1
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Feng J, Hosseinabadi P, de Clercq DM, Carwithen BP, Nielsen MP, Brett MW, Prasad SKK, Farahani AAD, Li HL, Sanders SN, Beves JE, Ekins-Daukes NJ, Cole JH, Thordarson P, Huang DM, Tayebjee MJY, Schmidt TW. Magnetic fields reveal signatures of triplet-pair multi-exciton photoluminescence in singlet fission. Nat Chem 2024:10.1038/s41557-024-01591-0. [PMID: 39054380 DOI: 10.1038/s41557-024-01591-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
The photophysical processes of singlet fission and triplet fusion have numerous emerging applications. They involve the separation of a photo-generated singlet exciton into two dark triplet excitons and the fusion of two dark triplet excitons into an emissive singlet exciton, respectively. The role of the excimer state and the nature of the triplet-pair state in these processes have been a matter of contention. Here we analyse the room temperature time-resolved emission of a neat liquid singlet fission chromophore and show that it exhibits three spectral components: two that correspond to the bright singlet and excimer states and a third component that becomes more prominent during triplet fusion. This spectrum is enhanced by magnetic fields, confirming its origins in the recombination of weakly coupled triplet pairs. It is thus attributed to a strongly coupled triplet pair state. These observations unite the view that there is an emissive intermediate in singlet fission and triplet fusion, distinct from the broad, unstructured excimer emission.
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Affiliation(s)
- Jiale Feng
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Parisa Hosseinabadi
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Damon M de Clercq
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Ben P Carwithen
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Michael P Nielsen
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Matthew W Brett
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Shyamal K K Prasad
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Adam A D Farahani
- The UNSW RNA Institute, The Australian Centre for Nanomedicine, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - Hsiu L Li
- The UNSW RNA Institute, The Australian Centre for Nanomedicine, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | | | - Jonathon E Beves
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - N J Ekins-Daukes
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Jared H Cole
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria, Australia
| | - Pall Thordarson
- The UNSW RNA Institute, The Australian Centre for Nanomedicine, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia
| | - David M Huang
- Department of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia
| | - Timothy W Schmidt
- ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia.
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2
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Collins AR, Zhang B, Bennison MJ, Evans RC. Ambient solid-state triplet-triplet annihilation upconversion in ureasil organic-inorganic hybrid hosts. JOURNAL OF MATERIALS CHEMISTRY. C 2024; 12:6310-6318. [PMID: 38707254 PMCID: PMC11064974 DOI: 10.1039/d4tc00562g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 03/27/2024] [Indexed: 05/07/2024]
Abstract
Triplet-triplet-annihilation upconversion (TTA-UC) has attracted significant attention as an approach to harvest low energy solar photons that cannot be captured by conventional photovoltaic devices. However, device integration requires the design of solid-state TTA-UC materials that combine high upconversion efficiency with long term stability. Herein, we report an efficient solid-state TTA-UC system based on organic-inorganic hybrid polymers known as ureasils as hosts for the archetypal sensitiser/emitter pair of palladium(ii) octaethylporphyrin and diphenylanthracene. The role of the ureasil structure on the TTA-UC performance was probed by varying the branching and molecular weight of the organic precursor to tune the structural, mechanical, and thermal properties. Solid-state green-to-blue UC quantum yields of up to 1.86% were observed under ambient conditions. Notably, depending on the ureasil structure, UC emission could be retained for >70 days without any special treatment, including deoxygenation. Detailed analysis of the structure-function trends revealed that while a low glass transition temperature is required to promote TTA-UC molecular collisions, a higher inorganic content is the primary factor that determines the UC efficiency and stability, due to the inherent oxygen barrier provided by the silica nanodomains.
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Affiliation(s)
- Abigail R Collins
- Department of Materials Science and Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Bolong Zhang
- Department of Materials Science and Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Michael J Bennison
- Department of Materials Science and Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
| | - Rachel C Evans
- Department of Materials Science and Metallurgy, University of Cambridge 27 Charles Babbage Road Cambridge CB3 0FS UK
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3
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de Clercq DM, Collins MI, Sloane NP, Feng J, McCamey DR, Tayebjee MJY, Nielsen MP, Schmidt TW. Singlet fission in TIPS-anthracene thin films. Chem Sci 2024; 15:6402-6409. [PMID: 38699250 PMCID: PMC11062091 DOI: 10.1039/d3sc06774b] [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: 12/18/2023] [Accepted: 03/24/2024] [Indexed: 05/05/2024] Open
Abstract
Singlet fission is an exciton multiplication process that allows for the conversion of one singlet exciton into two triplet excitons. Organic semiconductors, such as acenes and their soluble bis(triisopropylsilylethynyl) (TIPS) substituted counterparts, have played a major role in elucidating the understanding of the underlying mechanisms of singlet fission. Despite this, one prominent member of the acene family that has received little experimental attention to date is TIPS-anthracene, even with computational studies suggesting potential high singlet fission yields in the solid state. Here, time-resolved spectroscopic and magneto-photoluminescence measurements were performed on spin-cast films of TIPS-anthracene, showing evidence for singlet fission. A singlet fission yield of 19% (out of 200%) is estimated from transient absorption spectroscopy. Kinetic modeling of the magnetic field effect on photoluminescence suggests that fast rates of triplet dissociation lead to a low magnetic photoluminescence effect and that non-radiative decay of both the S1 and 1(TT) states is the cause for the low triplet yield.
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Affiliation(s)
- Damon M de Clercq
- School of Chemistry, ARC Centre of Excellence in Exciton Science, UNSW Sydney NSW 2052 Australia
| | - Miles I Collins
- School of Physics, ARC Centre of Excellence in Exciton Science, UNSW Sydney NSW 2052 Australia
| | - Nicholas P Sloane
- School of Physics, ARC Centre of Excellence in Exciton Science, UNSW Sydney NSW 2052 Australia
| | - Jiale Feng
- School of Chemistry, ARC Centre of Excellence in Exciton Science, UNSW Sydney NSW 2052 Australia
| | - Dane R McCamey
- School of Physics, ARC Centre of Excellence in Exciton Science, UNSW Sydney NSW 2052 Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney NSW 2052 Australia
| | - Michael P Nielsen
- School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney NSW 2052 Australia
| | - Timothy W Schmidt
- School of Chemistry, ARC Centre of Excellence in Exciton Science, UNSW Sydney NSW 2052 Australia
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4
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Okamoto T, Izawa S, Hiramoto M, Kobori Y. Efficient Spin Interconversion by Molecular Conformation Dynamics of a Triplet Pair for Photon Up-Conversion in an Amorphous Solid. J Phys Chem Lett 2024; 15:2966-2975. [PMID: 38479407 PMCID: PMC10961844 DOI: 10.1021/acs.jpclett.3c03602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/10/2024] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
Solid-state materials with improved light-to-energy conversions in organic photovoltaics and in optoelectronics are expected to be developed by realizing efficient triplet-triplet annihilation (TTA) by manipulating the spin conversion processes to the singlet state. In this study, we elucidate the spin conversion mechanism for delayed fluorescence by TTA from a microscopic view of the molecular conformations. We examine the time evolution of the electron spin polarization of the triplet-pair state (TT state) in an amorphous solid-state system exhibiting highly efficient up-conversion emission by using time-resolved electron paramagnetic resonance. We clarified that the spin-state population of the singlet TT increased through the spin interconversion from triplet and quintet TT states during exciton diffusion with random orientation dynamics between the two triplets for the modulation of the exchange interaction, achieving a high quantum yield of up-conversion emission. This understanding provides us with a guide for the development of efficient light-to-energy conversion devices utilizing TTA.
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Affiliation(s)
- Tsubasa Okamoto
- Molecular
Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657−8501, Japan
| | - Seiichiro Izawa
- Laboratory
for Materials and Structures, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- Precursory
Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Institute
for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Masahiro Hiramoto
- Institute
for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Yasuhiro Kobori
- Molecular
Photoscience Research Center, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan
- Department
of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657−8501, Japan
- CREST,
JST, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan
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5
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Bossanyi DG, Matthiesen M, Jayaprakash R, Bhattacharya S, Zaumseil J, Clark J. Singlet fission is incoherent in pristine orthorhombic single crystals of rubrene: no evidence of triplet-pair emission. Faraday Discuss 2024; 250:162-180. [PMID: 37991094 DOI: 10.1039/d3fd00150d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Singlet fission (SF) and its inverse, triplet-triplet annihilation (TTA), are promising strategies for enhancing photovoltaic efficiencies. However, detailed descriptions of the processes of SF/TTA are not fully understood, even in the most well-studied systems. Reports of the photophysics of crystalline rubrene, for example, are often inconsistent. Here we attempt to resolve these inconsistencies using time-resolved photoluminescence and transient absorption spectroscopy of 'pristine' rubrene orthorhombic single crystals. We find the reported time-resolved photoluminescence behaviour that hinted at triplet-pair emission is found only at specific sites on the crystals and likely arises from surface defects. Using transient absorption spectroscopy of the same crystals, we also observe no evidence of instantaneous generation of triplet-pair population with ∼100 fs excitation, independent of excitation wavelength (532 nm, 495 nm) or excitation angle. Our results suggest that SF occurs incoherently on a relatively slow (picosecond) timescale in rubrene single crystals, as expected from the original theoretical calculations. We conclude that the sub-100 fs formation of triplet pairs in crystalline rubrene films is likely to be due to static disorder.
