1
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Kim J, Bain DC, Ding V, Majumder K, Windemuller D, Feng J, Wu J, Patil S, Anthony J, Kim W, Musser AJ. Coherent photoexcitation of entangled triplet pair states. Nat Chem 2024:10.1038/s41557-024-01556-3. [PMID: 38898214 DOI: 10.1038/s41557-024-01556-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 05/13/2024] [Indexed: 06/21/2024]
Abstract
The functional properties of organic semiconductors are defined by the interplay between optically bright and dark states. Organic devices require rapid conversion between these bright and dark manifolds for maximum efficiency, and one way to achieve this is through multiexciton generation (S1→1TT). The dark state 1TT is typically generated from bright S1 after optical excitation; however, the mechanistic details are hotly debated. Here we report a 1TT generation pathway in which it can be coherently photoexcited, without any involvement of bright S1. Using <10-fs transient absorption spectroscopy and pumping sub-resonantly, 1TT is directly generated from the ground state. Applying this method to a range of pentacene dimers and thin films of various aggregation types, we determine the critical material properties that enable this forbidden pathway. Through a strikingly simple technique, this result opens the door for new mechanistic insights into 1TT and other dark states in organic materials.
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Affiliation(s)
- Juno Kim
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - David C Bain
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Vivian Ding
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Kanad Majumder
- Solid State and Structural Chemistry Unit, Indian Institute of Sciences, Bangalore, Republic of India
| | - Dean Windemuller
- Center for Applied Energy Research, University of Kentucky, Lexington, KY, USA
| | - Jiaqi Feng
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore
| | - Satish Patil
- Solid State and Structural Chemistry Unit, Indian Institute of Sciences, Bangalore, Republic of India
| | - John Anthony
- Center for Applied Energy Research, University of Kentucky, Lexington, KY, USA
| | - Woojae Kim
- Department of Chemistry, Yonsei University, Seoul, Republic of Korea.
| | - Andrew J Musser
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
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2
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Purdy M, Budden P, Fallon K, Gannett CN, Abruña HD, Zeng W, Friend R, Musser AJ, Bronstein H. Re-Thinking Dimer Design Principles with Indolonaphthyridine Intramolecular Singlet Fission. Chemistry 2023; 29:e202301547. [PMID: 37377132 DOI: 10.1002/chem.202301547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 06/29/2023]
Abstract
Singlet fission is a phenomenon that could significantly improve the efficiency of photovoltaic devices. Indolonaphthyridine thiophene (INDT) is a photostable singlet fission material that could potentially be utilised in singlet fission-based photovoltaic devices. This study investigates the intramolecular singlet fission (i-SF) mechanism of INDT dimers linked via para-phenyl, meta-phenyl and fluorene bridging groups. Using ultra-fast spectroscopy the highest rate of singlet fission is found in the para-phenyl linked dimer. Quantum calculations show the para-phenyl linker encourages enhanced monomer electronic coupling. Increased rates of singlet fission were also observed in the higher polarity o-dichlorobenzene, relative to toluene, indicating that charge-transfer states have a role in mediating the process. The mechanistic picture of polarisable singlet fission materials, such as INDT, extends beyond the traditional mechanistic landscape.
