1
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Wang H, Yin B, Bai J, Wei X, Huang W, Chang Q, Jia H, Chen R, Zhai Y, Wu Y, Zhang C. Giant magneto-photoluminescence at ultralow field in organic microcrystal arrays for on-chip optical magnetometer. Nat Commun 2024; 15:3995. [PMID: 38734699 PMCID: PMC11088683 DOI: 10.1038/s41467-024-48464-1] [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: 10/17/2023] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Optical detection of magnetic field is appealing for integrated photonics; however, the light-matter interaction is usually weak at low field. Here we observe that the photoluminescence (PL) decreases by > 40% at 10 mT in rubrene microcrystals (RMCs) prepared by a capillary-bridge assembly method. The giant magneto-PL (MPL) relies on the singlet-triplet conversion involving triplet-triplet pairs, through the processes of singlet fission (SF) and triplet fusion (TF) during radiative decay. Importantly, the size of RMCs is critical for maximizing MPL as it influences on the photophysical processes of spin state conversion. The SF/TF process is quantified by measuring the prompt/delayed PL with time-resolved spectroscopies, which shows that the geminate SF/TF associated with triplet-triplet pairs are responsible for the giant MPL. Furthermore, the RMC-based magnetometer is constructed on an optical chip, which takes advantages of remarkable low-field sensitivity over a broad range of frequencies, representing a prototype of emerging opto-spintronic molecular devices.
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Affiliation(s)
- Hong Wang
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Baipeng Yin
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Junli Bai
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Xiao Wei
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China
- Ji Hua Laboratory Foshan, Guangdong, China
| | - Wenjin Huang
- Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Department of Physics, Hunan Normal University, Changsha, China
| | - Qingda Chang
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hao Jia
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Rui Chen
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yaxin Zhai
- Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Department of Physics, Hunan Normal University, Changsha, China
| | - Yuchen Wu
- University of Chinese Academy of Sciences, Beijing, China.
- Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
| | - Chuang Zhang
- Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
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2
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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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3
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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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4
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Reid OG, Johnson JC, Eaves JD, Damrauer NH, Anthony JE. Molecular Control of Triplet-Pair Spin Polarization and Its Optoelectronic Magnetic Resonance Probes. Acc Chem Res 2024; 57:59-69. [PMID: 38103045 PMCID: PMC10765369 DOI: 10.1021/acs.accounts.3c00556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023]
Abstract
ConspectusPreparing and manipulating pure magnetic states in molecular systems are the key initial requirements for harnessing the power of synthetic chemistry to drive practical quantum sensing and computing technologies. One route for achieving the requisite higher spin states in organic systems exploits the phenomenon of singlet fission, which produces pairs of triplet excited states from initially photoexcited singlets in molecular assemblies with multiple chromophores. The resulting spin states are characterized by total spin (quintet, triplet, or singlet) and its projection onto a specified molecular or magnetic field axis. These excited states are typically highly polarized but exhibit an impure spin population pattern. Herein, we report the prediction and experimental verification of molecular design rules that drive the population of a single pure magnetic state and describe the progress toward its experimental realization.A vital feature of this work is the close partnership among theory, chemical synthesis, and spectroscopy. We begin by presenting our theoretical framework for understanding spin manifold interconversion in singlet fission systems. This theory makes specific testable predictions about the intermolecular structure and orientation relative to an external magnetic field that should lead to pure magnetic state preparation and provides a powerful tool for interpreting magnetic spectra. We then test these predictions through detailed magnetic spectroscopy experiments on a series of new molecular architectures that meet one or more of the identified structural criteria. Many of these architectures rely on the synthesis of molecules with features unique to this effort: rigid bridges between chromophores in dimers, heteroacenes with tailored singlet/triplet-pair energy level matching, or side-group engineering to produce specific crystal structures. The spin evolution of these systems is revealed through our application and development of several magnetic resonance methods, each of which has different sensitivities and relevance in environments relevant to quantum applications.Our theoretical predictions prove to be remarkably consistent with our experimental results, though experimentally meeting all the structural prescriptions demanded by theory for true pure-state preparation remains a challenge. Our magnetic spectra agree with our model of triplet-pair behavior, including funneling of the population to the ms = 0 magnetic sublevel of the quintet under specified conditions in dimers and crystals, showing that this phenomenon is subject to control through molecular design. Moreover, our demonstration of novel and/or highly sensitive detection mechanisms of spin states in singlet fission systems, including photoluminescence (PL), photoinduced absorption (PA), and magnetoconductance (MC), points the way toward both a deeper understanding of how these systems evolve and technologically feasible routes toward experiments at the single-molecule quantum limit that are desirable for computational applications.
