1
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Freudenberg J, Bunz UHF. How to Stabilize Large Soluble (Hetero-)Acenes. J Am Chem Soc 2024; 146:16937-16949. [PMID: 38862130 PMCID: PMC11212629 DOI: 10.1021/jacs.4c03484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/16/2024] [Accepted: 05/16/2024] [Indexed: 06/13/2024]
Abstract
The higher acenes and azaacenes (>(aza)heptacenes) are fascinating, yet elusive materials. Their reactivity and sensitivity increases concomitantly with their size. In recent years, confinement techniques, that is isolation of acenes in matrices and on surfaces, has surpassed solution-based chemistry with respect to accessing the larger (hetero)acenes at the price of the accessibility of no more than a couple thousands of molecules. Isolating acenes in bulk quantities and in processable form is vital for applications in organic electronics as well as from a viewpoint from basic research. In this Perspective, we will discuss after a short historical outline their degradation pathways, and then will selectively highlight recent efforts in stabilizing soluble (aza)acenes.
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Affiliation(s)
- Jan Freudenberg
- Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Uwe H. F. Bunz
- Ruprecht-Karls-Universität
Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
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2
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Zhang Q, Shao X, Li W, Mi W, Pavanello M, Akimov AV. Nonadiabatic molecular dynamics with subsystem density functional theory: application to crystalline pentacene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:385901. [PMID: 38866023 DOI: 10.1088/1361-648x/ad577d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/12/2024] [Indexed: 06/14/2024]
Abstract
In this work, we report the development and assessment of the nonadiabatic molecular dynamics approach with the electronic structure calculations based on the linearly scaling subsystem density functional method. The approach is implemented in an open-source embedded Quantum Espresso/Libra software specially designed for nonadiabatic dynamics simulations in extended systems. As proof of the applicability of this method to large condensed-matter systems, we examine the dynamics of nonradiative relaxation of excess excitation energy in pentacene crystals with the simulation supercells containing more than 600 atoms. We find that increased structural disorder observed in larger supercell models induces larger nonadiabatic couplings of electronic states and accelerates the relaxation dynamics of excited states. We conduct a comparative analysis of several quantum-classical trajectory surface hopping schemes, including two new methods proposed in this work (revised decoherence-induced surface hopping and instantaneous decoherence at frustrated hops). Most of the tested schemes suggest fast energy relaxation occurring with the timescales in the 0.7-2.0 ps range, but they significantly overestimate the ground state recovery rates. Only the modified simplified decay of mixing approach yields a notably slower relaxation timescales of 8-14 ps, with a significantly inhibited ground state recovery.
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Affiliation(s)
- Qingxin Zhang
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260, United States of America
| | - Xuecheng Shao
- Department of Physics, Rutgers University, The State University of New Jersey, Newark, NJ 07102, United States of America
| | - Wei Li
- School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, People's Republic of China
| | - Wenhui Mi
- Key Laboratory of Material Simulation Methods & Software of Ministry of Education, College of Physics, Jilin University, Changchun 130012, People's Republic of China
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China
| | - Michele Pavanello
- Department of Physics, Rutgers University, The State University of New Jersey, Newark, NJ 07102, United States of America
| | - Alexey V Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260, United States of America
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3
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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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4
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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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5
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Wang Z, Xie X, Ma H. Simultaneous Intra- and Intermolecular Singlet Fission in Bipentacene Macrocycle Aggregates. J Phys Chem Lett 2024; 15:3523-3530. [PMID: 38522085 DOI: 10.1021/acs.jpclett.4c00300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Singlet fission (SF) is a process where a singlet state splits into two triplet states, which is essential for enhancing optoelectronic devices. Macrocyclic structures allow for precise control of chromophore orientation and facilitate singlet fission in solutions. However, the behavior of these structures in thin films, crucial for solid-state device optimization, remains underexplored. This study examines the aggregation and singlet fission processes of bipentacene macrocycles (BPc) in thin films using molecular dynamics simulations and electronic structure calculations. Findings indicate that BPc aggregates more rapidly with less chloroform, aligning parallel to the substrate. Intramolecular singlet fission (iSF) rates are rarely changed during evaporation, but the efficiency of intermolecular singlet fission (xSF) improves due to the increase in packing domains, suggesting that orderly crystal domains are not necessary for device efficiency. This opens avenues for varied device designs and traditional solution-based methods for optimal device development.
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Affiliation(s)
- Zhangxia Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Xiaoyu Xie
- Qingdao Institute for Theoretical and Computational Sciences, School of Chemistry and Chemical Engineering, Shandong University, Qingdao, Shandong 266237, China
| | - Haibo Ma
- Qingdao Institute for Theoretical and Computational Sciences, School of Chemistry and Chemical Engineering, Shandong University, Qingdao, Shandong 266237, China
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6
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Cohen G, Haber JB, Neaton JB, Qiu DY, Refaely-Abramson S. Phonon-Driven Femtosecond Dynamics of Excitons in Crystalline Pentacene from First Principles. PHYSICAL REVIEW LETTERS 2024; 132:126902. [PMID: 38579218 DOI: 10.1103/physrevlett.132.126902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 08/24/2023] [Accepted: 02/11/2024] [Indexed: 04/07/2024]
Abstract
Nonradiative exciton relaxation processes are critical for energy transduction and transport in optoelectronic materials, but how these processes are connected to the underlying crystal structure and the associated electron, exciton, and phonon band structures, as well as the interactions of all these particles, is challenging to understand. Here, we present a first-principles study of exciton-phonon relaxation pathways in pentacene, a paradigmatic molecular crystal and optoelectronic semiconductor. We compute the momentum- and band-resolved exciton-phonon interactions, and use them to analyze key scattering channels. We find that both exciton intraband scattering and interband scattering to parity-forbidden dark states occur on the same ∼100 fs timescale as a direct consequence of the longitudinal-transverse splitting of the bright exciton band. Consequently, exciton-phonon scattering exists as a dominant nonradiative relaxation channel in pentacene. We further show how the propagation of an exciton wave packet is connected with crystal anisotropy, which gives rise to the longitudinal-transverse exciton splitting and concomitant anisotropic exciton and phonon dispersions. Our results provide a framework for understanding the role of exciton-phonon interactions in exciton nonradiative lifetimes in molecular crystals and beyond.
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Affiliation(s)
- Galit Cohen
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jonah B Haber
- 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
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720, USA
| | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, USA
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
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7
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Deng CL, Obi AD, Tra BYE, Sarkar SK, Dickie DA, Gilliard RJ. Air- and photo-stable luminescent carbodicarbene-azaboraacenium ions. Nat Chem 2024; 16:437-445. [PMID: 38052948 DOI: 10.1038/s41557-023-01381-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/23/2023] [Indexed: 12/07/2023]
Abstract
Substitution of a C=C bond by an isoelectronic B-N bond is a well-established strategy to alter the electronic structure and stability of acenes. BN-substituted acenes that possess narrow energy gaps have attractive optoelectronic properties. However, they are susceptible to air and/or light. Here we present the design, synthesis and molecular structures of fully π-conjugated cationic BN-doped acenes stabilized by carbodicarbene ligands. They are luminescent in the solution and solid states and show high air and moisture stability. Compared with their neutral BN-substituted counterparts as well as the parent all-carbon acenes, these species display improved quantum yields and small optical gaps. The electronic structures of the azabora-anthracene and azabora-tetracene cations resemble higher-order acenes while possessing high photo-oxidative resistance. Investigations using density functional theory suggest that the stability and photo-physics of these conjugated systems may be ascribed to their cationic nature and the electronic properties of the carbodicarbene.
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Affiliation(s)
- Chun-Lin Deng
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Akachukwu D Obi
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Bi Youan E Tra
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Samir Kumar Sarkar
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Robert J Gilliard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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8
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Majumder K, Mukherjee S, Panjwani NA, Lee J, Bittl R, Kim W, Patil S, Musser AJ. Controlling Intramolecular Singlet Fission Dynamics via Torsional Modulation of Through-Bond versus Through-Space Couplings. J Am Chem Soc 2023; 145:20883-20896. [PMID: 37705333 DOI: 10.1021/jacs.3c06075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Covalent dimers, particularly pentacenes, are the dominant platform for developing a mechanistic understanding of intramolecular singlet fission (iSF). Numerous studies have demonstrated that a photoexcited singlet state in these structures can rapidly and efficiently undergo exciton multiplication to form a correlated pair of triplets within a single molecule, with potential applications from photovoltaics to quantum information science. One of the most significant barriers limiting such dimers is the fast recombination of the triplet pair, which prevents spatial separation and the formation of long-lived triplet states. There is an ever-growing need to develop general synthetic strategies to control the evolution of triplets following iSF and enhance their lifetime. Here, we rationally tune the dihedral angle and interchromophore separation between pairs of pentacenes in a systematic series of bridging units to facilitate triplet separation. Through a combination of transient optical and spin-resonance techniques, we demonstrate that torsion within the linker provides a simple synthetic handle to tune the fine balance between through-bond and through-space interchromophore couplings that steer iSF. We show that the full iSF pathway from femtosecond to microsecond timescales is tuned through the static coupling set by molecular design and structural fluctuations that can be biased through steric control. Our approach highlights a straightforward design principle to generate paramagnetic spin pair states with higher yields.
