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Feng J, Hosseinabadi P, de Clercq DM, Carwithen BP, Nielsen MP, Brett MW, Prasad SKK, Farahani AAD, Li HL, Sanders SN, Beves JE, Ekins-Daukes NJ, Cole JH, Thordarson P, Huang DM, Tayebjee MJY, Schmidt TW. Magnetic fields reveal signatures of triplet-pair multi-exciton photoluminescence in singlet fission. Nat Chem 2024:10.1038/s41557-024-01591-0. [PMID: 39054380 DOI: 10.1038/s41557-024-01591-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
The photophysical processes of singlet fission and triplet fusion have numerous emerging applications. They involve the separation of a photo-generated singlet exciton into two dark triplet excitons and the fusion of two dark triplet excitons into an emissive singlet exciton, respectively. The role of the excimer state and the nature of the triplet-pair state in these processes have been a matter of contention. Here we analyse the room temperature time-resolved emission of a neat liquid singlet fission chromophore and show that it exhibits three spectral components: two that correspond to the bright singlet and excimer states and a third component that becomes more prominent during triplet fusion. This spectrum is enhanced by magnetic fields, confirming its origins in the recombination of weakly coupled triplet pairs. It is thus attributed to a strongly coupled triplet pair state. These observations unite the view that there is an emissive intermediate in singlet fission and triplet fusion, distinct from the broad, unstructured excimer emission.
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Affiliation(s)
- Jiale Feng
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Parisa Hosseinabadi
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Damon M de Clercq
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Ben P Carwithen
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Michael P Nielsen
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Matthew W Brett
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Shyamal K K Prasad
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Adam A D Farahani
- The UNSW RNA Institute, The Australian Centre for Nanomedicine, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Hsiu L Li
- The UNSW RNA Institute, The Australian Centre for Nanomedicine, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | | | - Jonathon E Beves
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - N J Ekins-Daukes
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Jared H Cole
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria, Australia
| | - Pall Thordarson
- The UNSW RNA Institute, The Australian Centre for Nanomedicine, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - David M Huang
- Department of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Timothy W Schmidt
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia.
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Hudson RJ, MacDonald TSC, Cole JH, Schmidt TW, Smith TA, McCamey DR. A framework for multiexcitonic logic. Nat Rev Chem 2024:10.1038/s41570-023-00566-y. [PMID: 38273177 DOI: 10.1038/s41570-023-00566-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2023] [Indexed: 01/27/2024]
Abstract
Exciton science sits at the intersection of chemical, optical and spin-based implementations of information processing, but using excitons to conduct logical operations remains relatively unexplored. Excitons encoding information could be read optically (photoexcitation-photoemission) or electrically (charge recombination-separation), travel through materials via exciton energy transfer, and interact with one another in stimuli-responsive molecular excitonic devices. Excitonic logic offers the potential to mediate electrical, optical and chemical information. Additionally, high-spin triplet and quintet (multi)excitons offer access to well defined spin states of relevance to magnetic field effects, classical spintronics and spin-based quantum information science. In this Roadmap, we propose a framework for developing excitonic computing based on singlet fission (SF) and triplet-triplet annihilation (TTA). Various molecular components capable of modulating SF/TTA for logical operations are suggested, including molecular photo-switching and multi-colour photoexcitation. We then outline a pathway for constructing excitonic logic devices, considering aspects of circuit assembly, logical operation synchronization, and exciton transport and amplification. Promising future directions and challenges are identified, and the potential for realizing excitonic computing in the near future is discussed.
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Affiliation(s)
- Rohan J Hudson
- School of Chemistry, University of Melbourne, Melbourne, Victoria, Australia
- Australian Research Council Centre of Excellence in Exciton Science
| | - Thomas S C MacDonald
- Australian Research Council Centre of Excellence in Exciton Science
- School of Physics, UNSW Sydney, Sydney, New South Wales, Australia
| | - Jared H Cole
- Australian Research Council Centre of Excellence in Exciton Science
- School of Science, RMIT University, Melbourne, Victoria, Australia
| | - Timothy W Schmidt
- Australian Research Council Centre of Excellence in Exciton Science
- School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Trevor A Smith
- School of Chemistry, University of Melbourne, Melbourne, Victoria, Australia
- Australian Research Council Centre of Excellence in Exciton Science
| | - Dane R McCamey
- Australian Research Council Centre of Excellence in Exciton Science, .
