacsau.1c00322] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 06/14/2023]
Abstract
Triplet-triplet annihilation upconversion (TTA-UC) has great potential to significantly improve the light harvesting capabilities of photovoltaic cells and is also sought after for biomedical applications. Many factors combine to influence the overall efficiency of TTA-UC, the most fundamental of which is the spin statistical factor, η, that gives the probability that a bright singlet state is formed from a pair of annihilating triplet states. The value of η is also critical in determining the contribution of TTA to the overall efficiency of organic light-emitting diodes. Using solid rubrene as a model system, we reiterate why experimentally measured magnetic field effects prove that annihilating triplets first form weakly exchange-coupled triplet-pair states. This is contrary to conventional discussions of TTA-UC that implicitly assume strong exchange coupling, and we show that it has profound implications for the spin statistical factor η. For example, variations in intermolecular orientation tune η from to through spin mixing of the triplet-pair wave functions. Because the fate of spin-1 triplet-pair states is particularly crucial in determining η, we investigate it in rubrene using pump-push-probe spectroscopy and find additional evidence for the recently reported high-level reverse intersystem crossing channel. We incorporate all of these factors into an updated model framework with which to understand the spin statistics of TTA-UC and use it to rationalize the differences in reported values of η among different common annihilator systems. We suggest that harnessing high-level reverse intersystem crossing channels in new annihilator molecules may be a highly promising strategy to exceed any spin statistical limit.
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Affiliation(s)
- David G. Bossanyi
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Yoichi Sasaki
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shuangqing Wang
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Dimitri Chekulaev
- Department
of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Nobuo Kimizuka
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Nobuhiro Yanai
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Jenny Clark
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
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24
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Lewis SG, Smyser KE, Eaves JD. Clock transitions guard against spin decoherence in singlet fission. J Chem Phys 2021; 155:194109. [PMID: 34800954 DOI: 10.1063/5.0069344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Short coherence times present a primary obstacle in quantum computing and sensing applications. In atomic systems, clock transitions (CTs), formed from avoided crossings in an applied Zeeman field, can substantially increase coherence times. We show how CTs can dampen intrinsic and extrinsic sources of quantum noise in molecules. Conical intersections between two periodic potentials form CTs in electron paramagnetic resonance experiments of the spin-polarized singlet fission photoproduct. We report on a pair of CTs for a two-chromophore molecule in terms of the Zeeman field strength, molecular orientation relative to the field, and molecular geometry.
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Affiliation(s)
- Sina G Lewis
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Kori E Smyser
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Joel D Eaves
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, USA
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25
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Abraham V, Mayhall NJ. Revealing the Contest between Triplet-Triplet Exchange and Triplet-Triplet Energy Transfer Coupling in Correlated Triplet Pair States in Singlet Fission. J Phys Chem Lett 2021; 12:10505-10514. [PMID: 34677988 DOI: 10.1021/acs.jpclett.1c03217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Understanding the separation of the correlated triplet pair state 1(TT) intermediate is critical for leveraging singlet fission to improve solar cell efficiency. This separation mechanism is dominated by two key interactions: (i) the exchange interaction (K) between the triplets which leads to the spin splitting of the biexciton state into 1(TT),3(TT) and 5(TT) states, and (ii) the triplet-triplet energy transfer integral (t) which enables the formation of the spatially separated (but still spin entangled) state 1(T···T). We develop a simple ab initio technique to compute both the biexciton exchange (K) and biexciton transfer coupling. Our key findings reveal new conditions for successful correlated triplet pair state dissociation. The biexciton exchange interaction needs to be ferromagnetic or negligible to the triplet energy transfer for favorable dissociation. We also explore the effect of chromophore packing to reveal geometries where these conditions are achieved for tetracene.
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Affiliation(s)
- Vibin Abraham
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
| | - Nicholas J Mayhall
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
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26
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Zhao X, O'Connor JP, Schultz JD, Bae YJ, Lin C, Young RM, Wasielewski MR. Temperature Tuning of Coherent Mixing between States Driving Singlet Fission in a Spiro-Fused Terrylenediimide Dimer. J Phys Chem B 2021; 125:6945-6954. [PMID: 34133180 DOI: 10.1021/acs.jpcb.1c02476] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The excited-state dynamics of a spiro-fused terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer (sTDI2) in toluene and 2-methyltetrahydrofuran (mTHF) were investigated as a function of temperature using femtosecond- and nanosecond-transient absorption spectroscopy, as well as two-dimensional electronic spectroscopy. The spiro conjugation and the corresponding geometry of this compound guarantee a short intermonomer distance along with a partial orbital overlap between the orthogonal TDI π-electron systems, providing electronic coupling between the TDIs. Photoexcitation of sTDI2 in toluene, a low dielectric solvent, at 295 K, results in the ultrafast formation of a state composed of a coherent mixture of singlet 1(S1S0), multiexciton 1(T1T1), and charge-transfer (CT) electronic characters. This mixed species decays to decorrelated triplet states on the nanosecond timescale, completing the process of intramolecular singlet fission (SF) in sTDI2. Upon decreasing the temperature from 295 to 200 K, the contribution of the 1(T1T1) state to the mixed species decreases concurrently with an increase in the CT state character. We attribute this behavior to the variation in the vibrational energy level alignment between the states comprising the mixture due to changes in the temperature and hence the local dielectric environment. In contrast, photoexcitation of sTDI2 in more polar mTHF at 295 K results in the formation of a mixed singlet and CT state before undergoing symmetry-breaking charge separation, owing to the increased stabilization of the CT state in the medium. However, in glassy mTHF at 85 K, photoexcited sTDI2 exhibits discernible multiexciton character, comparable to that observed in toluene at 200 K, which we rationalize by the similarity of the dielectric constants under these two sets of conditions. These observations of mixed states of varying diabatic contributions over the range of experimental conditions show that the temperature and the static dielectric constant can directly control the composition of the electronically mixed excited state of sTDI2 and thus the fate of the SF process.