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Affiliation(s)
- Kanad Majumder
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Soham Mukherjee
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Naitik A Panjwani
- Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität, Berlin, Berlin 14195, Berlin, Germany
| | - Jieun Lee
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Robert Bittl
- Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität, Berlin, Berlin 14195, Berlin, Germany
| | - Woojae Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Satish Patil
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Andrew J Musser
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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9
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Li S, Misiewicz JP, Evangelista FA. Intruder-free cumulant-truncated driven similarity renormalization group second-order multireference perturbation theory. J Chem Phys 2023; 159:114106. [PMID: 37712785 DOI: 10.1063/5.0159403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/14/2023] [Indexed: 09/16/2023] Open
Abstract
Accurate multireference electronic structure calculations are important for constructing potential energy surfaces. Still, even in the case of low-scaling methods, their routine use is limited by the steep growth of the computational and storage costs as the active space grows. This is primarily due to the occurrence of three- and higher-body density matrices or, equivalently, their cumulants. This work examines the effect of various cumulant truncation schemes on the accuracy of the driven similarity renormalization group second-order multireference perturbation theory. We test four different levels of three-body reduced density cumulant truncations that set different classes of cumulant elements to zero. Our test cases include the singlet-triplet gap of CH2, the potential energy curves of the XΣg+1 and AΣu+3 states of N2, and the singlet-triplet splittings of oligoacenes. Our results show that both relative and absolute errors introduced by these cumulant truncations can be as small as 0.5 kcal mol-1 or less. At the same time, the amount of memory required is reduced from O(NA6) to O(NA5), where NA is the number of active orbitals. No additional regularization is needed to prevent the intruder state problem in the cumulant-truncated second-order driven similarity renormalization group multireference perturbation theory methods.
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Affiliation(s)
- Shuhang Li
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Jonathon P Misiewicz
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Francesco A Evangelista
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
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10
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Kim J, Teo HT, Hong Y, Liau YC, Yim D, Han Y, Oh J, Kim H, Chi C, Kim D. Leveraging Charge-Transfer Interactions in Through-Space-Coupled Pentacene Dendritic Oligomer for Singlet Exciton Fission. J Am Chem Soc 2023; 145:19812-19823. [PMID: 37656929 DOI: 10.1021/jacs.3c05660] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
Singlet exciton fission in organic chromophores has received much attention during the past decade. Inspired by numerous spectroscopic studies in the solid state, there have been vigorous efforts to study singlet exciton fission dynamics in covalently bonded oligomers, which aims to investigate underlying mechanisms of this intriguing process in simplified model systems. In terms of through-space orbital interactions, however, most of covalently bonded pentacene oligomers studied so far fall into weakly interacting systems since they manifest chain-like structures based on various (non)conjugated linkers. Therefore, it remains as a compelling question to answer how through-space interactions in the solid state intervene this photophysical process since it is hypersensitive to displacements and orientations between neighboring chromophores. Herein, as one of experimental studies to answer this question, we introduced a tight-packing dendritic structure whose mesityl-pentacene constituents are coupled via moderate through-space orbital interactions. Based on the comparison with a suitably controlled dendritic structure, which is in a weak coupling regime, important mechanistic viewpoints are tackled such as configurational mixings between singlet, charge-transfer, and triplet pair states and the role of chromophore multiplication. We underscore that our through-space-coupled dendritic oligomer in a quasi-intermediate coupling regime provides a hint on the interplay of multiconfigurational excited-states, which might have drawn complexity in singlet exciton fission kinetics throughout numerous solid-state morphologies.
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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
| | - Yuan Cheng Liau
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Daniel Yim
- Department of Chemistry, Incheon National University, Incheon 22012, Korea
| | - Yi Han
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Juwon Oh
- Department of ICT Environmental Health System and Department of Chemistry, Soonchunhyang University, Asan 31538, Korea
| | - Hyungjun Kim
- Department of Chemistry, Incheon National University, Incheon 22012, 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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11
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Steer RP. Prospects for useful fission from singlet states higher than S 1 in aggregated organic chromophores. Phys Chem Chem Phys 2023; 25:23384-23394. [PMID: 37646175 DOI: 10.1039/d3cp03201a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
The few known reports and the likely prospects of finding new efficient routes to exciton fission from higher excited singlet states, Sn (n > 1), are reviewed. Aggregates of molecules that have large S2-S1 electronic energy spacings and/or emit measurable "contra-Kasha" emission may offer further opportunities. Among these, electronically excited molecular systems that exhibit known efficient (T1 + T1) triplet-triplet annihilation producing S2 could exhibit efficient singlet fission in aggregates when appropriately substituted to meet the necessary energy requirements. The potential problem of loss of triplet excitons via 2T1 → Tn>1 + S0 triplet-triplet annihilation following (S2 + S0) singlet fission is addressed. Aggregates of substituted azulenes and aliphatic thiones and dithiones are particularly attractive and are discussed in detail.
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Affiliation(s)
- Ronald P Steer
- Department of Chemistry University of Saskatchewan Saskatoon, SK, S7N5C9, Canada.
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12
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Theurer CP, Laible F, Tang J, Broch K, Fleischer M, Schreiber F. Strong light-matter coupling in pentacene thin films on plasmonic arrays. NANOSCALE 2023. [PMID: 37387269 DOI: 10.1039/d3nr01108a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
Utilizing strong light-matter coupling is an elegant and powerful way to modify the energy landscapes of excited states of organic semiconductors. Consequently, the chemical and photophysical properties of these organic semiconductors can be influenced without the need of chemical modification but simply by implementing them in optical microcavities. This has so far mostly been shown in Fabry-Pérot cavities and with organic single crystals or diluted molecules in a host matrix. Here, we demonstrate strong, simultaneous coupling of the two Davydov transitions in polycrystalline pentacene thin films to surface lattice resonances supported by open cavities made of silver nanoparticle arrays. Such thin films are more easily fabricated and, together with the open architecture, more suitable for device applications.
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Affiliation(s)
- Christoph P Theurer
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Florian Laible
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Jia Tang
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Katharina Broch
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Monika Fleischer
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
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13
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Wu Y, Lu L, Yu B, Zhang S, Luo P, Chen M, He J, Li Y, Zhang C, Zhu J, Yao J, Fu H. Dynamic Evolving Exothermicity Steers Ultrafast Formation of a Correlated Triplet Pair State. J Phys Chem Lett 2023; 14:4233-4240. [PMID: 37126526 DOI: 10.1021/acs.jpclett.3c00193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Singlet fission (SF) presents an attractive solution to overcome the Shockley-Queisser limit of single-junction solar cells. The conversion from an initial singlet state to final triplet is mediated by the correlated triplet pair state 1(T1T1). Despite significant advancement on 1(T1T1) properties and its role in SF, a comprehensive understanding of the energetic landscape during SF is still unclear. Here, we study an unconventional SF system with excited-state aromaticity, i.e., cyano-substituted dipyrrolonaphtheridinedione derivative (DPND-CN), using time-resolved spectroscopy as a function of the temperature. We demonstrate that the population transfer from S1 to 1(T1T1) is driven by a time-dependent exothermicity resulting from the coherent coupling between electronic and spin degrees of freedom. This is followed by thermal-activated dissociation of 1(T1T1) to yield free triplets. Our results provide some new insight into the SF mechanism, which may guide the development of new efficient and stable SF materials for practical applications.
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Affiliation(s)
- Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Lina Lu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Buyang Yu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - San Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Pengdong Luo
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Mingxing Chen
- Analytical Instrumentation Center, Peking University, Beijing 100871, People's Republic of China
| | - Jingping He
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Yongyao Li
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, People's Republic of China
| | - Jiannian Yao
- Beijing National Laboratory for Molecules Science (BNLMS), Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, People's Republic of China
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14
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Musser AJ, Stern H. Elusive excited states identified from cutting-edge molecular movies. Nature 2023; 616:255-256. [PMID: 37045916 DOI: 10.1038/d41586-023-00980-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
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15
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Huang YY, Wu B, Shi D, Liu D, Meng W, Ma J, Qin L, Li C, Zhang G, Zhang XS, Zhang D. A Heptacene Analogue Entailing a Quinoidal Benzodi[7]annulene (7/6/7 Ring) Core with a Tunable Configuration and Multiple Redox Properties. Angew Chem Int Ed Engl 2023; 62:e202300990. [PMID: 36861376 DOI: 10.1002/anie.202300990] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/26/2023] [Accepted: 03/01/2023] [Indexed: 03/03/2023]
Abstract
Non-benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi[7]annulene core. Derivatives of this new non-benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels-Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6-triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non-benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new non-benzenoid acene can be oxidized or reduced by NOSbF6 or KC8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic.
