1
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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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2
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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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3
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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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4
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Medagedara H, Teferi MY, Wanasinghe ST, Burson W, Kizi S, Zaslona B, Mardis KL, Niklas J, Poluektov OG, Rury AS. Decorrelated singlet and triplet exciton delocalization in acetylene-bridged Zn-porphyrin dimers. Chem Sci 2024; 15:1736-1751. [PMID: 38303928 PMCID: PMC10829018 DOI: 10.1039/d3sc03327a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/12/2023] [Indexed: 02/03/2024] Open
Abstract
The controlled delocalization of molecular excitons remains an important goal towards the application of organic chromophores in processes ranging from light-initiated chemical transformations to classical and quantum information processing. In this study, we present a methodology to couple optical and magnetic spectroscopic techniques and assess the delocalization of singlet and triplet excitons in model molecular chromophores. By comparing the steady-state and time-resolved optical spectra of Zn-porphyrin monomers and weakly coupled dimers, we show that we can use the identity of substituents bound at specific positions of the macromolecules' rings to control the inter-ring delocalization of singlet excitons stemming from their B states through acetylene bridges. While broadened steady-state absorption spectra suggest the presence of delocalized B state excitons in mesityl-substituted Zn-tetraphenyl porphyrin dimers (Zn2U-D), we confirm this conclusion by measuring an enhanced ultrafast non-radiative relaxation from these inter-ring excitonic states to lower lying electronic states relative to their monomer. In contrast to the delocalized nature of singlet excitons, we use time-resolved EPR and ENDOR spectroscopies to show that the triplet states of the Zn-porphyrin dimers remain localized on one of the two macrocyclic sub-units. We use the analysis of EPR and ENDOR measurements on unmetallated model porphyrin monomers and dimers to support this conclusion. The results of DFT calculations also support the interpretation of localized triplet states. These results demonstrate researchers cannot conclude triplet excitons delocalize in macromolecular based on the presence of spatially extended singlet excitons, which can help in the design of chromophores for application in spin conversion and information processing technologies.
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Affiliation(s)
- Hasini Medagedara
- Department of Chemistry, Wayne State University Detroit MI 48202 USA
| | - Mandefro Y Teferi
- Chemical Sciences and Engineering Division, Argonne National Laboratory Lemont IL 60439 USA
| | | | - Wade Burson
- Department of Chemistry, Wayne State University Detroit MI 48202 USA
| | - Shahad Kizi
- Department of Chemistry, Wayne State University Detroit MI 48202 USA
| | - Bradly Zaslona
- Department of Chemistry, Wayne State University Detroit MI 48202 USA
| | - Kristy L Mardis
- Department of Chemistry, Physics, and Engineering Sciences, Chicago State University Chicago IL 60628 USA
| | - Jens Niklas
- Chemical Sciences and Engineering Division, Argonne National Laboratory Lemont IL 60439 USA
| | - Oleg G Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory Lemont IL 60439 USA
| | - Aaron S Rury
- Department of Chemistry, Wayne State University Detroit MI 48202 USA
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5
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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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6
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Wu Y, Lu L, Yu B, Zhang S, Luo P, Chen M, He J, Li Y, Zhang C, Zhu J, Yao J, Fu H. Dynamic Evolving Exothermicity Steers Ultrafast Formation of a Correlated Triplet Pair State. J Phys Chem Lett 2023; 14:4233-4240. [PMID: 37126526 DOI: 10.1021/acs.jpclett.3c00193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Singlet fission (SF) presents an attractive solution to overcome the Shockley-Queisser limit of single-junction solar cells. The conversion from an initial singlet state to final triplet is mediated by the correlated triplet pair state 1(T1T1). Despite significant advancement on 1(T1T1) properties and its role in SF, a comprehensive understanding of the energetic landscape during SF is still unclear. Here, we study an unconventional SF system with excited-state aromaticity, i.e., cyano-substituted dipyrrolonaphtheridinedione derivative (DPND-CN), using time-resolved spectroscopy as a function of the temperature. We demonstrate that the population transfer from S1 to 1(T1T1) is driven by a time-dependent exothermicity resulting from the coherent coupling between electronic and spin degrees of freedom. This is followed by thermal-activated dissociation of 1(T1T1) to yield free triplets. Our results provide some new insight into the SF mechanism, which may guide the development of new efficient and stable SF materials for practical applications.
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Affiliation(s)
- Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Lina Lu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Buyang Yu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - San Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Pengdong Luo
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Mingxing Chen
- Analytical Instrumentation Center, Peking University, Beijing 100871, People's Republic of China
| | - Jingping He
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Yongyao Li
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
| | - Jiannian Yao
- Beijing National Laboratory for Molecules Science (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
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7
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Wakikawa Y, Ikoma T. Radio-wave Effect on Singlet Fission in Polycrystalline Tetracene near Zero Magnetic Field. J Phys Chem Lett 2023; 14:3907-3911. [PMID: 37073997 DOI: 10.1021/acs.jpclett.3c00341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A triplet-triplet pair is a key intermediate in singlet fission (SF), which has the potential to overcome the theoretical limit of solar cell efficiency. Here, we report a new spectroscopy to directly detect a short-lived triplet-triplet pair via the effects of radio-wave (RF) irradiation near zero magnetic field at room temperature. The fluorescence of polycrystalline powder of tetracene is reduced by RF irradiation at zero field, which is caused by a quasi-static RF field effect on spin mixing and electron-spin resonance among zero-field-splitting sublevels of the triplet-triplet pair. The curve for the quasi-static RF field effect can be reproduced numerically from that for the observed magnetophotoluminescence (MPL) effect. The simultaneous simulation of the RF and MPL effects using the density matrix formalism estimates rate constants of 1.2 × 108 and 6.0 × 108 s-1 for the fusion and dissociation, respectively, of the triplet-triplet pair.
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Affiliation(s)
- Yusuke Wakikawa
- Shizuoka Institute of Science and Technology, 2200-2 Toyosawa, Fukuroi, Shizuoka 437-8555, Japan
| | - Tadaaki Ikoma
- Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
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8
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Gotfredsen H, Thiel D, Greißel PM, Chen L, Krug M, Papadopoulos I, Ferguson MJ, Nielsen MB, Torres T, Clark T, Guldi DM, Tykwinski RR. Sensitized Singlet Fission in Rigidly Linked Axial and Peripheral Pentacene-Subphthalocyanine Conjugates. J Am Chem Soc 2023; 145:9548-9563. [PMID: 37083447 DOI: 10.1021/jacs.2c13353] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
The goal of harnessing the theoretical potential of singlet fission (SF), a process in which one singlet excited state is split into two triplet excited states, has become a central challenge in solar energy research. Covalently linked dimers provide crucial models for understanding the role of chromophore arrangement and coupling in SF. Sensitizers can be integrated into these systems to expand the absorption bandwidth through which SF can be accessed. Here, we define the role of the sensitizer-chromophore geometry in a sensitized SF model system. To this end, two conjugates have been synthesized consisting of a pentacene dimer (SF motif) connected via a rigid alkynyl bridge to a subphthalocyanine (the sensitizer motif) in either an axial or a peripheral arrangement. Steady-state and time-resolved photophysical measurements are used to confirm that both conjugates operate as per design, displaying near unity energy transfer efficiencies and high triplet quantum yields from SF. Decisively, energy transfer between the subphthalocyanine and pentacene dimer occurs ca. 26 times faster in the peripheral conjugate, even though the two chromophores are ca. 3 Å farther apart than in the axial conjugate. Following a theoretical evaluation of the dipolar coupling, Vdip2, and the orientation factor, κ2, of both the axial (Vdip2 = 140 cm-2; κ2 = 0.08) and the peripheral (Vdip2 = 724 cm-2; κ2 = 1.46) arrangements, we establish that this rate acceleration is due to a more favorable (nearly co-planar) relative orientation of the transition dipole moments of the subphthalocyanine and pentacenes in the peripheral constellation.