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Affiliation(s)
- Xingang Zhao
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - James P O'Connor
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Jonathan D Schultz
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Youn Jue Bae
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Chenjian Lin
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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27
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Open questions on the photophysics of ultrafast singlet fission. Commun Chem 2021; 4:85. [PMID: 36697779 PMCID: PMC9814646 DOI: 10.1038/s42004-021-00527-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/07/2021] [Indexed: 01/28/2023] Open
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28
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Wang Z, Liu H, Xie X, Zhang C, Wang R, Chen L, Xu Y, Ma H, Fang W, Yao Y, Sang H, Wang X, Li X, Xiao M. Free-triplet generation with improved efficiency in tetracene oligomers through spatially separated triplet pair states. Nat Chem 2021; 13:559-567. [PMID: 33833447 DOI: 10.1038/s41557-021-00665-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 02/22/2021] [Indexed: 02/01/2023]
Abstract
Singlet fission (SF) can potentially boost the efficiency of solar energy conversion by converting a singlet exciton (S1) into two free triplets (T1 + T1) through an intermediate state of a correlated triplet pair (TT). Although efficient TT generation has been recently realized in many intramolecular SF materials, their potential applications have been hindered by the poor efficiency of TT dissociation. Here we demonstrate that this can be overcome by employing a spatially separated 1(T…T) state with weak intertriplet coupling in tetracene oligomers with three or more chromophores. By using transient magneto-optical spectroscopic methods, we show that free-triplet generation can be markedly enhanced through the SF pathway that involves the spatially separated 1(T…T) state rather than the pathway mediated by the spatially adjacent TT state, leading to a marked improvement in free-triplet generation with an efficiency increase from 21% for the dimer to 85% (124%) for the trimer (tetramer).
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Affiliation(s)
- Zhiwei Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Heyuan Liu
- School of Materials Science and Engineering, Institute of New Energy, China University of Petroleum (East China), Qingdao, China
| | - Xiaoyu Xie
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Lan Chen
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Yihe Xu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Haibo Ma
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
| | - Weihai Fang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.,Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Beijing, China
| | - Yao Yao
- Department of Physics and State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, China
| | - Hai Sang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Xiyou Li
- School of Materials Science and Engineering, Institute of New Energy, China University of Petroleum (East China), Qingdao, China.
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China. .,Department of Physics, University of Arkansas, Fayetteville, AR, USA.
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29
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Kim T, Kim J, Ke XS, Brewster JT, Oh J, Sessler JL, Kim D. Magnetic-Field-Induced Modulation of Charge-Recombination Dynamics in a Rosarin-Fullerene Complex. Angew Chem Int Ed Engl 2021; 60:9379-9383. [PMID: 33590640 DOI: 10.1002/anie.202017332] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Indexed: 11/10/2022]
Abstract
Charge-recombination processes are critical for photovoltaic applications and should be suppressed for efficient charge transport. Here, we report that an applied magnetic field (0-1 T) can be used control the charge-recombination dynamics in an expanded rosarin-C60 complex. In the low magnetic field regime (<100 mT), the charge-recombination rate slows down due to hyperfine coupling, as inferred from transient absorption spectroscopic analyses. In contrast, in the high field regime, i.e., over 500 mT, the charge-recombination rate recovers and increases because the Δg mechanism facilitates spin conversion to a triplet charge-separated state (S to T0 ) that undergoes rapid charge-recombination to a localized rosarin triplet state. Therefore, we highlight the charge-recombination rate and the localized triplet state population can be modulated by the magnetic field in charge donor/acceptor non-covalent complexes.