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Affiliation(s)
- David G Bossanyi
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, UK.
| | - Maik Matthiesen
- Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Rahul Jayaprakash
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, UK.
| | | | - Jana Zaumseil
- Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany
| | - Jenny Clark
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, UK.
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6
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Greißel PM, Thiel D, Gotfredsen H, Chen L, Krug M, Papadopoulos I, Miskolzie M, Torres T, Clark T, Brøndsted Nielsen M, Tykwinski RR, Guldi DM. Intramolecular Triplet Diffusion Facilitates Triplet Dissociation in a Pentacene Hexamer. Angew Chem Int Ed Engl 2024; 63:e202315064. [PMID: 38092707 DOI: 10.1002/anie.202315064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Indexed: 01/26/2024]
Abstract
Triplet dynamics in singlet fission depend strongly on the strength of the electronic coupling. Covalent systems in solution offer precise control over such couplings. Nonetheless, efficient free triplet generation remains elusive in most systems, as the intermediate triplet pair 1 (T1 T1 ) is prone to triplet-triplet annihilation due to its spatial confinement. In the solid state, entropically driven triplet diffusion assists in the spatial separation of triplets, resulting in higher yields of free triplets. Control over electronic coupling in the solid state is, however, challenging given its sensitivity to molecular packing. We have thus developed a hexameric system (HexPnc) to enable solid-state-like triplet diffusion at the molecular scale. This system is realized by covalently tethering three pentacene dimers to a central subphthalocyanine scaffold. Transient absorption spectroscopy, complemented by theoretical structural optimizations and steady-state spectroscopy, reveals that triplet diffusion is indeed facilitated due to intramolecular cluster formation. The yield of free triplets in HexPnc is increased by a factor of up to 14 compared to the corresponding dimeric reference (DiPnc). Thus, HexPnc establishes crucial design aspects for achieving efficient triplet dissociation in strongly coupled systems by providing avenues for diffusive separation of 1 (T1 T1 ), while, concomitantly, retaining strong interchromophore coupling which preserves rapid formation of 1 (T1 T1 ).
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Affiliation(s)
- Phillip M Greißel
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Dominik Thiel
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Henrik Gotfredsen
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
- Current address: Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, OX1 3TA, UK
| | - Lan Chen
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Marcel Krug
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Ilias Papadopoulos
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
- Department of Applied Chemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Mark Miskolzie
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Tomás Torres
- Department of Organic Chemistry, Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
- IMDEA Nanociencia, C/Faraday 9, Cantoblanco, 28049, Madrid, Spain
| | - Timothy Clark
- Department of Chemistry and Pharmacy &, Computer-Chemie-Center (CCC), Friedrich-Alexander-University Erlangen-Nuremberg, Nägelsbachstraße 25, 91052, Erlangen, Germany
| | - Mogens Brøndsted Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark
| | - Rik R Tykwinski
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, T6G 2G2, Canada
| | - Dirk M Guldi
- Department of Chemistry and Pharmacy &, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstraße 3, 91058, Erlangen, Germany
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7
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Strain JM, Ruiz GN, Roberts ST, Rose MJ. Methylation of Si(111) Modulates Molecular Orientation in Perylenediimide Thin Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:2519-2530. [PMID: 38284168 DOI: 10.1021/acs.langmuir.3c02569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
Singlet fission produces a pair of low-energy spin-triplet excitons from a single high-energy spin-singlet exciton. While this process offers the potential to enhance the efficiency of silicon solar cells by ∼30%, meeting this goal requires overlayer materials that can efficiently transport triplet excitons to an underlying silicon substrate. Herein, we demonstrate that the chemical functionalization of silicon surfaces controls the structure of vapor-deposited thin films of perylenediimide (PDI) dyes, which are prototypical singlet fission materials. Using a combination of atomic force microscopy (AFM) and grazing-incidence wide-angle X-ray scattering (GIWAXS), we find terminating Si(111) with either a thin, polar oxide layer (SiOx) or with hydrophobic methyl groups (Si-CH3) alters the structures of the resulting PDI films. While PDI films grown on SiOx are comprised of small crystalline grains that largely adopt an "edge-on" orientation with respect to the silicon surface, films grown on Si-CH3 contain large grains that prefer to align in a "face-on" manner with respect to the substrate. This "face-on" orientation is expected to enhance exciton transport to silicon. Interestingly, we find that the preferred mode of growth for different PDIs correlates with the space group associated with bulk crystals of these compounds. While PDIs that inhabit a monoclinic (P21/c) space group nucleate films by forming tall and sparse crystalline columns, PDIs that inhabit triclinic (P1̅) space groups afford films comprised of uniform, lamellar PDI domains. The results highlight that silicon surface functionalization profoundly impacts PDI thin film growth, and rational selection of a hydrophobic surface that promotes "face-on" adsorption may improve energy transfer to silicon.
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Affiliation(s)
- Jacob M Strain
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Gabriella N Ruiz
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Sean T Roberts
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Michael J Rose
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
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8
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Herbert JM. Visualizing and characterizing excited states from time-dependent density functional theory. Phys Chem Chem Phys 2024; 26:3755-3794. [PMID: 38226636 DOI: 10.1039/d3cp04226j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Time-dependent density functional theory (TD-DFT) is the most widely-used electronic structure method for excited states, due to a favorable combination of low cost and semi-quantitative accuracy in many contexts, even if there are well recognized limitations. This Perspective describes various ways in which excited states from TD-DFT calculations can be visualized and analyzed, both qualitatively and quantitatively. This includes not just orbitals and densities but also well-defined statistical measures of electron-hole separation and of Frenkel-type exciton delocalization. Emphasis is placed on mathematical connections between methods that have often been discussed separately. Particular attention is paid to charge-transfer diagnostics, which provide indicators of when TD-DFT may not be trustworthy due to its categorical failure to describe long-range electron transfer. Measures of exciton size and charge separation that are directly connected to the underlying transition density are recommended over more ad hoc metrics for quantifying charge-transfer character.
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Affiliation(s)
- John M Herbert
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
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9
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Pradhan E, Zeng T. The Lack of Triplet Fusion for an Intramolecular Singlet Fission Chromophore: The Expected, the Unexpected, and a Reconciliation. J Phys Chem Lett 2024; 15:43-50. [PMID: 38127796 DOI: 10.1021/acs.jpclett.3c03238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Singlet fission (SF) has the potential to play a key role in photovoltaics since it generates a larger number of longer-lived triplet excitons after photoabsorption. Intramolecular SF (iSF) is of special interest since it enables tuning of SF efficiency by adjusting interchromophore configuration through covalent interaction. However, as elaborated in the present work, iSF chromophores are doomed to dissatisfy one general thermodynamic criterion for all SF chromophores, intramolecular or not: E(T2) ≥ 2E(T1), and therefore, the fusion of two triplet excitons to one triplet exciton is thermodynamically favorable. In our nonadiabatic quantum dynamics simulation for a model iSF chromophore, this expected fusion does not occur, because of the inefficient intersystem crossing hidden under the cover of internal conversion of the triplet fusion. A reconciliation is achieved between the dissatisfaction of E(T2) ≥ 2E(T1) and the large tetraradical character for general iSF chromophores.