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Affiliation(s)
- Henrik Gotfredsen
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford OX1 3TA, U.K
| | - Dominik Thiel
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Phillip M Greißel
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Lan Chen
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Marcel Krug
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy and 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 Moto-oka, Nishi-ku, Fukuoka819-0395, Japan
| | - Michael J Ferguson
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Mogens Brøndsted Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
| | - Tomás Torres
- Department of Organic Chemistry and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid 28049, Spain
- IMDEA Nanociencia, C/Faraday 9, Cantoblanco, Madrid 28049, Spain
| | - Timothy Clark
- Department of Chemistry and Pharmacy and Computer-Chemie-Center (CCC), Friedrich-Alexander-University Erlangen-Nuremberg, Nägelsbachstraße 25, Erlangen 91052, Germany
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy and 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
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9
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Andrusenko I, Hall CL, Mugnaioli E, Potticary J, Hall SR, Schmidt W, Gao S, Zhao K, Marom N, Gemmi M. True molecular conformation and structure determination by three-dimensional electron diffraction of PAH by-products potentially useful for electronic applications. IUCRJ 2023; 10:131-142. [PMID: 36598508 PMCID: PMC9812223 DOI: 10.1107/s205225252201154x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
The true molecular conformation and the crystal structure of benzo[e]dinaphtho[2,3-a;1',2',3',4'-ghi]fluoranthene, 7,14-diphenylnaphtho[1,2,3,4-cde]bisanthene and 7,16-diphenylnaphtho[1,2,3,4-cde]helianthrene were determined ab initio by 3D electron diffraction. All three molecules are remarkable polycyclic aromatic hydrocarbons. The molecular conformation of two of these compounds could not be determined via classical spectroscopic methods due to the large size of the molecule and the occurrence of multiple and reciprocally connected aromatic rings. The molecular structure of the third molecule was previously considered provisional. These compounds were isolated as by-products in the synthesis of similar products and were at the same time nanocrystalline and available only in very limited amounts. 3D electron diffraction data, taken from submicrometric single crystals, allowed for direct ab initio structure solution and the unbiased determination of the internal molecular conformation. Detailed synthetic routes and spectroscopic analyses are also discussed. Based on many-body perturbation theory simulations, benzo[e]dinaphtho[2,3-a;1',2',3',4'-ghi]fluoranthene may be a promising candidate for triplet-triplet annihilation and 7,14-diphenylnaphtho[1,2,3,4-cde]bisanthene may be a promising candidate for intermolecular singlet fission in the solid state.
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Affiliation(s)
- Iryna Andrusenko
- Center for Material Interfaces, Electron Crystallography, Instituto Italiano di Tecnologia, Pontedera 56025, Italy
| | - Charlie L. Hall
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Enrico Mugnaioli
- Center for Material Interfaces, Electron Crystallography, Instituto Italiano di Tecnologia, Pontedera 56025, Italy
- Department of Earth Sciences, University of Pisa, Pisa 56126, Italy
| | - Jason Potticary
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Simon R. Hall
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | | | - Siyu Gao
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Kaiji Zhao
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Noa Marom
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Mauro Gemmi
- Center for Material Interfaces, Electron Crystallography, Instituto Italiano di Tecnologia, Pontedera 56025, Italy
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10
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Kulishov AA, Yurasik GA, Grebenev VV, Postnikov VA. Tetracene Crystals: Growth from Solutions, Solubility, and Thermal Properties. CRYSTALLOGR REP+ 2022. [DOI: 10.1134/s1063774522060153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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11
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Nagaoka T, Matsui Y, Fuki M, Ogaki T, Ohta E, Kobori Y, Ikeda H. Diphenyldihydropentalenediones: Wide Singlet-Triplet Energy Gap Compounds Possessing the Planarly Fixed Diene Subunit. ACS OMEGA 2022; 7:40364-40373. [PMID: 36385848 PMCID: PMC9648098 DOI: 10.1021/acsomega.2c05341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
2,2,5,5-Tetramethyl-3,6-diphenyl-2,5-dihydropentalene-1,4-dione (PD-H) and its dimethoxy (PD-OCH3) and bis(trifluoromethyl) derivatives (PD-CF3) were developed as a new class of compounds possessing a wide excited singlet-triplet energy gap. The PD derivatives would also have a high energy level of the triplet-excited state (E T) due to the planarity of the fused-diene subunit. The results of photophysical studies revealed that the energy level of the singlet-excited state (E S) and E T of PD-H are 2.88 and 1.43 eV, respectively. These values indicate that PD-H has the energy relationship, E S > 2E T, required for it to be a singlet fission (SF) material. Moreover, the introduction of electron-donating or -withdrawing groups on the benzene rings in PD-H enables fine-tuning of E S and E T. The results of transient absorption spectroscopic studies show that PD-H, PD-OCH3, and PD-CF3 in CH2Cl2 have respective T1 lifetimes of 71, 118, and 107 μs, which are long enough to utilize its triplet exciton in other optoelectronic systems. These findings suggest that the PDs are potential candidates for SF materials with high E T levels.
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Affiliation(s)
- Tomoki Nagaoka
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka599-8531, Japan
| | - Yasunori Matsui
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka599-8531, Japan
- The
Research Institute for Molecular Electronic Devices (RIMED), Osaka Metropolitan University, 1-1 Gakuen-cho,
Nakaku, Sakai, Osaka599-8531, Japan
| | - Masaaki Fuki
- Molecular
Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo657-8501, Japan
| | - Takuya Ogaki
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka599-8531, Japan
- The
Research Institute for Molecular Electronic Devices (RIMED), Osaka Metropolitan University, 1-1 Gakuen-cho,
Nakaku, Sakai, Osaka599-8531, Japan
| | - Eisuke Ohta
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka599-8531, Japan
| | - Yasuhiro Kobori
- Molecular
Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo657-8501, Japan
- Graduate
School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo657-8501, Japan
| | - Hiroshi Ikeda
- Department
of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka599-8531, Japan
- The
Research Institute for Molecular Electronic Devices (RIMED), Osaka Metropolitan University, 1-1 Gakuen-cho,
Nakaku, Sakai, Osaka599-8531, Japan
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12
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Symmetry Breaking Charge Transfer in DNA-Templated Perylene Dimer Aggregates. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27196612. [PMID: 36235149 PMCID: PMC9571668 DOI: 10.3390/molecules27196612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 09/20/2022] [Accepted: 09/28/2022] [Indexed: 11/19/2022]
Abstract
Molecular aggregates are of interest to a broad range of fields including light harvesting, organic optoelectronics, and nanoscale computing. In molecular aggregates, nonradiative decay pathways may emerge that were not present in the constituent molecules. Such nonradiative decay pathways may include singlet fission, excimer relaxation, and symmetry-breaking charge transfer. Singlet fission, sometimes referred to as excitation multiplication, is of great interest to the fields of energy conversion and quantum information. For example, endothermic singlet fission, which avoids energy loss, has been observed in covalently bound, linear perylene trimers and tetramers. In this work, the electronic structure and excited-state dynamics of dimers of a perylene derivative templated using DNA were investigated. Specifically, DNA Holliday junctions were used to template the aggregation of two perylene molecules covalently linked to a modified uracil nucleobase through an ethynyl group. The perylenes were templated in the form of monomer, transverse dimer, and adjacent dimer configurations. The electronic structure of the perylene monomers and dimers were characterized via steady-state absorption and fluorescence spectroscopy. Initial insights into their excited-state dynamics were gleaned from relative fluorescence intensity measurements, which indicated that a new nonradiative decay pathway emerges in the dimers. Femtosecond visible transient absorption spectroscopy was subsequently used to elucidate the excited-state dynamics. A new excited-state absorption feature grows in on the tens of picosecond timescale in the dimers, which is attributed to the formation of perylene anions and cations resulting from symmetry-breaking charge transfer. Given the close proximity required for symmetry-breaking charge transfer, the results shed promising light on the prospect of singlet fission in DNA-templated molecular aggregates.