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Affiliation(s)
- Taeyeon Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul, 03722, Republic of Korea.,Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois, 60208-3113, United States
| | - Juno Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul, 03722, Republic of Korea
| | - Xian-Sheng Ke
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712-1224, USA
| | - James T Brewster
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712-1224, USA
| | - Juwon Oh
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul, 03722, Republic of Korea.,Department of Chemistry, Soonchunhyang University, Chungnam, 31538, Republic of Korea
| | - Jonathan L Sessler
- Department of Chemistry, The University of Texas at Austin, Austin, TX, 78712-1224, USA
| | - Dongho Kim
- Department of Chemistry, Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University, Seoul, 03722, Republic of Korea
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30
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Kim T, Kim J, Ke X, Brewster JT, Oh J, Sessler JL, Kim D. Magnetic‐Field‐Induced Modulation of Charge‐Recombination Dynamics in a Rosarin‐Fullerene Complex. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202017332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Taeyeon Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University Seoul 03722 Republic of Korea
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern Northwestern University Evanston, Illinois 60208-3113 United States
| | - Juno Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University Seoul 03722 Republic of Korea
| | - Xian‐Sheng Ke
- Department of Chemistry The University of Texas at Austin Austin TX 78712-1224 USA
| | - James T. Brewster
- Department of Chemistry The University of Texas at Austin Austin TX 78712-1224 USA
| | - Juwon Oh
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University Seoul 03722 Republic of Korea
- Department of Chemistry Soonchunhyang University Chungnam 31538 Republic of Korea
| | - Jonathan L. Sessler
- Department of Chemistry The University of Texas at Austin Austin TX 78712-1224 USA
| | - Dongho Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University Seoul 03722 Republic of Korea
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31
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Olesund A, Gray V, Mårtensson J, Albinsson B. Diphenylanthracene Dimers for Triplet-Triplet Annihilation Photon Upconversion: Mechanistic Insights for Intramolecular Pathways and the Importance of Molecular Geometry. J Am Chem Soc 2021; 143:5745-5754. [PMID: 33835789 PMCID: PMC8154513 DOI: 10.1021/jacs.1c00331] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Novel approaches
to modify the spectral output of the sun have
seen a surge in interest recently, with triplet–triplet annihilation
driven photon upconversion (TTA-UC) gaining widespread recognition
due to its ability to function under low-intensity, noncoherent light.
Herein, four diphenylanthracene (DPA) dimers are investigated to explore
how the structure of these dimers affects upconversion efficiency.
Also, the mechanism responsible for intramolecular upconversion is
elucidated. In particular, two models are compared using steady-state
and time-resolved simulations of the TTA-UC emission intensities and
kinetics. All dimers perform TTA-UC efficiently in the presence of
the sensitizer platinum octaethylporphyrin. The meta-coupled dimer
1,3-DPA2 performs best yielding a 21.2% upconversion quantum
yield (out of a 50% maximum), which is close to that of the reference
monomer DPA (24.0%). Its superior performance compared to the other
dimers is primarily ascribed to the longer triplet lifetime of this
dimer (4.7 ms), thus reinforcing the importance of this parameter.
Comparisons between simulations and experiments reveal that the double-sensitization
mechanism is part of the mechanism of intramolecular upconversion
and that this additional pathway could be of great significance under
specific conditions. The results from this study can thus act as a
guide not only in terms of annihilator design but also for the design
of future solid-state systems where intramolecular exciton migration
is anticipated to play a major role.
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Affiliation(s)
- Axel Olesund
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Victor Gray
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.,Department of Chemistry, Ångström Laboratory, Uppsala University, Box 532, 751 20 Uppsala, Sweden
| | - Jerker Mårtensson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Bo Albinsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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32
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Schultz JD, Shin JY, Chen M, O'Connor JP, Young RM, Ratner MA, Wasielewski MR. Influence of Vibronic Coupling on Ultrafast Singlet Fission in a Linear Terrylenediimide Dimer. J Am Chem Soc 2021; 143:2049-2058. [PMID: 33464054 DOI: 10.1021/jacs.0c12201] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Singlet fission (SF) is a photophysical process capable of boosting the efficiency of solar cells. Recent experimental investigations into the mechanism of SF provide evidence for coherent mixing between the singlet, triplet, and charge transfer basis states. Up until now, this interpretation has largely focused on electronic interactions; however, nuclear motions resulting in vibronic coupling have been suggested to support rapid and efficient SF in organic chromophore assemblies. Further information about the complex interactions between vibronic excited states is needed to understand the potential role of this coupling in SF. Here, we report mixed singlet and correlated triplet pair states giving rise to sub-50 fs SF in a terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer in which the two TDI molecules are covalently linked by a direct N-N connection at one of their imide positions, leading to a linear dimer with perpendicular TDI π systems. We observe the transfer of low-frequency coherent wavepackets between the initial predominantly singlet states to the product triplet-dominated states. This implies a non-negligible dependence of SF on nonadiabatic coupling in this dimer. We interpret our experimental results in the framework of a modified Holstein Hamiltonian, which predicts that vibronic interactions between low-frequency singlet modes and high-frequency correlated triplet pair motions lead to mixing of the pure basis states. These results highlight how nonadiabatic mixing can shape the complex potential energy landscape underlying ultrafast SF.