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Affiliation(s)
- Obadiah G. Reid
- National
Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
| | - Justin C. Johnson
- National
Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
| | - Joel D. Eaves
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Niels H. Damrauer
- Renewable
and Sustainable Energy Institute, Boulder, Colorado 80309, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - John E. Anthony
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
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5
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Ye L, Zhao Y, Xu R, Li S, Zhang C, Li H, Zhu H. Above 100% Efficiency Photocharge Generation in Monolayer Semiconductors by Singlet Fission Sensitization. J Am Chem Soc 2023; 145:26257-26265. [PMID: 37994880 DOI: 10.1021/jacs.3c09119] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Sensitizing inorganic semiconductors using singlet fission (SF) materials, which produce two excitons from one absorbed photon, can potentially boost their light-to-electricity conversion efficiency. The SF sensitization is particularly exciting for two-dimensional (2D) layered semiconductors with atomically flat surface and high carrier mobility but limited light absorption. However, efficiently harnessing triplet excitons from SF by charge transfer at organic/inorganic interface has been challenging, and the intricate interplay among competing processes remains unresolved. Here, we investigate SF sensitization in high-quality organic/2D bilayer heterostructures featuring TIPS-Pc single crystals. Through transient magneto-optical spectroscopy, we demonstrate that despite an ultrafast SF process in sub-100 fs, a significant fraction of singlet excitons in TIPS-Pc dissociate at the interface before fission, while triplet excitons from SF undergo diffusion-limited charge transfer at the interface in ∼10 ps to ns. Remarkably, the photocharge generation efficiency reaches 126% in heterostructures with optimal thickness, resulting from the competitive interplay between singlet exciton fission, dissociation, and triplet exciton transport. This presents a promising strategy for advancing SF-enhanced 2D optoelectronics beyond the conventional limits.
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Affiliation(s)
- Lei Ye
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
| | - Yujie Zhao
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310058, China
| | - Rong Xu
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210046, China
| | - Shuangshuang Li
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210046, China
| | - Hanying Li
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310058, China
| | - Haiming Zhu
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou 310058, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311215, China
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6
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Sutherland GA, Pidgeon JP, Lee HKH, Proctor MS, Hitchcock A, Wang S, Chekulaev D, Tsoi WC, Johnson MP, Hunter CN, Clark J. Twisted Carotenoids Do Not Support Efficient Intramolecular Singlet Fission in the Orange Carotenoid Protein. J Phys Chem Lett 2023:6135-6142. [PMID: 37364284 DOI: 10.1021/acs.jpclett.3c01139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Singlet exciton fission is the spin-allowed generation of two triplet electronic excited states from a singlet state. Intramolecular singlet fission has been suggested to occur on individual carotenoid molecules within protein complexes provided that the conjugated backbone is twisted out of plane. However, this hypothesis has been forwarded only in protein complexes containing multiple carotenoids and bacteriochlorophylls in close contact. To test the hypothesis on twisted carotenoids in a "minimal" one-carotenoid system, we study the orange carotenoid protein (OCP). OCP exists in two forms: in its orange form (OCPo), the single bound carotenoid is twisted, whereas in its red form (OCPr), the carotenoid is planar. To enable room-temperature spectroscopy on canthaxanthin-binding OCPo and OCPr without laser-induced photoconversion, we trap them in a trehalose glass. Using transient absorption spectroscopy, we show that there is no evidence of long-lived triplet generation through intramolecular singlet fission despite the canthaxanthin twist in OCPo.