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13
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Berghuis AM, Tichauer RH, de Jong LMA, Sokolovskii I, Bai P, Ramezani M, Murai S, Groenhof G, Gómez Rivas J. Controlling Exciton Propagation in Organic Crystals through Strong Coupling to Plasmonic Nanoparticle Arrays. ACS PHOTONICS 2022; 9:2263-2272. [PMID: 35880071 PMCID: PMC9306002 DOI: 10.1021/acsphotonics.2c00007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Exciton transport in most organic materials is based on an incoherent hopping process between neighboring molecules. This process is very slow, setting a limit to the performance of organic optoelectronic devices. In this Article, we overcome the incoherent exciton transport by strongly coupling localized singlet excitations in a tetracene crystal to confined light modes in an array of plasmonic nanoparticles. We image the transport of the resulting exciton-polaritons in Fourier space at various distances from the excitation to directly probe their propagation length as a function of the exciton to photon fraction. Exciton-polaritons with an exciton fraction of 50% show a propagation length of 4.4 μm, which is an increase by 2 orders of magnitude compared to the singlet exciton diffusion length. This remarkable increase has been qualitatively confirmed with both finite-difference time-domain simulations and atomistic multiscale molecular dynamics simulations. Furthermore, we observe that the propagation length is modified when the dipole moment of the exciton transition is either parallel or perpendicular to the cavity field, which opens a new avenue for controlling the anisotropy of the exciton flow in organic crystals. The enhanced exciton-polariton transport reported here may contribute to the development of organic devices with lower recombination losses and improved performance.
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Affiliation(s)
- Anton Matthijs Berghuis
- Department
of Applied Physics and Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ruth H. Tichauer
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Lianne M. A. de Jong
- Department
of Applied Physics and Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Ilia Sokolovskii
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Ping Bai
- Department
of Applied Physics and Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Mohammad Ramezani
- Department
of Applied Physics and Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Shunsuke Murai
- Department
of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo, 6158510, Kyoto, Japan
| | - Gerrit Groenhof
- Nanoscience
Center and Department of Chemistry, University
of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Jaime Gómez Rivas
- Department
of Applied Physics and Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Institute
for Complex Molecular Systems ICMS, Eindhoven
University of Technology, P.O. Box 513, 5612 AJ, Eindhoven, The Netherlands
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14
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Pensack RD, Purdum GE, Mazza SM, Grieco C, Asbury JB, Anthony JE, Loo YL, Scholes GD. Excited-State Dynamics of 5,14- vs 6,13-Bis(trialkylsilylethynyl)-Substituted Pentacenes: Implications for Singlet Fission. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:9784-9793. [PMID: 35756579 PMCID: PMC9210346 DOI: 10.1021/acs.jpcc.2c00897] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 05/20/2022] [Indexed: 05/16/2023]
Abstract
Singlet fission is a process in conjugated organic materials that has the potential to considerably improve the performance of devices in many applications, including solar energy conversion. In any application involving singlet fission, efficient triplet harvesting is essential. At present, not much is known about molecular packing arrangements detrimental to singlet fission. In this work, we report a molecular packing arrangement in crystalline films of 5,14-bis(triisopropylsilylethynyl)-substituted pentacene, specifically a local (pairwise) packing arrangement, responsible for complete quenching of triplet pairs generated via singlet fission. We first demonstrate that the energetic condition necessary for singlet fission is satisfied in amorphous films of the 5,14-substituted pentacene derivative. However, while triplet pairs form highly efficiently in the amorphous films, only a modest yield of independent triplets is observed. In crystalline films, triplet pairs also form highly efficiently, although independent triplets are not observed because triplet pairs decay rapidly and are quenched completely. We assign the quenching to a rapid nonadiabatic transition directly to the ground state. Detrimental quenching is observed in crystalline films of two additional 5,14-bis(trialkylsilylethynyl)-substituted pentacenes with either ethyl or isobutyl substituents. Developing a better understanding of the losses identified in this work, and associated molecular packing, may benefit overcoming losses in solids of other singlet fission materials.
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Affiliation(s)
- Ryan D. Pensack
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Geoffrey E. Purdum
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Samuel M. Mazza
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Christopher Grieco
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - John B. Asbury
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - John E. Anthony
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Yueh-Lin Loo
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger
Center for Energy and the Environment, Princeton
University, Princeton, New Jersey 08544, United States
| | - Gregory D. Scholes
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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15
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16
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Dimitriev OP. Dynamics of Excitons in Conjugated Molecules and Organic Semiconductor Systems. Chem Rev 2022; 122:8487-8593. [PMID: 35298145 DOI: 10.1021/acs.chemrev.1c00648] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The exciton, an excited electron-hole pair bound by Coulomb attraction, plays a key role in photophysics of organic molecules and drives practically important phenomena such as photoinduced mechanical motions of a molecule, photochemical conversions, energy transfer, generation of free charge carriers, etc. Its behavior in extended π-conjugated molecules and disordered organic films is very different and very rich compared with exciton behavior in inorganic semiconductor crystals. Due to the high degree of variability of organic systems themselves, the exciton not only exerts changes on molecules that carry it but undergoes its own changes during all phases of its lifetime, that is, birth, conversion and transport, and decay. The goal of this review is to give a systematic and comprehensive view on exciton behavior in π-conjugated molecules and molecular assemblies at all phases of exciton evolution with emphasis on rates typical for this dynamic picture and various consequences of the above dynamics. To uncover the rich variety of exciton behavior, details of exciton formation, exciton transport, exciton energy conversion, direct and reverse intersystem crossing, and radiative and nonradiative decay are considered in different systems, where these processes lead to or are influenced by static and dynamic disorder, charge distribution symmetry breaking, photoinduced reactions, electron and proton transfer, structural rearrangements, exciton coupling with vibrations and intermediate particles, and exciton dissociation and annihilation as well.