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Affiliation(s)
- Jonathan D Schultz
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Jae Yoon Shin
- Department of Advanced Materials Chemistry, Korea University, 30019 Sejong-ro, Sejong, South Korea
| | - Michelle Chen
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - James P O'Connor
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Mark A Ratner
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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33
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Karlsson JKG, Atahan A, Harriman A, Tkachenko NV, Ward AD, Schaberle FA, Serpa C, Arnaut LG. Singlet Exciton Fission and Associated Enthalpy Changes with a Covalently Linked Bichromophore Comprising TIPS-Pentacenes Held in an Open Conformation. J Phys Chem A 2021; 125:1184-1197. [DOI: 10.1021/acs.jpca.0c09961] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua K. G. Karlsson
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, U.K
| | - Alparslan Atahan
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, U.K
| | - Anthony Harriman
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, U.K
| | - Nikolai V. Tkachenko
- Faculty of Engineering and Natural Sciences, Tampere University, Koereakoulunkatu 7, FIN-33720 Tampere, Finland
| | - Andrew D. Ward
- Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot OX11 0FA, U.K
| | - Fabio A. Schaberle
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Carlos Serpa
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Luis G. Arnaut
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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34
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Bancroft L, Zhang J, Harvey SM, Krzyaniak MD, Zhang P, Schaller RD, Beratan DN, Young RM, Wasielewski MR. Charge Transfer and Spin Dynamics in a Zinc Porphyrin Donor Covalently Linked to One or Two Naphthalenediimide Acceptors. J Phys Chem A 2021; 125:825-834. [PMID: 33449684 DOI: 10.1021/acs.jpca.0c10471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Quantum coherence effects on charge transfer and spin dynamics in a system having two degenerate electron acceptors are studied using a zinc 5,10,15-tri(n-pentyl)-20-phenylporphyrin (ZnP) electron donor covalently linked to either one or two naphthalene-1,8:4,5-bis(dicarboximide) (NDI) electron acceptors using an anthracene (An) spacer, ZnP-An-NDI (1) and ZnP-An-NDI2 (2), respectively. Following photoexcitation of 1 and 2 in toluene at 295 K, femtosecond transient absorption spectroscopy shows that the electron transfer (ET) rate constant for 2 is about three times larger than that of 1, which can be accounted for by the statistical nature of incoherent ET as well as the electron couplings for the charge separation reactions. In contrast, the rate constant for charge recombination (CR) of 1 is about 25% faster than that of 2. Using femtosecond transient infrared spectroscopy and theoretical analysis, we find that the electron on NDI2•- in 2 localizes onto one of the two NDIs prior to CR, thus precluding electronically coherent CR from NDI2•-. Conversely, CR in both 1 and 2 is spin coherent as indicated by the observation of a resonance in the 3*ZnP yield following CR as a function of applied magnetic field, giving spin-spin exchange interaction energies of 2J = 210 and 236 mT, respectively, where the line width of the resonance for 2 is greater than 1. These data show that while CR is a spin-coherent process, incoherent hopping of the electron between the two NDIs in 2, consistent with the lack of delocalization noted above, results in greater spin decoherence in 2 relative to 1.
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Affiliation(s)
- Laura Bancroft
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Jinyuan Zhang
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Samantha M Harvey
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew D Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Richard D Schaller
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States.,Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Departments of Biochemistry and Physics, Duke University, Durham, North Carolina 27708, United States
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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35
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Abstract
Singlet fission (SF) is a photophysical downconversion pathway, in which a singlet excitation transforms into two triplet excited states. As such, it constitutes an exciton multiplication generation process, which is currently at the focal point for future integration into solar energy conversion devices. Beyond this, various other exciting applications were proposed, including quantum cryptography or organic light emitting diodes. Also, the mechanistic understanding evolved rapidly during the last year. Unfortunately, the number of suitable SF-chromophores is still limited. This is per se problematic, considering the wide range of envisaged applicability. With that in mind, we emphasize uncommon SF-scaffolds and outline requirements as well as strategies to expand the chromophore pool of SF-materials.
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Affiliation(s)
- Tobias Ullrich
- Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Department für Chemie und Pharmazie, Egerlandstr. 1-3, 91058 Erlangen, Germany.
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36
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Zhao X, Bae YJ, Chen M, Harvey SM, Lin C, Zhou J, Schaller RD, Young RM, Wasielewski MR. Singlet fission in core-linked terrylenediimide dimers. J Chem Phys 2020; 153:244306. [PMID: 33380082 DOI: 10.1063/5.0026254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xingang Zhao
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Youn Jue Bae
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Michelle Chen
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Samantha M. Harvey
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Chenjian Lin
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Jiawang Zhou
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Richard D. Schaller
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Ryan M. Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
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37
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Cruz CD, Chronister EL, Bardeen CJ. Using temperature dependent fluorescence to evaluate singlet fission pathways in tetracene single crystals. J Chem Phys 2020; 153:234504. [PMID: 33353314 DOI: 10.1063/5.0031458] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The temperature-dependent fluorescence spectrum, decay rate, and spin quantum beats are examined in single tetracene crystals to gain insight into the mechanism of singlet fission. Over the temperature range of 250 K-500 K, the vibronic lineshape of the emission indicates that the singlet exciton becomes localized at 400 K. The fission process is insensitive to this localization and exhibits Arrhenius behavior with an activation energy of 550 ± 50 cm-1. The damping rate of the triplet pair spin quantum beats in the delayed fluorescence also exhibits an Arrhenius temperature dependence with an activation energy of 165 ± 70 cm-1. All the data for T > 250 K are consistent with direct production of a spatially separated 1(T⋯T) state via a thermally activated process, analogous to spontaneous parametric downconversion of photons. For temperatures in the range of 20 K-250 K, the singlet exciton continues to undergo a rapid decay on the order of 200 ps, leaving a red-shifted emission that decays on the order of 100 ns. At very long times (≈1 µs), a delayed fluorescence component corresponding to the original S1 state can still be resolved, unlike in polycrystalline films. A kinetic analysis shows that the redshifted emission seen at lower temperatures cannot be an intermediate in the triplet production. When considered in the context of other results, our data suggest that the production of triplets in tetracene for temperatures below 250 K is a complex process that is sensitive to the presence of structural defects.