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Affiliation(s)
- Ekadashi Pradhan
- Department of Chemistry, York University, Toronto, Ontario M3J1P3, Canada
| | - Tao Zeng
- Department of Chemistry, York University, Toronto, Ontario M3J1P3, Canada
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10
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Volek TS, Armstrong ZT, Sowa JK, Wilson KS, Bohlmann Kunz M, Bera K, Koble M, Frontiera RR, Rossky PJ, Zanni MT, Roberts ST. Structural Disorder at the Edges of Rubrene Crystals Enhances Singlet Fission. J Phys Chem Lett 2023; 14:11497-11505. [PMID: 38088867 DOI: 10.1021/acs.jpclett.3c02845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Materials that undergo singlet fission are of interest for their use in light-harvesting, photocatalysis, and quantum information science, but their ability to undergo fission can be sensitive to local variations in molecular packing. Herein we employ transient absorption microscopy, molecular dynamics simulations, and electronic structure calculations to interrogate how structures found at the edges of orthorhombic rubrene crystals impact singlet fission. Within a micrometer-scale spatial region at the edges of rubrene crystals, we find that the rate of singlet fission increases nearly 4-fold. This observation is consistent with formation of a region at crystal edges with reduced order that accelerates singlet fission by disrupting the symmetry found in rubrene's orthorhombic crystal structure. Our work demonstrates that structural distortions of singlet fission materials can be used to control fission in time and in space, potentially offering a means of controlling this process in light harvesting and quantum information applications.
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Affiliation(s)
- Tanner S Volek
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
| | - Zachary T Armstrong
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Wisconsin Madison, Madison, Wisconsin 53706, United States
| | - Jakub K Sowa
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Kelly S Wilson
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
| | - Miriam Bohlmann Kunz
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Wisconsin Madison, Madison, Wisconsin 53706, United States
| | - Kajari Bera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - MaKenna Koble
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Renee R Frontiera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Peter J Rossky
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Martin T Zanni
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Wisconsin Madison, Madison, Wisconsin 53706, United States
| | - Sean T Roberts
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Center for Adopting Flaws as Features, Urbana, Illinois 61801, United States
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11
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Forecast R, Campaioli F, Cole JH. Magnetic Field Effects in Triplet-Triplet Annihilation Upconversion: Revisiting Atkins and Evans' Theory. J Chem Theory Comput 2023; 19:7816-7824. [PMID: 37898956 PMCID: PMC10653108 DOI: 10.1021/acs.jctc.3c00927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/23/2023] [Accepted: 09/27/2023] [Indexed: 10/31/2023]
Abstract
In their seminal description of magnetic field effects on chemiluminescent fluid solutions, Atkins and Evans considered the spin-dependent interactions between two triplets, incorporating the effects of the diffusion of the molecules in the liquid phase. Their results, crucial for the advancement of photochemical upconversion, have received renewed attention due to the increasing interest in triplet-triplet annihilation for photovoltaic and optoelectronic applications. Here we revisit their approach, using a modern formulation of open quantum system dynamics and extend their results. We provide corrections to the theory of the magnetic field response of the fluorescent triplet pair state with singlet multiplicity. These corrections are timely, as improvements in the precision and range of available experimental methods are supported by the determination of quantitatively accurate rotational and interaction model parameters. We then extend Atkins and Evans' theory to obtain the magnetic field response of triplet pair states with triplet and quintet multiplicity. Although these states are not optically active, transitions between them are becoming imperative to study the working mechanism of spin-mediated upconversion and downconversion processes, thanks to advances in electron spin resonance and time-resolved transient absorption spectroscopy.
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Affiliation(s)
- Roslyn Forecast
- ARC
Centre of Excellence in Exciton Science and Chemical and Quantum Physics,
School of Science, RMIT University, Melbourne, 3000, Victoria, Australia
| | - Francesco Campaioli
- ARC
Centre of Excellence in Exciton Science and Chemical and Quantum Physics,
School of Science, RMIT University, Melbourne, 3000, Victoria, Australia
- Dipartimento
di Fisica e Astronomia “G. Galilei”, Università degli Studi di Padova, I-35131 Padua, Italy
- Padua
Quantum Technologies Research Center, Università
degli Studi di Padova, I-35131 Padua, Italy
| | - Jared H. Cole
- ARC
Centre of Excellence in Exciton Science and Chemical and Quantum Physics,
School of Science, RMIT University, Melbourne, 3000, Victoria, Australia
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12
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Lin LC, Smith T, Ai Q, Rugg BK, Risko C, Anthony JE, Damrauer NH, Johnson JC. Multiexciton quintet state populations in a rigid pyrene-bridged parallel tetracene dimer. Chem Sci 2023; 14:11554-11565. [PMID: 37886089 PMCID: PMC10599476 DOI: 10.1039/d3sc03153e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/01/2023] [Indexed: 10/28/2023] Open
Abstract
The multiexciton quintet state, 5TT, generated as a singlet fission intermediate in pairs of molecular chromophores, is a promising candidate as a qubit or qudit in future quantum information science schemes. In this work, we synthesize a pyrene-bridged parallel tetracene dimer, TPT, with an optimized interchromophore coupling strength to prevent the dissociation of 5TT to two decorrelated triplet (T1) states, which would contaminate the spin-state mixture. Long-lived and strongly spin-polarized pure 5TT state population is observed via transient absorption spectroscopy and transient/pulsed electron paramagnetic resonance spectroscopy, and its lifetime is estimated to be >35 µs, with the dephasing time (T2) for the 5TT-based qubit measured to be 726 ns at 10 K. Direct relaxation from 1TT to the ground state does diminish the overall excited state population, but the exclusive 5TT population at large enough persistent density for pulsed echo determination of spin coherence time is consistent with recent theoretical models that predict such behavior for strict parallel chromophore alignment and large exchange coupling.
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Affiliation(s)
- Liang-Chun Lin
- Department of Chemistry, University of Colorado Boulder Boulder CO 80309 USA
| | - Tanner Smith
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - Qianxiang Ai
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - Brandon K Rugg
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
| | - Chad Risko
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - John E Anthony
- Department of Chemistry & Center for Applied Energy Research, University of Kentucky Lexington Kentucky 40506-0055 USA
| | - Niels H Damrauer
- Department of Chemistry, University of Colorado Boulder Boulder CO 80309 USA
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder Boulder CO 80309 USA
| | - Justin C Johnson
- National Renewable Energy Laboratory 15013 Denver West Parkway Golden Colorado 80401 USA
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder Boulder CO 80309 USA
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13
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Song J, Guan Y, Wang C, Li W, Bao X, Niu L. Effect of Conductive Polymers PEDOT:PSS on Exciton Recombination and Conversion in Doped-Type BioLEDs. Polymers (Basel) 2023; 15:3275. [PMID: 37571169 PMCID: PMC10421517 DOI: 10.3390/polym15153275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/13/2023] Open
Abstract
Although the effect of the conductive polymers PEDOT:PSS on the electroluminescence performance of doped-type organic light-emitting diodes (OLEDs) has been studied, the process of PEDOT:PSS regulation of exciton recombination region and concentration within the deoxyribonucleic acid (DNA)-based doped-type BioLEDs is still obscure. In this study, we fabricated Bio-devices with and without PEDOT:PSS using varying spin-coating speeds of PEDOT:PSS. The Alq3:Rubrene-based BioLEDs achieve higher luminance (44,010 cd/m2) and higher luminance efficiency (8.1 cd/A), which are increased by 186% and 478%, respectively, compared to the reference BioLEDs without PEDOT:PSS. Similarly, the maximum luminance and efficiency of blue TCTA:TPBi exciplex-type BioLEDs are increased by 224% and 464%. In particular, our findings reveal that with an increasing thickness of PEDOT:PSS, the region of exciton recombination shifts towards the interface between the emitting layer (EML) and the hole transport layer (HTL). Meanwhile, the concentration of singlet exciton (S1,Rub) and triplet exciton (T1,Rub) increases, and the triplet-triplet annihilation (TTA) process is enhanced, resulting in the enhanced luminescence and efficiency of the devices. Accordingly, we provide a possible idea for achieving high performance doped-type BioLEDs by adding conductive polymers PEDOT:PSS, and revealing the effect of exciton recombination and conversion in BioLEDs given different PEDOT:PSS thicknesses.
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Affiliation(s)
| | - Yunxia Guan
- College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331, China; (J.S.); (C.W.); (W.L.); (X.B.)
| | | | | | | | - Lianbin Niu
- College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 401331, China; (J.S.); (C.W.); (W.L.); (X.B.)
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14
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Forecast R, Gholizadeh EM, Prasad SKK, Blacket S, Tapping PC, McCamey DR, Tayebjee MJY, Huang DM, Cole JH, Schmidt TW. Power Dependence of the Magnetic Field Effect on Triplet Fusion: A Quantitative Model. J Phys Chem Lett 2023; 14:4742-4747. [PMID: 37184362 DOI: 10.1021/acs.jpclett.3c00919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Two strategies for improving solar energy efficiencies, triplet fusion and singlet fission, rely on the details of triplet-triplet interactions. In triplet fusion, there are several steps, each of which is a possible loss mechanism. In solution, the parameters describing triplet fusion collisions are difficult to inspect. Here we show that these parameters can be determined by examining the magnetic field dependence of triplet fusion upconversion. We show that there is a reduction of the magnetic field effect for perylene triplet fusion as the system moves from the quadratic to linear annihilation regimes with an increase in laser power. Our data are modeled with a small set of parameters that characterize the triplet fusion dynamics. These parameters are cross-validated with molecular dynamics simulations. This approach can be applied to both solution and solid state materials, providing a tool for screening potential annihilators for photon upconversion.