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Affiliation(s)
- Michael Purdy
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Baker Lab, 122, E Ave, Ithaca, NY, USA
| | - Peter Budden
- Department of Physics, University of Cambridge, Cavendish Laboratory, Cambridge, CB3 0HE, UK
| | - Kealan Fallon
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Baker Lab, 122, E Ave, Ithaca, NY, USA
| | - Cara N Gannett
- Department of Chemistry & Chemical Biology, Cornell University, Baker Lab, 122, E Ave, Ithaca, NY, USA
| | - Héctor D Abruña
- Department of Chemistry & Chemical Biology, Cornell University, Baker Lab, 122, E Ave, Ithaca, NY, USA
| | - Weixuan Zeng
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Baker Lab, 122, E Ave, Ithaca, NY, USA
| | - Richard Friend
- Department of Physics, University of Cambridge, Cavendish Laboratory, Cambridge, CB3 0HE, UK
| | - Andrew J Musser
- Department of Chemistry & Chemical Biology, Cornell University, Baker Lab, 122, E Ave, Ithaca, NY, USA
| | - Hugo Bronstein
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Baker Lab, 122, E Ave, Ithaca, NY, USA
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3
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Lin LC, Smith T, Ai Q, Rugg BK, Risko C, Anthony JE, Damrauer NH, Johnson JC. Multiexciton quintet state populations in a rigid pyrene-bridged parallel tetracene dimer. Chem Sci 2023; 14:11554-11565. [PMID: 37886089 PMCID: PMC10599476 DOI: 10.1039/d3sc03153e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/01/2023] [Indexed: 10/28/2023] Open
Abstract
The multiexciton quintet state, 5TT, generated as a singlet fission intermediate in pairs of molecular chromophores, is a promising candidate as a qubit or qudit in future quantum information science schemes. In this work, we synthesize a pyrene-bridged parallel tetracene dimer, TPT, with an optimized interchromophore coupling strength to prevent the dissociation of 5TT to two decorrelated triplet (T1) states, which would contaminate the spin-state mixture. Long-lived and strongly spin-polarized pure 5TT state population is observed via transient absorption spectroscopy and transient/pulsed electron paramagnetic resonance spectroscopy, and its lifetime is estimated to be >35 µs, with the dephasing time (T2) for the 5TT-based qubit measured to be 726 ns at 10 K. Direct relaxation from 1TT to the ground state does diminish the overall excited state population, but the exclusive 5TT population at large enough persistent density for pulsed echo determination of spin coherence time is consistent with recent theoretical models that predict such behavior for strict parallel chromophore alignment and large exchange coupling.
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Affiliation(s)
- Liang-Chun Lin
- Department of Chemistry, University of Colorado Boulder Boulder CO 80309 USA
| | - Tanner Smith
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - Qianxiang Ai
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - Brandon K Rugg
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
| | - Chad Risko
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - John E Anthony
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - Niels H Damrauer
- Department of Chemistry, University of Colorado Boulder Boulder CO 80309 USA
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder Boulder CO 80309 USA
| | - Justin C Johnson
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder Boulder CO 80309 USA
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4
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Ringström R, Schroeder ZW, Mencaroni L, Chabera P, Tykwinski RR, Albinsson B. Triplet Formation in a 9,10-Bis(phenylethynyl)anthracene Dimer and Trimer Occurs by Charge Recombination Rather than Singlet Fission. J Phys Chem Lett 2023; 14:7897-7902. [PMID: 37642563 PMCID: PMC10494225 DOI: 10.1021/acs.jpclett.3c02050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
We present an experimental study investigating the solvent-dependent dynamics of a 9,10-bis(phenylethynyl)anthracene monomer, dimer, and trimer. Using transient absorption spectroscopy, we have discovered that triplet excited state formation in the dimer and trimer molecules in polar solvents is a consequence of charge recombination subsequent to symmetry-breaking charge separation rather than singlet fission. Total internal reflection emission measurements of the monomer demonstrate that excimer formation serves as the primary decay pathway at a high concentration. In the case of highly concentrated solutions of the trimer, we observe evidence of triplet formation without the prior formation of a charge-separated state. We postulate that this is attributed to the formation of small aggregates, suggesting that oligomers mimicking the larger chromophore counts in crystals could potentially facilitate singlet fission. Our experimental study sheds light on the intricate dynamics of the 9,10-bis(phenylethynyl)anthracene system, elucidating the role of solvent- and concentration-dependent factors for triplet formation and charge separation.
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Affiliation(s)
- Rasmus Ringström
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Zachary W. Schroeder
- Department
of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Letizia Mencaroni
- Department
of Chemistry Biology and Biotechnology, University of Perugia, via elce di sotto n. 8, 06123 Perugia, Italy
| | - Pavel Chabera
- The
Division of Chemical Physics and NanoLund, Lund University, 22100 Lund, Sweden
| | - Rik R. Tykwinski
- Department
of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
| | - Bo Albinsson
- Department
of Chemistry and Chemical Engineering, Chalmers
University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
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5
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Kefer O, Ahrens L, Han J, Wollscheid N, Misselwitz E, Rominger F, Freudenberg J, Dreuw A, Bunz UHF, Buckup T. Efficient Intramolecular Singlet Fission in Spiro-Linked Heterodimers. J Am Chem Soc 2023; 145:17965-17974. [PMID: 37535495 DOI: 10.1021/jacs.3c05518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
We investigate intramolecular singlet fission (iSF) of spiro-linked azaacene heterodimers by time-resolved spectroscopy and quantum chemical calculations. Combining two different azaacenes through a nonconjugated linker using condensation chemistry furnishes azaacene heterodimers. Compared to their homodimers, iSF quantum yields are improved at an extended absorption range. The driving force of iSF, the energy difference ΔEiSF between the S1 state and the correlated triplet pair 1(TT), is tuned by the nature of the heterodimers. iSF is exothermic in all of the herein studied molecules. The overall quantum yield for triplet exciton formation reaches approximately 174%. This novel concept exploits large energy differences between singlet electronic states in combination with spatially fixed chromophores, which achieves efficient heterogeneous iSF, if the through-space interaction between the chromophores is minimal.