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Affiliation(s)
- Oleg P Dimitriev
- V. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine, pr. Nauki 41, Kyiv 03028, Ukraine
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17
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Jacobberger RM, Qiu Y, Williams ML, Krzyaniak MD, Wasielewski MR. Using Molecular Design to Enhance the Coherence Time of Quintet Multiexcitons Generated by Singlet Fission in Single Crystals. J Am Chem Soc 2022; 144:2276-2283. [PMID: 35099963 DOI: 10.1021/jacs.1c12414] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Multiexciton quintet states, 5(TT), photogenerated in organic semiconductors using singlet fission (SF), consist of four quantum entangled spins, promising to enable new applications in quantum information science. However, the factors that determine the spin coherence of these states remain underexplored. Here, we engineer the packing of tetracene molecules within single crystals of 5,12-bis(tricyclohexylsilylethynyl)tetracene (TCHS-tetracene) to demonstrate a 5(TT) state that exhibits promising spin qubit properties, including a coherence time, T2, = 3 μs at 10 K, a population lifetime, Tpop, = 130 μs at 5 K, and stability even at room temperature. The single-crystal platform also enables global alignment of the spins and, consequently, individual addressability of the spin-sublevel transitions. Decoherence mechanisms, including exciton diffusion, electronic dipolar coupling, and nuclear hyperfine interactions, are elucidated, providing design principles for increasing T2 and the operational temperature of 5(TT). By dynamically decoupling 5(TT) from the surrounding spin bath, T2 = 10 μs is achieved. These results demonstrate the viability of harnessing singlet fission to initiate multiple electron spins in a well-defined quantum state for next-generation molecular-based quantum technologies.
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Affiliation(s)
- Robert M Jacobberger
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Yunfan Qiu
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Malik L Williams
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Matthew D Krzyaniak
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
| | - Michael R Wasielewski
- Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3313, United States
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18
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Valianti S, Skourtis SS. The Role of Bridge-State Intermediates in Singlet Fission for Donor-Bridge-Acceptor Systems: A Semianalytical Approach to Bridge-Tuning of the Donor-Acceptor Fission Coupling. J Phys Chem Lett 2022; 13:939-946. [PMID: 35050642 PMCID: PMC9836358 DOI: 10.1021/acs.jpclett.1c03700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We describe a semianalytical/computational framework to explore structure-function relationships for singlet fission in Donor (D)-Bridge (B)-Acceptor (A) molecular architectures. The aim of introducing a bridging linker between the D and A molecules is to tune, by modifying the bridge structure, the electronic pathways that lead to fission and to D-A-separated correlated triplets. We identify different bridge-mediation regimes for the effective singlet-fission coupling in the coherent tunneling limit and show how to derive the dominant fission pathways in each regime. We describe the dependence of these regimes on D-B-A many-electron state energetics and on D-B (A-B) one-electron and two-electron matrix elements. This semianalytical approach can be used to guide computational and experimental searches for D-B-A systems with tuned singlet fission rates. We use this approach to interpret the bridge-resonance effect of singlet fission that has been observed in recent experiments.
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19
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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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20
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Bischof D, Tripp MW, Hofmann PE, Ip CH, Ivlev SI, Gerhard M, Koert U, Witte G. Regioselective Fluorination of Acenes: Tailoring of Molecular Electronic Levels and Solid State Properties. Chemistry 2021; 28:e202103653. [PMID: 34874080 PMCID: PMC9305256 DOI: 10.1002/chem.202103653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Indexed: 12/13/2022]
Abstract
Optoelectronic properties of molecular solids are important for organic electronic devices and are largely determined by the adopted molecular packing motifs. In this study, we analyzed such structure‐property relationships for the partially regioselective fluorinated tetracenes 1,2,12‐trifluorotetracene, 1,2,10,12‐tetrafluorotetracene and 1,2,9,10,11‐pentafluorotetracene that were further compared with tetracene and perfluoro‐tetracene. Quantum chemical DFT calculations in combination with optical absorption spectroscopy data show that the frontier orbital energies are lowered with the degree of fluorination, while their optical gap is barely affected. However, the crystal structure changes from a herringbone packing motif of tetracene towards a planar stacking motif of the fluorinated tetracene derivatives, which is accompanied by the formation of excimers and leads to strongly red‐shifted photoluminescence with larger lifetimes.
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Affiliation(s)
- Daniel Bischof
- Philipps-Universitat Marburg, Fachbereich Physik, Renthof 5, 35032, Marburg, GERMANY
| | - Matthias W Tripp
- Philipps-Universitat Marburg, Fachbereich Chemie, Hans-Meerwein-Straße 4, 35043, Marburg, GERMANY
| | - Philipp E Hofmann
- Philipps-Universitat Marburg, Fachbereich Chemie, Hans-Meerwein-Straße 4, 35043, Marburg, GERMANY
| | - Chun-Ho Ip
- Philipps-Universitat Marburg, Fachbereich Chemie, Hans-Meerwein-Straße 4, 35043, Marburg, GERMANY
| | - Sergei I Ivlev
- Philipps-Universitat Marburg, Fachbereich Chemie, Hans-Meerwein-Straße 4, 35043, Marburg, GERMANY
| | - Marina Gerhard
- Philipps-Universitat Marburg, Fachbereich Physik, Renthof 7, 35032, Marburg, GERMANY
| | - Ulrich Koert
- Philipps-Universitat Marburg, Fachbereich Chemie, Hans-Meerwein-Straße 4, 35043, Marburg, GERMANY
| | - Gregor Witte
- Philipps-Universitat Marburg Fachbereich 13 Physik, Physik, Renthof 7, 35032, Marburg, GERMANY
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21
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Vacancy control in acene blends links exothermic singlet fission to coherence. Nat Commun 2021; 12:5149. [PMID: 34446726 PMCID: PMC8390483 DOI: 10.1038/s41467-021-25395-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 07/20/2021] [Indexed: 11/09/2022] Open
Abstract
The fission of singlet excitons into triplet pairs in organic materials holds great technological promise, but the rational application of this phenomenon is hampered by a lack of understanding of its complex photophysics. Here, we use the controlled introduction of vacancies by means of spacer molecules in tetracene and pentacene thin films as a tuning parameter complementing experimental observables to identify the operating principles of different singlet fission pathways. Time-resolved spectroscopic measurements in combination with microscopic modelling enables us to demonstrate distinct scenarios, resulting from different singlet-to-triplet pair energy alignments. For pentacene, where fission is exothermic, coherent mixing between the photoexcited singlet and triplet-pair states is promoted by vibronic resonances, which drives the fission process with little sensitivity to the vacancy concentration. Such vibronic resonances do not occur for endothermic materials such as tetracene, for which we find fission to be fully incoherent; a process that is shown to slow down with increasing vacancy concentration.