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Affiliation(s)
- Roslyn Forecast
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Elham M Gholizadeh
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Shyamal K K Prasad
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of New South Wales, Kensington, NSW 2052, Australia
| | - Simon Blacket
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Patrick C Tapping
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Dane R McCamey
- ARC Centre of Excellence in Exciton Science, School of Physics, The University of New South Wales, Kensington, NSW 2052, Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, The University of New South Wales, Kensington, NSW 2052, Australia
| | - David M Huang
- Department of Chemistry, School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Jared H Cole
- ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, VIC 3001, Australia
| | - Timothy W Schmidt
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of New South Wales, Kensington, NSW 2052, Australia
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15
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Influence of core-twisted structure on singlet fission in perylenediimide film. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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16
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Eschenbach P, Neugebauer J. Subsystem density-functional theory: A reliable tool for spin-density based properties. J Chem Phys 2022; 157:130902. [PMID: 36209003 DOI: 10.1063/5.0103091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Subsystem density-functional theory compiles a set of features that allow for efficiently calculating properties of very large open-shell radical systems such as organic radical crystals, proteins, or deoxyribonucleic acid stacks. It is computationally less costly than correlated ab initio wave function approaches and can pragmatically avoid the overdelocalization problem of Kohn-Sham density-functional theory without employing hard constraints on the electron-density. Additionally, subsystem density-functional theory calculations commonly start from isolated fragment electron densities, pragmatically preserving a priori specified subsystem spin-patterns throughout the calculation. Methods based on subsystem density-functional theory have seen a rapid development over the past years and have become important tools for describing open-shell properties. In this Perspective, we address open questions and possible developments toward challenging future applications in connection with subsystem density-functional theory for spin-dependent properties.
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Affiliation(s)
- Patrick Eschenbach
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Johannes Neugebauer
- Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Simulation, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149 Münster, Germany
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17
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Zhou J, Liu H, Liu S, Su P, Wang W, Li Z, Liu Z, Chen Y, Dong Y, Li X. Singlet Fission in Colloidal Nanoparticles of Amphipathic Diketopyrrolopyrrole Derivatives: Probing the Role of the Charge Transfer State. J Phys Chem B 2022; 126:6483-6492. [PMID: 35979942 DOI: 10.1021/acs.jpcb.2c03163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To evaluate the role of the charge transfer (CT) state in the singlet fission (SF) process, we prepared three 3,6-bis(thiophen-2-yl)diketopyrrolopyrrole (TDPP) derivatives with zero (Ph2TDPP), one (Ph2TDPP-COOH), and two (Ph2TDPP-(COOH)2) carboxylic groups, respectively. Their colloidal nanoparticles were also prepared by a simple precipitation method. The SF dynamics and mechanism in these colloid nanoparticles were investigated by using steady-state/transient absorption and fluorescence spectroscopy. Steady-state absorption spectra reveal that the strength of the CT resonance interactions between the adjacent DPP units is increased gradually from Ph2TDPP to Ph2TDPP-COOH and then to Ph2TDPP-(COOH)2. Fluorescence and transient absorption spectra demonstrate that SF is proceeded via a CT-assisted superexchange mechanism in these three nanoparticles. Furthermore, SF rate and yield are enhanced gradually with the increase of the number of the carboxylic group, which may be attributed to the enhancement of the CT coupling strength. The result of this work not only provides a better understanding of the SF mechanism especially for the role of the CT state but also gives some new insights for the design of efficient SF materials based on DPP derivatives.
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Affiliation(s)
- Jun Zhou
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Heyuan Liu
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China.,National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - Shanshan Liu
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Pengkun Su
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Weijie Wang
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Zhi Li
- Shandong Energy Group Co., Ltd., Jinan, Shandong 250014, China
| | - Zhaobin Liu
- Shandong Energy Group Co., Ltd., Jinan, Shandong 250014, China
| | - Yanli Chen
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China
| | - Yunqin Dong
- College of Chemical Engineering and Materials Science, Zaozhuang University, Zaozhuang 277160, China
| | - Xiyou Li
- College of Chemical Engineering, School of Materials Science and Engineering, College of New Energy, China University of Petroleum (East China), Qingdao, Shandong 266580, China
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18
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Liu H, Wang X, Ma L, Wang W, Liu S, Zhou J, Su P, Liu Z, Li Z, Lin X, Chen Y, Li X. Effects of the Separation Distance between Two Triplet States Produced from Intramolecular Singlet Fission on the Two-Electron-Transfer Process. J Am Chem Soc 2022; 144:15509-15518. [PMID: 35930671 DOI: 10.1021/jacs.2c03550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To harvest two triplet excitons of singlet fission (SF) via a two-electron transfer efficiently, the revelation of the key factors that influence the two-electron-transfer process is necessary. Here, by using steady-state and transient absorption/fluorescence spectroscopy, we investigated the two-electron-transfer process from the two triplet excitons of intramolecular SF (iSF) in a series of tetracene oligomers (dimer, trimer, and tetramer) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) as an electron acceptor in solution. Quantitative two-electron transfer could be conducted for the trimer and tetramer, and the rate for the tetramer is faster than that for the trimer. However, the maximum efficiency of the two-electron transfer in the dimer is relatively low (∼47%). The calculation result of the free energy change (ΔG) of the second-electron transfer for these three compounds (-0.024, -0.061, and -0.074 eV for the dimer, trimer, and tetramer, respectively) is consistent with the experimental observation. The much closer ΔG value to zero for the dimer should be responsible for its low efficiency of the two-electron transfer. Different ΔG values for these three oligomers are attributed to the different Coulomb repulsive energies between the two positive charges generated after the two-electron transfer that is caused by their various intertriplet distances. This result reveals for the first time the important effect of the Coulomb repulsive energy, which depends on the intertriplet distance, on the two-electron transfer process from the two triplet excitons of iSF.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhaobin Liu
- Shandong Energy Group Co., Ltd., Jinan, Shandong 250014, People's Republic of China
| | - Zhi Li
- Shandong Energy Group Co., Ltd., Jinan, Shandong 250014, People's Republic of China
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19
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Jadhav SD, Sasikumar D, Hariharan M. Modulating singlet fission through interchromophoric rotation. Phys Chem Chem Phys 2022; 24:16193-16199. [PMID: 35749225 DOI: 10.1039/d2cp01116f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Singlet fission (SF) is a spin-allowed, exciton-multiplying phenomenon that can be utilized to improve the efficiency of organic solar cells. It is well-understood that SF is sensitive to the local crystal morphology and an appropriately balanced coupling is essential to facilitate efficient SF. In this study, we show how the interchromophoric rotation selectively modulates the interaction between the monomer frontier molecular orbitals, promoting both fast and exothermal SF. We evaluate the effective electronic coupling for SF (VSF), the square of which is proportional to the SF rate, and the effective energies of the Frenkel exciton (FE/S1S0) and triplet pair exciton (TT) in a terrylene dimer model. Optimal interplanar rotation of the chromophoric moieties in slip-stacked arrangements pulls the effective energy of the TT state below that of the FE state. Consequently, SF is favored over competing pathways such as excimer formation, thereby enhancing the overall triplet yield. This work represents a step towards improvising the molecular design guidelines for SF and understanding the importance of interchromophoric rotation over the conventional slip-stacked arrangements for achieving favorable intermolecular electronic coupling towards efficient SF.
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Affiliation(s)
- Sohan D Jadhav
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram, Kerala, 695551, India.
| | - Devika Sasikumar
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram, Kerala, 695551, India.
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Vithura, Thiruvananthapuram, Kerala, 695551, India.