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Affiliation(s)
- Oskar Kefer
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Lukas Ahrens
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Jie Han
- Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Nikolaus Wollscheid
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Erik Misselwitz
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Jan Freudenberg
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Andreas Dreuw
- Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
- Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Uwe H F Bunz
- Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
- Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Tiago Buckup
- Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
- Centre for Advanced Materials, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany
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6
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Quantum interference effects elucidate triplet-pair formation dynamics in intramolecular singlet-fission molecules. Nat Chem 2023; 15:339-346. [PMID: 36585444 DOI: 10.1038/s41557-022-01107-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 11/03/2022] [Indexed: 12/31/2022]
Abstract
Quantum interference (QI)-the constructive or destructive interference of conduction pathways through molecular orbitals-plays a fundamental role in enhancing or suppressing charge and spin transport in organic molecular electronics. Graphical models were developed to predict constructive versus destructive interference in polyaromatic hydrocarbons and have successfully estimated the large conductivity differences observed in single-molecule transport measurements. A major challenge lies in extending these models to excitonic (photoexcited) processes, which typically involve distinct orbitals with different symmetries. Here we investigate how QI models can be applied as bridging moieties in intramolecular singlet-fission compounds to predict relative rates of triplet pair formation. In a series of bridged intramolecular singlet-fission dimers, we found that destructive QI always leads to a slower triplet pair formation across different bridge lengths and geometries. A combined experimental and theoretical approach reveals the critical considerations of bridge topology and frontier molecular orbital energies in applying QI conductance principles to predict rates of multiexciton generation.
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7
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Bansal D, Kundu A, Singh VP, Pal AK, Datta A, Dasgupta J, Mukhopadhyay P. A highly contorted push-pull naphthalenediimide dimer and evidence of intramolecular singlet exciton fission. Chem Sci 2022; 13:11506-11512. [PMID: 36320404 PMCID: PMC9555572 DOI: 10.1039/d2sc04187a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/05/2022] [Indexed: 08/05/2023] Open
Abstract
Singlet fission is a process by which two molecular triplet excitons are generated subsequent to the absorption of one photon. Molecules that enable singlet fission have triplet state energy at least half of the bright singlet state energy. This stringent energy criteria have challenged chemists to device new molecular and supramolecular design principles to modulate the singlet-triplet energy gap and build singlet fission systems from a wide range of organic chromophores. Herein, we report for the first time intramolecular singlet fission in the seminal naphthalenediimide (NDI) scaffold constrained in a push-pull cyclophane architecture, while individually the NDI chromophore does not satisfy the energy criterion. The challenging synthesis of this highly contorted push-pull cyclophane is possible from the preorganized pincer-like precursor. The special architecture establishes the shortest co-facial NDI⋯NDI contacts (3.084 Å) realized to date. Using broadband femtosecond transient absorption, we find that the correlated T-T pair forms rapidly within 380 fs of photoexcitation. Electronic structure calculations at the level of state-averaged CASSCF (ne,mo)/XMCQDPT2 support the existence of the multi-excitonic T-T pair state, thereby confirming the first example of singlet exciton fission in a NDI scaffold.
