1
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Sharma H, Ankita, Mittal V, Pandey UK, Das S. Syntheses and Properties of Hole-Transporting Biindenofluorenes. Org Lett 2024; 26:2617-2622. [PMID: 38512391 DOI: 10.1021/acs.orglett.4c00630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Described herein is a straightforward approach to synthesizing three biindenofluorene (BIF) derivatives, composed of antiaromatic indenofluorene units, which are the first non-alternant congeners of known bipentacene. Dimerization of indeno[1,2-b]fluorene and indeno[2,1-c]fluorene units by connecting carbons 3 and 3' and carbons 2 and 2', respectively, is shown to influence the highest occupied and lowest unoccupied molecular orbital energy levels of the resulting BIFs, affording band gaps (1.5-1.6 eV) that are smaller than that of a known indenofluorene polymer (2.3 eV). The hole mobilities of BIFs were determined to be ∼10-2 cm2 V-1 s-1.
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Affiliation(s)
- Himanshu Sharma
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Ankita
- Organic & Flexible Electronics Laboratory, Department of Electrical Engineering, School of Engineering, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Vishal Mittal
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Upendra Kumar Pandey
- Organic & Flexible Electronics Laboratory, Department of Electrical Engineering, School of Engineering, Shiv Nadar Institution of Eminence, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Soumyajit Das
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
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2
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Hameed F, Maity A, Francis VS, Gavvalapalli N. Pyrazinacene conjugated polymers: a breakthrough in synthesis and unraveling the conjugation continuum. Chem Sci 2024; 15:4054-4067. [PMID: 38487242 PMCID: PMC10935667 DOI: 10.1039/d3sc06552a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 01/29/2024] [Indexed: 03/17/2024] Open
Abstract
Pyrazinacenes are next generation N-heteroacenes and represent a novel class of stable n-type materials capable of accepting more than one electron and displaying intriguing features, including prototropism, halochromism, and redox chromism. Astonishingly, despite a century since their discovery, there have been no reports on the conjugated polymers of pyrazinacenes due to unknown substrate scope and lack of pyrazinacene monomers that are conducive to condensation polymerization. Breaking through these challenges, in this work, we report the synthesis of previously undiscovered and highly coveted conjugated polymers of pyrazinacenes. In order to understand the intricacies of conjugation extension within the acene and along the polymer backbone, a series of electronically diverse four pyrazinacene conjugated polymers were synthesized. Polymers synthesis required optimizing a few synthetic steps along the 12-step synthetic pathway. The generated pyrazinacene monomers are not amenable to the popular condensation polymerizations involving Pd or Cu catalysts. Gratifyingly, Pd and Cu free dehydrohalogenation polymerization of the monomer with HgCl2 resulted in high molecular weight organometallic conjugated pyrazinacene polymers within a few minutes at room temperature. The dual role played by the Hg(ii) during the polymerization, combined with the self-coupling of the RHgCl (intermediate), is at the core of successful polymerization. Notably, the self-coupling of intermediates challenges the strict stoichiometric balance typically required for step-growth polymerization and offers a novel synthetic strategy to generate high molecular weight conjugated polymers even with imbalanced monomer stoichiometries. A combination of electrochemical studies and DFT-B3LYP simulations indicated that the presence of the reduced pyrazine ring promotes interacene π-conjugation through the metal center, in contrast to completely oxidized tetrazaazaanthracene. The extension of conjugation results in ca. 2 eV lower reduction potential for polymers compared to the monomer, placing the LUMO energy levels of these polymers on par with some of the best-known n-type polymers. Also, the presence of NH protons in the pyrazinacene polymers show ionochromism and red-shift UV-vis absorption maximum by ca. 100 nm. This work not only shows a way to realize highly desirable and elusive pyrazinacene conjugated polymers but also paves the way for a library of n-type conjugated polymers that can undergo multi-electron reduction.
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Affiliation(s)
- Fatima Hameed
- Department of Chemistry, Georgetown University USA
- Institute for Soft Matter Synthesis and Metrology, Georgetown University Washington, D.C. 20057 USA
| | - Arindam Maity
- Department of Chemistry, Georgetown University USA
- Institute for Soft Matter Synthesis and Metrology, Georgetown University Washington, D.C. 20057 USA
| | - Victor S Francis
- Department of Chemistry, Georgetown University USA
- Institute for Soft Matter Synthesis and Metrology, Georgetown University Washington, D.C. 20057 USA
| | - Nagarjuna Gavvalapalli
- Department of Chemistry, Georgetown University USA
- Institute for Soft Matter Synthesis and Metrology, Georgetown University Washington, D.C. 20057 USA
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3
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He G, Churchill EM, Parenti KR, Zhang J, Narayanan P, Namata F, Malkoch M, Congreve DN, Cacciuto A, Sfeir MY, Campos LM. Promoting multiexciton interactions in singlet fission and triplet fusion upconversion dendrimers. Nat Commun 2023; 14:6080. [PMID: 37770472 PMCID: PMC10539328 DOI: 10.1038/s41467-023-41818-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 09/20/2023] [Indexed: 09/30/2023] Open
Abstract
Singlet fission and triplet-triplet annihilation upconversion are two multiexciton processes intimately related to the dynamic interaction between one high-lying energy singlet and two low-lying energy triplet excitons. Here, we introduce a series of dendritic macromolecules that serve as platform to study the effect of interchromophore interactions on the dynamics of multiexciton generation and decay as a function of dendrimer generation. The dendrimers (generations 1-4) consist of trimethylolpropane core and 2,2-bis(methylol)propionic acid (bis-MPA) dendrons that provide exponential growth of the branches, leading to a corona decorated with pentacenes for SF or anthracenes for TTA-UC. The findings reveal a trend where a few highly ordered sites emerge as the dendrimer generation grows, dominating the multiexciton dynamics, as deduced from optical spectra, and transient absorption spectroscopy. While the dendritic structures enhance TTA-UC at low annihilator concentrations in the largest dendrimers, the paired chromophore interactions induce a broadened and red-shifted excimer emission. In SF dendrimers of higher generations, the triplet dynamics become increasingly dominated by pairwise sites exhibiting strong coupling (Type II), which can be readily distinguished from sites with weaker coupling (Type I) by their spectral dynamics and decay kinetics.