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Affiliation(s)
- Chad D Cruz
- Department of Chemistry, University of California Riverside, Riverside, California 92521, USA
| | - Eric L Chronister
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154, USA
| | - Christopher J Bardeen
- Department of Chemistry, University of California Riverside, Riverside, California 92521, USA
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38
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Powers-Riggs NE, Zuo X, Young RM, Wasielewski MR. Solvent independent symmetry-breaking charge separation in terrylenediimide guanine-quadruplex nanoparticles. J Chem Phys 2020; 153:204302. [DOI: 10.1063/5.0027471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Natalia E. Powers-Riggs
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Xiaobing Zuo
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Ryan M. Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
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39
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Zirzlmeier J, Lavarda G, Gotfredsen H, Papadopoulos I, Chen L, Clark T, Tykwinski RR, Torres T, Guldi DM. Modulating the dynamics of Förster resonance energy transfer and singlet fission by variable molecular spacers. NANOSCALE 2020; 12:23061-23068. [PMID: 33179680 DOI: 10.1039/d0nr06285e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In contrast to previous work, the synergy between panchromatic absorption and molecular singlet fission (SF) is exploited to optimize solar energy conversion through evaluation of the distance dependence of intramolecular Förster Resonance Energy Transfer (i-FRET) in a series of subphthalocyanines (SubPcs) linked to pentacene dimers (Pnc2s). To provide control over i-FRET, the molecular spacer rather than the energy donating SubPc is tailored in the corresponding SubPc-Pnc2 conjugates in terms of length (i.e., the number of aryl units) and flexibility (i.e., presence or absence of a CH2 group). AM1-CIS calculations support the experiments, which underline the importance of the molecular spacer to impact not only the i-FRET dynamics, but also the dynamics of intramolecular singlet fission (i-SF). For example, an additional phenyl group slows down both i-FRET and i-SF by a factor of ∼3.8 and ∼1.6, respectively, by a quinone-like conjugation pattern that affords a pentacene acceptor orbital that is fairly delocalized over both pentacenes and the bridging phenyl.
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Affiliation(s)
- Johannes Zirzlmeier
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany.
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40
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Ribson RD, Choi G, Hadt RG, Agapie T. Controlling Singlet Fission with Coordination Chemistry-Induced Assembly of Dipyridyl Pyrrole Bipentacenes. ACS CENTRAL SCIENCE 2020; 6:2088-2096. [PMID: 33274285 PMCID: PMC7706079 DOI: 10.1021/acscentsci.0c01044] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Indexed: 05/28/2023]
Abstract
Singlet fission has the potential to surpass current efficiency limits in next-generation photovoltaics and to find use in quantum information science. Despite the demonstration of singlet fission in various materials, there is still a great need for fundamental design principles that allow for tuning of photophysical parameters, including the rate of fission and triplet lifetimes. Here, we describe the synthesis and photophysical characterization of a novel bipentacene dipyridyl pyrrole (HDPP-Pent) and its Li- and K-coordinated derivatives. HDPP-Pent undergoes singlet fission at roughly 50% efficiency (τSF = 730 ps), whereas coordination in the Li complex induces significant structural changes to generate a dimer, resulting in a 7-fold rate increase (τSF = 100 ps) and more efficient singlet fission with virtually no sacrifice in triplet lifetime. We thus illustrate novel design principles to produce favorable singlet fission properties, wherein through-space control can be achieved via coordination chemistry-induced multipentacene assembly.
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Affiliation(s)
- Ryan D. Ribson
- Division of Chemistry and
Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Gyeongshin Choi
- Division of Chemistry and
Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Ryan G. Hadt
- Division of Chemistry and
Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and
Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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41
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Smyser KE, Eaves JD. Singlet fission for quantum information and quantum computing: the parallel JDE model. Sci Rep 2020; 10:18480. [PMID: 33116218 PMCID: PMC7595132 DOI: 10.1038/s41598-020-75459-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 09/22/2020] [Indexed: 11/09/2022] Open
Abstract
Singlet fission is a photoconversion process that generates a doubly excited, maximally spin entangled pair state. This state has applications to quantum information and computing that are only beginning to be realized. In this article, we construct and analyze a spin-exciton hamiltonian to describe the dynamics of the two-triplet state. We find the selection rules that connect the doubly excited, spin-singlet state to the manifold of quintet states and comment on the mechanism and conditions for the transition into formally independent triplets. For adjacent dimers that are oriented and immobilized in an inert host, singlet fission can be strongly state-selective. We make predictions for electron paramagnetic resonance experiments and analyze experimental data from recent literature. Our results give conditions for which magnetic resonance pulses can drive transitions between optically polarized magnetic sublevels of the two-exciton states, making it possible to realize quantum gates at room temperature in these systems.
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Affiliation(s)
- Kori E Smyser
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Joel D Eaves
- Department of Chemistry, University of Colorado Boulder, Boulder, CO, 80309, USA.