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Affiliation(s)
- Deepak Bansal
- School of Physical Sciences, Jawaharlal Nehru University New Delhi 110067 India
| | - Arup Kundu
- Department of Chemical Sciences, Tata Institute of Fundamental Research Mumbai 400005 India
| | - Vijay Pal Singh
- School of Physical Sciences, Jawaharlal Nehru University New Delhi 110067 India
| | - Arun K Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science Kolkata 700032 West Bengal India
| | - Ayan Datta
- School of Chemical Sciences, Indian Association for the Cultivation of Science Kolkata 700032 West Bengal India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research Mumbai 400005 India
| | - Pritam Mukhopadhyay
- School of Physical Sciences, Jawaharlal Nehru University New Delhi 110067 India
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8
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Sharma A, Athanasopoulos S, Li Y, Sanders SN, Kumarasamy E, Campos LM, Lakhwani G. Probing Through-Bond and Through-Space Interactions in Singlet Fission-Based Pentacene Dimers. J Phys Chem Lett 2022; 13:8978-8986. [PMID: 36149007 DOI: 10.1021/acs.jpclett.2c02061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Interchromophoric interactions such as Coulombic coupling and exchange interactions are crucial to the functional properties of numerous π-conjugated systems. Here, we use magnetic circular dichroism (MCD) spectroscopy to investigate interchromophoric interactions in singlet fission relevant pentacene dimers. Using a simple analytical model, we outline a general relationship between the geometry of pentacene dimers and their calculated MCD response. We analyze experimental MCD spectra of different covalently bridged pentacene dimers to reveal how the molecular structure of the "bridge" affects the magnitude of through-space Coulombic and through-bond exchange interactions in the system. Our results show that through-bond interactions are significant in dimers with conjugated molecules as bridging units and these interactions promote the overall electronic coupling in the system. Our generalized approach paves the way for the application of MCD in investigating interchromophoric interactions across a range of π-conjugated systems.
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Affiliation(s)
- Ashish Sharma
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Stavros Athanasopoulos
- Departamento de Física, Universidad Carlos III de Madrid, Avenida Universidad 30, Leganés, 28911 Madrid, Spain
| | - Yun Li
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Elango Kumarasamy
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Girish Lakhwani
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
- The University of Sydney Nano Institute, Sydney, New South Wales 2006, Australia
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9
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Parallel triplet formation pathways in a singlet fission material. Nat Commun 2022; 13:5244. [PMID: 36068233 PMCID: PMC9448805 DOI: 10.1038/s41467-022-32844-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 08/18/2022] [Indexed: 11/08/2022] Open
Abstract
Harvesting long-lived free triplets in high yields by utilizing organic singlet fission materials can be the cornerstone for increasing photovoltaic efficiencies potentially. However, except for polyacenes, which are the most studied systems in the singlet fission field, spin-entangled correlated triplet pairs and free triplets born through singlet fission are relatively poorly characterized. By utilizing transient absorption and photoluminescence spectroscopy in supramolecular aggregate thin films consisting of Hamilton-receptor-substituted diketopyrrolopyrrole derivatives, we show that photoexcitation gives rise to the formation of spin-0 correlated triplet pair 1(TT) from the lower Frenkel exciton state. The existence of 1(TT) is proved through faint Herzberg-Teller emission that is enabled by vibronic coupling and correlated with an artifact-free triplet-state photoinduced absorption in the near-infrared. Surprisingly, transient electron paramagnetic resonance reveals that long-lived triplets are produced through classical intersystem crossing instead of 1(TT) dissociation, with the two pathways in competition. Moreover, comparison of the triplet-formation dynamics in J-like and H-like thin films with the same energetics reveals that spin-orbit coupling mediated intersystem crossing persists in both. However, 1(TT) only forms in the J-like film, pinpointing the huge impact of intermolecular coupling geometry on singlet fission dynamics.
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10
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Paul S, Karunakaran V. Excimer Formation Inhibits the Intramolecular Singlet Fission Dynamics: Systematic Tilting of Pentacene Dimers by Linking Positions. J Phys Chem B 2022; 126:1054-1062. [PMID: 35107283 DOI: 10.1021/acs.jpcb.1c07951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The role of excimer formation in inhibiting or enhancing the efficiency of the intramolecular singlet fission (iSF) process has been a subject of recent debate. Here, we investigated the effect of excimer formation on iSF dynamics by modifying its configuration by connecting pentacenes at various positions. Hence, pentacene dimers having slip-stacked (2,2' BP, J-type), oblique (2,6' BP), and facial (6,6' BP, H-type) configurations were synthesized by covalently linking pentacenes at positions 2,2', 2,6', and 6,6', respectively, with an ethynyl bridge, and their ultrafast excited-state relaxation dynamics were characterized. Femtosecond time-resolved transient absorption spectra revealed that the efficiency of iSF dynamics decreased from slip-stacked (182%) to oblique configuration (97%),whereas in the 6,6' BP with facial configuration, strong electronic coupling led to the formation of excimers that decayed nonradiatively without formation of correlated triplet pairs. These studies reveal the formation of excimers by strong intrapentacene electronic coupling upon ultrafast excitation, preventing the efficient iSF process.