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Affiliation(s)
- Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, NY, 10016, USA
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
| | - Emily M Churchill
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Kaia R Parenti
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Jocelyn Zhang
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Pournima Narayanan
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Faridah Namata
- KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, SE-100 44, Stockholm, Sweden
| | - Michael Malkoch
- KTH Royal Institute of Technology, Department of Fibre and Polymer Technology, SE-100 44, Stockholm, Sweden
| | - Daniel N Congreve
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Angelo Cacciuto
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, NY, 10016, USA.
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA.
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.
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4
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Orsborne SE, Gorman J, Weiss LR, Sridhar A, Panjwani NA, Divitini G, Budden P, Palecek D, Ryan ST, Rao A, Collepardo-Guevara R, El-Sagheer AH, Brown T, Behrends J, Friend RH, Auras F. Photogeneration of Spin Quintet Triplet-Triplet Excitations in DNA-Assembled Pentacene Stacks. J Am Chem Soc 2023; 145:5431-5438. [PMID: 36825550 PMCID: PMC9999418 DOI: 10.1021/jacs.2c13743] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Indexed: 02/25/2023]
Abstract
Singlet fission (SF), an exciton-doubling process observed in certain molecular semiconductors where two triplet excitons are generated from one singlet exciton, requires correctly tuned intermolecular coupling to allow separation of the two triplets to different molecular units. We explore this using DNA-encoded assembly of SF-capable pentacenes into discrete π-stacked constructs of defined size and geometry. Precise structural control is achieved via a combination of the DNA duplex formation between complementary single-stranded DNA and the local molecular geometry that directs the SF chromophores into a stable and predictable slip-stacked configuration, as confirmed by molecular dynamics (MD) modeling. Transient electron spin resonance spectroscopy revealed that within these DNA-assembled pentacene stacks, SF evolves via a bound triplet pair quintet state, which subsequently converts into free triplets. SF evolution via a long-lived quintet state sets specific requirements on intermolecular coupling, rendering the quintet spectrum and its zero-field-splitting parameters highly sensitive to intermolecular geometry. We have found that the experimental spectra and zero-field-splitting parameters are consistent with a slight systematic strain relative to the MD-optimized geometry. Thus, the transient electron spin resonance analysis is a powerful tool to test and refine the MD-derived structure models. DNA-encoded assembly of coupled semiconductor molecules allows controlled construction of electronically functional structures, but brings with it significant dynamic and polar disorders. Our findings here of efficient SF through quintet states demonstrate that these conditions still allow efficient and controlled semiconductor operation and point toward future opportunities for constructing functional optoelectronic systems.
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Affiliation(s)
- Sarah
R. E. Orsborne
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - Jeffrey Gorman
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - Leah R. Weiss
- Pritzker
School of Molecular Engineering, University
of Chicago, Chicago, Illinois 60637, United
States
| | - Akshay Sridhar
- Department
of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, 17121 Solna, Sweden
| | - Naitik A. Panjwani
- Berlin
Joint EPR Laboratory, Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Giorgio Divitini
- Department
of Materials Science & Metallurgy, University
of Cambridge, CB3 0FS Cambridge, U.K.
| | - Peter Budden
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - David Palecek
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - Seán T.
J. Ryan
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - Akshay Rao
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - Rosana Collepardo-Guevara
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
- Yusuf Hamied
Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Afaf H. El-Sagheer
- Department
of Chemistry, University of Oxford, OX1 3TA Oxford, U.K.
- Department
of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez 43721, Egypt
| | - Tom Brown
- Department
of Chemistry, University of Oxford, OX1 3TA Oxford, U.K.
| | - Jan Behrends
- Berlin
Joint EPR Laboratory, Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Richard H. Friend
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
| | - Florian Auras
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, CB3 0HE Cambridge, U.K.
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5
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Anderson CL, Zhang T, Qi M, Chen Z, Yang C, Teat SJ, Settineri NS, Dailing EA, Garzón-Ruiz A, Navarro A, Lv Y, Liu Y. Exceptional Electron-Rich Heteroaromatic Pentacycle for Ultralow Band Gap Conjugated Polymers and Photothermal Therapy. J Am Chem Soc 2023; 145:5474-5485. [PMID: 36812073 DOI: 10.1021/jacs.3c00036] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Stable redox-active conjugated molecules with exceptional electron-donating abilities are key components for the design and synthesis of ultralow band gap conjugated polymers. While hallmark electron-rich examples such as pentacene derivatives have been thoroughly explored, their poor air stability has hampered their broad incorporation into conjugated polymers for practical applications. Herein, we describe the synthesis of the electron-rich, fused pentacyclic pyrazino[2,3-b:5,6-b']diindolizine (PDIz) motif and detail its optical and redox behavior. The PDIz ring system exhibits a lower oxidation potential and a reduced optical band gap than the isoelectronic pentacene while retaining greater air stability in both solution and the solid state. The enhanced stability and electron density, together with readily installed solubilizing groups and polymerization handles, allow for the use of the PDIz motif in the synthesis of a series of conjugated polymers with band gaps as small as 0.71 eV. The tunable absorbance throughout the biologically relevant near-infrared I and II regions enables the use of these PDIz-based polymers as efficient photothermal therapeutic reagents for laser ablation of cancer cells.