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42
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Kobori Y, Fuki M, Nakamura S, Hasobe T. Geometries and Terahertz Motions Driving Quintet Multiexcitons and Ultimate Triplet–Triplet Dissociations via the Intramolecular Singlet Fissions. J Phys Chem B 2020; 124:9411-9419. [DOI: 10.1021/acs.jpcb.0c07984] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yasuhiro Kobori
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Masaaki Fuki
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
| | - Shunta Nakamura
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
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43
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Young RM, Wasielewski MR. Mixed Electronic States in Molecular Dimers: Connecting Singlet Fission, Excimer Formation, and Symmetry-Breaking Charge Transfer. Acc Chem Res 2020; 53:1957-1968. [PMID: 32786248 DOI: 10.1021/acs.accounts.0c00397] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ConspectusChromophore aggregates are capable of a wide variety of excited-state dynamics that are potentially of great use in optoelectronic devices based on organic molecules. For example, singlet fission, the process by which a singlet exciton is down converted into two triplet excitons, holds promise for extending the efficiency of solar cells, while other processes, such as excimer formation, are commonly regarded as parasitic pathways or traps. Other processes, such as symmetry-breaking charge transfer, where the excited dimer charge separates into a radical ion pair, can be both a trap and potentially useful in devices, depending on the context. Thus, an understanding of the precise mechanisms of each of these processes is vital to designing tailor-made organic chromophores for molecular optoelectronics.These excited-state phenomena have each been well-studied in recent years and show tantalizing connections as the molecular systems and environments are subtly changed. These seemingly disparate phenomena can be described within the same unifying framework, where each case can be represented as one point in continuum of mixed states. The coherent mixed state is observed experimentally, and it collapses to each of the limiting cases under well-defined conditions. This framework is especially useful in demonstrating the connections between these different states so that we can determine the factors that control their evolution and may ultimately guide the state mixtures to the product state of choice. The emerging picture shows that tuning the electronic coupling through proper arrangement of the chromophores must accompany environmental tuning of the chromophore energies to produce a fully mixed state. Changes in either of these quantities leads to evolution of the admixture and ultimately collapsing the superposition onto a given state, producing one of the photophysical pathways discussed above.In our laboratory, we are utilizing covalent dimers to precisely arrange the chromophores in rigid, well-defined geometries to systematically study the factors that determine the degree of state mixing and its fate. We interrogate these dynamics with transient absorption spectroscopy from the UV continuously into the mid-infrared, along with time-resolved Raman and emission and magnetic resonance spectroscopies to build a complete and detailed molecular level picture of the dynamics of these dimers. The knowledge gained from dimer studies can also be applied to the understanding the dynamics in extended molecular solids. The insight afforded by these studies will help guide the creation of new designer chromophores with control over the fate of the excited state.
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Affiliation(s)
- Ryan M. Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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44
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Chen M, Shin JY, Young RM, Wasielewski MR. Tuning the charge transfer character of the multiexciton state in singlet fission. J Chem Phys 2020; 153:094302. [DOI: 10.1063/5.0017919] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Michelle Chen
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Jae Yoon Shin
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Ryan M. Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
| | - Michael R. Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA
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45
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Sutherland GA, Polak D, Swainsbury DJK, Wang S, Spano FC, Auman DB, Bossanyi DG, Pidgeon JP, Hitchcock A, Musser AJ, Anthony JE, Dutton PL, Clark J, Hunter CN. A Thermostable Protein Matrix for Spectroscopic Analysis of Organic Semiconductors. J Am Chem Soc 2020; 142:13898-13907. [PMID: 32672948 DOI: 10.1021/jacs.0c05477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Advances in protein design and engineering have yielded peptide assemblies with enhanced and non-native functionalities. Here, various molecular organic semiconductors (OSCs), with known excitonic up- and down-conversion properties, are attached to a de novo-designed protein, conferring entirely novel functions on the peptide scaffolds. The protein-OSC complexes form similarly sized, stable, water-soluble nanoparticles that are robust to cryogenic freezing and processing into the solid-state. The peptide matrix enables the formation of protein-OSC-trehalose glasses that fix the proteins in their folded states under oxygen-limited conditions. The encapsulation dramatically enhances the stability of protein-OSC complexes to photodamage, increasing the lifetime of the chromophores from several hours to more than 10 weeks under constant illumination. Comparison of the photophysical properties of astaxanthin aggregates in mixed-solvent systems and proteins shows that the peptide environment does not alter the underlying electronic processes of the incorporated materials, exemplified here by singlet exciton fission followed by separation into weakly bound, localized triplets. This adaptable protein-based approach lays the foundation for spectroscopic assessment of a broad range of molecular OSCs in aqueous solutions and the solid-state, circumventing the laborious procedure of identifying the experimental conditions necessary for aggregate generation or film formation. The non-native protein functions also raise the prospect of future biocompatible devices where peptide assemblies could complex with native and non-native systems to generate novel functional materials.