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Affiliation(s)
- George A Sutherland
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - James P Pidgeon
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Harrison Ka Hin Lee
- SPECIFIC, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - Matthew S Proctor
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Andrew Hitchcock
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Shuangqing Wang
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Dimitri Chekulaev
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Wing Chung Tsoi
- SPECIFIC, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - Matthew P Johnson
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - C Neil Hunter
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Jenny Clark
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
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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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9
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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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10
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Shushin A. Kinetic specific features of singlet fission in highly anisotropic organic semiconductors. J Chem Phys 2022; 156:074703. [DOI: 10.1063/5.0078158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A.I. Shushin
- Kinetics, Semenov Institute of Chemical Physics RAS, Russia
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11
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Bossanyi DG, Sasaki Y, Wang S, Chekulaev D, Kimizuka N, Yanai N, Clark J. Spin Statistics for Triplet-Triplet Annihilation Upconversion: Exchange Coupling, Intermolecular Orientation, and Reverse Intersystem Crossing. JACS AU 2021; 1:2188-2201. [PMID: 34977890 PMCID: PMC8715495 DOI: 10.1021/jacsau.1c00322] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 06/14/2023]
Abstract
Triplet-triplet annihilation upconversion (TTA-UC) has great potential to significantly improve the light harvesting capabilities of photovoltaic cells and is also sought after for biomedical applications. Many factors combine to influence the overall efficiency of TTA-UC, the most fundamental of which is the spin statistical factor, η, that gives the probability that a bright singlet state is formed from a pair of annihilating triplet states. The value of η is also critical in determining the contribution of TTA to the overall efficiency of organic light-emitting diodes. Using solid rubrene as a model system, we reiterate why experimentally measured magnetic field effects prove that annihilating triplets first form weakly exchange-coupled triplet-pair states. This is contrary to conventional discussions of TTA-UC that implicitly assume strong exchange coupling, and we show that it has profound implications for the spin statistical factor η. For example, variations in intermolecular orientation tune η from to through spin mixing of the triplet-pair wave functions. Because the fate of spin-1 triplet-pair states is particularly crucial in determining η, we investigate it in rubrene using pump-push-probe spectroscopy and find additional evidence for the recently reported high-level reverse intersystem crossing channel. We incorporate all of these factors into an updated model framework with which to understand the spin statistics of TTA-UC and use it to rationalize the differences in reported values of η among different common annihilator systems. We suggest that harnessing high-level reverse intersystem crossing channels in new annihilator molecules may be a highly promising strategy to exceed any spin statistical limit.
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Affiliation(s)
- David G. Bossanyi
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Yoichi Sasaki
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shuangqing Wang
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Dimitri Chekulaev
- Department
of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Nobuo Kimizuka
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Nobuhiro Yanai
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Jenny Clark
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
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12
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Wang Z, Liu H, Xie X, Zhang C, Wang R, Chen L, Xu Y, Ma H, Fang W, Yao Y, Sang H, Wang X, Li X, Xiao M. Free-triplet generation with improved efficiency in tetracene oligomers through spatially separated triplet pair states. Nat Chem 2021; 13:559-567. [PMID: 33833447 DOI: 10.1038/s41557-021-00665-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 02/22/2021] [Indexed: 02/01/2023]
Abstract
Singlet fission (SF) can potentially boost the efficiency of solar energy conversion by converting a singlet exciton (S1) into two free triplets (T1 + T1) through an intermediate state of a correlated triplet pair (TT). Although efficient TT generation has been recently realized in many intramolecular SF materials, their potential applications have been hindered by the poor efficiency of TT dissociation. Here we demonstrate that this can be overcome by employing a spatially separated 1(T…T) state with weak intertriplet coupling in tetracene oligomers with three or more chromophores. By using transient magneto-optical spectroscopic methods, we show that free-triplet generation can be markedly enhanced through the SF pathway that involves the spatially separated 1(T…T) state rather than the pathway mediated by the spatially adjacent TT state, leading to a marked improvement in free-triplet generation with an efficiency increase from 21% for the dimer to 85% (124%) for the trimer (tetramer).
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Affiliation(s)
- Zhiwei Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Heyuan Liu
- School of Materials Science and Engineering, Institute of New Energy, China University of Petroleum (East China), Qingdao, China
| | - Xiaoyu Xie
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Lan Chen
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Yihe Xu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Haibo Ma
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
| | - Weihai Fang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.,Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Beijing, China
| | - Yao Yao
- Department of Physics and State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, China
| | - Hai Sang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Xiyou Li
- School of Materials Science and Engineering, Institute of New Energy, China University of Petroleum (East China), Qingdao, China.
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China. .,Department of Physics, University of Arkansas, Fayetteville, AR, USA.
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13
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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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14
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Engmann S, Bittle EG, Richter LJ, Hallani RK, Anthony JE, Gundlach DJ. The role of orientation in the MEL response of OLEDs. JOURNAL OF MATERIALS CHEMISTRY. C 2021; 9:10.1039/d1tc00314c. [PMID: 36967733 PMCID: PMC10037669 DOI: 10.1039/d1tc00314c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Magneto electroluminescence (MEL) is emerging as a powerful tool to study spin dynamics in organic light emitting diodes (OLEDs). The shape of the MEL response is typically used to draw qualitative inference on the dominant process (singlet fission or triplet fusion) in the device. In this study, we develop a quantitative model for MEL and apply it to devices based on Rubrene, and three solution processable anthradithiophene emitters. The four emitters allow us to systematically vary the film structure between highly textured, poly-crystalline to amorphous. We find significant diversity in the MEL, with the textured films giving highly structured responses. We find that the additional structure does not coincide with energy anti-crossings, but intersections in the singlet character between adjacent states. In all cases the MEL can be adequately described by an extended Merrifield model. Via the inclusion of charge injection, we are able to draw additional information on underlying physics in OLED devices.