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Affiliation(s)
- Christopher L Anderson
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Tong Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China
| | - Miao Qi
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ziman Chen
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chongqing Yang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Simon J Teat
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Nicholas S Settineri
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Eric A Dailing
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrés Garzón-Ruiz
- Department of Physical Chemistry, Faculty of Pharmacy, Universidad de Castilla-La Mancha, Cronista Francisco Ballesteros Gómez, Albacete 02071, Spain
| | - Amparo Navarro
- Department of Physical and Analytical Chemistry, Faculty of Experimental Sciences, Universidad de Jaén, Campus Las Lagunillas, Jaén 23071, Spain
| | - Yongqin Lv
- State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yi Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Mohamed Abdelmoniem A, Abdelshafy Abdelhamid I, Butenschön H. Bidirectional Synthesis, Photophysical and Electrochemical Characterization of Polycyclic Quinones Using Benzocyclobutenes and Benzodicyclobutenes as Precursors. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Amr Mohamed Abdelmoniem
- Institut für Organische Chemie Leibniz Universität Hannover Schneiderberg 1B 30167 Hannover Germany
- Department of Chemistry Faculty of Science Cairo University 12613 Giza A. R. Egypt
| | | | - Holger Butenschön
- Institut für Organische Chemie Leibniz Universität Hannover Schneiderberg 1B 30167 Hannover Germany
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7
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Walia R, Deng Z, Yang J. Towards multistate multimode landscapes in singlet fission of pentacene: the dual role of charge-transfer states. Chem Sci 2021; 12:12928-12938. [PMID: 34745523 PMCID: PMC8514007 DOI: 10.1039/d1sc01703a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/30/2021] [Indexed: 12/03/2022] Open
Abstract
Singlet fission duplicates triplet excitons for improving light harvesting efficiency. The presence of the interaction between electronic and nuclear degrees of freedom complicates the interpretation of correlated triplet pairs. We report a quantum chemistry study on the significance and subtleties of multistate and multimode pathways in forming triplet pair states of the pentacene dimer through a six-state vibronic-coupling Hamiltonian derived from many-electron adiabatic wavefunctions of an ab initio density matrix renormalization group. The resulting spin values of the singlet manifolds on each pentacene center are computed, and the varying spin nature can be distinguished clearly with respect to dimer stacking and vibronic progression. Our monomer spin assignments reveal the coexistence of both lower-lying weak and higher-lying strong charge transfer states which interact vibronically with the triplet pair state, providing important implications for its generation and separation occurring in vibronic regions. This work conveys the importance of the many-electron process requiring close low-lying singlet manifolds to determine the subtle fission details, and represents an important step for understanding vibronically resolved spin states and conversions underlying efficient singlet fission.
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Affiliation(s)
- Rajat Walia
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Zexiang Deng
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
| | - Jun Yang
- Department of Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
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8
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Ogbonna ND, Dearman M, Bharti B, Peters AJ, Lawrence J. Elucidating the impact of side chain dispersity on the assembly of bottlebrush polymers at the
air‐water
interface. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Nduka D. Ogbonna
- Department of Chemical Engineering Louisiana State University Baton Rouge Louisiana USA
| | - Michael Dearman
- Department of Chemical Engineering Louisiana State University Baton Rouge Louisiana USA
| | - Bhuvnesh Bharti
- Department of Chemical Engineering Louisiana State University Baton Rouge Louisiana USA
| | - Andrew J. Peters
- Department of Chemical Engineering Louisiana Tech University Ruston Louisiana USA
| | - Jimmy Lawrence
- Department of Chemical Engineering Louisiana State University Baton Rouge Louisiana USA
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9
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Shi X, Liu M, Li L, Zhang J, Li H, Huang Z, Zhang W, Zhang Z, Zhou N, Zhu X. Efficient synthesis of discrete oligo(fluorenediacetylene)s toward chain-length-dependent optical and structural properties. Polym Chem 2021. [DOI: 10.1039/d1py00165e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of discrete oligo(fluorenediacetylene)s with a degree of polymerization up to 10 were obtained by automated flash column chromatography, which indicated the chain-length dependent photophysical properties and crystalline behavior.
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10
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Parenti KR, He G, Sanders SN, Pun AB, Kumarasamy E, Sfeir MY, Campos LM. Bridge Resonance Effects in Singlet Fission. J Phys Chem A 2020; 124:9392-9399. [PMID: 33138366 DOI: 10.1021/acs.jpca.0c08427] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A major benefit of intramolecular singlet fission (iSF) materials, in which through-bond interactions mediate triplet pair formation, is the ability to control the triplet formation dynamics through molecular engineering. One common design strategy is the use of molecular bridges to mediate interchromophore interactions, decreasing electronic coupling by increasing chromophore-chromophore separation. Here, we report how the judicious choice of aromatic bridges can enhance chromophore-chromophore electronic coupling. This molecular engineering strategy takes advantage of "bridge resonance", in which the frontier orbital energies are nearly degenerate with those of the covalently linked singlet fission chromophores, resulting in fast iSF even at large interchromophore separations. Using transient absorption spectroscopy, we investigate this bridge resonance effect in a series of pentacene and tetracene-bridged dimers, and we find that the rate of triplet formation is enhanced as the bridge orbitals approach resonance. This work highlights the important role of molecular connectivity in controlling the rate of iSF through chemical bonds and establishes critical design principles for future use of iSF materials in optoelectronic devices.