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Affiliation(s)
- Yan-Ying Huang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Botao Wu
- College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Dandan Shi
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Dan Liu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Wei Meng
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Junlong Ma
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liyuan Qin
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Cheng Li
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Guanxin Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Xi-Sha Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Deqing Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Center of Excellence in Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
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16
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Unger F, Moretti L, Hausch J, Bredehoeft J, Zeiser C, Haug S, Tempelaar R, Hestand NJ, Cerullo G, Broch K. Modulating Singlet Fission by Scanning through Vibronic Resonances in Pentacene-Based Blends. J Am Chem Soc 2022; 144:20610-20619. [DOI: 10.1021/jacs.2c07237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Frederik Unger
- Institute for Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Luca Moretti
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan 20133, Italy
| | - Julian Hausch
- Institute for Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Jona Bredehoeft
- Institute for Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Clemens Zeiser
- Institute for Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Sara Haug
- Institute for Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
| | - Roel Tempelaar
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Nicholas J. Hestand
- Department of Natural and Applied Sciences, Evangel University, 1111 North Glenstone Avenue, Springfield, Missouri 65802, United States
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, Milan 20133, Italy
| | - Katharina Broch
- Institute for Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, Tuebingen, 72076, Germany
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17
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Graf L, Liu F, Naumann M, Roth F, Debnath B, Büchner B, Krupskaya Y, Popov AA, Knupfer M. Optical Anisotropy and Momentum-Dependent Excitons in Dibenzopentacene Single Crystals. ACS OMEGA 2022; 7:21183-21191. [PMID: 35755348 PMCID: PMC9219101 DOI: 10.1021/acsomega.2c01987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
High-quality single crystals of the organic semiconductor (1,2;8,9)-dibenzopentacene were grown via physical vapor transport. The crystal structure-unknown before-was determined by single-crystal X-ray diffraction; polarization-dependent optical absorption measurements display a large anisotropy in the ac plane of the crystals. The overall Davydov splitting is ∼110 meV, which is slightly lower than that in the close relative pentacene (120 meV). Momentum-dependent electron energy-loss spectroscopy measurements show a clear exciton dispersion of the Davydov components. An analysis of the dispersion using a simple 1D model indicates smaller electron- and hole-transfer integrals in dibenzopentacene as compared to pentacene. The spectral weight distribution of the excitation spectra is strongly momentum-dependent and demonstrates a strong momentum-dependent admixture of Frenkel excitons, charge-transfer excitons, and vibrational modes.
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Affiliation(s)
- Lukas Graf
- IFW
Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Fupin Liu
- IFW
Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Marco Naumann
- IFW
Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
| | - Friedrich Roth
- Institute
of Experimental Physics, TU Bergakademeie
Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany
- Center
for Efficient High Temperature Processes and Materials Conversion
(ZeHS), TU Bergakademie Freiberg, Winklerstraße 5, 09599 Freiberg, Germany
| | | | - Bernd Büchner
- IFW
Dresden, Helmholtzstraße 20, 01069 Dresden, Germany
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18
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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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19
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Yablon LM, Sanders SN, Miyazaki K, Kumarasamy E, He G, Choi B, Ananth N, Sfeir MY, Campos LM. Singlet fission and triplet pair recombination in bipentacenes with a twist. MATERIALS HORIZONS 2022; 9:462-470. [PMID: 34846410 DOI: 10.1039/d1mh01201k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We investigate triplet pair dynamics in pentacene dimers that have varying degrees of coplanarity (pentacene-pentacene twist angle). The fine-tuning of the twist angle was achieved by alternating connectivity at the 1-position or 2-positions of pentacene. This mix-and-match connectivity leads to tunable twist angles between the two covalently linked pentacenes. These twisted dimers allow us to investigate the subtle effects that the dihedral angle between the covalently linked pentacenes imparts on singlet fission and triplet pair recombination dynamics. We observe that as the dihedral angle between the two bonded pentacenes is increased, the rates of singlet fission decrease, while the accompanying decrease in triplet recombination rates is stark. Temperature-dependent transient optical studies combined with theoretical calculations show that the triplet pair recombination proceeds primarily through a direct multiexciton internal conversion process. Calculations further show that the significant decrease in recombination rates can be directly attributed to a corresponding decrease in the magnitude of the nonadiabatic coupling between the singlet multiexcitonic state and the ground state. These results highlight the importance of the twist angle in designing systems that exhibit rapid singlet fission, while maintaining long triplet pair lifetimes in pentacene dimers.
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Affiliation(s)
- Lauren M Yablon
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Ken Miyazaki
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
| | - Elango Kumarasamy
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, USA.
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA
| | - Bonnie Choi
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
| | - Nandini Ananth
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, USA.
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, USA
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, USA.
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20
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Shunak L, Adeniran O, Voscoboynik G, Liu ZF, Refaely-Abramson S. Exciton Modulation in Perylene-Based Molecular Crystals Upon Formation of a Metal-Organic Interface From Many-Body Perturbation Theory. Front Chem 2021; 9:743391. [PMID: 34616715 PMCID: PMC8488370 DOI: 10.3389/fchem.2021.743391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 09/07/2021] [Indexed: 11/22/2022] Open
Abstract
Excited-state processes at organic-inorganic interfaces consisting of molecular crystals are essential in energy conversion applications. While advances in experimental methods allow direct observation and detection of exciton transfer across such junctions, a detailed understanding of the underlying excitonic properties due to crystal packing and interface structure is still largely lacking. In this work, we use many-body perturbation theory to study structure-property relations of excitons in molecular crystals upon adsorption on a gold surface. We explore the case of the experimentally-studied octyl perylene diimide (C8-PDI) as a prototypical system, and use the GW and Bethe-Salpeter equation (BSE) approach to quantify the change in quasiparticle and exciton properties due to intermolecular and substrate screening. Our findings provide a close inspection of both local and environmental structural effects dominating the excitation energies and the exciton binding and nature, as well as their modulation upon the metal-organic interface composition.
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Affiliation(s)
- Liran Shunak
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Olugbenga Adeniran
- Department of Chemistry, Wayne State University, Detroit, MI, United States
| | - Guy Voscoboynik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Zhen-Fei Liu
- Department of Chemistry, Wayne State University, Detroit, MI, United States
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
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21
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Abstract
Pyrazinacenes are a class of nitrogen-containing heteroacene molecules composed of linearly fused pyrazine units, which might also include dihydropyrazine groups leading to different reduced states of the compounds. While they are structurally similar to hydrocarbon acenes (e.g., pentacene) the presence of increasing numbers of N-heteroatoms introduces several different additional features of the compounds so that they can be considered for investigations beyond those suggested for acenes (i.e., organic field-effect transistors, solar cell components). Pyrazinacenes are in several ways complementary to C-H-only acenes based on the increasing stability of reduced states of the compounds with increasing numbers of fused pyrazine rings, although an acene-like electronic structure persists in the compounds so far studied. However, the introduction of multiple N atoms leads to properties that depart from C-H-only acenes. In particular, the compounds exhibit a delocalization of NH protons in extended reduced compounds and oxidation state switchability in solution and at interfaces. The presence of NH groups also allows an easy introduction of solubilizing groups at the pyrazinacene chromophore. In this Account, we will describe the preparation of extended pyrazinacenes from dipyrazino[2,3-b:2',3'-e]pyrazine (1,4,5,8,9,10-hexaazaanthracene; N6) derivatives up to 1,4,5,6,7,8,9,12,13,14,15,16,17,18-tetradecaazaheptacene (N14) and also assess structures of the relevant compounds based on X-ray crystallographic studies. Emergent properties of the molecules include highly unusual linear tautomeric processes based on a delocalization of protons (and the corresponding formation of orbitals based on multiple adjacent N lone electron pair interactions), which suggest special transport properties based on molecular protonics. Molecules such as decazapentacene (N10) exhibit multistability of oxidation state, and this is predicted to promote the redox catalytic properties of the compounds. The oxidation-state switching of on-surface processes is also described and has been investigated using scanning tunneling microscopy. The longest known pyrazinacene chromophore (N14) exhibits amphiprotism with its state of protonation being strongly coupled to its fluorescence emission properties in the near-infrared region indicating possible uses in pH-coupled bioimaging applications. The synthesis of the pyrazinacenes is flexible and allows the preparation of symmetrically or unsymmetrically substituted derivatives for the development of more complex molecules and for control of the electronic structure of the acene unit. Overall, the pyrazinacenes represent an emerging class of highly nitrogenous heteroacenes with unique properties and excellent potential for development in different applications based on their special supramolecular properties including guest binding or interactions in biological systems.