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22
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Hall CL, Andrusenko I, Potticary J, Gao S, Liu X, Schmidt W, Marom N, Mugnaioli E, Gemmi M, Hall SR. 3D Electron Diffraction Structure Determination of Terrylene, a Promising Candidate for Intermolecular Singlet Fission. Chemphyschem 2021; 22:1631-1637. [PMID: 34117821 PMCID: PMC8457070 DOI: 10.1002/cphc.202100320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/05/2021] [Indexed: 12/13/2022]
Abstract
Herein we demonstrate the prowess of the 3D electron diffraction approach by unveiling the structure of terrylene, the third member in the series of peri‐condensed naphthalene analogues, which has eluded structure determination for 65 years. The structure was determined by direct methods using electron diffraction data and corroborated by dispersion‐inclusive density functional theory optimizations. Terrylene crystalizes in the monoclinic space group P21/a, arranging in a sandwich‐herringbone packing motif, similar to analogous compounds. Having solved the crystal structure, we use many‐body perturbation theory to evaluate the excited‐state properties of terrylene in the solid‐state. We find that terrylene is a promising candidate for intermolecular singlet fission, comparable to tetracene and rubrene.
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Affiliation(s)
- Charlie L Hall
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | - Iryna Andrusenko
- Istituto Italiano di Tecnologia, Center for Nanotechnology Innovation@NEST, Pisa, 56127, Italy
| | - Jason Potticary
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | - Siyu Gao
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Xingyu Liu
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | | | - Noa Marom
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Enrico Mugnaioli
- Istituto Italiano di Tecnologia, Center for Nanotechnology Innovation@NEST, Pisa, 56127, Italy
| | - Mauro Gemmi
- Istituto Italiano di Tecnologia, Center for Nanotechnology Innovation@NEST, Pisa, 56127, Italy
| | - Simon R Hall
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
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23
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Tan Y, Tao G. Exploring the State Space Structure of Multiple Spins via Modular Tensor Diagram Approach: Going beyond the Exciton Pair State. J Phys Chem A 2021; 125:1972-1980. [PMID: 33648334 DOI: 10.1021/acs.jpca.0c07832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fully understanding of multistate quantum systems could become formidable if not impossible as the system dimensionality increases. One ideal strategy to comprehend complex systems is to transform the system representation into a more structural one so that major characteristics, connections, and even underlying mechanisms can stand out from the huge unstructured information, e.g., the construction of spin eigenfunctions for a system of multiple spins through the diagonalization of the system Hamiltonian matrix. Here, instead of direct matrix diagonalization, the recently developed modular tensor diagram approach is applied to reorganize the state space structure of multispin systems, extending previous investigations on exciton pair states to exciton trimer states. This implementation demonstrates that the proposed approach not only provides a systematical way to transform the high dimensional multistate system into a well organized structure based on basic (exciton) modules but also paves the way to further analysis on potential applications. For example, the analysis on the state space of the exciton trimer system suggests a possible scheme to improve the laser performance via single fission involving multiexcitations and/or multiple fission steps.
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Affiliation(s)
- Yunshu Tan
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen 518055, China.,Shenzhen Key Laboratory of New Energy Materials by Design, Peking University, Shenzhen 518055, China
| | - Guohua Tao
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen 518055, China
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Aster A, Zinna F, Rumble C, Lacour J, Vauthey E. Singlet Fission in a Flexible Bichromophore with Structural and Dynamic Control. J Am Chem Soc 2021; 143:2361-2371. [PMID: 33512153 DOI: 10.1021/jacs.0c12384] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Singlet fission (SF), i.e., the splitting of a high-energy exciton into two lower-energy triplet excitons, has the potential to increase the efficiency for harvesting spectrally broad light. The path from the photopopulated singlet state to free triplets is complicated by competing processes that decrease the overall SF efficiency. A detailed understanding of the whole cascade and the nature of the photoexcited singlet state is still a major challenge. Here, we introduce a pentacene dimer with a flexible crown ether spacer enabling a control of the interchromophore coupling upon solvent-induced self-aggregation as well as cation binding. The systematic change of solvent polarity and viscosity and excitation wavelength, as well as the available conformational phase space, allows us to draw a coherent picture of the whole SF cascade from the femtosecond to microsecond time scales. High coupling leads to ultrafast SF (<2 ps), independent of the solvent polarity, and to highly coupled correlated triplet pairs. The absence of a polarity effect indicates that the solvent coordinate does not play a significant role and that SF is driven by intramolecular modes. Low coupling results in much slower SF (∼500 ps), which depends on viscosity, and leads to weakly coupled correlated triplet pairs. These two triplet pairs could be spectrally distinguished and their contribution to the overall SF efficiency, i.e., to the population of free triplets, could be determined. Our results reveal how the overall SF efficiency can be increased by conformational restrictions and control of the structural fluctuation dynamics.
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Affiliation(s)
- Alexander Aster
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Francesco Zinna
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Christopher Rumble
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
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25
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Aster A, Bornhof AB, Sakai N, Matile S, Vauthey E. Lifetime Broadening and Impulsive Generation of Vibrational Coherence Triggered by Ultrafast Electron Transfer. J Phys Chem Lett 2021; 12:1052-1057. [PMID: 33470820 DOI: 10.1021/acs.jpclett.0c03641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The absorption band shape of chromophores in liquid solution at room temperature is usually dominated by pure electronic dephasing dynamics, which occurs on the sub-100 fs time scale. Herein, we report on a series of dyads consisting of a naphthalenediimide (NDI) electron acceptor with one or two phenyl-based donors for which photoinduced intramolecular electron transfer is fast enough to be competitive with pure electronic dephasing. As a consequence, the absorption band of the π-π* transition of these dyads is broader than that of the NDI alone to an extent that scales with the electron transfer rate. Additionally, this reaction is so fast that it leads to the impulsive excitation of a low-frequency vibrational mode of the charge-separated product. Quantum-chemical calculations suggest that this vibration involves the C-N donor-acceptor bond, which shortens considerably upon electron transfer.
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Affiliation(s)
- Alexander Aster
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Anna-Bea Bornhof
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
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26
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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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27
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Rather SR, Fu B, Kudisch B, Scholes GD. Interplay of vibrational wavepackets during an ultrafast electron transfer reaction. Nat Chem 2021; 13:70-76. [PMID: 33288893 DOI: 10.1038/s41557-020-00607-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/10/2020] [Indexed: 01/05/2023]
Abstract
Electron transfer reactions facilitate energy transduction and photoredox processes in biology and chemistry. Recent findings show that molecular vibrations can enable the dramatic acceleration of some electron transfer reactions, and control it by suppressing and enhancing reaction paths. Here, we report ultrafast spectroscopy experiments and quantum dynamics simulations that resolve how quantum vibrations participate in an electron transfer reaction. We observe ballistic electron transfer (~30 fs) along a reaction coordinate comprising high-frequency promoting vibrations. Along another vibrational coordinate, the system becomes impulsively out of equilibrium as a result of the electron transfer reaction. This leads to the generation (by the electron transfer reaction, not the laser pulse) of a new vibrational coherence along this second reaction coordinate in a mode associated with the reaction product. These results resolve a complex reaction trajectory composed of multiple vibrational coordinates that, like a sequence of ratchets, progressively diminish the recurrence of the reactant state.