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Affiliation(s)
- Kaia R Parenti
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Guiying He
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, United States.,Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Andrew B Pun
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Elango Kumarasamy
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Matthew Y Sfeir
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, United States.,Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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11
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Yin X, Low JZ, Fallon KJ, Paley DW, Campos LM. The butterfly effect in bisfluorenylidene-based dihydroacenes: aggregation induced emission and spin switching. Chem Sci 2019; 10:10733-10739. [PMID: 32153748 PMCID: PMC7020927 DOI: 10.1039/c9sc04096j] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/04/2019] [Indexed: 11/30/2022] Open
Abstract
Linear acenes are a well-studied class of polycyclic aromatic hydrocarbons and their established physical properties have led to their widespread application across the field of organic electronics. However, their quinoidal forms - dihydroacenes - are much less explored and exhibit vastly different photophysical and electronic properties due to their non-planar, cross-conjugated nature. In this work, we present a series of difluorenylidene dihydroacenes which exhibit a butterfly-like structure with a quinoidal skeleton, resulting in comparatively higher optical gaps and lower redox activities than those of their planar analogs. We found that these compounds exhibit aggregation induced emission (AIE), activated through restriction of the "flapping" vibrational mode of the molecules in the solid state. Furthermore, anthracene-containing dihydroacenes exhibit thermally activated ground-state spin switching as evidenced by planarization of the acene core and diradical activity recorded by EPR. These two characteristics in this relatively unexplored class of materials provide new insights for the design of multifunctional materials.
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Affiliation(s)
- Xiaodong Yin
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials , School of Chemistry and Chemical Engineering , Beijing Institute of Technology , Beijing 102488 , P. R. China
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Jonathan Z Low
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Kealan J Fallon
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Daniel W Paley
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Luis M Campos
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
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12
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Sanders SN, Kumarasamy E, Fallon KJ, Sfeir MY, Campos LM. Singlet fission in a hexacene dimer: energetics dictate dynamics. Chem Sci 2019; 11:1079-1084. [PMID: 34084363 PMCID: PMC8146228 DOI: 10.1039/c9sc05066c] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Singlet fission (SF) is an exciton multiplication process with the potential to raise the efficiency limit of single junction solar cells from 33% to up to 45%. Most chromophores generally undergo SF as solid-state crystals. However, when such molecules are covalently coupled, the dimers can be used as model systems to study fundamental photophysical dynamics where a singlet exciton splits into two triplet excitons within individual molecules. Here we report the synthesis and photophysical characterization of singlet fission of a hexacene dimer. Comparing the hexacene dimer to analogous tetracene and pentacene dimers reveals that excess exoergicity slows down singlet fission, similar to what is observed in molecular crystals. Conversely, the lower triplet energy of hexacene results in an increase in the rate of triplet pair recombination, following the energy gap law for radiationless transitions. These results point to design rules for singlet fission chromophores: the energy gap between singlet and triplet pair should be minimal, and the gap between triplet pair and ground state should be large. We report the synthesis and photophysical characterization of highly exoergic singlet fission in a hexacene dimer revealing exciton dynamics that follow the energy gap law.![]()
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Affiliation(s)
- Samuel N Sanders
- Department of Chemistry, Columbia University New York NY 10027 USA
| | | | - Kealan J Fallon
- Department of Chemistry, Columbia University New York NY 10027 USA
| | - Matthew Y Sfeir
- Photonics Initiative, Advanced Science Research Center, City University of New York New York NY 10031 USA .,Department of Physics, Graduate Center, City University of New York New York NY 10016 USA
| | - Luis M Campos
- Department of Chemistry, Columbia University New York NY 10027 USA
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13
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Hetzer C, Basel BS, Kopp SM, Hampel F, White FJ, Clark T, Guldi DM, Tykwinski RR. Chromophore Multiplication To Enable Exciton Delocalization and Triplet Diffusion Following Singlet Fission in Tetrameric Pentacene. Angew Chem Int Ed Engl 2019; 58:15263-15267. [PMID: 31342607 PMCID: PMC7497398 DOI: 10.1002/anie.201907221] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Indexed: 11/06/2022]
Abstract
A tetrameric pentacene, PT, has been used to explore the effects of exciton delocalization on singlet fission (SF). For the first time, triplet decorrelation through intramolecular triplet diffusion was observed following SF. Transient absorption spectroscopy was used to examine different decorrelation mechanisms (triplet diffusion versus structural changes) for PT and its dimeric equivalent PD on the basis of the rate and activation barrier of the decorrelation step. Charge-separation experiments using tetracyano-p-quinodimethane (TCNQ) to quench triplet excitons formed through SF demonstrate that enhanced intersystem crossing, that is, spin catalysis, is a widely underestimated obstacle to quantitative harvesting of the SF products. The importance of spatial separation of the decorrelated triplet states is emphasized, and independent proof that the decorrelated triplet pair state consists of two (T1 ) states per molecule is provided.