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Affiliation(s)
- Gary J. Richards
- Department of Applied Chemistry, Graduate School of Engineering and Science, Shibaura Institute of Technology, Fukasaku 307, Minuma-ku, Saitama-shi, Saitama 337-8570, Japan
| | - Jonathan P. Hill
- Functional Chromophores Group, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
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22
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Dvořák M, Prasad SKK, Dover CB, Forest CR, Kaleem A, MacQueen RW, Petty AJ, Forecast R, Beves JE, Anthony JE, Tayebjee MJY, Widmer-Cooper A, Thordarson P, Schmidt TW. Singlet Fission in Concentrated TIPS-Pentacene Solutions: The Role of Excimers and Aggregates. J Am Chem Soc 2021; 143:13749-13758. [PMID: 34397219 DOI: 10.1021/jacs.1c05767] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The excited-state dynamics of 6,13-bis(triisopropylsilylethynyl)pentacene is investigated to determine the role of excimer and aggregate formation in singlet fission in high-concentration solutions. Photoluminescence spectra were measured by excitation with the evanescent wave in total internal reflection, in order to avoid reabsorption effects. The spectra over nearly two magnitudes of concentration were nearly identical, with no evidence for excimer emission. Time-correlated single-photon counting measurements confirm that the fluorescence lifetime shortens with concentration. The observed rate constant grows at high concentrations, and this effect is modeled in terms of the hard-sphere radial distribution function. NMR measurements confirm that aggregation takes place with a binding constant of between 0.14 and 0.43 M-1. Transient absorption measurements are consistent with a diffusive encounter mechanism for singlet fission, with hints of more rapid singlet fission in aggregates at the highest concentration measured. These data show that excimers do not play the role of an emissive intermediate in exothermic singlet fission in solution and that, while aggregation occurs at higher concentrations, the mechanism of singlet fission remains dominated by diffusive encounters.
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Affiliation(s)
- Miroslav Dvořák
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia.,Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, V Holešovičkách 2, 180 00 Prague 8, Czechia
| | - Shyamal K K Prasad
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Cameron B Dover
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Chelsea R Forest
- Australian Centre for Nanomedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Akasha Kaleem
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Rowan W MacQueen
- Department of Spins in Energy Conversion and Quantum Information Science, Helmholtz-Zentrum Berlin für Materialen und Energie GmbH, Berlin 14109, Germany
| | - Anthony J Petty
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Roslyn Forecast
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Jonathon E Beves
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Asaph Widmer-Cooper
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Pall Thordarson
- Australian Centre for Nanomedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
| | - Timothy W Schmidt
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales 2052, Australia
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23
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Fumanal M, Corminboeuf C. Pushing the Limits of the Donor-Acceptor Copolymer Strategy for Intramolecular Singlet Fission. J Phys Chem Lett 2021; 12:7270-7277. [PMID: 34318679 DOI: 10.1021/acs.jpclett.1c01986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Donor-acceptor (D-A) copolymers have shown great potential for intramolecular singlet fission (iSF). Nonetheless, very few design principles exist for optimizing these systems for iSF, with very little knowledge about how to engineer them for this purpose. In recent work, a fundamental trade-off between the main electronic ingredients required for iSF capable D-A coplanar copolymers was revealed. Still, further investigations are needed to understand these limitations and learn how to bypass them. In this work, we propose to induce torsion as an effective way to circumvent the limits of the coplanar approach. We disclose the potential of noncoplanar copolymers with inherently low triplet energies that encompass all the characteristics required for iSF beyond the limiting values associated with fully coplanar systems. Our findings shed some light on the electronic structure aspects of D-A copolymers for iSF and offer a new avenue for the rational design of novel promising candidates.
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Affiliation(s)
- Maria Fumanal
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Clémence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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24
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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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25
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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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26
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Gu B, Mukamel S. Optical-Cavity Manipulation of Conical Intersections and Singlet Fission in Pentacene Dimers. J Phys Chem Lett 2021; 12:2052-2056. [PMID: 33615792 DOI: 10.1021/acs.jpclett.0c03829] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We demonstrate how the singlet fission process in pentacene dimers mediated by a conical intersection is controlled by coupling the molecule to a confined optical cavity photon mode. By following the polariton quantum dynamics of a conical intersection coupled to a cavity mode taking into account vibrational relaxation and cavity loss, we find that the singlet fission can be significantly suppressed because the polaritonic conical intersection is pushed away from the initial Franck-Condon excitation region.
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Affiliation(s)
- Bing Gu
- Department of Chemistry and Department of Physics & Astronomy, University of California, Irvine, CA 92697, United States
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics & Astronomy, University of California, Irvine, CA 92697, United States
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27
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Gunjo Y, Kamebuchi H, Tsuruta R, Iwashita M, Takahashi K, Takeuchi R, Kanai K, Koganezawa T, Mase K, Tadokoro M, Nakayama Y. Interface Structures and Electronic States of Epitaxial Tetraazanaphthacene on Single-Crystal Pentacene. MATERIALS 2021; 14:ma14051088. [PMID: 33652700 PMCID: PMC7956789 DOI: 10.3390/ma14051088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/19/2021] [Accepted: 02/19/2021] [Indexed: 02/04/2023]
Abstract
The structural and electronic properties of interfaces composed of donor and acceptor molecules play important roles in the development of organic opto-electronic devices. Epitaxial growth of organic semiconductor molecules offers a possibility to control the interfacial structures and to explore precise properties at the intermolecular contacts. 5,6,11,12-tetraazanaphthacene (TANC) is an acceptor molecule with a molecular structure similar to that of pentacene, a representative donor material, and thus, good compatibility with pentacene is expected. In this study, the physicochemical properties of the molecular interface between TANC and pentacene single crystal (PnSC) substrates were analyzed by atomic force microscopy, grazing-incidence X-ray diffraction (GIXD), and photoelectron spectroscopy. GIXD revealed that TANC molecules assemble into epitaxial overlayers of the (010) oriented crystallites by aligning an axis where the side edges of the molecules face each other along the [1¯10] direction of the PnSC. No apparent interface dipole was found, and the energy level offset between the highest occupied molecular orbitals of TANC and the PnSC was determined to be 1.75 eV, which led to a charge transfer gap width of 0.7 eV at the interface.
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Affiliation(s)
- Yuki Gunjo
- Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; (Y.G.); (R.T.); (M.I.); (K.T.); (R.T.)
| | - Hajime Kamebuchi
- Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan; (H.K.); (M.T.)
| | - Ryohei Tsuruta
- Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; (Y.G.); (R.T.); (M.I.); (K.T.); (R.T.)
| | - Masaki Iwashita
- Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; (Y.G.); (R.T.); (M.I.); (K.T.); (R.T.)
| | - Kana Takahashi
- Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; (Y.G.); (R.T.); (M.I.); (K.T.); (R.T.)
| | - Riku Takeuchi
- Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; (Y.G.); (R.T.); (M.I.); (K.T.); (R.T.)
| | - Kaname Kanai
- Department of Physics, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan;
- Division of Colloid and Interface Science, Research Institute for Science & Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Tomoyuki Koganezawa
- Industrial Application Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan;
| | - Kazuhiko Mase
- Institute for Materials Structure Science, High Energy Accelerator Research Organization (KEK) and SOKENDAI, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan;
| | - Makoto Tadokoro
- Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan; (H.K.); (M.T.)
- Division of Colloid and Interface Science, Research Institute for Science & Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Yasuo Nakayama
- Department of Pure and Applied Chemistry, Graduate School of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; (Y.G.); (R.T.); (M.I.); (K.T.); (R.T.)