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Affiliation(s)
| | - Bo Fu
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Bryan Kudisch
- Department of Chemistry, Princeton University, Princeton, NJ, USA
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28
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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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29
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Wang G, Zhang C, Liu Z, Wang R, Ma H, Wang X, Xiao M. Singlet Fission Dynamics in Tetracene Single Crystals Probed by Polarization-Dependent Two-Dimensional Electronic Spectroscopy. J Phys Chem A 2020; 124:10447-10456. [PMID: 33290074 DOI: 10.1021/acs.jpca.0c08440] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The exact mechanism of endothermic singlet fission in crystalline polyacene remains to be clarified. It has been elusive whether the excess energy of vibrational hot states and the upper branch of Davydov splitting is important for the energy compensation. Here, we probe the excited-state specified singlet fission dynamics in tetracene single crystals by polarization-dependent two-dimensional electronic spectroscopy (2DES). While a major spectral transfer with a characteristic lifetime of 86 ps is observed to be largely independent of the excitation energy due to formation of the spatially separated triplet pairs (1(T···T)), the excitation-energy dependent subpicosecond dynamics show marked differences for different states probed, implying the possible involvement of a coherently formed triplet pair state (1(TT)). Analysis of coherent vibrational modes suggests the coupling to high energy modes may offset the energy difference between singlet and triplet pair states. Moreover, the beating map of the low frequency mode indicates a vibrational hot state violating the aggregation behavior of Davydov exciton, which can be explained as a resonance of the 1(TT) state. These results suggest that the coherent vibronic mixing between local excitation and triplet pair states is essential for the singlet fission dynamics in molecule aggregates.
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Affiliation(s)
- Guodong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Zhixing Liu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Haibo Ma
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China.,Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States
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30
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Bossanyi DG, Matthiesen M, Wang S, Smith JA, Kilbride RC, Shipp JD, Chekulaev D, Holland E, Anthony JE, Zaumseil J, Musser AJ, Clark J. Emissive spin-0 triplet-pairs are a direct product of triplet-triplet annihilation in pentacene single crystals and anthradithiophene films. Nat Chem 2020; 13:163-171. [PMID: 33288892 DOI: 10.1038/s41557-020-00593-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/27/2020] [Indexed: 02/01/2023]
Abstract
Singlet fission and triplet-triplet annihilation represent two highly promising ways of increasing the efficiency of photovoltaic devices. Both processes are believed to be mediated by a biexcitonic triplet-pair state, 1(TT). Recently however, there has been debate over the role of 1(TT) in triplet-triplet annihilation. Here we use intensity-dependent, low-temperature photoluminescence measurements, combined with kinetic modelling, to show that distinct 1(TT) emission arises directly from triplet-triplet annihilation in high-quality pentacene single crystals and anthradithiophene (diF-TES-ADT) thin films. This work demonstrates that a real, emissive triplet-pair state acts as an intermediate in both singlet fission and triplet-triplet annihilation and that this is true for both endo- and exothermic singlet fission materials.
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Affiliation(s)
- David G Bossanyi
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK.
| | - Maik Matthiesen
- Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Shuangqing Wang
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK
| | - Joel A Smith
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK
| | - Rachel C Kilbride
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK
| | - James D Shipp
- Department of Chemistry, The University of Sheffield, Sheffield, UK
| | | | - Emma Holland
- Department of Chemistry, University of Kentucky, Lexington, KY, USA
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Lexington, KY, USA
| | - Jana Zaumseil
- Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Andrew J Musser
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Jenny Clark
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK.
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31
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Walwark DJ, Grey JK. Steady-State Fluorescence Signatures of Intramolecular Singlet Fission from Stochastic Predictions. J Phys Chem A 2020; 124:8918-8930. [PMID: 33052044 DOI: 10.1021/acs.jpca.0c06966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The advent of new multichromophoric systems capable of undergoing efficient intramolecular singlet fission (iSF) has greatly expanded the range of possible motifs for multiexciton generation approaches for organic light energy harvesting materials. Transient absorption (TA) spectroscopic probes are typically used to characterize singlet fission processes that may place limitations on sensitivity and time resolution on scales comparable to the full lifespan of spin-forbidden triplets and interactions. Here, we investigate the ability of fluorescence-based spectroscopic probes to detect iSF activity in isolated dyads based on large substituted conjugated acenes (e.g., tetracene and pentacene derivatives). Photophysical models are simulated from several iSF-active dyad systems reported in the literature using a stochastic approach to assess the sensitivity of steady-state fluorescence to the presence of triplet excitons. The results demonstrate large fluctuations in expected fluorescence yields with varying excitation rate constants for systems with ΦiSF > 0.5 (assuming weak interchromophore coupling). Exciton-exciton interactions are also investigated, and we further demonstrate how treating iSF dyads stochastically (i.e., finite number of chromophores) accentuates dependences of photophysical yields with excitation rates. Last, our approach reveals the potential ability of single molecule level fluorescence spectroscopy to detect iSF activity that can aid efforts to design and optimize candidate iSF systems.
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Affiliation(s)
- David J Walwark
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - John K Grey
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, United States
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32
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Van Schenck JDB, Mayonado G, Anthony JE, Graham MW, Ostroverkhova O. Molecular packing-dependent exciton dynamics in functionalized anthradithiophene derivatives: From solutions to crystals. J Chem Phys 2020; 153:164715. [PMID: 33138416 DOI: 10.1063/5.0026072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Understanding the impact of inter-molecular orientation on the optical properties of organic semiconductors is important for designing next-generation organic (opto)electronic and photonic devices. However, fundamental aspects of how various features of molecular packing in crystalline systems determine the nature and dynamics of excitons have been a subject of debate. Toward this end, we present a systematic study of how various molecular crystal packing motifs affect the optical properties of a class of high-performance organic semiconductors: functionalized derivatives of fluorinated anthradithiophene. The absorptive and emissive species present in three such derivatives (exhibiting "brickwork," "twisted-columnar," and "sandwich-herringbone" motifs, controlled by the side group R) were analyzed both in solution and in single crystals, using various modalities of optical and photoluminescence spectroscopy, revealing the nature of these excited states. In solution, in the emission band, two states were identified: a Franck-Condon state present at all concentrations and an excimer that emerged at higher concentrations. In single crystal systems, together with ab initio calculations, it was found in the absorptive band that Frenkel and Charge Transfer (CT) excitons mixed due to nonvanishing CT integrals in all derivatives, but the amount of admixture and exciton delocalization depended on the packing, with the "sandwich-herringbone" packing motif least conducive to delocalization. Three emissive species in the crystal phase were also identified: Frenkel excitons, entangled triplet pairs 1(TT) (which are precursors to forming free triplet states via singlet fission), and self-trapped excitons (STEs, similar in origin to excimers present in concentrated solution). The "twisted-columnar" packing motif was most conducive to the formation of Frenkel excitons delocalized over 4-7 molecules depending on the temperature. These delocalized Frenkel states were dominant across the full temperature range (78 K-293 K), though at lower temperatures, the entangled triplet states and STEs were present. In the derivative with the "brickwork" packing, all three emissive species were observed across the full temperature range and, most notably, the 1(TT) state was present at room temperature. Finally, the derivative with the "sandwich-herringbone" packing exhibited localized Frenkel excitons and had a strong propensity for self-trapped exciton formation even at higher temperatures. In this derivative, no formation of the 1(TT) state was observed. The temperature-dependent dynamics of these emissive states are reported, as well as their origin in fundamental inter-molecular interactions.