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Affiliation(s)
- Constantin Hetzer
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM)Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)Nikolaus-Fiebiger-Strasse 1091058ErlangenGermany
| | - Bettina S. Basel
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), FAUEgerlandstrasse 391058ErlangenGermany
| | - Sebastian M. Kopp
- Department of ChemistryUniversity of AlbertaEdmontonAlbertaT6G 2G2Canada
| | - Frank Hampel
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM)Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)Nikolaus-Fiebiger-Strasse 1091058ErlangenGermany
| | - Fraser J. White
- Rigaku Europe, Unit B6Chaucer Business ParkWatery Lane, KemsingSevenoaksTN15 6QYUK
| | - Timothy Clark
- Computer Chemistry CenterDepartment of Chemistry and Pharmacy, FAUNägelsbachstrasse 2591052ErlangenGermany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), FAUEgerlandstrasse 391058ErlangenGermany
| | - Rik R. Tykwinski
- Department of ChemistryUniversity of AlbertaEdmontonAlbertaT6G 2G2Canada
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14
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Hetzer C, Basel BS, Kopp SM, Hampel F, White FJ, Clark T, Guldi DM, Tykwinski RR. Chromophore Multiplication To Enable Exciton Delocalization and Triplet Diffusion Following Singlet Fission in Tetrameric Pentacene. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Constantin Hetzer
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Nikolaus-Fiebiger-Strasse 10 91058 Erlangen Germany
| | - Bettina S. Basel
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), FAU Egerlandstrasse 3 91058 Erlangen Germany
| | - Sebastian M. Kopp
- Department of Chemistry University of Alberta Edmonton Alberta T6G 2G2 Canada
| | - Frank Hampel
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM) Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Nikolaus-Fiebiger-Strasse 10 91058 Erlangen Germany
| | - Fraser J. White
- Rigaku Europe, Unit B6 Chaucer Business Park Watery Lane, Kemsing Sevenoaks TN15 6QY UK
| | - Timothy Clark
- Computer Chemistry Center Department of Chemistry and Pharmacy, FAU Nägelsbachstrasse 25 91052 Erlangen Germany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials (ICMM), FAU Egerlandstrasse 3 91058 Erlangen Germany
| | - Rik R. Tykwinski
- Department of Chemistry University of Alberta Edmonton Alberta T6G 2G2 Canada
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15
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Tykwinski RR. Synthesis of Unsymmetrical Derivatives of Pentacene for Materials Applications. Acc Chem Res 2019; 52:2056-2069. [PMID: 31310504 DOI: 10.1021/acs.accounts.9b00216] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Pentacene shows unique electronic properties that have long been appreciated and exploited. Over the past 20 years, new synthetic schemes have been developed to address some of the problems encountered with pristine pentacene (e.g., stability and solubility), and pentacene derivatives have become a mainstay in the realm of organic semiconductors in applications such as organic light-emitting diodes, organic field-effect transistors (OFETs), and organic photovoltaics. At the onset of our work, the vast majority of known pentacene derivatives featured a symmetrical structure, often as the result of synthetic protocols that rely on nucleophilic additions to 6,13-pentacenequinone (PQ). The assembly of pentacenes featuring an unsymmetrical framework held great appeal, but the stepwise formation of derivatives, in which a specific function might be incorporated through each individual addition step, did not exist. This Account presents contributions from our lab and others to the synthesis and study of unsymmetrical pentacene derivatives. PQ offers an ideal platform for desymmetrization through the sequential addition of nucleophiles to each of the two ketone groups. Addition can be completed in a one-pot protocol, or through individual steps in which the product of the first addition is isolated and used as a precursor in the divergent synthesis of a series of structurally related molecules. This general approach has been used to assemble pentacene derivatives appended with alkynyl/aryl/alkyl groups, polarized frameworks via substitution with donor and/or acceptor groups, and conjugated oligomers linked by butadiynyl moieties. Stepwise substitution also provides derivatives with remarkable functionality, including pentacene-porphyrin dyads, pendent TEMPO free radicals, cyanoacrylic acid anchor groups (for incorporation into dye-sensitized solar cells), and derivatives with ambipolar behavior for OFET devices. The study of intramolecular singlet fission (iSF) has emerged as one of the most fruitful applications of unsymmetrical pentacene derivatives. SF involves the spontaneous splitting of a photoexcited singlet state (S1) in one chromophore into a pair of triplets (T1) shared with a neighboring chromophore. Pentacene derivatives are particularly well suited for this since E(S1) ≥ 2E(T1) satisfies the thermodynamic requirements for SF, and they have the additional feature that two chromophores can be tethered together by a "spacer" that allows spectroscopic studies of iSF to be done in dilute solution. From a synthetic perspective, the major advantage of the dimeric structure is the ability to modify the spacer, which allows for control over the distance, geometric relationship, and electronic coupling between the two pentacene groups. Dimeric pentacenes are central to providing an in-depth understanding of the molecular mechanism of SF, often providing advances not possible from measurements in the solid state.
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Affiliation(s)
- Rik R. Tykwinski
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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16
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Pun AB, Asadpoordarvish A, Kumarasamy E, Tayebjee MJY, Niesner D, McCamey DR, Sanders SN, Campos LM, Sfeir MY. Ultra-fast intramolecular singlet fission to persistent multiexcitons by molecular design. Nat Chem 2019; 11:821-828. [PMID: 31406323 DOI: 10.1038/s41557-019-0297-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 06/14/2019] [Indexed: 11/10/2022]
Abstract
Singlet fission-that is, the generation of two triplets from a lone singlet state-has recently resurfaced as a promising process for the generation of multiexcitons in organic systems. Although advances in this area have led to the discovery of modular classes of chromophores, controlling the fate of the multiexciton states has been a major challenge; for example, promoting fast multiexciton generation while maintaining long triplet lifetimes. Unravelling the dynamical evolution of the spin- and energy conversion processes from the transition of singlet excitons to correlated triplet pairs and individual triplet excitons is necessary to design materials that are optimized for translational technologies. Here, we engineer molecules featuring a discrete energy gradient that promotes the migration of strongly coupled triplet pairs to a spatially separated, weakly coupled state that readily dissociates into free triplets. This 'energy cleft' concept allows us to combine the amplification and migration processes within a single molecule, with rapid dissociation of tightly bound triplet pairs into individual triplets that exhibit lifetimes of ~20 µs.