- Division of Colloid and Interface Science, Research Institute for Science & Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
- Correspondence: ; Tel.: +81-04-7124-1501 (ext. 3601)
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28
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Amsterdam SH, LaMountain T, Stanev TK, Sangwan VK, López-Arteaga R, Padgaonkar S, Watanabe K, Taniguchi T, Weiss EA, Marks TJ, Hersam MC, Stern NP. Tailoring the Optical Response of Pentacene Thin Films via Templated Growth on Hexagonal Boron Nitride. J Phys Chem Lett 2021; 12:26-31. [PMID: 33296212 DOI: 10.1021/acs.jpclett.0c03132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The optoelectronic properties of organic thin films are strongly dependent on their molecular orientation and packing, which in turn is sensitive to the underlying substrate. Hexagonal boron nitride (hBN) and other van der Waals (vdW) materials are known to template different organic thin film growth modalities from conventional inorganic substrates such as SiO2. Here, the morphology and temperature-dependent optical properties of pentacene films grown on hBN are reported. Pentacene deposited on hBN forms large-grain films with a molecular π-face-on orientation unlike the dendritic edge-on thin-film phase on SiO2. Pentacene/hBN films exhibit a 40 meV lower free exciton emission than pentacene/SiO2 and an unconventional emission energy temperature dependence. Time-resolved photoluminescence (PL) decay measurements show a long-lived signal in the π-face-on phase related to delayed emission from triplet-triplet fusion. This work demonstrates that growth on vdW materials provides a pathway for controlling optoelectronic functionality in molecular thin films.
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Affiliation(s)
- Samuel H Amsterdam
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Trevor LaMountain
- Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Teodor K Stanev
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinod K Sangwan
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Rafael López-Arteaga
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Suyog Padgaonkar
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Emily A Weiss
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
- Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
- Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
- Department of Electrical Engineering and Computer Science and the Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Nathaniel P Stern
- Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, United States
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29
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He G, Busby E, Appavoo K, Wu Q, Xia J, Campos LM, Sfeir MY. Charge transfer states impact the triplet pair dynamics of singlet fission polymers. J Chem Phys 2020; 153:244902. [PMID: 33380093 DOI: 10.1063/5.0029858] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Polymers are desirable optoelectronic materials, stemming from their solution processability, tunable electronic properties, and large absorption coefficients. An exciting development is the recent discovery that singlet fission (SF), the conversion of a singlet exciton to a pair of triplet states, can occur along the backbone of an individual conjugated polymer chain. Compared to other intramolecular SF compounds, the nature of the triplet pair state in SF polymers remains poorly understood, hampering the development of new materials with optimized excited state dynamics. Here, we investigate the effect of solvent polarity on the triplet pair dynamics in the SF polymer polybenzodithiophene-thiophene-1,1-dioxide. We use transient emission measurements to study isolated polymer chains in solution and use the change in the solvent polarity to investigate the role of charge transfer character in both the singlet exciton and the triplet pair multiexciton. We identify both singlet fluorescence and direct triplet pair emission, indicating significant symmetry breaking. Surprisingly, the singlet emission peak is relatively insensitive to solvent polarity despite its nominal "charge-transfer" nature. In contrast, the redshift of the triplet pair energy with increasing solvent polarity indicates significant charge transfer character. While the energy separation between singlet and triplet pair states increases with solvent polarity, the overall SF rate constant depends on both the energetic driving force and additional environmental factors. The triplet pair lifetime is directly determined by the solvent effect on its overall energy. The dominant recombination channel is a concerted, radiationless decay process that scales as predicted by a simple energy gap law.
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Affiliation(s)
- Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, USA
| | - Erik Busby
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Kannatassen Appavoo
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Qin Wu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Jianlong Xia
- School of Chemistry, Chemical Engineering and Life Science; State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, USA
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30
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Wang G, Zhang C, Liu Z, Wang R, Ma H, Wang X, Xiao M. Singlet Fission Dynamics in Tetracene Single Crystals Probed by Polarization-Dependent Two-Dimensional Electronic Spectroscopy. J Phys Chem A 2020; 124:10447-10456. [PMID: 33290074 DOI: 10.1021/acs.jpca.0c08440] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The exact mechanism of endothermic singlet fission in crystalline polyacene remains to be clarified. It has been elusive whether the excess energy of vibrational hot states and the upper branch of Davydov splitting is important for the energy compensation. Here, we probe the excited-state specified singlet fission dynamics in tetracene single crystals by polarization-dependent two-dimensional electronic spectroscopy (2DES). While a major spectral transfer with a characteristic lifetime of 86 ps is observed to be largely independent of the excitation energy due to formation of the spatially separated triplet pairs (1(T···T)), the excitation-energy dependent subpicosecond dynamics show marked differences for different states probed, implying the possible involvement of a coherently formed triplet pair state (1(TT)). Analysis of coherent vibrational modes suggests the coupling to high energy modes may offset the energy difference between singlet and triplet pair states. Moreover, the beating map of the low frequency mode indicates a vibrational hot state violating the aggregation behavior of Davydov exciton, which can be explained as a resonance of the 1(TT) state. These results suggest that the coherent vibronic mixing between local excitation and triplet pair states is essential for the singlet fission dynamics in molecule aggregates.
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Affiliation(s)
- Guodong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Zhixing Liu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Rui Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Haibo Ma
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China
| | - Xiaoyong Wang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China
| | - Min Xiao
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China.,Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701, United States
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31
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Alipour M, Safari Z. Singlet fission relevant energetics from optimally tuned range-separated hybrids. Phys Chem Chem Phys 2020; 22:27060-27076. [PMID: 33215617 DOI: 10.1039/d0cp03951a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
As a promising idea to design high-efficiency organic photovoltaics, singlet fission (SF) mechanism, i.e., generating two triplet excitons out of a single photon absorption, has recently come into the spotlight. Even though much effort has been devoted to this arena, accurately accounting for the SF process from the theoretical perspective has proven to be challenging. Herein, the SF energetics have thoroughly been investigated with the help of optimally tuned range-separated hybrid functionals (OT-RSHs) in both gas and solvent phases. Taking a series of experimentally known SF chromophores as working models, we have proposed and validated several variants of OT-RSH approximations for the reliable prediction of the energy levels which match the crucial criteria for the SF process, namely, the negative singlet-triplet and triplet-triplet energy gaps. We scrutinize the role of the OT-RSH ingredients, i.e., the underlying density functional approximations, short- and long-range exact-like exchange, as well as the range-separation parameter, for our purpose. The newly designed OT-RSHs outperform the standard RSHs and other related schemes such as screened-exchange approximations as well as other density functionals from different rungs for describing the SF energetics. More importantly, it is unveiled that although the OT-RSH coupled with the polarizable continuum model, OT-RSH-PCM, as well as the screened versions, OT-SRSHs, which account for the screening effect by the electron correlation through the scalar dielectric constant have some advantages over gas-phase computations using OT-RSHs, the energetics criteria of the SF process may not necessarily be satisfied. This in turn corroborates the idea of performing both the optimal tuning procedure and subsequent computations of the SF relevant energetics using OT-RSHs as a more reliable and affordable framework, at least for the present purpose. The applicability of the proposed models is also put into broader perspective, where they are used for the computational design of several chromophores as promising candidates prone to utilization in the SF-based materials. Hopefully, our recommended OT-RSHs can function as efficient models for both the theoretical modeling of SF chromophores and confirming the experimental observations in the field.
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Affiliation(s)
- Mojtaba Alipour
- Department of Chemistry, School of Science, Shiraz University, Shiraz 71946-84795, Iran.
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32
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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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33
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Ondrušková G, Veselý L, Zezula J, Bachler J, Loerting T, Heger D. Using Excimeric Fluorescence to Study How the Cooling Rate Determines the Behavior of Naphthalenes in Freeze-Concentrated Solutions: Vitrification and Crystallization. J Phys Chem B 2020; 124:10556-10566. [PMID: 33156630 DOI: 10.1021/acs.jpcb.0c07817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We utilized fluorescence spectroscopy to learn about the molecular arrangement of naphthalene (Np) and 1-methylnaphthalene (MeNp) in frozen aqueous solutions. The freezing induces pronounced compound aggregation in the freeze-concentrated solution (FCS) in between the ice grains. The fluorescence spectroscopy revealed prevalent formation of a vitrified solution and minor crystallization of aromatic compounds. The FCS is shown as a specific environment, differing significantly from not only the pure compounds but also the ice surfaces. The results indicate marked disparity between the behavior of the Np and the MeNp; the cooling rate has a major impact on the former but not on the latter. The spectrum of the Np solution frozen at a faster cooling rate (ca 20 K/min) exhibited a temperature-dependent spectral behavior, whereas the spectrum of the solution frozen at a slower rate (ca 2 K/min) did not alter before melting. We interpret the observation through considering the varied composition of the FCS: Fast freezing leads to a higher water content expressed by the plasticizing effect, allowing molecular rearrangement, while slow cooling produces a more concentrated and drier environment. The experiments were conceived as generalizable for environmentally relevant pollutants and human-made freezing.