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Affiliation(s)
- Sebastian Engmann
- Theiss Research, La Jolla, California 92037, United States
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Emily G Bittle
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Lee J Richter
- Materials Science and Engineering Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
| | - Rawad K Hallani
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, 40506, United States
- Current address: KAUST Solar Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, 40506, United States
| | - David J Gundlach
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 101 Bureau Drive, Gaithersburg, Maryland, 20899, United States
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15
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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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16
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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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17
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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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18
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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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19
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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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20
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Reddy SR, Coto PB, Thoss M. Quantum dynamical simulation of intramolecular singlet fission in covalently coupled pentacene dimers. J Chem Phys 2019; 151:044307. [DOI: 10.1063/1.5109897] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. Rajagopala Reddy
- Institute of Physics, Albert-Ludwigs University Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Pedro B. Coto
- Department of Physical and Analytical Chemistry, University of Oviedo, Avda. Julián Clavería 8, 33006, Oviedo, Spain
| | - Michael Thoss
- Institute of Physics, Albert-Ludwigs University Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
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21
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Shushin AI. Kinetics of singlet fission in organic semiconductors: Specific features of T-exciton migration effects. J Chem Phys 2019; 151:034103. [DOI: 10.1063/1.5099667] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- A. I. Shushin
- Institute of Chemical Physics, Russian Academy of Sciences, 119991, GSP-1, Kosygin St. 4, Moscow, Russian Federation and Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny 141700, Moscow Region, Russian Federation
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22
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Abstract
Entanglement of states is one of the most surprising and counterintuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic semiconductor materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which consists of a pair of localized triplet excitons coupled into an overall spin-0, -1, or -2 configuration. The most widely analyzed of these is the spin-0 pair, denoted 1(TT), which was initially invoked in the 1960s to explain delayed fluorescence in acene films. It is considered an essential gateway state for triplet-triplet annihilation and the reverse process, singlet fission, enabling interconversion between one singlet and two triplet excitons without any change in overall spin. This state has returned to the forefront of organic materials research in recent years, thanks both to its central role in the resurgent field of singlet fission and to its implication in a host of exotic new photophysical behaviors. Here we review the properties of triplet-pair states, from first principles to recent experimental results.
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Affiliation(s)
- Andrew J Musser
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom; ,
| | - Jenny Clark
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom; ,
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23
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Gilligan AT, Miller EG, Sammakia T, Damrauer NH. Using Structurally Well-Defined Norbornyl-Bridged Acene Dimers to Map a Mechanistic Landscape for Correlated Triplet Formation in Singlet Fission. J Am Chem Soc 2019; 141:5961-5971. [PMID: 30888804 DOI: 10.1021/jacs.9b00904] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structurally well-defined TIPS-acetylene substituted tetracene (TIPS-BT1') and pentacene (TIPS-BP1') dimers utilizing a [2.2.1] bicyclic norbornyl bridge have been studied-primarily using time-resolved spectroscopic methods-to uncover mechanistic details about primary steps in singlet fission leading to formation of the biexcitonic 1TT state as well as decay pathways to the ground state. For TIPS-BP1' in room-temperature toluene, 1TT formation is rapid and complete, occurring in 4.4 ps. Decay to the ground state in 100 ns is the primary loss pathway for 1TT in this system. For TIPS-BT1', the 1TT is also observed to form rapidly (with a time constant of 5 ps), but in this case it occurs in concert with establishment of an excited-state equilibrium ( K ∼ 1) with the singlet exciton state S1 at an energy of 2.3 eV above the ground state. The equilibrated states survive for 36 ns and are lost to ground state through both radiative and nonradiative pathways via the S1 and nonradiative pathways via the 1TT. The rapidity of 1TT formation in TIPS-BT1' is at first glance surprising. However, our analysis suggests that the few-parameter rate constant expression of Marcus theory explains both individual and comparative findings in the set of systems, thus establishing benchmarks for diabatic coupling and reorganization energy needed for efficient 1TT formation. Finally, a comparison of TIPS-BT1' with previous results obtained for a close constitutional isomer (TIPS-BT1) differing in the placement of TIPS-acetylene side groups suggests that the magnitude of exchange interaction in the correlated triplet manifold plays a critical role dictating 1TT yield in the tetracenic systems.