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Affiliation(s)
- George A Sutherland
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| | - Daniel Polak
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - David J K Swainsbury
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| | - Shuangqing Wang
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Frank C Spano
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Dirk B Auman
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - David G Bossanyi
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - James P Pidgeon
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| | - Andrew J Musser
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Kentucky 40511, United States
| | - P Leslie Dutton
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jenny Clark
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
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46
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Pace NA, Rugg BK, Chang CH, Reid OG, Thorley KJ, Parkin S, Anthony JE, Johnson JC. Conversion between triplet pair states is controlled by molecular coupling in pentadithiophene thin films. Chem Sci 2020; 11:7226-7238. [PMID: 34123008 PMCID: PMC8159287 DOI: 10.1039/d0sc02497j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 06/21/2020] [Indexed: 11/21/2022] Open
Abstract
In singlet fission (SF) the initially formed correlated triplet pair state, 1(TT), may evolve toward independent triplet excitons or higher spin states of the (TT) species. The latter result is often considered undesirable from a light harvesting perspective but may be attractive for quantum information sciences (QIS) applications, as the final exciton pair can be spin-entangled and magnetically active with relatively long room temperature decoherence times. In this study we use ultrafast transient absorption (TA) and time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy to monitor SF and triplet pair evolution in a series of alkyl silyl-functionalized pentadithiophene (PDT) thin films designed with systematically varying pairwise and long-range molecular interactions between PDT chromophores. The lifetime of the (TT) species varies from 40 ns to 1.5 μs, the latter of which is associated with extremely weak intermolecular coupling, sharp optical spectroscopic features, and complex TR-EPR spectra that are composed of a mixture of triplet and quintet-like features. On the other hand, more tightly coupled films produce broader transient optical spectra but simpler TR-EPR spectra consistent with significant population in 5(TT)0. These distinctions are rationalized through the role of exciton diffusion and predictions of TT state mixing with low exchange coupling J versus pure spin substate population with larger J. The connection between population evolution using electronic and spin spectroscopies enables assignments that provide a more detailed picture of triplet pair evolution than previously presented and provides critical guidance for designing molecular QIS systems based on light-induced spin coherence.
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Affiliation(s)
- Natalie A Pace
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
| | - Brandon K Rugg
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
| | - Christopher H Chang
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
| | - Obadiah G Reid
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder Boulder Colorado 80309 USA
| | - Karl J Thorley
- Department of Chemistry, University of Kentucky Lexington KY 40506 USA
| | - Sean Parkin
- Department of Chemistry, University of Kentucky Lexington KY 40506 USA
| | - John E Anthony
- Department of Chemistry, University of Kentucky Lexington KY 40506 USA
| | - Justin C Johnson
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
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47
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Spatial separation of triplet excitons drives endothermic singlet fission. Nat Chem 2020; 12:391-398. [PMID: 32123340 DOI: 10.1038/s41557-020-0422-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/14/2020] [Indexed: 11/08/2022]
Abstract
Molecules that undergo singlet fission, converting singlet excitons into pairs of triplet excitons, have potential as photovoltaic materials. The possible advantages of endothermic singlet fission (enhanced use of photon energy and larger triplet energies for coupling with common absorbers) motivated us to assess the role of exciton delocalization in the activation of this process. Here we report the synthesis of a series of linear perylene oligomers that undergo endothermic singlet fission and have endothermicities in the range 5-10 kBT at room temperature in solution. We study these compounds using transient spectroscopy and modelling to unravel the singlet and triplet dynamics. We show that the minimal number of coupled chromophores needed to undergo endothermic singlet fission is three, which provides sufficient statistical space for triplet excitons to separate and avoid annihilation-and a subsequent fast return to the singlet state. Our data additionally suggest that torsional motion of chromophores about the molecular axis following triplet-pair separation contributes to the increase in entropy, thus lengthening the triplet lifetime in longer oligomers.
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48
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Korovina NV, Pompetti NF, Johnson JC. Lessons from intramolecular singlet fission with covalently bound chromophores. J Chem Phys 2020; 152:040904. [PMID: 32007061 DOI: 10.1063/1.5135307] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Molecular dimers, oligomers, and polymers are versatile components in photophysical and optoelectronic architectures that could impact a variety of applications. We present a perspective on such systems in the field of singlet fission, which effectively multiplies excitons and produces a unique excited state species, the triplet pair. The choice of chromophore and the nature of the attachment between units, both geometrical and chemical, play a defining role in the dynamical scheme that evolves upon photoexcitation. Specific final outcomes (e.g., separated and uncorrelated triplet pairs) are being sought through rational design of covalently bound chromophore architectures built with guidance from recent fundamental studies that correlate structure with excited state population flow kinetics.