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Affiliation(s)
- Sumitha Paul
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala 695 019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Venugopal Karunakaran
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, Kerala 695 019, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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11
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Manna B, Nandi A, Vats BG. Role of nanosize and defect trapping upon singlet fission yield and singlet fission dynamics of 1,6-Diphenyl-1,3,5-hexatriene nanoaggregates. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113262] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Manna B, Nandi A. Singlet fission in nanoaggregate of bis(phenylethynyl) derivative of benzene (BPEB): High energy triplet exciton generation with >100 % yield. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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13
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Kundu A, Dasgupta J. Photogeneration of Long-Lived Triplet States through Singlet Fission in Lycopene H-Aggregates. J Phys Chem Lett 2021; 12:1468-1474. [PMID: 33528257 DOI: 10.1021/acs.jpclett.0c03301] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Molecular triplet excitons produced through singlet fission (SF) usually have shorter triplet lifetimes due to exciton-exciton recombination and relaxation pathways, thereby resulting in complex device architectures for SF-boosted solar cells. Using broadband transient absorption spectroscopy, we here show that the photoexcitation of nanostructured lycopene H-aggregates at room temperature produces free triplets with an unprecedented 35-fold enhancement in the lifetime compared to those localized on the monomer backbone. The observed rise of a spectrally blue-shifted correlated T-T pair state in ∼19 ps with distinct vibronic features provides the basis for SF-induced triplet generation.
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Affiliation(s)
- Arup Kundu
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400005, India
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14
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Salzner U. Optoelectronic properties of diketopyrrolopyrrole homopolymers compared to donor-acceptor copolymers. J Chem Phys 2021; 154:054309. [PMID: 33557558 DOI: 10.1063/5.0038284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Diketopyrrolopyrrole (DPP) is a component of a large number of materials used for optoelectronic applications. As it is exclusively used in combination with aromatic donors, the properties of its homopolymers are unknown. Because donor-acceptor character has been shown for other systems to reduce bandwidths, DPP homopolymers should have even larger conduction bands and better n-type conductivity than the thiophene-flanked systems, which have exceptional n-type conductivity and ambipolar character. Therefore, a theoretical study was carried out to elucidate the properties of the unknown DPP homopolymer. Calculations were done with density functional theory and with the complete active space self-consistent field method plus n-electron valence state perturbation theory for the dynamic correlation. Poly-DPP is predicted to have radical character and an extremely wide low-lying conduction band. If it were possible to produce this material, it should have unprecedented n-type conductivity and might be a synthetic metal. A comparison with various unknown donor-acceptor systems containing vinyl groups and thienyl rings with a higher concentration of DPP than the known copolymers reveals how donor-acceptor substitution reduces bandwidths and decreases electron affinities.
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Affiliation(s)
- Ulrike Salzner
- Department of Chemistry, Bilkent University, 06800 Bilkent, Ankara, Turkey
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15
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Zirzlmeier J, Lavarda G, Gotfredsen H, Papadopoulos I, Chen L, Clark T, Tykwinski RR, Torres T, Guldi DM. Modulating the dynamics of Förster resonance energy transfer and singlet fission by variable molecular spacers. NANOSCALE 2020; 12:23061-23068. [PMID: 33179680 DOI: 10.1039/d0nr06285e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In contrast to previous work, the synergy between panchromatic absorption and molecular singlet fission (SF) is exploited to optimize solar energy conversion through evaluation of the distance dependence of intramolecular Förster Resonance Energy Transfer (i-FRET) in a series of subphthalocyanines (SubPcs) linked to pentacene dimers (Pnc2s). To provide control over i-FRET, the molecular spacer rather than the energy donating SubPc is tailored in the corresponding SubPc-Pnc2 conjugates in terms of length (i.e., the number of aryl units) and flexibility (i.e., presence or absence of a CH2 group). AM1-CIS calculations support the experiments, which underline the importance of the molecular spacer to impact not only the i-FRET dynamics, but also the dynamics of intramolecular singlet fission (i-SF). For example, an additional phenyl group slows down both i-FRET and i-SF by a factor of ∼3.8 and ∼1.6, respectively, by a quinone-like conjugation pattern that affords a pentacene acceptor orbital that is fairly delocalized over both pentacenes and the bridging phenyl.