- School of Physics, UNSW Sydney, Sydney, New South Wales, Australia.
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3
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Abstract
Triplet-triplet annihilation (TTA) is a spin-allowed conversion of two triplet states into one singlet excited state, which provides an efficient route to generate a photon of higher frequency than the incident light. Multiple energy transfer steps between absorbing (sensitizer) and emitting (annihilator) molecular species are involved in the TTA based photon upconversion process. TTA compounds have recently been studied for solar energy applications, even though the maximum upconversion efficiency of 50 % is yet to be achieved. With the aid of quantum calculations and based on a few key requirements, several design principles have been established to develop the well-functioning annihilators. However, a complete molecular level understanding of triplet fusion dynamics is still missing. In this work, we have employed multi-reference electronic structure methods along with quantum dynamics to obtain a detailed and fundamental understanding of TTA mechanism in naphthalene. Our results suggest that the TTA process in naphthalene is mediated by conical intersections. In addition, we have explored the triplet fusion dynamics under the influence of strong light-matter coupling and found an increase of the TTA based upconversion efficiency.
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Affiliation(s)
- Mahesh Gudem
- Department of PhysicsStockholm UniversityAlbanova University CentreSE-106 91StockholmSweden
| | - Markus Kowalewski
- Department of PhysicsStockholm UniversityAlbanova University CentreSE-106 91StockholmSweden
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4
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Dvořák M, Prasad SKK, Dover CB, Forest CR, Kaleem A, MacQueen RW, Petty AJ, Forecast R, Beves JE, Anthony JE, Tayebjee MJY, Widmer-Cooper A, Thordarson P, Schmidt TW. Singlet Fission in Concentrated TIPS-Pentacene Solutions: The Role of Excimers and Aggregates. J Am Chem Soc 2021; 143:13749-13758. [PMID: 34397219 DOI: 10.1021/jacs.1c05767] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excited-state dynamics of 6,13-bis(triisopropylsilylethynyl)pentacene is investigated to determine the role of excimer and aggregate formation in singlet fission in high-concentration solutions. Photoluminescence spectra were measured by excitation with the evanescent wave in total internal reflection, in order to avoid reabsorption effects. The spectra over nearly two magnitudes of concentration were nearly identical, with no evidence for excimer emission. Time-correlated single-photon counting measurements confirm that the fluorescence lifetime shortens with concentration. The observed rate constant grows at high concentrations, and this effect is modeled in terms of the hard-sphere radial distribution function. NMR measurements confirm that aggregation takes place with a binding constant of between 0.14 and 0.43 M-1. Transient absorption measurements are consistent with a diffusive encounter mechanism for singlet fission, with hints of more rapid singlet fission in aggregates at the highest concentration measured. These data show that excimers do not play the role of an emissive intermediate in exothermic singlet fission in solution and that, while aggregation occurs at higher concentrations, the mechanism of singlet fission remains dominated by diffusive encounters.
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Affiliation(s)
- Miroslav Dvořák
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia.,Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, V Holešovičkách 2, 180 00 Prague 8, Czechia
| | - Shyamal K K Prasad
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Cameron B Dover
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Chelsea R Forest
- Australian Centre for Nanomedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Akasha Kaleem
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Rowan W MacQueen
- Department of Spins in Energy Conversion and Quantum Information Science, Helmholtz-Zentrum Berlin für Materialen und Energie GmbH, Berlin 14109, Germany
| | - Anthony J Petty
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Roslyn Forecast
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Jonathon E Beves
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Asaph Widmer-Cooper
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Pall Thordarson
- Australian Centre for Nanomedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Timothy W Schmidt
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
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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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Affiliation(s)
- David R Reichman
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York, New York 10027, USA
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