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20
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Bowman AR, Stranks SD, Monserrat B. Investigation of Singlet Fission-Halide Perovskite Interfaces. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2022; 34:4865-4875. [PMID: 35722200 PMCID: PMC9202303 DOI: 10.1021/acs.chemmater.1c04310] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/22/2022] [Indexed: 06/15/2023]
Abstract
A method for improving the efficiency of solar cells is combining a low-band-gap semiconductor with a singlet fission material (which converts one high-energy singlet into two low-energy triplets following photoexcitation). Here, we present a study of the interface between singlet fission molecules and low-band-gap halide pervoskites. We briefly present 150 experiments screening for triplet transfer into a halide perovskite. However, in all cases, triplet transfer was not observed. This motivated us to understand the halide perovskite-singlet fission interface better by carrying out first-principles calculations using tetracene and cesium lead iodide. We found that tetracene molecules/thin films preferentially orient themselves parallel to/perpendicular to the halide perovskite's surface. This result is in agreement with simulations of tetracene (and other rodlike molecules) on a wide range of inorganic semiconductors. We present formation energies of all interfaces, which are significantly less favorable than for bulk tetracene, indicative of weak interaction at the interface. It was not possible to calculate excitonic states at the full interface due to computational limitations, so we instead present highly speculative toy interfaces between tetracene and a halide-perovskite-like structure. In these models, we focus on replicating tetracene's electronic states correctly. We find that tetracene's singlet and triplet energies are comparable to that of bulk tetracene, and the triplet is strongly localized on a single tetracene molecule, even at an interface. Our work provides new understanding of the interface between tetracene and halide perovskites, explores the potential for modeling excitons at interfaces, and begins to explain the difficulties in extracting triplets directly into inorganic semiconductors.
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Affiliation(s)
- Alan R. Bowman
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Samuel D. Stranks
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K.
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, U.K.
| | - Bartomeu Monserrat
- Cavendish
Laboratory, Department of Physics, University
of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K.
- Department
of Materials Science & Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, U.K.
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21
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Alam B, Jiang H, Zimmerman PM, Herbert JM. State-specific solvation for restricted active space spin-flip (RAS-SF) wave functions based on the polarizable continuum formalism. J Chem Phys 2022; 156:194110. [PMID: 35597663 DOI: 10.1063/5.0091636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The restricted active space spin-flip (RAS-SF) formalism is a particular form of single-reference configuration interaction that can describe some forms of strong correlation at a relatively low cost and which has recently been formulated for the description of charge-transfer excited states. Here, we introduce both equilibrium and nonequilibrium versions of a state-specific solvation correction for vertical transition energies computed using RAS-SF wave functions, based on the framework of a polarizable continuum model (PCM). Ground-state polarization is described using the solvent's static dielectric constant and in the nonequilibrium solvation approach that polarization is modified upon vertical excitation using the solvent's optical dielectric constant. Benchmark calculations are reported for well-studied models of photo-induced charge transfer, including naphthalene dimer, C2H4⋯C2F4, pentacene dimer, and perylene diimide (PDI) dimer, several of which are important in organic photovoltaic applications. For the PDI dimer, we demonstrate that the charge-transfer character of the excited states is enhanced in the presence of a low-dielectric medium (static dielectric constant ɛ0 = 3) as compared to a gas-phase calculation (ɛ0 = 1). This stabilizes mechanistic traps for singlet fission and helps to explain experimental singlet fission rates. We also examine the effects of nonequilibrium solvation on charge-separated states in an intramolecular singlet fission chromophore, where we demonstrate that the energetic ordering of the states changes as a function of solvent polarity. The RAS-SF + PCM methodology that is reported here provides a framework to study charge-separated states in solution and in photovoltaic materials.
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Affiliation(s)
- Bushra Alam
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Hanjie Jiang
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Paul M Zimmerman
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - John M Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
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22
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Miyashita T, Jaimes P, Lian T, Tang ML, Xu Z. Quantifying the Ligand-Induced Triplet Energy Transfer Barrier in a Quantum Dot-Based Upconversion System. J Phys Chem Lett 2022; 13:3002-3007. [PMID: 35347991 DOI: 10.1021/acs.jpclett.2c00514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
During photon upconversion, quantum dots (QDs) transfer energy to molecules in solution through a long ligand shell. This insulating ligand shell imparts colloidal stability at the expense of efficient photosensitization. For the first time, we quantify the barrier these aliphatic ligands pose for triplet energy transfer in solution. Using transient absorption spectroscopy, we experimentally measure a small damping coefficient of 0.027 Å-1 for a ligand exceeding 10 carbons in length. The dynamic nature of ligands in solution lowers the barrier to charge or energy transfer compared to organic thin films. In addition, we show that surface ligands shorter than 8 carbons in length allow direct energy transfer from the QD, bypassing the need for a transmitter ligand to mediate energy transfer, leading to a 6.9% upconversion quantum yield compared with 0.01% for ligands with 18 carbons. This experimentally derived insight will enable the design of efficient QD-based photosensitizers for catalysis and energy conversion.
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Affiliation(s)
- Tsumugi Miyashita
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah 84112, United States
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Paulina Jaimes
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Department of Materials Science and Engineering, University of California, Riverside, Riverside, California 92521, United States
| | - Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Ming Lee Tang
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
- Department of Materials Science and Engineering, University of California, Riverside, Riverside, California 92521, United States
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Zihao Xu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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23
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Bossanyi DG, Sasaki Y, Wang S, Chekulaev D, Kimizuka N, Yanai N, Clark J. Spin Statistics for Triplet-Triplet Annihilation Upconversion: Exchange Coupling, Intermolecular Orientation, and Reverse Intersystem Crossing. JACS AU 2021; 1:2188-2201. [PMID: 34977890 PMCID: PMC8715495 DOI: 10.1021/jacsau.1c00322] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 06/14/2023]
Abstract
Triplet-triplet annihilation upconversion (TTA-UC) has great potential to significantly improve the light harvesting capabilities of photovoltaic cells and is also sought after for biomedical applications. Many factors combine to influence the overall efficiency of TTA-UC, the most fundamental of which is the spin statistical factor, η, that gives the probability that a bright singlet state is formed from a pair of annihilating triplet states. The value of η is also critical in determining the contribution of TTA to the overall efficiency of organic light-emitting diodes. Using solid rubrene as a model system, we reiterate why experimentally measured magnetic field effects prove that annihilating triplets first form weakly exchange-coupled triplet-pair states. This is contrary to conventional discussions of TTA-UC that implicitly assume strong exchange coupling, and we show that it has profound implications for the spin statistical factor η. For example, variations in intermolecular orientation tune η from to through spin mixing of the triplet-pair wave functions. Because the fate of spin-1 triplet-pair states is particularly crucial in determining η, we investigate it in rubrene using pump-push-probe spectroscopy and find additional evidence for the recently reported high-level reverse intersystem crossing channel. We incorporate all of these factors into an updated model framework with which to understand the spin statistics of TTA-UC and use it to rationalize the differences in reported values of η among different common annihilator systems. We suggest that harnessing high-level reverse intersystem crossing channels in new annihilator molecules may be a highly promising strategy to exceed any spin statistical limit.
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Affiliation(s)
- David G. Bossanyi
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Yoichi Sasaki
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Shuangqing Wang
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
| | - Dimitri Chekulaev
- Department
of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
| | - Nobuo Kimizuka
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Nobuhiro Yanai
- Department
of Chemistry and Biochemistry, Graduate School of Engineering, Center
for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Jenny Clark
- Department
of Physics and Astronomy, The University
of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, U.K.
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24
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López-Carballeira D, Polcar T. A new protocol for the identification of singlet fission sensitizers through computational screening. J Comput Chem 2021; 42:2241-2249. [PMID: 34590727 DOI: 10.1002/jcc.26753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/10/2021] [Accepted: 09/15/2021] [Indexed: 11/11/2022]
Abstract
Although singlet fission presents deep advantages or the generation of solar energy, the list of efficient singlet fission sensitizers is still very short, encouraging the theoreticians to focus their efforts on selecting and designing new candidates. Here, it is presented a computational protocol for the efficient screening of databases to select those species matching the energy requirements for singlet fission. Hence, out of the initial 29,123 species, 254 molecules (0.87%) were found to match singlet fission energy conditions. The consideration of practical concerns such as availability or stability reduced the number to just 24 (0.08%), among which the aminoanthraquinone derivatives are found particularly promising. The proposed protocol correct the deficiencies of the preceding ones, reaching DFT accuracy and minimizing the risk of getting false negatives especially at the early stages of the screening. In addition, this protocol can be used in future high-throughput investigations using datasets composed of millions of species.