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Affiliation(s)
- Andrew B Pun
- Department of Chemistry, Columbia University, NewYork, NY, USA
| | - Amir Asadpoordarvish
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | | | - Murad J Y Tayebjee
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.,School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales, Australia
| | - Daniel Niesner
- Department of Chemistry, Columbia University, NewYork, NY, USA.,Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, MA, USA
| | - Dane R McCamey
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, NewYork, NY, USA. .,Rowland Institute at Harvard, Cambridge, MA, USA.
| | - Luis M Campos
- Department of Chemistry, Columbia University, NewYork, NY, USA.
| | - Matthew Y Sfeir
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, MA, USA. .,Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA. .,Department of Physics, Graduate Center, City University of New York, New York, NY, USA.
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17
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Sanders SN, Pun AB, Parenti KR, Kumarasamy E, Yablon LM, Sfeir MY, Campos LM. Understanding the Bound Triplet-Pair State in Singlet Fission. Chem 2019. [DOI: 10.1016/j.chempr.2019.05.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Sanders SN, Gangishetty MK, Sfeir MY, Congreve DN. Photon Upconversion in Aqueous Nanodroplets. J Am Chem Soc 2019; 141:9180-9184. [DOI: 10.1021/jacs.9b03992] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Samuel N. Sanders
- Rowland Institute at Harvard, Cambridge, Massachusetts 02142, United States
| | | | - Matthew Y. Sfeir
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
- Department of Physics, Graduate Center, City University of New York, New York, New York 10016, United States
| | - Daniel N. Congreve
- Rowland Institute at Harvard, Cambridge, Massachusetts 02142, United States
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19
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Pun AB, Sanders SN, Sfeir MY, Campos LM, Congreve DN. Annihilator dimers enhance triplet fusion upconversion. Chem Sci 2019; 10:3969-3975. [PMID: 31015937 PMCID: PMC6457208 DOI: 10.1039/c8sc03725f] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/20/2019] [Indexed: 12/12/2022] Open
Abstract
Optical upconversion is a net process by which two low energy photons are converted into one higher energy photon. There is vast potential to exploit upconversion in applications ranging from solar energy and biological imaging to data storage and photocatalysis. Here, we link two upconverting chromophores together to synthesize a series of novel tetracene dimers for use as annihilators. When compared with the monomer annihilator, TIPS-tetracene, the dimers yield a strong enhancement in the triplet fusion process, also known as triplet-triplet annihilation, as demonstrated via a large increase in upconversion efficiency and an order of magnitude reduction of the threshold power for maximum yield. Along with the ongoing rapid improvements to sensitizer materials, the dimerization improvements demonstrated here open the way to a wide variety of emerging upconversion applications.
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Affiliation(s)
- Andrew B Pun
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Samuel N Sanders
- Rowland Institute at Harvard University , Cambridge , Massachusetts 02142 , USA .
| | - Matthew Y Sfeir
- Photonics Initiative , Advanced Science Research Center , City University of New York , New York , New York 10031 , USA
- Department of Physics , Graduate Center , City University of New York , New York , New York 10016 , USA
| | - Luis M Campos
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Daniel N Congreve
- Rowland Institute at Harvard University , Cambridge , Massachusetts 02142 , USA .
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20
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Hele TJH, Fuemmeler EG, Sanders SN, Kumarasamy E, Sfeir MY, Campos LM, Ananth N. Anticipating Acene-Based Chromophore Spectra with Molecular Orbital Arguments. J Phys Chem A 2019; 123:2527-2536. [PMID: 30802051 DOI: 10.1021/acs.jpca.8b12222] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent synthetic studies on the organic molecules tetracene and pentacene have found certain dimers and oligomers to exhibit an intense absorption in the visible region of the spectrum that is not present in the monomer or many previously studied dimers. In this article we combine experimental synthesis with electronic structure theory and spectral computation to show that this absorption arises from an otherwise dark charge-transfer excitation "borrowing intensity" from an intense UV excitation. Further, by characterizing the role of relevant monomer molecular orbitals, we arrive at a design principle that allows us to predict the presence or absence of an additional absorption based on the bonding geometry of the dimer. We find this rule correctly explains the spectra of a wide range of acene derivatives and solves an unexplained structure-spectrum phenomenon first observed over 70 years ago. These results pave the way for the design of highly absorbent chromophores with applications ranging from photovoltaics to liquid crystals.