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Affiliation(s)
- J D B Van Schenck
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - G Mayonado
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - J E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - M W Graham
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - O Ostroverkhova
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
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33
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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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34
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The Effect of Magnetic Fields on Singlet Fission in Organic Semiconductors: its Understanding and Applications. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.202000091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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35
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Sardar S. Effects of site-specific substitution to hexacene and its effect towards singlet fission. J Mol Graph Model 2020; 98:107608. [DOI: 10.1016/j.jmgm.2020.107608] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/25/2020] [Accepted: 03/25/2020] [Indexed: 01/08/2023]
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36
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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: 51] [Impact Index Per Article: 12.8] [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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37
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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: 64] [Impact Index Per Article: 16.0] [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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38
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Sakun VP, Balashov EM, Shushin AI. Microwave effect on a pulse-excited prompt fluorescence of molecular crystals. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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39
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Tao G. Topology of quantum coherence networks in singlet fission: mapping exciton states into real space and the dislocation induced three dimensional manifolds. Phys Chem Chem Phys 2020; 22:1258-1267. [PMID: 31850461 DOI: 10.1039/c9cp05102c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An understanding of the global structure of quantum coherence networks in coupled multistate systems is of great importance for the development of emerging quantum technologies such as quantum control and quantum materials design. Here, we study the topology of a quantum coherence network of a typical singlet exciton fission system by mapping the exciton states into crystal structures in real space. The defects in crystals could lead to changes in the topological structures, and also fission dynamics. In particular, we demonstrate that the dislocation induced three dimensional manifold, which differs from its lower dimensional counterparts globally, could generate exotic global structures, such as chiral spirals, and modulate singlet fission substantially. The findings may shed light on the new possibilities of engineering effective structures for fission materials.
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Affiliation(s)
- Guohua Tao
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. and Shenzhen Key Laboratory of New Energy Materials by Design, Peking University, Shenzhen, 518055, China
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40
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Nieman R, Silva NJ, Aquino AJA, Haley MM, Lischka H. Interplay of Biradicaloid Character and Singlet/Triplet Energy Splitting for cis-/trans-Diindenoacenes and Related Benzothiophene-Capped Oligomers as Revealed by Extended Multireference Calculations. J Org Chem 2020; 85:3664-3675. [DOI: 10.1021/acs.joc.9b03308] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Reed Nieman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
| | - Nadeesha J. Silva
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
| | - Adelia J. A. Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
- School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Michael M. Haley
- Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, Oregon 97403, United States
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
- School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China
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41
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Imperiale CJ, Green PB, Miller EG, Damrauer NH, Wilson MWB. Triplet-Fusion Upconversion Using a Rigid Tetracene Homodimer. J Phys Chem Lett 2019; 10:7463-7469. [PMID: 31751145 DOI: 10.1021/acs.jpclett.9b03115] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We demonstrate that a structurally rigid, weakly coupled molecular dimer can replace traditional monomeric annihilators for triplet fusion upconversion (TUC) in solution by observing emitted photons (λ = 540 nm) from a norbornyl-bridged tetracene homodimer following excitation of a triplet sensitizer at λ = 730 nm. Intriguingly, steady-state spectroscopy, kinetic simulations, and Stern-Volmer quenching experiments show that the dimer exhibits qualitatively different photophysics than its parent monomer: it is less effective at diffusion-mediated triplet exciton transfer, but it fuses extracted triplets more efficiently. Our results support the development of composite triplet-fusion platforms that go beyond diffusion-mediated triplet extraction, ultimately circumventing the concentration dependence of solution-phase TUC.
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Affiliation(s)
| | - Philippe B Green
- Department of Chemistry , University of Toronto , Toronto , Ontario M5S3H6 , Canada
| | - Ethan G Miller
- Department of Chemistry and Biochemistry , University of Colorado, Boulder , Boulder , Colorado 80302 , United States
| | - Niels H Damrauer
- Department of Chemistry and Biochemistry , University of Colorado, Boulder , Boulder , Colorado 80302 , United States
| | - Mark W B Wilson
- Department of Chemistry , University of Toronto , Toronto , Ontario M5S3H6 , Canada
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42
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Polak D, Jayaprakash R, Lyons TP, Martínez-Martínez LÁ, Leventis A, Fallon KJ, Coulthard H, Bossanyi DG, Georgiou K, Petty Ii AJ, Anthony J, Bronstein H, Yuen-Zhou J, Tartakovskii AI, Clark J, Musser AJ. Manipulating molecules with strong coupling: harvesting triplet excitons in organic exciton microcavities. Chem Sci 2019; 11:343-354. [PMID: 32190258 PMCID: PMC7067247 DOI: 10.1039/c9sc04950a] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/05/2019] [Indexed: 01/18/2023] Open
Abstract
Exciton-polaritons are quasiparticles with mixed photon and exciton character with the potential to modify chemical properties of materials. Here, they are used to provide dark, high-spin triplet-pair states a new pathway to emit light.
Exciton-polaritons are quasiparticles with mixed photon and exciton character that demonstrate rich quantum phenomena, novel optoelectronic devices and the potential to modify chemical properties of materials. Organic materials are of current interest as active materials for their ability to sustain exciton-polaritons even at room temperature. However, within organic optoelectronic devices, it is often the ‘dark’ spin-1 triplet excitons that dominate operation. These triplets have been largely ignored in treatments of polaritons, which instead only consider the role of states that directly and strongly interact with light. Here we demonstrate that these ‘dark’ states can also play a major role in polariton dynamics, observing polariton population transferred directly from the triplet manifold via triplet–triplet annihilation. The process leads to polariton emission that is longer-lived (>μs) even than exciton emission in bare films. This enhancement is directly linked to spin-2 triplet-pair states, which are formed in films and microcavities by singlet fission or triplet–triplet annihilation. Such high-spin multiexciton states are generally non-emissive and cannot directly couple to light, yet the formation of polaritons creates for them entirely new radiative decay pathways. This is possible due to weak mixing between singlet and triplet-pair manifolds, which – in the strong coupling regime – enables direct interaction between the bright polariton states and those that are formally non-emissive. Our observations offer the enticing possibility of using polaritons to harvest or manipulate population from states that are formally dark.
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Affiliation(s)
- Daniel Polak
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Rahul Jayaprakash
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Thomas P Lyons
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Luis Á Martínez-Martínez
- Department of Chemistry and Biochemistry , University of California San Diego , La Jolla , California 92093 , USA
| | - Anastasia Leventis
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , UK
| | - Kealan J Fallon
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , UK
| | - Harriet Coulthard
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - David G Bossanyi
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Kyriacos Georgiou
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Anthony J Petty Ii
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - John Anthony
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506-0055 , USA
| | - Hugo Bronstein
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , UK
| | - Joel Yuen-Zhou
- Department of Chemistry and Biochemistry , University of California San Diego , La Jolla , California 92093 , USA
| | - Alexander I Tartakovskii
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Jenny Clark
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK .
| | - Andrew J Musser
- Department of Physics and Astronomy , University of Sheffield , Hicks Building, Hounsfield Road , Sheffield S3 7RH , UK . .,Department of Chemistry and Biochemistry , Cornell University , Ithaca , New York 14853 , USA .