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Affiliation(s)
- Gabriela Ondrušková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jan Zezula
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Johannes Bachler
- Institute of Physical Chemistry, University of Innsbruck, Innrine 52c, A-6020 Innsbruck, Austria
| | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, Innrine 52c, A-6020 Innsbruck, Austria
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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34
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Li X, Parrish RM, Martínez TJ. An ab initio exciton model for singlet fission. J Chem Phys 2020; 153:184116. [PMID: 33187442 DOI: 10.1063/5.0028605] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We present an ab initio exciton model that extends the Frenkel exciton model and includes valence, charge-transfer, and multiexcitonic excited states. It serves as a general, parameter-free, yet computationally efficient and scalable approach for simulation of singlet fission processes in multichromophoric systems. A comparison with multiconfigurational methods confirms that our exciton model predicts consistent energies and couplings for the pentacene dimer and captures the correct physics. Calculations of larger pentacene clusters demonstrate the computational scalability of the exciton model and suggest that the mixing between local and charge-transfer excitations narrows the gap between singlet and multiexcitonic states. Local vibrations of pentacene molecules are found to facilitate singlet-multiexcitonic state-crossing and hence are important for understanding singlet fission. The exciton model developed in this work also sets the stage for further implementation of the nuclear gradients and nonadiabatic couplings needed for first principles nonadiabatic quantum molecular dynamics simulations of singlet fission.
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Affiliation(s)
- Xin Li
- Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, USA and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Robert M Parrish
- Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, USA and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Todd J Martínez
- Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, USA and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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35
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Van Schenck JDB, Mayonado G, Anthony JE, Graham MW, Ostroverkhova O. Molecular packing-dependent exciton dynamics in functionalized anthradithiophene derivatives: From solutions to crystals. J Chem Phys 2020; 153:164715. [PMID: 33138416 DOI: 10.1063/5.0026072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Understanding the impact of inter-molecular orientation on the optical properties of organic semiconductors is important for designing next-generation organic (opto)electronic and photonic devices. However, fundamental aspects of how various features of molecular packing in crystalline systems determine the nature and dynamics of excitons have been a subject of debate. Toward this end, we present a systematic study of how various molecular crystal packing motifs affect the optical properties of a class of high-performance organic semiconductors: functionalized derivatives of fluorinated anthradithiophene. The absorptive and emissive species present in three such derivatives (exhibiting "brickwork," "twisted-columnar," and "sandwich-herringbone" motifs, controlled by the side group R) were analyzed both in solution and in single crystals, using various modalities of optical and photoluminescence spectroscopy, revealing the nature of these excited states. In solution, in the emission band, two states were identified: a Franck-Condon state present at all concentrations and an excimer that emerged at higher concentrations. In single crystal systems, together with ab initio calculations, it was found in the absorptive band that Frenkel and Charge Transfer (CT) excitons mixed due to nonvanishing CT integrals in all derivatives, but the amount of admixture and exciton delocalization depended on the packing, with the "sandwich-herringbone" packing motif least conducive to delocalization. Three emissive species in the crystal phase were also identified: Frenkel excitons, entangled triplet pairs 1(TT) (which are precursors to forming free triplet states via singlet fission), and self-trapped excitons (STEs, similar in origin to excimers present in concentrated solution). The "twisted-columnar" packing motif was most conducive to the formation of Frenkel excitons delocalized over 4-7 molecules depending on the temperature. These delocalized Frenkel states were dominant across the full temperature range (78 K-293 K), though at lower temperatures, the entangled triplet states and STEs were present. In the derivative with the "brickwork" packing, all three emissive species were observed across the full temperature range and, most notably, the 1(TT) state was present at room temperature. Finally, the derivative with the "sandwich-herringbone" packing exhibited localized Frenkel excitons and had a strong propensity for self-trapped exciton formation even at higher temperatures. In this derivative, no formation of the 1(TT) state was observed. The temperature-dependent dynamics of these emissive states are reported, as well as their origin in fundamental inter-molecular interactions.
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Affiliation(s)
- J D B Van Schenck
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - G Mayonado
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - J E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - M W Graham
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
| | - O Ostroverkhova
- Department of Physics, Oregon State University, Corvallis, Oregon 97330, USA
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36
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Duan HG, Jha A, Li X, Tiwari V, Ye H, Nayak PK, Zhu XL, Li Z, Martinez TJ, Thorwart M, Miller RJD. Intermolecular vibrations mediate ultrafast singlet fission. SCIENCE ADVANCES 2020; 6:eabb0052. [PMID: 32948583 PMCID: PMC7500928 DOI: 10.1126/sciadv.abb0052] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/31/2020] [Indexed: 05/20/2023]
Abstract
Singlet fission is a spin-allowed exciton multiplication process in organic semiconductors that converts one spin-singlet exciton to two triplet excitons. It offers the potential to enhance solar energy conversion by circumventing the Shockley-Queisser limit on efficiency. We study the primary steps of singlet fission in a pentacene film by using a combination of TG and 2D electronic spectroscopy complemented by quantum chemical and nonadiabatic dynamics calculations. We show that the coherent vibrational dynamics induces the ultrafast transition from the singlet excited electronic state to the triplet-pair state via a degeneracy of potential energy surfaces, i.e., a multidimensional conical intersection. Significant vibronic coupling of the electronic wave packet to a few key intermolecular rocking modes in the low-frequency region connect the excited singlet and triplet-pair states. Along with high-frequency local vibrations acting as tuning modes, they open a new channel for the ultrafast exciton transfer through the resulting conical intersection.
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Affiliation(s)
- Hong-Guang Duan
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Ajay Jha
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Xin Li
- Department of Chemistry and PULSE Institute, Stanford University, Stanford, CA 94305, USA
| | - Vandana Tiwari
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Chemistry, University of Hamburg, Martin-Luther-King Platz 6, 20146 Hamburg, Germany
| | - Hanyang Ye
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
| | - Pabitra K Nayak
- TIFR Centre for Interdisciplinary Sciences, 36/P, Gopanpally Village, Ranga Reddy District, Hyderabad 500107, India
| | - Xiao-Lei Zhu
- Department of Chemistry and PULSE Institute, Stanford University, Stanford, CA 94305, USA
| | - Zheng Li
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany.
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Todd J Martinez
- Department of Chemistry and PULSE Institute, Stanford University, Stanford, CA 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Michael Thorwart
- I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany.
- The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - R J Dwayne Miller
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany.
- The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
- Departments of Chemistry and Physics, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
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37
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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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38
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Sharma A, Zhang L, Tollerud JO, Dong M, Zhu Y, Halbich R, Vogl T, Liang K, Nguyen HT, Wang F, Sanwlani S, Earl SK, Macdonald D, Lam PK, Davis JA, Lu Y. Supertransport of excitons in atomically thin organic semiconductors at the 2D quantum limit. LIGHT, SCIENCE & APPLICATIONS 2020; 9:116. [PMID: 32655861 PMCID: PMC7338549 DOI: 10.1038/s41377-020-00347-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 05/14/2020] [Accepted: 06/09/2020] [Indexed: 05/20/2023]
Abstract
Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications. However, most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities, as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in materials. Here, by confining coherent excitons at the 2D quantum limit, we first observed molecular aggregation-enabled 'supertransport' of excitons in atomically thin two-dimensional (2D) organic semiconductors between coherent states, with a measured high effective exciton diffusion coefficient of ~346.9 cm2/s at room temperature. This value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic materials. Without coupling to any optical cavities, the monolayer pentacene sample, a very clean 2D quantum system (~1.2 nm thick) with high crystallinity (J-type aggregation) and minimal interfacial states, showed superradiant emission from Frenkel excitons, which was experimentally confirmed by the temperature-dependent photoluminescence (PL) emission, highly enhanced radiative decay rate, significantly narrowed PL peak width and strongly directional in-plane emission. The coherence in monolayer pentacene samples was observed to be delocalised over ~135 molecules, which is significantly larger than the values (a few molecules) observed for other organic thin films. In addition, the supertransport of excitons in monolayer pentacene samples showed highly anisotropic behaviour. Our results pave the way for the development of future high-speed excitonic circuits, fast OLEDs, and other optoelectronic devices.