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Affiliation(s)
- Timothy J H Hele
- Cavendish Laboratory , Cambridge University , JJ Thomson Avenue , Cambridge CB3 0HE , U.K
| | - Eric G Fuemmeler
- Baker Laboratory , Cornell University , 259 East Avenue , Ithaca , New York 14850 , United States
| | - Samuel N Sanders
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Elango Kumarasamy
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Matthew Y Sfeir
- Center for Functional Nanomaterials , Brookhaven National Laboratory , Upton , New York 11973 , United States
| | - Luis M Campos
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Nandini Ananth
- Baker Laboratory , Cornell University , 259 East Avenue , Ithaca , New York 14850 , United States
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21
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Sakai H, Inaya R, Tkachenko NV, Hasobe T. High‐Yield Generation of Triplet Excited States by an Efficient Sequential Photoinduced Process from Energy Transfer to Singlet Fission in Pentacene‐Modified CdSe/ZnS Quantum Dots. Chemistry 2018; 24:17062-17071. [DOI: 10.1002/chem.201803257] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Hayato Sakai
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Ryutaro Inaya
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
| | - Nikolai V Tkachenko
- Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, 33101, Tampere, Finland
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, Kanagawa, 223-8522, Japan
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22
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Hetzer C, Guldi DM, Tykwinski RR. Pentacene Dimers as a Critical Tool for the Investigation of Intramolecular Singlet Fission. Chemistry 2018; 24:8245-8257. [DOI: 10.1002/chem.201705355] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Constantin Hetzer
- Department of Chemistry and Pharmacy; Interdisciplinary Center for Molecular Materials (ICMM); Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU); Nikolaus-Fiebiger-Straße 10 91058 Erlangen Germany
| | - Dirk M. Guldi
- Department of Chemistry and Pharmacy; Interdisciplinary Center for Molecular Materials (ICMM); Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU); Egerlandstrasse 3 91058 Erlangen Germany
| | - Rik R. Tykwinski
- Department of Chemistry; University of Alberta; Edmonton Alberta T6G 2G2 Canada
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23
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Pun AB, Sanders SN, Kumarasamy E, Sfeir MY, Congreve DN, Campos LM. Triplet Harvesting from Intramolecular Singlet Fission in Polytetracene. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1701416. [PMID: 28910503 DOI: 10.1002/adma.201701416] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/30/2017] [Indexed: 06/07/2023]
Abstract
Singlet fission (SF), a promising mechanism of multiple exciton generation, has only recently been engineered as a fast, efficient, intramolecular process (iSF). The challenge now lies in designing and optimizing iSF materials that can be practically applied in high-performance optoelectronic devices. However, most of the reported iSF systems, such as those based on donor-acceptor polymers or pentacene, have low triplet energies, which limits their applications. Tetracene-based materials can overcome significant challenges, as the tetracene triplet state is practically useful, ≈1.2 eV. Here, the synthesis and excited state dynamics of a conjugated tetracene homopolymer are studied. This polymer undergoes ultrafast iSF in solution, generating high-energy triplets on a sub-picosecond time scale. Magnetic-field-dependent photocurrent measurements of polytetracene-based devices demonstrate the first example of iSF-generated triplet extraction in devices, exhibiting the potential of iSF materials for use in next-generation devices.
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Affiliation(s)
- Andrew B Pun
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Samuel N Sanders
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Elango Kumarasamy
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Matthew Y Sfeir
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Daniel N Congreve
- Energy Frontier Research Center for Excitonics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Luis M Campos
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
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24
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Kumarasamy E, Sanders SN, Tayebjee MJY, Asadpoordarvish A, Hele TJH, Fuemmeler EG, Pun AB, Yablon LM, Low JZ, Paley DW, Dean JC, Choi B, Scholes GD, Steigerwald ML, Ananth N, McCamey DR, Sfeir MY, Campos LM. Tuning Singlet Fission in π-Bridge-π Chromophores. J Am Chem Soc 2017; 139:12488-12494. [PMID: 28799752 DOI: 10.1021/jacs.7b05204] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We have designed a series of pentacene dimers separated by homoconjugated or nonconjugated bridges that exhibit fast and efficient intramolecular singlet exciton fission (iSF). These materials are distinctive among reported iSF compounds because they exist in the unexplored regime of close spatial proximity but weak electronic coupling between the singlet exciton and triplet pair states. Using transient absorption spectroscopy to investigate photophysics in these molecules, we find that homoconjugated dimers display desirable excited-state dynamics, with significantly reduced recombination rates as compared to conjugated dimers with similar singlet fission rates. In addition, unlike conjugated dimers, the time constants for singlet fission are relatively insensitive to the interplanar angle between chromophores, since rotation about σ bonds negligibly affects the orbital overlap within the π-bonding network. In the nonconjugated dimer, where the iSF occurs with a time constant >10 ns, comparable to the fluorescence lifetime, we used electron spin resonance spectroscopy to unequivocally establish the formation of triplet-triplet multiexcitons and uncoupled triplet excitons through singlet fission. Together, these studies enable us to articulate the role of the conjugation motif in iSF.
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Affiliation(s)
| | | | - Murad J Y Tayebjee
- Cavendish Laboratory, University of Cambridge , J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | | | - Timothy J H Hele
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14850, United States.,Jesus College, Cambridge University , Cambridge CB5 8BL, United Kingdom
| | - Eric G Fuemmeler
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14850, United States
| | | | | | | | | | - Jacob C Dean
- 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
| | | | - Nandini Ananth
- Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14850, United States
| | | | - Matthew Y Sfeir
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
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25
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Synthesis and photophysical properties of a bistetracene compound with slipped stacked structure. J Photochem Photobiol A Chem 2017. [DOI: 10.1016/j.jphotochem.2017.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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27
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Fuemmeler EG, Sanders SN, Pun A, Kumarasamy E, Zeng T, Miyata K, Steigerwald ML, Zhu XY, Sfeir MY, Campos LM, Ananth N. A Direct Mechanism of Ultrafast Intramolecular Singlet Fission in Pentacene Dimers. ACS CENTRAL SCIENCE 2016; 2:316-24. [PMID: 27280166 PMCID: PMC4882733 DOI: 10.1021/acscentsci.6b00063] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 05/05/2023]
Abstract
Interest in materials that undergo singlet fission (SF) has been catalyzed by the potential to exceed the Shockley-Queisser limit of solar power conversion efficiency. In conventional materials, the mechanism of SF is an intermolecular process (xSF), which is mediated by charge transfer (CT) states and depends sensitively on crystal packing or molecular collisions. In contrast, recently reported covalently coupled pentacenes yield ∼2 triplets per photon absorbed in individual molecules: the hallmark of intramolecular singlet fission (iSF). However, the mechanism of iSF is unclear. Here, using multireference electronic structure calculations and transient absorption spectroscopy, we establish that iSF can occur via a direct coupling mechanism that is independent of CT states. We show that a near-degeneracy in electronic state energies induced by vibronic coupling to intramolecular modes of the covalent dimer allows for strong mixing between the correlated triplet pair state and the local excitonic state, despite weak direct coupling.