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Affiliation(s)
- Johannes Zirzlmeier
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058 Erlangen, Germany.
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16
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Taffet EJ, Beljonne D, Scholes GD. Overlap-Driven Splitting of Triplet Pairs in Singlet Fission. J Am Chem Soc 2020; 142:20040-20047. [PMID: 33190497 DOI: 10.1021/jacs.0c09276] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We analyze correlated-triplet-pair (TT) singlet-fission intermediates toward two-triplet separation (T...T) using spin-state-averaged density matrix renormalization group electronic-structure calculations. Specifically, we compare the triplet-triplet exchange (J) for tetracene dimers, bipentacene, a subunit of the benzodithiophene-thiophene dioxide polymer, and a carotenoid (neurosporene). Exchange-split energy gaps of J and 3J separate a singlet from a triplet and a singlet from a quintet, respectively. We draw two new insights: (a) the canonical tetracene singlet-fission unit cell supports precisely three low-lying TT intermediates with order-of-magnitude differences in J, and (b) the separable TT intermediate in carotenoids emanates from a pair of excitations to the second triplet state. Therefore, unlike with tetracenes, carotenoid fission requires above-gap excitations. In all cases, the distinguishability of the molecular triplets-that is, the extent of orbital overlap-determines the splitting within the spin manifold of TT states. Consequently, J represents a spectroscopic observable that distnguishes the resemblance between TT intermediates and the T...T product.
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Affiliation(s)
- Elliot J Taffet
- Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - David Beljonne
- Department of Chemistry, University of Mons, 7000 Mons, Belgium
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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17
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Saes BW, Lutz M, Wienk MM, Meskers SCJ, Janssen RAJ. Tuning the Optical Characteristics of Diketopyrrolopyrrole Molecules in the Solid State by Alkyl Side Chains. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:25229-25238. [PMID: 33244323 PMCID: PMC7682139 DOI: 10.1021/acs.jpcc.0c07334] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/25/2020] [Indexed: 06/11/2023]
Abstract
The optical properties of two sets of donor-acceptor-donor molecules with terminal bithiophene donor units and a central diketopyrrolopyrrole (DPP) acceptor unit are studied. The two sets differ in the alkyl chains on the DPP, which are either branched at the α-carbon (3-pentyl) (1-4) or linear (n-hexyl) (5-8). Within each set, the molecules differ by the absence or presence of n-hexyl chains on the terminal thiophene rings in the 3', 4', or 5' positions. While in solution, the optical spectra differ only subtly; they differ dramatically in the solid state. In contrast to 5-8, 1-4 are nonplanar as a consequence of the sterically demanding 3-pentyl groups, which inhibit π-stacking of the DPP units. Using the crystal structures of 2 (brick layer stacking) and 6 (slipped stacking), we quantitatively explain the solid state absorption spectra. By computing the molecular transition charge density and solving the dispersion relation, the optical absorption of the molecules in the crystal is predicted and in agreement with experiments. For 2, a single resonance frequency is obtained, while for 6 two transitions are seen, with the lower-energy transition being less intense. The results demonstrate how subtle changes in substitution exert large effects in optical properties.
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Affiliation(s)
- Bart W.
H. Saes
- Molecular
Materials and Nanosystems & Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Martin Lutz
- Utrecht
University, Crystal and Structural
Chemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, 3584 CH Utrecht, The Netherlands
| | - Martijn M. Wienk
- Molecular
Materials and Nanosystems & Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Stefan C. J. Meskers
- Molecular
Materials and Nanosystems & Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - René A. J. Janssen
- Molecular
Materials and Nanosystems & Institute for Complex Molecular Systems, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
- Dutch
Institute for Fundamental Energy Research, 5612 AJ Eindhoven, The Netherlands
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18
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Wollscheid N, Lustres JLP, Brosius V, Motzkus M, Bunz UHF, Buckup T. Diffusion-Controlled Singlet Fission in a Chlorinated Phenazinothiadiazole by Broadband Femtosecond Transient Absorption. J Phys Chem B 2020; 124:10186-10194. [PMID: 33118824 DOI: 10.1021/acs.jpcb.0c05056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Singlet fission (SF) is a process by which one excited singlet state yields two triplet states upon close interaction with a ground-state chromophore of the same kind. This photoreaction was first observed in solid state and has important implications in organic photovoltaics. Singlet fission was also reported in concentrated solutions, where the need for diffusion of the reaction partners slows the dynamics. This helps to single out reaction stages and to identify the involved species. In this work, ultrafast transient absorption spectroscopy and time-correlated single photon counting are applied to the concentration-dependent (from 10-1 to 102 mM) photodynamics of a tetrachlorinated phenazinothiadiazole in toluene. Time-resolved emission shows a monoexponential decay, which is constant across the emission band. The corresponding decay rate depends linearly on the concentration of the phenazinothiadiazole. Femtosecond transient absorption demonstrates that a concentration-dependent singlet-to-triplet conversion hides behind the emission decay which is diffusion controlled. Contrary to previous reports on SF in pentacenes and tetracenes, no indication of intermediate states has been found. Efficient, direct and barrierless SF is concluded. The strong enhancement of the triplet yield at increasingly higher concentrations of the thiadiazole indicates very efficient singlet fission with a triplet yield up to 189 ± 5%.