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Affiliation(s)
- Diego López-Carballeira
- Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic
| | - Tomáš Polcar
- Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic
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25
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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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26
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Li X, Liu W, Fang J, Huang H, Zhu C, Ni Y, Fang L, Kou J, Lu C, Xu Z. Dual-layered up-conversion films with tunable multi-peaks spectrum for efficient photocatalytic degradation. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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27
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Bennison M, Collins AR, Zhang B, Evans RC. Organic Polymer Hosts for Triplet-Triplet Annihilation Upconversion Systems. Macromolecules 2021; 54:5287-5303. [PMID: 34176961 PMCID: PMC8223484 DOI: 10.1021/acs.macromol.1c00133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/29/2021] [Indexed: 11/29/2022]
Abstract
Triplet-triplet annihilation upconversion (TTA-UC) is a process by which a lower energy photon can be upconverted to a higher energy state. The incorporation of TTA-UC materials into solid-state hosts has enabled advances in solar energy and many other applications. The choice of host system is, however, far from trivial and often calls for a careful compromise between characteristics such as high molecular mobility, low oxygen diffusion, and high material stability, factors that often contradict one another. Here, we evaluate these challenges in the context of the state-of-the-art of primarily polymer hosts and the advantages they hold in terms of material selection and tunability of their diffusion or mechanical or thermal properties. We encourage more collaborative research between polymer scientists and photophysicists in order to further optimize the current systems and outline our thoughts for the future direction of the field.
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Affiliation(s)
| | | | | | - Rachel C. Evans
- Department of Materials Science and
Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
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28
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Ye C, Mallick S, Hertzog M, Kowalewski M, Börjesson K. Direct Transition from Triplet Excitons to Hybrid Light-Matter States via Triplet-Triplet Annihilation. J Am Chem Soc 2021; 143:7501-7508. [PMID: 33973463 PMCID: PMC8154526 DOI: 10.1021/jacs.1c02306] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
![]()
Strong light–matter
coupling generates hybrid states that
inherit properties of both light and matter, effectively allowing
the modification of the molecular potential energy landscape. This
phenomenon opens up a plethora of options for manipulating the properties
of molecules, with a broad range of applications in photochemistry
and photophysics. In this article, we use strong light–matter
coupling to transform an endothermic triplet–triplet annihilation
process into an exothermic one. The resulting gradual on–off
photon upconversion experiment demonstrates a direct conversion between
molecular states and hybrid light–matter states. Our study
provides a direct evidence that energy can relax from nonresonant
low energy molecular states directly into hybrid light–matter
states and lays the groundwork for tunable photon upconversion systems
that modify molecular properties in situ by optical cavities rather
than with chemical modifications.
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Affiliation(s)
- Chen Ye
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96 Gothenburg, Sweden
| | - Suman Mallick
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96 Gothenburg, Sweden
| | - Manuel Hertzog
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96 Gothenburg, Sweden
| | - Markus Kowalewski
- Department of Physics, Stockholm University, Albanova University Centre, 106 91 Stockholm, Sweden
| | - Karl Börjesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96 Gothenburg, Sweden
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29
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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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30
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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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31
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Huang T, Koh TT, Schwan J, Tran TTT, Xia P, Wang K, Mangolini L, Tang ML, Roberts ST. Bidirectional triplet exciton transfer between silicon nanocrystals and perylene. Chem Sci 2021; 12:6737-6746. [PMID: 34040750 PMCID: PMC8132999 DOI: 10.1039/d1sc00311a] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hybrid materials comprised of inorganic quantum dots functionalized with small-molecule organic chromophores have emerged as promising materials for reshaping light's energy content. Quantum dots in these structures can serve as light harvesting antennas that absorb photons and pass their energy to molecules bound to their surface in the form of spin-triplet excitons. Energy passed in this manner can fuel upconversion schemes that use triplet fusion to convert infrared light into visible emission. Likewise, triplet excitons passed in the opposite direction, from molecules to quantum dots, can enable solar cells that use singlet fission to circumvent the Shockley–Queisser limit. Silicon QDs represent a key target for these hybrid materials due to silicon's biocompatibility and preeminence within the solar energy market. However, while triplet transfer from silicon QDs to molecules has been observed, no reports to date have shown evidence of energy moving in the reverse direction. Here, we address this gap by creating silicon QDs functionalized with perylene chromophores that exhibit bidirectional triplet exciton transfer. Using transient absorption, we find triplet transfer from silicon to perylene takes place over 4.2 μs while energy transfer in the reverse direction occurs two orders of magnitude faster, on a 22 ns timescale. To demonstrate this system's utility, we use it to create a photon upconversion system that generates blue emission at 475 nm using photons with wavelengths as long as 730 nm. Our work shows formation of covalent linkages between silicon and organic molecules can provide sufficient electronic coupling to allow efficient bidirectional triplet exchange, enabling new technologies for photon conversion. We demonstrate that silicon quantum dots can exchange spin triplet excitons with molecules covalently attached to their surface. Such hybrid materials can enable systems that upconvert incoherent far-red light into the visible spectral range.![]()
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Affiliation(s)
- Tingting Huang
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
| | - Timothy T Koh
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
| | - Joseph Schwan
- Department of Mechanical Engineering, University of California Riverside Riverside CA 92521 USA
| | - Tiffany T-T Tran
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
| | - Pan Xia
- Materials Science & Engineering Program, University of California Riverside Riverside CA 92521 USA
| | - Kefu Wang
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA
| | - Lorenzo Mangolini
- Department of Mechanical Engineering, University of California Riverside Riverside CA 92521 USA .,Materials Science & Engineering Program, University of California Riverside Riverside CA 92521 USA
| | - Ming L Tang
- Department of Chemistry, University of California Riverside Riverside CA 92521 USA .,Materials Science & Engineering Program, University of California Riverside Riverside CA 92521 USA
| | - Sean T Roberts
- Department of Chemistry, The University of Texas at Austin Austin TX 78712 USA .,Center for Dynamics and Control of Materials, The University of Texas at Austin Austin TX 78712 USA
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33
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The triplet exciton dynamics and diffusion properties of zinc and platinum-octaethylporphyrin nanoaggregates. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.113105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Aster A, Zinna F, Rumble C, Lacour J, Vauthey E. Singlet Fission in a Flexible Bichromophore with Structural and Dynamic Control. J Am Chem Soc 2021; 143:2361-2371. [PMID: 33512153 DOI: 10.1021/jacs.0c12384] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Singlet fission (SF), i.e., the splitting of a high-energy exciton into two lower-energy triplet excitons, has the potential to increase the efficiency for harvesting spectrally broad light. The path from the photopopulated singlet state to free triplets is complicated by competing processes that decrease the overall SF efficiency. A detailed understanding of the whole cascade and the nature of the photoexcited singlet state is still a major challenge. Here, we introduce a pentacene dimer with a flexible crown ether spacer enabling a control of the interchromophore coupling upon solvent-induced self-aggregation as well as cation binding. The systematic change of solvent polarity and viscosity and excitation wavelength, as well as the available conformational phase space, allows us to draw a coherent picture of the whole SF cascade from the femtosecond to microsecond time scales. High coupling leads to ultrafast SF (<2 ps), independent of the solvent polarity, and to highly coupled correlated triplet pairs. The absence of a polarity effect indicates that the solvent coordinate does not play a significant role and that SF is driven by intramolecular modes. Low coupling results in much slower SF (∼500 ps), which depends on viscosity, and leads to weakly coupled correlated triplet pairs. These two triplet pairs could be spectrally distinguished and their contribution to the overall SF efficiency, i.e., to the population of free triplets, could be determined. Our results reveal how the overall SF efficiency can be increased by conformational restrictions and control of the structural fluctuation dynamics.
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Affiliation(s)
- Alexander Aster
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Francesco Zinna
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Christopher Rumble
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
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35
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Garnett EC, Ehrler B, Polman A, Alarcon-Llado E. Photonics for Photovoltaics: Advances and Opportunities. ACS PHOTONICS 2021; 8:61-70. [PMID: 33506072 PMCID: PMC7821300 DOI: 10.1021/acsphotonics.0c01045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/31/2020] [Accepted: 09/12/2020] [Indexed: 05/03/2023]
Abstract
Photovoltaic systems have reached impressive efficiencies, with records in the range of 20-30% for single-junction cells based on many different materials, yet the fundamental Shockley-Queisser efficiency limit of 34% is still out of reach. Improved photonic design can help approach the efficiency limit by eliminating losses from incomplete absorption or nonradiative recombination. This Perspective reviews nanopatterning methods and metasurfaces for increased light incoupling and light trapping in light absorbers and describes nanophotonics opportunities to reduce carrier recombination and utilize spectral conversion. Beyond the state-of-the-art single junction cells, photonic design plays a crucial role in the next generation of photovoltaics, including tandem and self-adaptive solar cells, and to extend the applicability of solar cells in many different ways. We address the exciting research opportunities and challenges in photonic design principles and fabrication that will accelerate the massive upscaling and (invisible) integration of photovoltaics into every available surface.