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Affiliation(s)
- Alexander T Gilligan
- Department of Chemistry and Biochemistry , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | - Ethan G Miller
- Department of Chemistry and Biochemistry , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | - Tarek Sammakia
- Department of Chemistry and Biochemistry , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | - Niels H Damrauer
- Department of Chemistry and Biochemistry , University of Colorado Boulder , Boulder , Colorado 80309 , United States
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24
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Hu FQ, Zhao Q, Peng XB. Improved model on fluorescence decay in singlet fission materials. Phys Chem Chem Phys 2019; 21:2153-2165. [PMID: 30644475 DOI: 10.1039/c8cp06380j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Singlet fission (SF) materials are a kind of promising material for breaking the solar cell efficiency limit. Here we rebuild the four-electron spin Hamiltonian under our coordinate system and present an improved model described by the population evolution equations on fluorescence decay (FD) dynamics that contain several detailed physical processes. The improved model for total random molecular orientation gives a more consistent fitting on the experimental data [G. B. Piland et al., J. Phys. Chem. C, 2013, 117, 1224] about time-resolved FD of amorphous rubrene thin films in the presence of a strong magnetic field. The fitting can reflect the relative rates of the real physical processes. Further on, our results show two kinds of magnetic field effect for the variety of two molecular relative orientations with respect to each other and the magnetic field by investigating the singlet projection and FD dynamics of the system.
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Affiliation(s)
- Fang-Qi Hu
- Center for Quantum Technology Research, School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
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25
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Jang HJ, Bittle EG, Zhang Q, Biacchi AJ, Richter CA, Gundlach DJ. Electrical Detection of Singlet Fission in Single Crystal Tetracene Transistors. ACS NANO 2019; 13:616-623. [PMID: 30608649 PMCID: PMC6541755 DOI: 10.1021/acsnano.8b07625] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present the electrical detection of singlet fission in tetracene by using a field-effect transistor (FET). Singlet fission is a photoinduced spin-dependent process, yielding two triplet excitons from the absorption of a single photon. In this study, we engineered a more deterministic platform composed of an organic single crystal FET rather than amorphous or polycrystalline FETs to elucidate spin-dependent processes under magnetic fields. Despite the unipolar operation and relatively high mobility of single crystal tetracene FETs, we were able to manipulate spin dependent processes to detect magnetoconductance (MC) at room temperature by illuminating the FETs and tuning the bias voltage to adjust majority charge carrier density and trap occupancy. In considering the crystalline direction and magnetic field interactions in tetracene, we show the MC response observed in tetracene FETs to be the result of the singlet fission process.
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Affiliation(s)
- Hyuk-Jae Jang
- Theiss Research, La Jolla, CA 92037, USA
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
- Western Digital Corporation, 5601 Great Oaks Parkway, San Jose, CA 95119, USA
| | - Emily G. Bittle
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Qin Zhang
- Theiss Research, La Jolla, CA 92037, USA
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Adam J. Biacchi
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Curt A. Richter
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - David J. Gundlach
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
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26
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Shushin A. Kinetic curves crossing effect. Manifestation of the effect in singlet fission in organic semiconductors. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.09.071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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27
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Site-selective measurement of coupled spin pairs in an organic semiconductor. Proc Natl Acad Sci U S A 2018; 115:5077-5082. [PMID: 29720443 DOI: 10.1073/pnas.1718868115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
From organic electronics to biological systems, understanding the role of intermolecular interactions between spin pairs is a key challenge. Here we show how such pairs can be selectively addressed with combined spin and optical sensitivity. We demonstrate this for bound pairs of spin-triplet excitations formed by singlet fission, with direct applicability across a wide range of synthetic and biological systems. We show that the site sensitivity of exchange coupling allows distinct triplet pairs to be resonantly addressed at different magnetic fields, tuning them between optically bright singlet ([Formula: see text]) and dark triplet quintet ([Formula: see text]) configurations: This induces narrow holes in a broad optical emission spectrum, uncovering exchange-specific luminescence. Using fields up to 60 T, we identify three distinct triplet-pair sites, with exchange couplings varying over an order of magnitude (0.3-5 meV), each with its own luminescence spectrum, coexisting in a single material. Our results reveal how site selectivity can be achieved for organic spin pairs in a broad range of systems.