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Affiliation(s)
- Nikolaus Wollscheid
- Physikalisch-Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany.,Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - Jose Luis Pérez Lustres
- Physikalisch-Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany.,Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - Victor Brosius
- Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany.,Organisch-Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - Marcus Motzkus
- Physikalisch-Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany.,Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - Uwe H F Bunz
- Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany.,Organisch-Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
| | - Tiago Buckup
- Physikalisch-Chemisches Institut, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany.,Centre for Advanced Materials, Ruprecht-Karls Universität, D-69120 Heidelberg, Germany
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19
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Ullrich T, Pinter P, Messelberger J, Haines P, Kaur R, Hansmann MM, Munz D, Guldi DM. Singlet Fission in Carbene-Derived Diradicaloids. Angew Chem Int Ed Engl 2020; 59:7906-7914. [PMID: 32129920 PMCID: PMC7317569 DOI: 10.1002/anie.202001286] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/21/2020] [Indexed: 01/12/2023]
Abstract
Herein, we present a new class of singlet fission (SF) materials based on diradicaloids of carbene scaffolds, namely cyclic (alkyl)(amino)carbenes (CAACs). Our modular approach allows the tuning of two key SF criteria: the steric factor and the diradical character. In turn, we modified the energy landscapes of excited states in a systematic manner to accommodate the needs for SF. We report the first example of intermolecular SF in solution by dimer self-assembly at cryogenic temperatures.
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Affiliation(s)
- Tobias Ullrich
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Piermaria Pinter
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM), Allgemeine und Anorganische ChemieFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 191058ErlangenGermany
| | - Julian Messelberger
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM), Allgemeine und Anorganische ChemieFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 191058ErlangenGermany
| | - Philipp Haines
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Ramandeep Kaur
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
| | - Max M. Hansmann
- Fakultät für Chemie und Chemische BiologieTechnische Universität DortmundOtto-Hahn Straße 644227DortmundGermany
| | - Dominik Munz
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM), Allgemeine und Anorganische ChemieFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 191058ErlangenGermany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM)Friedrich-Alexander-Universität Erlangen-NürnbergEgerlandstraße 391058ErlangenGermany
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20
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Ullrich T, Pinter P, Messelberger J, Haines P, Kaur R, Hansmann MM, Munz D, Guldi DM. Singlet Fission in Carbene‐Derived Diradicaloids. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001286] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tobias Ullrich
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Germany
| | - Piermaria Pinter
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM), Allgemeine und Anorganische Chemie Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Julian Messelberger
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM), Allgemeine und Anorganische Chemie Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Philipp Haines
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Germany
| | - Ramandeep Kaur
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Germany
| | - Max M. Hansmann
- Fakultät für Chemie und Chemische Biologie Technische Universität Dortmund Otto-Hahn Straße 6 44227 Dortmund Germany
| | - Dominik Munz
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM), Allgemeine und Anorganische Chemie Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 1 91058 Erlangen Germany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy Interdisciplinary Center for Molecular Materials (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstraße 3 91058 Erlangen Germany
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21
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Korovina NV, Pompetti NF, Johnson JC. Lessons from intramolecular singlet fission with covalently bound chromophores. J Chem Phys 2020; 152:040904. [PMID: 32007061 DOI: 10.1063/1.5135307] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Molecular dimers, oligomers, and polymers are versatile components in photophysical and optoelectronic architectures that could impact a variety of applications. We present a perspective on such systems in the field of singlet fission, which effectively multiplies excitons and produces a unique excited state species, the triplet pair. The choice of chromophore and the nature of the attachment between units, both geometrical and chemical, play a defining role in the dynamical scheme that evolves upon photoexcitation. Specific final outcomes (e.g., separated and uncorrelated triplet pairs) are being sought through rational design of covalently bound chromophore architectures built with guidance from recent fundamental studies that correlate structure with excited state population flow kinetics.