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Affiliation(s)
- Erik C. Garnett
- Center for Nanophotonics, NWO-Institute
AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Bruno Ehrler
- Center for Nanophotonics, NWO-Institute
AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Albert Polman
- Center for Nanophotonics, NWO-Institute
AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Esther Alarcon-Llado
- Center for Nanophotonics, NWO-Institute
AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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36
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Paul S, Govind C, Karunakaran V. Planarity and Length of the Bridge Control Rate and Efficiency of Intramolecular Singlet Fission in Pentacene Dimers. J Phys Chem B 2020; 125:231-239. [PMID: 33371685 DOI: 10.1021/acs.jpcb.0c08590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Singlet fission (SF) improves the power conversion efficiency of optoelectronic devices by converting high-energy photons into two triplet excitons. SF dynamics and efficiency (Φ) are controlled by various factors. Here, the effect of planarity and length of the bridge in pentacene dimers on the intramolecular SF (iSF) process was investigated by synthesizing the dimers connected by bridges having fluorene (FL-PD, planar), methyl-substituted biphenyl (MBP-PD, twisted), and diphenyl acetylene (DPA-PD, longer) groups and characterizing their excited-state relaxation dynamics using nanosecond and femtosecond pump-probe spectroscopy. Transient absorption studies reveal that iSF dynamics of FL-PD having a planar bridge are ∼787 times faster (187 ps) and exhibit higher Φ (198%) by feasible electronic coupling, compared to MBP-PD possessing a twisted bridge showing a low Φ of ∼16%. However compared to FL-PD, iSF dynamics of DPA-PD with an increase of bridge length are slower by an order (1.09 ns) and show comparable Φ of 185% through extended conjugation. Thus, the planarity and length of the bridge in pentacene dimers control the rate and efficiency of the iSF process.
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Affiliation(s)
- Sumitha Paul
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Chinju Govind
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Venugopal Karunakaran
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
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37
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Sherrie B, Funston AM, Frazer L. Optimal quantum dot size for photovoltaics with fusion. NANOSCALE 2020; 12:24362-24367. [PMID: 33313628 DOI: 10.1039/d0nr07061k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Light fusion increases the efficiency of solar cells by converting photons with lower energy than the bandgap into higher energy photons. The solar cell converts the product photons to current. We use Monte Carlo simulation to predict that lead sulfide (PbS) quantum dot sensitizers will enable fusion with a figure of merit on the mA cm-2 scale, exceeding current records, while enabling silicon cell compatibility. Performance is highly sensitive to quantum dot size, on the order of mA cm-2 nm-1.
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Affiliation(s)
- Benedicta Sherrie
- ARC Centre of Excellence in Exciton Science and School of Chemistry, Monash University, 17 Rainforest Walk, Clayton, VIC 3800, Australia.
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38
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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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39
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Arcidiacono A, Zhou Y, Zhang W, Ellison JO, Ayad S, Knorr ES, Peters AN, Zheng L, Yang W, Saavedra SS, Hanson K. Examining the influence of bilayer structure on energy transfer and molecular photon upconversion in metal ion linked multilayers. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:23597-23610. [PMID: 33354274 PMCID: PMC7750814 DOI: 10.1021/acs.jpcc.0c08715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Metal ion linked multilayers is a unique motif to spatially control and geometrically restrict molecules on a metal oxide surface and is of interest in a number of promising applications. Here we use a bilayer composed of a metal oxide surface, an anthracene annihilator molecule, Zn(II) linking ion, and porphyrin sensitizers to probe the influence of the position of the metal ion binding site on energy transfer, photon upconversion, and photocurrent generation. Despite being energetically similar, varying the position of the carboxy metal ion binding group (i.e. ortho, meta, para) of the Pt(II) tetraphenyl porphyrin sensitizer had a large impact on energy transfer rates and upconverted photocurrent that can be attributed to differences in their geometries. From polarized attenuated total reflectance measurements of the bilayers on ITO, we found that the orientation of the first layer (anthracene) was largely unperturbed by subsequent layers. However, the tilt angle of the porphyrin plane varies dramatically from 41° to 64° to 57° for the para-, meta-, and ortho-COOH substituted porphyrin molecules, which is likely responsible for the variation in energy transfer rates. We go on to show using molecular dynamics simulations that there is considerable flexibility in porphyrin orientation, indicating that an average structure is insufficient to predict the ensemble behavior. Instead, even a small subset of the population with highly favorable energy transfer rates can be the primary driver in increasing the likelihood of energy transfer. Gaining control of the orientation and its distribution will be a critical step in maximizing the potential of the metal ion linked structures.
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Affiliation(s)
- Ashley Arcidiacono
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Yan Zhou
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Wendi Zhang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
| | - Jeffrey O. Ellison
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Suliman Ayad
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Erica S. Knorr
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Autumn N. Peters
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Lianqing Zheng
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - Wei Yang
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - S. Scott Saavedra
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA
| | - Kenneth Hanson
- Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
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40
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Beimborn JC, Zagorec-Marks W, Weber JM. Spectroscopy of Resonant Intermediate States for Triplet-Triplet Annihilation Upconversion in Crystalline Rubrene: Radical Ions as Sensitizers. J Phys Chem Lett 2020; 11:7212-7217. [PMID: 32787307 DOI: 10.1021/acs.jpclett.0c01999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photoluminescence upconversion in crystalline rubrene can proceed without an added sensitizer, but the mechanism for this process has not been well-understood. In particular, the species responsible for photon absorption has not been identified to date. To gain insight into the identity of the intermediate state, we measured the near-infrared (NIR) upconversion photoluminescence (UCPL) excitation spectrum of rubrene crystals and found three distinct spectral features. The UCPL yield has a quartic dependence on the laser intensity, implying a four-photon process. On the basis of electronic spectra of radical cations and anions of rubrene, we propose a mechanism in which photoexcited radical anions and cations undergo recombination, forming an excited neutral triplet while conserving spin. The triplets formed this way ultimately undergo triplet-triplet annihilation, resulting in the observed photoluminescence. This mechanism explains the origin of the NIR absorption as well as the four-photon nature of the UCPL process.
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Affiliation(s)
- J Curtis Beimborn
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Wyatt Zagorec-Marks
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - J Mathias Weber
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
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41
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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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42
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Sutherland GA, Polak D, Swainsbury DJK, Wang S, Spano FC, Auman DB, Bossanyi DG, Pidgeon JP, Hitchcock A, Musser AJ, Anthony JE, Dutton PL, Clark J, Hunter CN. A Thermostable Protein Matrix for Spectroscopic Analysis of Organic Semiconductors. J Am Chem Soc 2020; 142:13898-13907. [PMID: 32672948 DOI: 10.1021/jacs.0c05477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Advances in protein design and engineering have yielded peptide assemblies with enhanced and non-native functionalities. Here, various molecular organic semiconductors (OSCs), with known excitonic up- and down-conversion properties, are attached to a de novo-designed protein, conferring entirely novel functions on the peptide scaffolds. The protein-OSC complexes form similarly sized, stable, water-soluble nanoparticles that are robust to cryogenic freezing and processing into the solid-state. The peptide matrix enables the formation of protein-OSC-trehalose glasses that fix the proteins in their folded states under oxygen-limited conditions. The encapsulation dramatically enhances the stability of protein-OSC complexes to photodamage, increasing the lifetime of the chromophores from several hours to more than 10 weeks under constant illumination. Comparison of the photophysical properties of astaxanthin aggregates in mixed-solvent systems and proteins shows that the peptide environment does not alter the underlying electronic processes of the incorporated materials, exemplified here by singlet exciton fission followed by separation into weakly bound, localized triplets. This adaptable protein-based approach lays the foundation for spectroscopic assessment of a broad range of molecular OSCs in aqueous solutions and the solid-state, circumventing the laborious procedure of identifying the experimental conditions necessary for aggregate generation or film formation. The non-native protein functions also raise the prospect of future biocompatible devices where peptide assemblies could complex with native and non-native systems to generate novel functional materials.