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28
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Basel BS, Zirzlmeier J, Hetzer C, Reddy SR, Phelan BT, Krzyaniak MD, Volland MK, Coto PB, Young RM, Clark T, Thoss M, Tykwinski RR, Wasielewski MR, Guldi DM. Evidence for Charge-Transfer Mediation in the Primary Events of Singlet Fission in a Weakly Coupled Pentacene Dimer. Chem 2018. [DOI: 10.1016/j.chempr.2018.04.006] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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29
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Structure and dynamics of triplet-exciton pairs generated from singlet fission studied via magnetic field effects. Commun Chem 2018. [DOI: 10.1038/s42004-018-0008-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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31
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Shushin AI. Kinetics of Prompt Fluorescence Decay in Rubrene Films. Manifestations of the Migration of T Excitons. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2018. [DOI: 10.1134/s1990793117060082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Refaely-Abramson S, da Jornada FH, Louie SG, Neaton JB. Origins of Singlet Fission in Solid Pentacene from an ab initio Green's Function Approach. PHYSICAL REVIEW LETTERS 2017; 119:267401. [PMID: 29328724 DOI: 10.1103/physrevlett.119.267401] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Indexed: 05/24/2023]
Abstract
We develop a new first-principles approach to predict and understand rates of singlet fission with an ab initio Green's-function formalism based on many-body perturbation theory. Starting with singlet and triplet excitons computed from a GW plus Bethe-Salpeter equation approach, we calculate the exciton-biexciton coupling to lowest order in the Coulomb interaction, assuming a final state consisting of two noninteracting spin-correlated triplets with finite center-of-mass momentum. For crystalline pentacene, symmetries dictate that the only purely Coulombic fission decay process from a bright singlet state requires a final state consisting of two inequivalent nearly degenerate triplets of nonzero, equal and opposite, center-of-mass momenta. For such a process, we predict a singlet lifetime of 30-70 fs, in very good agreement with experimental data, indicating that this process can dominate singlet fission in crystalline pentacene. Our approach is general and provides a framework for predicting and understanding multiexciton interactions in solids.
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Affiliation(s)
- Sivan Refaely-Abramson
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Felipe H da Jornada
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Steven G Louie
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeffrey B Neaton
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Ivanov KL, Wagenpfahl A, Deibel C, Matysik J. Spin-chemistry concepts for spintronics scientists. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:1427-1445. [PMID: 28900597 PMCID: PMC5530719 DOI: 10.3762/bjnano.8.143] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/13/2017] [Indexed: 05/03/2023]
Abstract
Spin chemistry and spintronics developed independently and with different terminology. Until now, the interaction between the two fields has been very limited. In this review, we compile the two "languages" in an effort to enhance communication. We expect that knowledge of spin chemistry will accelerate progress in spintronics.
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Affiliation(s)
- Konstantin L Ivanov
- International Tomography Center, Siberian Branch of Russian Academy of Science, Institutskaya 3а, Novosibirsk, 630090 Russia
- Novosibirsk State University, Institutskaya 3а, Novosibirsk, 630090 Russia
| | | | - Carsten Deibel
- Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany
| | - Jörg Matysik
- Universität Leipzig, Institut für Analytische Chemie, Linnéstr. 3, D-04103 Leipzig, Germany
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34
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Shushin A. Manifestation of T-exciton migration in the kinetics of singlet fission in organic semiconductors. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.04.068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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35
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Liu H, Wang R, Shen L, Xu Y, Xiao M, Zhang C, Li X. A Covalently Linked Tetracene Trimer: Synthesis and Singlet Exciton Fission Property. Org Lett 2017; 19:580-583. [DOI: 10.1021/acs.orglett.6b03739] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Heyuan Liu
- College
of Science, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Rui Wang
- National
Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Li Shen
- College
of Science, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Yanqing Xu
- National
Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
| | - Min Xiao
- National
Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
- Synergetic
Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chunfeng Zhang
- National
Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
- Synergetic
Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiyou Li
- College
of Science, China University of Petroleum (East China), Qingdao, Shandong 266580, China
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36
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Scholes GD. Correlated Pair States Formed by Singlet Fission and Exciton–Exciton Annihilation. J Phys Chem A 2015; 119:12699-705. [DOI: 10.1021/acs.jpca.5b09725] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gregory D. Scholes
- Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544, United States
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37
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Teichen PE, Eaves JD. Collective aspects of singlet fission in molecular crystals. J Chem Phys 2015; 143:044118. [PMID: 26233118 DOI: 10.1063/1.4922644] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We present a model to describe collective features of singlet fission in molecular crystals and analyze it using many-body theory. The model we develop allows excitonic states to delocalize over several chromophores which is consistent with the character of the excited states in many molecular crystals, such as the acenes, where singlet fission occurs. As singlet states become more delocalized and triplet states more localized, the rate of singlet fission increases. We also determine the conditions under which the two triplets resulting from fission are correlated. Using the Bethe Ansatz and an entanglement measure for indistinguishable bipartite systems, we calculate the triplet-triplet entanglement as a function of the biexciton interaction strength. The biexciton interaction can produce bound biexciton states and provides a source of entanglement between the two triplets even when the triplets are spatially well separated. Significant entanglement between the triplet pair occurs well below the threshold for bound pair formation. Our results paint a dynamical picture that helps to explain why fission has been observed to be more efficient in molecular crystals than in their covalent dimer analogues and have consequences for photovoltaic efficiency models that assume that the two triplets can be extracted independently.