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Affiliation(s)
- Nadezhda V Korovina
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
| | - Nicholas F Pompetti
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
| | - Justin C Johnson
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
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49
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Sanders SN, Kumarasamy E, Fallon KJ, Sfeir MY, Campos LM. Singlet fission in a hexacene dimer: energetics dictate dynamics. Chem Sci 2019; 11:1079-1084. [PMID: 34084363 PMCID: PMC8146228 DOI: 10.1039/c9sc05066c] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Singlet fission (SF) is an exciton multiplication process with the potential to raise the efficiency limit of single junction solar cells from 33% to up to 45%. Most chromophores generally undergo SF as solid-state crystals. However, when such molecules are covalently coupled, the dimers can be used as model systems to study fundamental photophysical dynamics where a singlet exciton splits into two triplet excitons within individual molecules. Here we report the synthesis and photophysical characterization of singlet fission of a hexacene dimer. Comparing the hexacene dimer to analogous tetracene and pentacene dimers reveals that excess exoergicity slows down singlet fission, similar to what is observed in molecular crystals. Conversely, the lower triplet energy of hexacene results in an increase in the rate of triplet pair recombination, following the energy gap law for radiationless transitions. These results point to design rules for singlet fission chromophores: the energy gap between singlet and triplet pair should be minimal, and the gap between triplet pair and ground state should be large. We report the synthesis and photophysical characterization of highly exoergic singlet fission in a hexacene dimer revealing exciton dynamics that follow the energy gap law.![]()
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Affiliation(s)
- Samuel N Sanders
- Department of Chemistry, Columbia University New York NY 10027 USA
| | | | - Kealan J Fallon
- Department of Chemistry, Columbia University New York NY 10027 USA
| | - Matthew Y Sfeir
- Photonics Initiative, Advanced Science Research Center, City University of New York New York NY 10031 USA .,Department of Physics, Graduate Center, City University of New York New York NY 10016 USA
| | - Luis M Campos
- Department of Chemistry, Columbia University New York NY 10027 USA
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50
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Basel BS, Young RM, Krzyaniak MD, Papadopoulos I, Hetzer C, Gao Y, La Porte NT, Phelan BT, Clark T, Tykwinski RR, Wasielewski MR, Guldi DM. Influence of the heavy-atom effect on singlet fission: a study of platinum-bridged pentacene dimers. Chem Sci 2019; 10:11130-11140. [PMID: 32206262 PMCID: PMC7069226 DOI: 10.1039/c9sc04410h] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/20/2019] [Indexed: 12/11/2022] Open
Abstract
Two platinum-bridged pentacene dimers undergo efficient singlet fission to form a correlated triplet pair (T1T1). The internal heavy-atom effect of the platinum allows for 1(T1T1)–3(T1T1) mixing leading to the formation of mainly (T1S0).
The process of singlet fission (SF) produces two triplet excited states (T1 + T1) from one singlet excited exciton (S1) and a molecule in its ground state (S0). It, thus, possesses the potential to boost the solar cell efficiency above the thermodynamic Shockley–Queisser limit of 33%. A key intermediate in the SF mechanism is the singlet correlated triplet pair state 1(T1T1). This state is of great relevance, as its formation is spin-allowed and, therefore, very fast and efficient. Three fundamentally different pathways to formation of 1(T1T1) have been documented so far. The factors that influence which mechanism is associated with which chromophore, however, remain largely unknown. In order to harvest both triplet excitons independently, a decorrelation of the correlated triplet pair state to two individual triplets is required. This second step of the SF process implies a change in the total spin quantum number. In the case of a dimer, this is usually only possible if the coupling between the two pentacenes is sufficiently weak. In this study, we present two platinum-bridged pentacene dimers in which the pentacenes are coupled strongly, so that spin-decorrelation yielding (T1 + T1) was initially expected to be outcompeted by triplet–triplet annihilation (TTA) to the ground state. Both platinum-bridged pentacene dimers undergo quantitative formation of the (T1T1) state on a picosecond timescale that is unaffected by the internal heavy-atom effect of the platinum. Instead of TTA of (T1T1) to the ground state, the internal heavy-atom effect allows for 1(T1T1)–3(T1T1) and 1(T1T1)–5(T1T1) mixing and, thus, triggers subsequent TTA to the (T1S0) state and minor formation of (T1 + T1). A combination of transient absorption and transient IR spectroscopy is applied to investigate the mechanism of the (T1T1) formation in both dimers. Using a combination of experiment and quantum chemical calculations, we are able to observe a transition from the CT-mediated to the direct SF mechanism and identify relevant factors that influence the mechanism that dominates SF in pentacene. Moreover, a combination of time-resolved optical and electron paramagnetic resonance spectroscopic data allows us to develop a kinetic model that describes the effect of enhanced spin–orbit couplings on the correlated triplet pair state.
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Affiliation(s)
- Bettina S Basel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Egerlandstrasse 3 , 91058 Erlangen , Germany .
| | - Ryan M Young
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern (ISEN) , Northwestern University , Evanston , IL 60208-3113 , USA .
| | - Matthew D Krzyaniak
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern (ISEN) , Northwestern University , Evanston , IL 60208-3113 , USA .
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Egerlandstrasse 3 , 91058 Erlangen , Germany .
| | - Constantin Hetzer
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Nikolaus-Fiebiger-Strasse 10 , 91058 Erlangen , Germany
| | - Yueze Gao
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada .
| | - Nathan T La Porte
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern (ISEN) , Northwestern University , Evanston , IL 60208-3113 , USA .
| | - Brian T Phelan
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern (ISEN) , Northwestern University , Evanston , IL 60208-3113 , USA .
| | - Timothy Clark
- Department of Chemistry and Pharmacy & Computer-Chemistry-Center (CCC) , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Nägelsbachstrasse 25 , 91052 Erlangen , Germany .
| | - Rik R Tykwinski
- Department of Chemistry , University of Alberta , Edmonton , Alberta T6G 2G2 , Canada .
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern (ISEN) , Northwestern University , Evanston , IL 60208-3113 , USA .
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM) , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Egerlandstrasse 3 , 91058 Erlangen , Germany .
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