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Affiliation(s)
- George A Sutherland
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| | - Daniel Polak
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - David J K Swainsbury
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| | - Shuangqing Wang
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Frank C Spano
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Dirk B Auman
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - David G Bossanyi
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - James P Pidgeon
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - Andrew Hitchcock
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
| | - Andrew J Musser
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - John E Anthony
- Department of Chemistry, University of Kentucky, Kentucky 40511, United States
| | - P Leslie Dutton
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jenny Clark
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, U.K
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K
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43
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Palmer JR, Wells KA, Yarnell JE, Favale JM, Castellano FN. Visible-Light-Driven Triplet Sensitization of Polycyclic Aromatic Hydrocarbons Using Thionated Perinones. J Phys Chem Lett 2020; 11:5092-5099. [PMID: 32517474 DOI: 10.1021/acs.jpclett.0c01634] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Metal-free chromophores that efficiently generate triplet excited states represent promising alternatives with respect to transition metal-containing photosensitizers, such as those featuring metal-to-ligand charge transfer excited states. However, such molecular constructs have remained underexplored due to the unclear relationship(s) between molecular structure and efficient/rapid intersystem crossing. In this regard, we present a series of three thionated perinone chromophores serving as a newly conceived class of heavy metal-free triplet photosensitizers. We demonstrate that thionation of the lone C═O substituent in each highly fluorescent perinone imparts red-shifted absorbance bands that maintain intense extinction coefficients across the visible spectrum, as well as unusually efficient triplet excited state formation as inferred from the measured singlet O2 quantum yields at 1270 nm (ΦΔ = 0.78-1.0). Electronic structure calculations revealed the emergence of a low energy S1 (n → π*) excited state in the proximity of a slightly higher energy S2 (π → π*) excited state. The distinct character in each of the two lowest-lying singlet state manifolds resulted in the energetic inversion of the corresponding triplet excited states due to differences in electron exchange interactions. Rapid S1 → T1 intersystem crossing was thereby facilitated in this manner through spin-orbit coupling as predicted by the El Sayed rules. The lifetimes of the resultant triplet excited states persisted into the microsecond time regime, as measured by transient absorbance spectroscopy, enabling effective bimolecular triplet sensitization of some common polycyclic aromatic hydrocarbons. The synthetically facile interchange of a single O atom to an S atom in the investigated perinones resulted in marked changes to their photophysical properties, namely, conversion of dominant singlet state fluorescence in the former to long-lived triplet excited states in the latter. The combined results suggest a general strategy for accessing long-lived triplet excited states in organic chromophores featuring a lone C═O moiety residing within its structure, valuable for the design of metal-free triplet photosensitizers.
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Affiliation(s)
- Jonathan R Palmer
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Kaylee A Wells
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - James E Yarnell
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
- Department of Chemistry & Chemistry Research Center, United States Air Force Academy, Colorado Springs, Colorado 80840-6230, United States
| | - Joseph M Favale
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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44
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Singlet Fission in Self-assembled Amphipathic Tetracene Nanoparticles: Probing the Role of Charge-transfer State. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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45
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Korovina NV, Pompetti NF, Johnson JC. Lessons from intramolecular singlet fission with covalently bound chromophores. J Chem Phys 2020; 152:040904. [PMID: 32007061 DOI: 10.1063/1.5135307] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Molecular dimers, oligomers, and polymers are versatile components in photophysical and optoelectronic architectures that could impact a variety of applications. We present a perspective on such systems in the field of singlet fission, which effectively multiplies excitons and produces a unique excited state species, the triplet pair. The choice of chromophore and the nature of the attachment between units, both geometrical and chemical, play a defining role in the dynamical scheme that evolves upon photoexcitation. Specific final outcomes (e.g., separated and uncorrelated triplet pairs) are being sought through rational design of covalently bound chromophore architectures built with guidance from recent fundamental studies that correlate structure with excited state population flow kinetics.
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Affiliation(s)
- Nadezhda V Korovina
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
| | - Nicholas F Pompetti
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
| | - Justin C Johnson
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, USA
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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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Ye C, Gray V, Kushwaha K, Kumar Singh S, Erhart P, Börjesson K. Optimizing photon upconversion by decoupling excimer formation and triplet triplet annihilation. Phys Chem Chem Phys 2020; 22:1715-1720. [PMID: 31895392 DOI: 10.1039/c9cp06561j] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Perylene is a promising annihilator candidate for triplet-triplet annihilation photon upconversion, which has been successfully used in solar cells and in photocatalysis. Perylene can, however, form excimers, reducing the energy conversion efficiency and hindering further development of TTA-UC systems. Alkyl substitution of perylene can suppress excimer formation, but decelerate triplet energy transfer and triplet-triplet annihilation at the same time. Our results show that mono-substitution with small alkyl groups selectively blocks excimer formation without severly compromising the TTA-UC efficiency. The experimental results are complemented by DFT calculations, which demonstrate that excimer formation is suppressed by steric repulsion. The results demonstrate how the chemical structure can be modified to block unwanted intermolecular excited state relaxation pathways with minimal effect on the preferred ones.
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Affiliation(s)
- Chen Ye
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
| | - Victor Gray
- Department of Chemistry-Ångström Laboratory, Uppsala University, 75120, Uppsala, Sweden and Department of Physics, Cavendish Laboratory, University of Cambridge, 19 JJ Thompson Avenue, Cambridge, CB3 0HE, UK
| | - Khushbu Kushwaha
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
| | - Sandeep Kumar Singh
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Paul Erhart
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Karl Börjesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
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48
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Achieving spin-triplet exciton transfer between silicon and molecular acceptors for photon upconversion. Nat Chem 2019; 12:137-144. [PMID: 31792389 DOI: 10.1038/s41557-019-0385-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/28/2019] [Indexed: 12/14/2022]
Abstract
Inorganic semiconductor nanocrystals interfaced with spin-triplet exciton-accepting organic molecules have emerged as promising materials for converting incoherent long-wavelength light into the visible range. However, these materials to date have made exclusive use of nanocrystals containing toxic elements, precluding their use in biological or environmentally sensitive applications. Here, we address this challenge by chemically functionalizing non-toxic silicon nanocrystals with triplet-accepting anthracene ligands. Photoexciting these structures drives spin-triplet exciton transfer from silicon to anthracene through a single 15 ns Dexter energy transfer step with a nearly 50% yield. When paired with 9,10-diphenylanthracene emitters, these particles readily upconvert 488-640 nm photons to 425 nm violet light with efficiencies as high as 7 ± 0.9% and can be readily incorporated into aqueous micelles for biological use. Our demonstration of spin-triplet exciton transfer from silicon to molecular triplet acceptors can critically enable new technologies for solar energy conversion, quantum information and near-infrared driven photocatalysis.
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49
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Ryerson JL, Zaykov A, Aguilar Suarez LE, Havenith RWA, Stepp BR, Dron PI, Kaleta J, Akdag A, Teat SJ, Magnera TF, Miller JR, Havlas Z, Broer R, Faraji S, Michl J, Johnson JC. Structure and photophysics of indigoids for singlet fission: Cibalackrot. J Chem Phys 2019; 151:184903. [PMID: 31731849 DOI: 10.1063/1.5121863] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We report an investigation of structure and photophysics of thin layers of cibalackrot, a sturdy dye derived from indigo by double annulation at the central double bond. Evaporated layers contain up to three phases, two crystalline and one amorphous. Relative amounts of all three have been determined by a combination of X-ray diffraction and FT-IR reflectance spectroscopy. Initially, excited singlet state rapidly produces a high yield of a transient intermediate whose spectral properties are compatible with charge-transfer nature. This intermediate more slowly converts to a significant yield of triplet, which, however, does not exceed 100% and may well be produced by intersystem crossing rather than singlet fission. The yields were determined by transient absorption spectroscopy and corrected for effects of partial sample alignment by a simple generally applicable procedure. Formation of excimers was also observed. In order to obtain guidance for improving molecular packing by a minor structural modification, calculations by a simplified frontier orbital method were used to find all local maxima of singlet fission rate as a function of geometry of a molecular pair. The method was tested at 48 maxima by comparison with the ab initio Frenkel-Davydov exciton model.
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Affiliation(s)
- Joseph L Ryerson
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Alexandr Zaykov
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Luis E Aguilar Suarez
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Remco W A Havenith
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Brian R Stepp
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Paul I Dron
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Jiří Kaleta
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Akin Akdag
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Simon J Teat
- Advanced Light Source, Lawrence Berkeley National Lab, 1 Cyclotron Rd., Berkeley, California 94720, USA
| | - Thomas F Magnera
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - John R Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Zdeněk Havlas
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Ria Broer
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Shirin Faraji
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Josef Michl
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Justin C Johnson
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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50
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Collins MI, McCamey DR, Tayebjee MJY. Fluctuating exchange interactions enable quintet multiexciton formation in singlet fission. J Chem Phys 2019; 151:164104. [PMID: 31675884 DOI: 10.1063/1.5115816] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several recent electron spin resonance studies have observed a quintet multiexciton state during the singlet fission process. Here, we provide a general theoretical explanation for the generation of this state by invoking a time-varying exchange coupling between pairs of triplet excitons and subsequently solving the relevant time-varying spin Hamiltonian for different rates at which the exchange coupling varies. We simulate experimental ESR spectra and draw qualitative conclusions about the adiabatic and diabatic transitions between triplet pair spin states.
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Affiliation(s)
- Miles I Collins
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Dane R McCamey
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
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