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Affiliation(s)
- Nadezhda V Korovina
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
| | - Nicholas F Pompetti
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
| | - Justin C Johnson
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
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22
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Alvertis AM, Lukman S, Hele TJH, Fuemmeler EG, Feng J, Wu J, Greenham NC, Chin AW, Musser AJ. Switching between Coherent and Incoherent Singlet Fission via Solvent-Induced Symmetry Breaking. J Am Chem Soc 2019; 141:17558-17570. [DOI: 10.1021/jacs.9b05561] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Antonios M. Alvertis
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Steven Lukman
- Institute of Materials Research and Engineering, Agency for Science Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Timothy J. H. Hele
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Eric G. Fuemmeler
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jiaqi Feng
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore
| | - Neil C. Greenham
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Alex W. Chin
- CNRS & Institut des NanoSciences de Paris, Sorbonne Université, 4 place Jussieu boite courrier 840, 75252 Paris Cedex 05, France
| | - Andrew J. Musser
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, U.K
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23
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Ellis SR, Dietze DR, Rangel T, Brown-Altvater F, Neaton JB, Mathies RA. Resonance Raman Characterization of Tetracene Monomer and Nanocrystals: Excited State Lattice Distortions With Implications For Efficient Singlet Fission. J Phys Chem A 2019; 123:3863-3875. [PMID: 30952191 DOI: 10.1021/acs.jpca.9b02986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The characterization of specific phonon modes and exciton states that lead to efficient singlet fission (SF) may be instrumental in the design of the next generation of high-efficiency photovoltaic devices. To this end, we analyze the absolute resonance Raman (RR) cross sections for tetracene (Tc) both as a monomer in solution and as a crystalline solid in an aqueous suspension of nanocrystals. For both systems, a time-dependent wavepacket model is developed that is consistent with the absolute RR cross sections, the magnitude of the absorption cross sections, and the vibronic line shapes of the fluorescence. In the monomer, the intramolecular reorganization energy is between 1500 and 1800 cm-1 and the solvent reorganization energy is 70 cm-1. In nanocrystals, the total reorganization is diminished to less than 600 cm-1. The lowest energy exciton has an estimated intramolecular reorganization energy between 300 and 500 cm-1 while intermolecular librational phonons have a reorganization energy of about 130 cm-1. The diminished reorganization energy of the nanocrystal is interpreted in the context of the delocalization of the band-edge exciton onto about ∼7 molecules. When electron and electron-hole correlations are included within many-body perturbation theory, the polarized absorption spectra of crystalline Tc are calculated and found to be in agreement with experiment. The low-lying exciton states and optically active phonons that contribute to the polarized crystal absorption are identified. The likely role of coherent exciton phonon evolution in the SF process is discussed.
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Affiliation(s)
- Scott R Ellis
- Department of Chemistry, MC 1460 , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Daniel R Dietze
- Department of Chemistry, MC 1460 , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Tonatiuh Rangel
- Department of Physics, MC 7300 , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Florian Brown-Altvater
- Department of Physics, MC 7300 , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Jeffrey B Neaton
- Department of Physics, MC 7300 , University of California at Berkeley , Berkeley , California 94720 , United States
| | - Richard A Mathies
- Department of Chemistry, MC 1460 , University of California at Berkeley , Berkeley , California 94720 , United States
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24
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Basel BS, Papadopoulos I, Thiel D, Casillas R, Zirzlmeier J, Clark T, Guldi DM, Tykwinski RR. Pentacenes: A Molecular Ruler for Singlet Fission. TRENDS IN CHEMISTRY 2019. [DOI: 10.1016/j.trechm.2019.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Philip AM, Gudem M, Sebastian E, Hariharan M. Decoding the Curious Tale of Atypical Intersystem Crossing Dynamics in Regioisomeric Acetylanthracenes. J Phys Chem A 2019; 123:6105-6112. [DOI: 10.1021/acs.jpca.9b00766] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Abbey M. Philip
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Mahesh Gudem
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Ebin Sebastian
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Maruthamala P. O., Vithura, Thiruvananthapuram, Kerala 695551, India
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