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43
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Alagna N, Pérez Lustres JL, Wollscheid N, Luo Q, Han J, Dreuw A, Geyer FL, Brosius V, Bunz UHF, Buckup T, Motzkus M. Singlet Fission in Tetraaza-TIPS-Pentacene Oligomers: From fs Excitation to μs Triplet Decay via the Biexcitonic State. J Phys Chem B 2019; 123:10780-10793. [DOI: 10.1021/acs.jpcb.9b08031] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Nicolò Alagna
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
| | - J. Luis Pérez Lustres
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Nikolaus Wollscheid
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
| | | | | | - Andreas Dreuw
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
| | | | | | - Uwe H. F. Bunz
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Tiago Buckup
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Marcus Motzkus
- Centre for Advanced Materials, University of Heidelberg, D-69120 Heidelberg, Germany
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44
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Collins MI, McCamey DR, Tayebjee MJY. Fluctuating exchange interactions enable quintet multiexciton formation in singlet fission. J Chem Phys 2019; 151:164104. [PMID: 31675884 DOI: 10.1063/1.5115816] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several recent electron spin resonance studies have observed a quintet multiexciton state during the singlet fission process. Here, we provide a general theoretical explanation for the generation of this state by invoking a time-varying exchange coupling between pairs of triplet excitons and subsequently solving the relevant time-varying spin Hamiltonian for different rates at which the exchange coupling varies. We simulate experimental ESR spectra and draw qualitative conclusions about the adiabatic and diabatic transitions between triplet pair spin states.
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Affiliation(s)
- Miles I Collins
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Dane R McCamey
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
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45
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Kim VO, Broch K, Belova V, Chen YS, Gerlach A, Schreiber F, Tamura H, Della Valle RG, D'Avino G, Salzmann I, Beljonne D, Rao A, Friend R. Singlet exciton fission via an intermolecular charge transfer state in coevaporated pentacene-perfluoropentacene thin films. J Chem Phys 2019; 151:164706. [PMID: 31675857 DOI: 10.1063/1.5130400] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Singlet exciton fission is a spin-allowed process in organic semiconductors by which one absorbed photon generates two triplet excitons. Theory predicts that singlet fission is mediated by intermolecular charge-transfer states in solid-state materials with appropriate singlet-triplet energy spacing, but direct evidence for the involvement of such states in the process has not been provided yet. Here, we report on the observation of subpicosecond singlet fission in mixed films of pentacene and perfluoropentacene. By combining transient spectroscopy measurements to nonadiabatic quantum-dynamics simulations, we show that direct excitation in the charge-transfer absorption band of the mixed films leads to the formation of triplet excitons, unambiguously proving that they act as intermediate states in the fission process.
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Affiliation(s)
- Vincent O Kim
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Katharina Broch
- Fritz Haber Institute of the Max Planck Society, Department of Physical Chemistry, Faradayweg, 4-614195 Berlin, Germany
| | - Valentina Belova
- Eberhard-Karls Universität Tübingen, Institut für Angewandte Physik, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Y S Chen
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Alexander Gerlach
- Eberhard-Karls Universität Tübingen, Institut für Angewandte Physik, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Frank Schreiber
- Eberhard-Karls Universität Tübingen, Institut für Angewandte Physik, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Hiroyuki Tamura
- Department of Chemical System Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Raffaele Guido Della Valle
- Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna and INSTM-UdR Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
| | - Gabriele D'Avino
- Institut Néel, CNRS and Grenoble Alpes University, F-38042 Grenoble, France
| | - Ingo Salzmann
- Department of Physics, Department of Chemistry and Biochemistry, Centre for Research in Molecular Modeling (CERMM), Centre for NanoScience Research (CeNSR), Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec H4B 1R6, Canada
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, Department of Chemistry, Université de Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Akshay Rao
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Richard Friend
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom
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46
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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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47
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Alvertis AM, Lukman S, Hele TJH, Fuemmeler EG, Feng J, Wu J, Greenham NC, Chin AW, Musser AJ. Switching between Coherent and Incoherent Singlet Fission via Solvent-Induced Symmetry Breaking. J Am Chem Soc 2019; 141:17558-17570. [DOI: 10.1021/jacs.9b05561] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Antonios M. Alvertis
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Steven Lukman
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Timothy J. H. Hele
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Eric G. Fuemmeler
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jiaqi Feng
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Neil C. Greenham
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Alex W. Chin
- CNRS & Institut des NanoSciences de Paris, Sorbonne Université, 4 place Jussieu boite courrier 840, 75252 Paris Cedex 05, France
| | - Andrew J. Musser
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, U.K
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48
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Wang Z, Zhang C, Wang R, Wang G, Wang X, Xiao M. Weakly coupled triplet pair states probed by quantum beating in delayed fluorescence in tetracene crystals. J Chem Phys 2019; 151:134309. [DOI: 10.1063/1.5110188] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Zhiwei Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Guodong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
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49
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Bardeen CJ. Time dependent correlations of entangled states with nondegenerate branches and possible experimental realization using singlet fission. J Chem Phys 2019; 151:124503. [DOI: 10.1063/1.5117155] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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50
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Sun D, Deng GH, Xu B, Xu E, Li X, Wu Y, Qian Y, Zhong Y, Nuckolls C, Harutyunyan AR, Dai HL, Chen G, Chen H, Rao Y. Anisotropic Singlet Fission in Single Crystalline Hexacene. iScience 2019; 19:1079-1089. [PMID: 31522118 PMCID: PMC6745488 DOI: 10.1016/j.isci.2019.08.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 07/01/2019] [Accepted: 08/26/2019] [Indexed: 11/25/2022] Open
Abstract
Singlet fission is known to improve solar energy utilization by circumventing the Shockley-Queisser limit. The two essential steps of singlet fission are the formation of a correlated triplet pair and its subsequent quantum decoherence. However, the mechanisms of the triplet pair formation and decoherence still remain elusive. Here we examined both essential steps in single crystalline hexacene and discovered remarkable anisotropy of the overall singlet fission rate along different crystal axes. Since the triplet pair formation emerges on the same timescale along both crystal axes, the quantum decoherence is likely responsible for the directional anisotropy. The distinct quantum decoherence rates are ascribed to the notable difference on their associated energy loss according to the Redfield quantum dissipation theory. Our hybrid experimental/theoretical framework will not only further our understanding of singlet fission, but also shed light on the systematic design of new materials for the third-generation solar cells.
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Affiliation(s)
- Dezheng Sun
- Department of Physics, Columbia University, New York, NY 10027, USA
| | - Gang-Hua Deng
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - Bolei Xu
- Department of Chemistry, Temple University, Philadelphia, PA 19122, USA
| | - Enshi Xu
- Department of Chemistry, George Washington University, Washington, DC 20052, USA
| | - Xia Li
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - Yajing Wu
- Department of Chemistry, Temple University, Philadelphia, PA 19122, USA
| | - Yuqin Qian
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA
| | - Yu Zhong
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | - Colin Nuckolls
- Department of Chemistry, Columbia University, New York, NY 10027, USA
| | | | - Hai-Lung Dai
- Department of Chemistry, Temple University, Philadelphia, PA 19122, USA
| | - Gugang Chen
- Honda Research Institute USA, Inc., San Jose, CA 95134, USA.
| | - Hanning Chen
- Department of Chemistry, George Washington University, Washington, DC 20052, USA.
| | - Yi Rao
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322, USA.
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