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Affiliation(s)
- Ankur Sharma
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Linglong Zhang
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Jonathan O. Tollerud
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Miheng Dong
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Yi Zhu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Robert Halbich
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Tobias Vogl
- Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601 Australia
| | - Kun Liang
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, 100081 China
| | - Hieu T. Nguyen
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Fan Wang
- Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW 2007 Australia
| | - Shilpa Sanwlani
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Stuart K. Earl
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Daniel Macdonald
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
| | - Ping Koy Lam
- Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601 Australia
| | - Jeffrey A. Davis
- Optical Sciences Centre, Swinburne University of Technology, Hawthorn, VIC 3122 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
| | - Yuerui Lu
- Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601 Australia
- ARC Centre of Excellence for Future Low-Energy Electronics Technology, Australia
- Centre for Quantum Computation and Communication Technology, Department of Quantum Science, Research School of Physics and Engineering, The Australian National University, Acton, ACT 2601 Australia
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39
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The Photophysical Properties of Triisopropylsilyl-ethynylpentacene—A Molecule with an Unusually Large Singlet-Triplet Energy Gap—In Solution and Solid Phases. CHEMISTRY-SWITZERLAND 2020. [DOI: 10.3390/chemistry2020033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The process of singlet-exciton fission (SEF) has attracted much attention of late. One of the most popular SEF compounds is TIPS-pentacene (TIPS-P, where TIPS = triisopropylsilylethynyl) but, despite its extensive use as both a reference and building block, its photophysical properties are not so well established. In particular, the triplet state excitation energy remains uncertain. Here, we report quantitative data and spectral characterization for excited-singlet and -triplet states in dilute solution. The triplet energy is determined to be 7940 ± 1200 cm−1 on the basis of sensitization studies using time-resolved photoacoustic calorimetry. The triplet quantum yield at the limit of low concentration and low laser intensity is only ca. 1%. Self-quenching occurs at high solute concentration where the fluorescence yield and lifetime decrease markedly relative to dilute solution but we were unable to detect excimer emission by steady-state spectroscopy. Short-lived fluorescence, free from excimer emission or phosphorescence, occurs for crystals of TIPS-P, most likely from amorphous domains.
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40
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Abstract
AbstractPhotoinduced charge generation forms the physical basis for energy conversion in organic photovoltaic (OPV) technology. The fundamental initial steps involved are absorption of light by organic semiconductors (generally π-conjugated polymers) to generate photoexcited states (Frenkel excitons) followed by charge transfer and charge separation processes in presence of suitable acceptor. The absorbed photon energy must be utilized completely for achieving maximum device efficiency. However progressive relaxation losses of instantaneously generated high-energy or hot-excited states form major bottleneck for maximum derivable voltage. This efficiency limiting factor has been challenged recently by the role of hot-carriers in efficient generation of charges. Therefore tailoring the dissociation of hot-exciton to be temporally faster than all relaxation processes could minimize the energy loss pathways. Implementation of this concept of hot-carrier photovoltaics demands critical understanding of molecular parameters that circumvent all energy relaxation processes and favor hot-carrier generation. In my dissertation work, I have examined the fate of photo-generated excitons in the context of polymer backbone and morphology, and therefore obtain a fundamental structure-function correlation in organic semiconductors.
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Affiliation(s)
- Palas Roy
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai-400005, India
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai-400005, India
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41
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Zukun W, Wu R, Chen Z, Ye L, Li H, Zhu H. Ultrafast Electron Transfer Before Singlet Fission and Slow Triplet State Electron Transfer in Pentacene Single Crystal/C 60 Heterostructure. J Phys Chem A 2020; 124:4185-4192. [PMID: 32353232 DOI: 10.1021/acs.jpca.0c01791] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The singlet fission (SF) process converts one high-energy singlet exciton to two low-energy triplet excitons after absorbing one photon. Organic photovoltaic devices based on the SF process have shown great potential in solar energy conversion to exceed Shockley-Queisser limit. The key to SF photovoltaic devices requires efficient electron transfer (ET) from triplet exciton after SF, which is yet to be thoroughly investigated. Here, we performed thorough photophysical studies in 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene)/C60 heterostructures using TIPS-pentacene microsize single crystal as a well-defined model system. We show the SF process in TIPS-pentacene single crystal occurs by a two-step process, with triplet pair intermediates forming in 75 fs and then dissociating to non-interacting triplets in 1.6 ps. The SF process in single crystal is comparable to that in polycrystalline film. Importantly, we observe a considerable fraction of singlet excitons is quenched by ultrafast (<75 fs) interfacial ET prior to fission and no ET from triplet excitons in 1.5 ns time window. We confirm that the absence of ET is not limited by exciton diffusion but due to very slow (≫1.5 ns) interfacial ET from triplet exciton. The observations contradict expected singlet and triplet ET behaviors based on a simple two-state Marcus ET model and suggest long-range interfacial ET from delocalized photoexcitation. The ultrafast ET from singlet exciton before SF and slow ET from triplet exciton call for reconsideration and careful design of efficient SF photovoltaic devices.
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Affiliation(s)
- Wang Zukun
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Ruihan Wu
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Zeng Chen
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Lei Ye
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Hanying Li
- MOE Key Laboratory of Macromolecule Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Haiming Zhu
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, Zhejiang, China
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42
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Duan R, Han G, Zeng Y, Peng Q, Yi Y. Suppressing triplet decay in quinoidal singlet fission materials: the role of molecular planarity and rigidity. Phys Chem Chem Phys 2020; 22:7546-7551. [PMID: 32219273 DOI: 10.1039/c9cp06987a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Singlet fission, in which one singlet exciton is split into two triplet excitons, provides the potential to exceed the Shockley-Queisser limit for the power conversion efficiencies of organic solar cells. However, the charge transfer from the triplet state is found to be slow in singlet fission materials, so suppression of the triplet decay is crucial for effective utilization of singlet fission. Here, we first investigated triplet decay for the singlet fission molecular materials of ThBF and TThBF, which are characteristic of twisted and flexible quinoidal backbones. It is found that these compounds show rapid nonradiative decay in the Franck-Condon region and through the T1/S0 crossing point. Interestingly, upon locking the backbone twist by methylene, the LThBF and LTThBF compounds exhibit much higher energy barriers from T1 to the T1/S0 crossing point, vanishing spin-orbit couplings, and decreased reorganization energies due to the planar and rigid structures. Consequently, both the triplet decay pathways are effectively suppressed. Our work reveals the importance of molecular planarity and rigidity in suppressing triplet decay and will be very helpful for full utilization of singlet fission in organic photovoltaics.
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Affiliation(s)
- Ruihong Duan
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
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43
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Manna B, Nandi A. Exploration of photophysics and presence of Long singlet exciton diffusion length in dibenz[a,h]anthracene nanoaggregates. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112407] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Han J, Xie Q, Luo J, Deng GH, Qian Y, Sun D, Harutyunyan AR, Chen G, Rao Y. Anisotropic Geminate and Non-Geminate Recombination of Triplet Excitons in Singlet Fission of Single Crystalline Hexacene. J Phys Chem Lett 2020; 11:1261-1267. [PMID: 31971388 DOI: 10.1021/acs.jpclett.9b03800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Singlet fission is believed to improve the efficiency of solar energy conversion by breaking up the Shockley-Queisser thermodynamic limit. Understanding of triplet excitons generated by singlet fission is essential for solar energy exploitation. Here we employed transient absorption microscopy to examine dynamical behaviors of triplet excitons. We observed anisotropic recombination of triplet excitons in hexacene single crystals. The triplet exciton relaxations from singlet fission proceed in both geminate and non-geminate recombination. For the geminate recombination, the different rates were attributed to the significant difference in their related energy change based on the Redfield quantum dissipation theory. The process is mainly governed by the electron-phonon interaction in hexacene. On the other hand, the non-geminate recombination is of bimolecular origin through energy transfer. In the triplet-triplet bimolecular process, the rates along the two different optical axes in the a-b crystalline plane differ by a factor of 4. This anisotropy in the triplet-triplet recombination rates was attributed to the interference in the coupling probability of dipole-dipole interactions in the different geometric configurations of hexacene single crystals. Our experimental findings provide new insight into future design of singlet fission materials with desirable triplet exciton exploitations.
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Affiliation(s)
- Jian Han
- School of Chemical Engineering , Nanjing University of Science and Technology , Nanjing 210094 , China
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
| | - Qing Xie
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
| | - Jun Luo
- School of Chemical Engineering , Nanjing University of Science and Technology , Nanjing 210094 , China
| | - Gang-Hua Deng
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
| | - Yuqin Qian
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
| | - Dezheng Sun
- Department of Physics , Columbia University , New York , New York 10027 , United States
| | - Avetik R Harutyunyan
- Honda Research Institute, USA, Inc. , San Jose , California 95134 , United States
| | - Gugang Chen
- Honda Research Institute, USA, Inc. , San Jose , California 95134 , United States
| | - Yi Rao
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
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45
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Tao G. Topology of quantum coherence networks in singlet fission: mapping exciton states into real space and the dislocation induced three dimensional manifolds. Phys Chem Chem Phys 2020; 22:1258-1267. [PMID: 31850461 DOI: 10.1039/c9cp05102c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An understanding of the global structure of quantum coherence networks in coupled multistate systems is of great importance for the development of emerging quantum technologies such as quantum control and quantum materials design. Here, we study the topology of a quantum coherence network of a typical singlet exciton fission system by mapping the exciton states into crystal structures in real space. The defects in crystals could lead to changes in the topological structures, and also fission dynamics. In particular, we demonstrate that the dislocation induced three dimensional manifold, which differs from its lower dimensional counterparts globally, could generate exotic global structures, such as chiral spirals, and modulate singlet fission substantially. The findings may shed light on the new possibilities of engineering effective structures for fission materials.