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Affiliation(s)
- Paul E Teichen
- Department of Chemistry and Biochemistry, The University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - Joel D Eaves
- Department of Chemistry and Biochemistry, The University of Colorado at Boulder, Boulder, Colorado 80309, USA
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38
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Wang R, Zhang C, Zhang B, Liu Y, Wang X, Xiao M. Magnetic dipolar interaction between correlated triplets created by singlet fission in tetracene crystals. Nat Commun 2015; 6:8602. [PMID: 26456368 PMCID: PMC4633952 DOI: 10.1038/ncomms9602] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 09/09/2015] [Indexed: 01/15/2023] Open
Abstract
Singlet fission can potentially break the Shockley–Queisser efficiency limit in single-junction solar cells by splitting one photoexcited singlet exciton (S1) into two triplets (2T1) in organic semiconductors. A dark multiexciton state has been proposed as the intermediate connecting S1 to 2T1. However, the exact nature of this multiexciton state, especially how the doubly excited triplets interact, remains elusive. Here we report a quantitative study on the magnetic dipolar interaction between singlet-fission-induced correlated triplets in tetracene crystals by monitoring quantum beats relevant to the multiexciton sublevels at room temperature. The resonances of multiexciton sublevels approached by tuning an external magnetic field are observed to be avoided, which agrees well with the theoretical predictions considering a magnetic dipolar interaction of ∼0.008 GHz. Our work quantifies the magnetic dipolar interaction in certain organic materials and marks an important step towards understanding the underlying physics of the multiexciton state in singlet fission. The exact mechanism of singlet fission remains unresolved. Here, Wang et al. report a quantitative measurement of the interaction between singlet-fission-induced correlated triplets in tetracene crystals with quantum beat spectroscopy, indicating the role played by exciton delocalization in singlet fission.
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Affiliation(s)
- Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.,Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bo Zhang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.,Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yunlong Liu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.,Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China.,Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.,Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, USA
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39
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Thompson NJ, Hontz E, Chang W, Van Voorhis T, Baldo M. Magnetic field dependence of singlet fission in solutions of diphenyl tetracene. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0323. [PMID: 25987573 PMCID: PMC4455722 DOI: 10.1098/rsta.2014.0323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/18/2015] [Indexed: 06/04/2023]
Abstract
Magnetic field effects provide a convenient and specific probe of singlet exciton fission within optoelectronic devices. Here, we demonstrate that this tool may also be applied to screen potential fission material candidates in solution. We characterize the phenomenon in diphenyl tetracene (DPT), which shows strong fluorescence modulation and the expected field dependence in its transient decay as a function of concentration. Solution measurements may also be used to test for the presence of an intermediate charge transfer state, but we observe no changes to the field dependence of DPT singlet exciton fission in toluene relative to chloroform.
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Affiliation(s)
- Nicholas J Thompson
- Center for Excitonics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Eric Hontz
- Center for Excitonics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Wendi Chang
- Center for Excitonics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Troy Van Voorhis
- Center for Excitonics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Marc Baldo
- Center for Excitonics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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40
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Casanova D. Bright Fission: Singlet Fission into a Pair of Emitting States. J Chem Theory Comput 2015; 11:2642-50. [DOI: 10.1021/acs.jctc.5b00144] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- David Casanova
- Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
- IKERBASQUE, Basque Foundation
for Science, 48013 Bilbao, Euskadi, Spain
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41
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Liu H, Nichols VM, Shen L, Jahansouz S, Chen Y, Hanson KM, Bardeen CJ, Li X. Synthesis and photophysical properties of a “face-to-face” stacked tetracene dimer. Phys Chem Chem Phys 2015; 17:6523-31. [DOI: 10.1039/c4cp05444j] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first “face-to-face” stacked tetracene dimer is prepared and its photophysical properties are studied.
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Affiliation(s)
- Heyuan Liu
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- Department of Chemistry
- Shandong University
- Jinan
| | | | - Li Shen
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- Department of Chemistry
- Shandong University
- Jinan
| | - Setarah Jahansouz
- Department of Chemistry
- University of California, Riverside
- Riverside
- USA
| | - Yuhan Chen
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- Department of Chemistry
- Shandong University
- Jinan
| | - Kerry M. Hanson
- Department of Chemistry
- University of California, Riverside
- Riverside
- USA
| | | | - Xiyou Li
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- Department of Chemistry
- Shandong University
- Jinan
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42
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Piland GB, Burdett JJ, Dillon RJ, Bardeen CJ. Singlet Fission: From Coherences to Kinetics. J Phys Chem Lett 2014; 5:2312-9. [PMID: 26279552 DOI: 10.1021/jz500676c] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Singlet fission, in which an initially excited singlet state spontaneously splits into a pair of triplet excitons, is a process that can potentially boost the efficiency of solar energy conversion. The separate electronic bands in organic semiconductors make them especially useful for dividing a high-energy singlet exciton into a pair of lower-energy triplet excitons. Recent experiments illustrate the role of spin coherence in fission, while kinetic models are used to describe how triplet and singlet states interact on longer time scales. Despite insights gained from recent experiments, the detailed structure and dynamics of the electronic states involved in the initial step of singlet fission remain active areas of investigation. On longer time scales, finding ways to efficiently harvest the triplet excitons will be an important challenge for making devices based on this phenomenon. A full understanding of singlet fission requires consideration of a sequence of photophysical events (decoherence, relaxation, and diffusion) occurring on different time scales.