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Affiliation(s)
- Eric G. Fuemmeler
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United
States
| | - Samuel N. Sanders
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Andrew
B. Pun
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Elango Kumarasamy
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Tao Zeng
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United
States
| | - Kiyoshi Miyata
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | | | - X.-Y. Zhu
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Matthew Y. Sfeir
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
- E-mail:
| | - Luis M. Campos
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
- E-mail:
| | - Nandini Ananth
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United
States
- E-mail:
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28
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Lawrence J, Lee SH, Abdilla A, Nothling MD, Ren JM, Knight AS, Fleischmann C, Li Y, Abrams AS, Schmidt BVKJ, Hawker MC, Connal LA, McGrath AJ, Clark PG, Gutekunst WR, Hawker CJ. A Versatile and Scalable Strategy to Discrete Oligomers. J Am Chem Soc 2016; 138:6306-10. [PMID: 27152711 PMCID: PMC4879877 DOI: 10.1021/jacs.6b03127] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A versatile strategy is reported for the multigram synthesis of discrete oligomers from commercially available monomer families, e.g., acrylates, styrenics, and siloxanes. Central to this strategy is the identification of reproducible procedures for the separation of oligomer mixtures using automated flash chromatography systems with the effectiveness of this approach demonstrated through the multigram preparation of discrete oligomer libraries (Đ = 1.0). Synthetic availability, coupled with accurate structural control, allows these functional building blocks to be harnessed for both fundamental studies as well as targeted technological applications.
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Affiliation(s)
- Jimmy Lawrence
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Sang-Ho Lee
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Allison Abdilla
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Mitchell D. Nothling
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
- Department of Chemical Engineering, University of Melbourne, Victoria, Australia
| | - Jing M. Ren
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Abigail S. Knight
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Carolin Fleischmann
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Youli Li
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Austin S. Abrams
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Bernhard V. K. J. Schmidt
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Michael C. Hawker
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Luke A. Connal
- Department of Chemical Engineering, University of Melbourne, Victoria, Australia
| | - Alaina J. McGrath
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Paul G. Clark
- The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Will R. Gutekunst
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Craig J. Hawker
- Materials Research Laboratory and Departments of Materials, Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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29
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Sakuma T, Sakai H, Araki Y, Mori T, Wada T, Tkachenko NV, Hasobe T. Long-Lived Triplet Excited States of Bent-Shaped Pentacene Dimers by Intramolecular Singlet Fission. J Phys Chem A 2016; 120:1867-75. [PMID: 26930127 DOI: 10.1021/acs.jpca.6b00988] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Intramolecular singlet fission (ISF) is a promising photophysical process to construct more efficient light energy conversion systems as one excited singlet state converts into two excited triplet states. Herein we synthesized and evaluated bent-shaped pentacene dimers as a prototype of ISF to reveal intrinsic characters of triplet states (e.g., lifetimes of triplet excited states). In this study, meta-phenylene-bridged TIPS-pentacene dimer (PcD-3Ph) and 2,2'-bipheynyl bridged TIPS-pentacene dimer (PcD-Biph) were newly synthesized as bent-shaped dimers. In the steady-state spectroscopy, absorption and emission bands of these dimers were fully characterized, suggesting the appropriate degree of electronic coupling between pentacene moieties in these dimers. In addition, the electrochemical measurements were also performed to check the electronic interaction between two pentacene moieties. Whereas the successive two oxidation peaks owing to the delocalization were observed in a directly linked-pentacene dimer (PcD) by a single bond, the cyclic voltammograms in PcD-Biph and PcD-3Ph implied the weaker interaction compared to that of p-phenylene-bridged TIPS-pentacene dimer (PcD-4Ph) and PcD. The femtosecond and nanosecond transient absorption spectra clearly revealed the slower ISF process in bent-shaped pentacene dimers (PcD-Biph and PcD-3Ph), more notably, the slower relaxation of the excited triplet states in PcD-Biph and PcD-3Ph. Namely, the quantum yields of triplet states (ΦT) by ISF approximately remain constant (ca. 180-200%) in all dimer systems, whereas the lifetimes of the triplet excited states became much longer (up to 360 ns) in PcD-Biph as compared to PcD-4Ph (15 ns). Additionally, the lifetimes of the corresponding triplet states in PcD-Biph and PcD-3Ph were sufficiently affected by solvent viscosity. In particular, the lifetimes of PcD-Biph triplet state in THF/paraffin (1.0 μs) increased up to approximately three times as compared to that in THF (360 ns), whereas those of PcD-4Ph were quite similar in both solvent.
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Affiliation(s)
- Takao Sakuma
- Department of Chemistry, Faculty of Science and Technology, Keio University , Yokohama, 223-8522, Japan
| | - Hayato Sakai
- Department of Chemistry, Faculty of Science and Technology, Keio University , Yokohama, 223-8522, Japan
| | - Yasuyuki Araki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Tadashi Mori
- Department of Applied Chemistry, Osaka University , 2-1 Yamada-oka, Suita 565-0871, Japan
| | - Takehiko Wada
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Nikolai V Tkachenko
- Department of Chemistry and Bioengineering, Tampere University of Technology , 33720 Tampere, Finland
| | - Taku Hasobe
- Department of Chemistry, Faculty of Science and Technology, Keio University , Yokohama, 223-8522, Japan
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