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Affiliation(s)
- Guohua Tao
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. and Shenzhen Key Laboratory of New Energy Materials by Design, Peking University, Shenzhen, 518055, China
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46
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Hudson RJ, de la Perrelle JM, Pensack RD, Kudisch B, Scholes GD, Huang DM, Kee TW. Organizing Crystalline Functionalized Pentacene Using Periodicity of Poly(Vinyl Alcohol). J Phys Chem Lett 2020; 11:516-523. [PMID: 31884794 DOI: 10.1021/acs.jpclett.9b03373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nanoparticles of acenes exhibit highly efficient intermolecular singlet fission (SF). Recent reports indicate that altering the morphology of 6,13-bis-(triisopropylsilylethynyl)pentacene (TIPS-Pn) nanoparticles has a profound influence on their SF dynamics. Here, we show that poly(vinyl alcohol) (PVA) induces a phase transition in preformed TIPS-Pn nanoparticles. These nanoparticles are amorphous when initially formed but crystalline after addition of PVA. Surface characterization indicates that a diffuse PVA layer surrounds the nanoparticles. We propose that a periodic interaction between the hydroxyl groups of PVA and TIPS groups of TIPS-Pn on the nanoparticle surface induces a large-scale structural rearrangement to yield crystalline TIPS-Pn. Such reorganization in preformed organic nanoparticles is unprecedented, and we believe that this is the first report of such an effect induced by polymer adsorption. Transient absorption spectroscopic results reveal that SF within these nanoparticles is accelerated by an order of magnitude upon structural rearrangement.
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Affiliation(s)
- Rohan J Hudson
- Department of Chemistry , The University of Adelaide , Adelaide , South Australia 5005 , Australia
| | - Jessica M de la Perrelle
- Department of Chemistry , The University of Adelaide , Adelaide , South Australia 5005 , Australia
| | - Ryan D Pensack
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Bryan Kudisch
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Gregory D Scholes
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - David M Huang
- Department of Chemistry , The University of Adelaide , Adelaide , South Australia 5005 , Australia
| | - Tak W Kee
- Department of Chemistry , The University of Adelaide , Adelaide , South Australia 5005 , Australia
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47
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Mora‐Fuentes JP, Papadopoulos I, Thiel D, Álvarez‐Boto R, Cortizo‐Lacalle D, Clark T, Melle‐Franco M, Guldi DM, Mateo‐Alonso A. Singlet Fission in Pyrene‐Fused Azaacene Dimers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201911529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Juan P. Mora‐Fuentes
- POLYMAT University of the Basque Country UPV/EHU Avenida de Tolosa 72 20018 Donostia-San Sebastian Spain
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Dominik Thiel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Roberto Álvarez‐Boto
- CICECO—Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
| | - Diego Cortizo‐Lacalle
- POLYMAT University of the Basque Country UPV/EHU Avenida de Tolosa 72 20018 Donostia-San Sebastian Spain
| | - Timothy Clark
- Computer-Chemistry Centre Department of Chemistry and Pharmacy Friedrich-Alexander-Universität Erlangen-Nürnberg Naegelsbachstr. 25 91052 Erlangen Germany
| | - Manuel Melle‐Franco
- CICECO—Aveiro Institute of Materials Department of Chemistry University of Aveiro 3810-193 Aveiro Portugal
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Aurelio Mateo‐Alonso
- POLYMAT University of the Basque Country UPV/EHU Avenida de Tolosa 72 20018 Donostia-San Sebastian Spain
- Ikerbasque Basque Foundation for Science Bilbao Spain
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48
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Mora‐Fuentes JP, Papadopoulos I, Thiel D, Álvarez‐Boto R, Cortizo‐Lacalle D, Clark T, Melle‐Franco M, Guldi DM, Mateo‐Alonso A. Singlet Fission in Pyrene-Fused Azaacene Dimers. Angew Chem Int Ed Engl 2020; 59:1113-1117. [PMID: 31647593 PMCID: PMC7687256 DOI: 10.1002/anie.201911529] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Indexed: 02/02/2023]
Abstract
Singlet fission has emerged as a promising strategy to avoid the loss of extra energy through thermalization in solar cells. A family of dimers consisting of nitrogen-doped pyrene-fused acenes that undergo singlet fission with triplet quantum yields as high as 125 % are presented. They provide new perspectives for nitrogenated polycyclic aromatic hydrocarbons and for the design of new materials for singlet fission.
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Affiliation(s)
- Juan P. Mora‐Fuentes
- POLYMATUniversity of the Basque Country UPV/EHUAvenida de Tolosa 7220018Donostia-San SebastianSpain
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular MaterialsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Dominik Thiel
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular MaterialsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Roberto Álvarez‐Boto
- CICECO—Aveiro Institute of MaterialsDepartment of ChemistryUniversity of Aveiro3810-193AveiroPortugal
| | - Diego Cortizo‐Lacalle
- POLYMATUniversity of the Basque Country UPV/EHUAvenida de Tolosa 7220018Donostia-San SebastianSpain
| | - Timothy Clark
- Computer-Chemistry CentreDepartment of Chemistry and PharmacyFriedrich-Alexander-Universität Erlangen-NürnbergNaegelsbachstr. 2591052ErlangenGermany
| | - Manuel Melle‐Franco
- CICECO—Aveiro Institute of MaterialsDepartment of ChemistryUniversity of Aveiro3810-193AveiroPortugal
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular MaterialsFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Aurelio Mateo‐Alonso
- POLYMATUniversity of the Basque Country UPV/EHUAvenida de Tolosa 7220018Donostia-San SebastianSpain
- IkerbasqueBasque Foundation for ScienceBilbaoSpain
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49
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Ginsberg NS, Tisdale WA. Spatially Resolved Photogenerated Exciton and Charge Transport in Emerging Semiconductors. Annu Rev Phys Chem 2019; 71:1-30. [PMID: 31756129 DOI: 10.1146/annurev-physchem-052516-050703] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We review recent advances in the characterization of electronic forms of energy transport in emerging semiconductors. The approaches described all temporally and spatially resolve the evolution of initially localized populations of photogenerated excitons or charge carriers. We first provide a comprehensive background for describing the physical origin and nature of electronic energy transport both microscopically and from the perspective of the observer. We introduce the new family of far-field, time-resolved optical microscopies developed to directly resolve not only the extent of this transport but also its potentially temporally and spatially dependent rate. We review a representation of examples from the recent literature, including investigation of energy flow in colloidal quantum dot solids, organic semiconductors, organic-inorganic metal halide perovskites, and 2D transition metal dichalcogenides. These examples illustrate how traditional parameters like diffusivity are applicable only within limited spatiotemporal ranges and how the techniques at the core of this review,especially when taken together, are revealing a more complete picture of the spatiotemporal evolution of energy transport in complex semiconductors, even as a function of their structural heterogeneities.
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Affiliation(s)
- Naomi S Ginsberg
- Department of Chemistry and Department of Physics, University of California, Berkeley, California 94720, USA; .,Material Sciences Division and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Kavli Energy NanoSciences Institute, Berkeley, California 94720, USA
| | - William A Tisdale
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA;
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50
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Felter K, Grozema FC. Singlet Fission in Crystalline Organic Materials: Recent Insights and Future Directions. J Phys Chem Lett 2019; 10:7208-7214. [PMID: 31689105 PMCID: PMC6875870 DOI: 10.1021/acs.jpclett.9b00754] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 11/05/2019] [Indexed: 05/20/2023]
Abstract
Singlet fission (SF) involves the conversion of one excited singlet state into two lower excited triplet states and has received considerable renewed attention over the past decade. This Perspective highlights recent developments and emerging concepts of SF in solid-state crystalline materials. Recent experiments showed the crucial role of vibrational modes in speeding up SF, and theoretical modeling has started to define an optimal energetic landscape and intermolecular orientation of chromophores for highly efficient singlet fission. A critical analysis of these developments leads to directions for future research to eventually find singlet fission chromophores with excellent optoelectronic properties.
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Affiliation(s)
- Kevin
M. Felter
- Optoelectronic Materials
Section, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HS Delft, The Netherlands
| | - Ferdinand C. Grozema
- Optoelectronic Materials
Section, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HS Delft, The Netherlands
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