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Affiliation(s)
- Geoffrey B Piland
- Department of Chemistry, University of California, Riverside, Riverside, California 92506, United States
| | - Jonathan J Burdett
- Department of Chemistry, University of California, Riverside, Riverside, California 92506, United States
| | - Robert J Dillon
- Department of Chemistry, University of California, Riverside, Riverside, California 92506, United States
| | - Christopher J Bardeen
- Department of Chemistry, University of California, Riverside, Riverside, California 92506, United States
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43
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Bayliss SL, Chepelianskii AD, Sepe A, Walker BJ, Ehrler B, Bruzek MJ, Anthony JE, Greenham NC. Geminate and nongeminate recombination of triplet excitons formed by singlet fission. PHYSICAL REVIEW LETTERS 2014; 112:238701. [PMID: 24972236 DOI: 10.1103/physrevlett.112.238701] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Indexed: 06/03/2023]
Abstract
We report the simultaneous observation of geminate and nongeminate triplet-triplet annihilation in a solution-processable small molecule TIPS-tetracene undergoing singlet exciton fission. Using optically detected magnetic resonance, we identify recombination of triplet pairs directly following singlet fission, as well as recombination of triplet excitons undergoing bimolecular triplet-triplet annihilation. We show that the two processes give rise to distinct magnetic resonance spectra, and estimate the interaction between geminate triplet excitons to be 60 neV.
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Affiliation(s)
- Sam L Bayliss
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Alexei D Chepelianskii
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom and LPS, Université Paris-Sud, CNRS, UMR 8502, F-91405, Orsay, France
| | - Alessandro Sepe
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Brian J Walker
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Bruno Ehrler
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Matthew J Bruzek
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Neil C Greenham
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
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44
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Pati YA, Ramasesha S. Exact solution of the PPP model for correlated electronic states of tetracene and substituted tetracene. J Phys Chem A 2014; 118:4048-55. [PMID: 24842608 DOI: 10.1021/jp502813w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetracene is an important conjugated molecule for device applications. We have used the diagrammatic valence bond method to obtain the desired states, in a Hilbert space of about 450 million singlets and 902 million triplets. We have also studied the donor/acceptor (D/A)-substituted tetracenes with D and A groups placed symmetrically about the long axis of the molecule. In these cases, by exploiting a new symmetry, which is a combination of C2 symmetry and electron-hole symmetry, we are able to obtain their low-lying states. In the case of substituted tetracene, we find that optically allowed one-photon excitation gaps reduce with increasing D/A strength, while the lowest singlet-triplet gap is only weakly affected. In all the systems we have studied, the excited singlet state, S1, is at more than twice the energy of the lowest triplet state and the second triplet is very close to the S1 state. Thus, donor-acceptor-substituted tetracene could be a good candidate in photovoltaic device application as it satisfies energy criteria for singlet fission. We have also obtained the model exact second harmonic generation (SHG) coefficients using the correction vector method, and we find that the SHG responses increase with the increase in D/A strength.
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Affiliation(s)
- Y Anusooya Pati
- Solid State and Structural Chemistry Unit, Indian Institute of Science , Bangalore 560 012, India
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45
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Piland GB, Burdett JJ, Hung TY, Chen PH, Lin CF, Chiu TL, Lee JH, Bardeen CJ. Dynamics of molecular excitons near a semiconductor surface studied by fluorescence quenching of polycrystalline tetracene on silicon. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.075] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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Dillon RJ, Piland GB, Bardeen CJ. Different Rates of Singlet Fission in Monoclinic versus Orthorhombic Crystal Forms of Diphenylhexatriene. J Am Chem Soc 2013; 135:17278-81. [DOI: 10.1021/ja409266s] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Robert J. Dillon
- Department of Chemistry University of California, Riverside, California 92521, United States
| | - Geoffrey B. Piland
- Department of Chemistry University of California, Riverside, California 92521, United States
| | - Christopher J. Bardeen
- Department of Chemistry University of California, Riverside, California 92521, United States
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