Ultra-fast spin-mixing in a diketopyrrolopyrrole monomer/fullerene blend charge transfer state

Salvadori, Enrico; Luke, Nathaniel; Shaikh, Jordan; Leventis, Anastasia; Bronstein, Hugo; Kay, Christopher W. M.; Clarke, Tracey M.

doi:10.1039/c7ta07381j

Cited by 24 publications

(31 citation statements)

References 51 publications

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“…The initial encouraging reports [5,17] implied that SF is endemic in the solid states of these materials, and the structural details of their N,N'-aliphatic substituents change the rates and yields in relatively narrow range. These implications were subsequently contradicted [15] and it appeared desirable to resolve the issue. Our results indicate that properties of these materials show a striking dependence on details of the thin film preparation technique and the resulting sample morphology.…”

Section: Discussionmentioning

confidence: 99%

“…Slip‐stacking is a common feature in SF materials and several examples are 2,5‐dihydro‐3,6‐di‐2‐thienylpyrrolo[3,4‐ c ]pyrrole‐1,4‐dione (TDPP) derivatives, [5] perylenediimide derivatives, [12] and diphenylisobenzofuran [13,14] . The sensitivity of SF to solid phase structure, which can vary depending on the preparation conditions, is probably the reason why the occurrence of SF in TDPPs has been questioned [15] …”

Section: Introductionmentioning

confidence: 99%

“…[13,14] The sensitivity of SF to solid phase structure, which can vary depending on the preparation conditions, is probably the reason why the occurrence of SF in TDPPs has been questioned. [15] In this report, we present transient optical absorption and fluorescence spectra of three TDPP derivatives (structures R-1 in Scheme 1) containing n-hexyl, n-butyl, or 2-(adamant-1-yl) ethyl [16] substituents on both N-heteroatoms of the conjugated core. We focused on the exciton fission mechanism and found that the SF rate constants are nearly the same for all three compounds.…”

Section: Introductionmentioning

confidence: 99%

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Singlet Fission in Thin Solid Films of Bis(thienyl)diketopyrrolopyrroles

et al. 2020

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The singlet fission (SF) process discovered in bis(thienyl) diketopyrrolopyrroles (TDPPs) can boost their potential for photovoltaics (PV). The crystal structures of TDPP analogs carrying n-hexyl, n-butyl, or 2-(adamant-1-yl)ethyl substituents are similar, but contain increasingly slipped stacked neighbor molecules. The observed SF rate constants, k SF , (7 � 4), (9 � 3) and (5.6 � 1.9) ns À 1 for thin films of the three compounds, respectively, are roughly equal, but the triplet quantum yields vary strongly: (120 � 40), (160 � 40) and (70 � 16), respectively. The recent molecular pair model reproduces the near equality of all three k SF at the crystal geometries and identifies all possible pair arrangements in which SF is predicted to be faster, by up to two orders of magnitude. However, it is also clear that the presently non-existent ability to predict the rates of processes competing with SF is pivotal for providing a guide for efforts to optimize the materials for PV.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Singlet Fission in Thin Solid Films of Bis(thienyl)diketopyrrolopyrroles

et al. 2020

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“…DPPT monomers are also known to undergo intersystem crossing in the solid state (Fig 3b) 35 . Films were prepared containing DPPT dispersed in polystyrene matrix (1:4 DPPT:polystyrene).…”

Section: Diketopyrrolopyrrole Thiophene (Dpptmentioning

confidence: 99%

Manipulating molecules with strong coupling: harvesting triplet excitons in organic exciton microcavities

et al. 2020

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Exciton-polaritons are quasiparticles with mixed photon and exciton character that demonstrate rich quantum phenomena, novel optoelectronic devices and the potential to modify chemical properties of materials. Organic semiconductors are of current interest for their room-temperature polariton formation. However, within organic optoelectronic devices, it is often the 'dark' spin-1 triplet excitons that dominate operation. These triplets have been largely ignored in treatments of polariton physics. Here we demonstrate polariton population from the triplet manifold via triplettriplet annihilation, leading to polariton emission that is longer-lived (>μs) even than exciton emission in bare films. This enhancement arises from spin-2 triplet-pair states, formed by singlet fission or triplet-triplet annihilation, feeding the polariton. This is possible due to state mixing, which -in the strong coupling regime-leads to sharing of photonic character with states that are formally non-emissive. Such 'photonic sharing' offers the enticing possibility of harvesting or manipulating even states that are formally dark.

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“…As reference groups we have somewhat arbitrarily chosen those of Marina Bennati (Göttingen) [209][210][211], Robert Bittl (Berlin) [212][213][214], Dave Britt (UC Davis) [215][216][217], Jack Freed (Cornell) [218][219][220], Daniella Goldfarb (Weizmann) [221][222][223], Brian Hoffman (Northwestern) [224][225][226], Gunnar Jeschke (Zurich) [227][228][229], Chris Kay (London) [230,231], Yasuhiro Kobori (Kobe) [232][233][234], Wolfgang Lubitz (Mülheim/Ruhr) [235][236][237], Damian Murphy (Cardiff) [238][239][240], Thomas Prisner (Frankfurt/Main) [241][242][243], Christiane Timmel (Oxford) [244][245][246], Sabine van Doorslaer (Antwerp) [247][248][249], and Stefan Weber (Freiburg) [250][251][252].…”

Section: Pulse Endormentioning

confidence: 99%

Biomolecular EPR Meets NMR at High Magnetic Fields

et al. 2018

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In this review on advanced biomolecular EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR regarding the measurement of interactions and dynamics of large molecules embedded in fluid-solution or solid-state environments. Our focus is on the characterization of protein structure, dynamics and interactions, using sophisticated EPR spectroscopy methods. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed the limits of EPR spectroscopy to new horizons reaching millimeter and sub-millimeter wavelengths and 15 T Zeeman fields. Expanding traditional applications to paramagnetic systems, spin-labeling of biomolecules has become a mainstream multifrequency approach in EPR spectroscopy. In the high-frequency/high-field EPR region, sub-micromolar concentrations of nitroxide spin-labeled molecules are now sufficient to characterize reaction intermediates of complex biomolecular processes. This offers promising analytical applications in biochemistry and molecular biology where sample material is often difficult to prepare in sufficient concentration for NMR characterization. For multifrequency EPR experiments on frozen solutions typical sample volumes are of the order of 250 μL (S-band), 150 μL (X-band), 10 μL (Q-band) and 1 μL (W-band). These are orders of magnitude smaller than the sample volumes required for modern liquid- or solid-state NMR spectroscopy. An important additional advantage of EPR over NMR is the ability to detect and characterize even short-lived paramagnetic reaction intermediates (down to a lifetime of a few ns). Electron–nuclear and electron–electron double-resonance techniques such as electron–nuclear double resonance (ENDOR), ELDOR-detected NMR, PELDOR (DEER) further improve the spectroscopic selectivity for the various magnetic interactions and their evolution in the frequency and time domains. PELDOR techniques applied to frozen-solution samples of doubly spin-labeled proteins allow for molecular distance measurements ranging up to about 100 Å. For disordered frozen-solution samples high-field EPR spectroscopy allows greatly improved orientational selection of the molecules within the laboratory axes reference system by means of the anisotropic electron Zeeman interaction. Single-crystal resolution is approached at the canonical g-tensor orientations—even for molecules with very small g-anisotropies. Unique structural, functional, and dynamic information about molecular systems is thus revealed that can hardly be obtained by other analytical techniques. On the other hand, the limitation to systems with unpaired electrons means that EPR is less widely used than NMR. However, this limitation also means that EPR offers greater specificity, since ordinary chemical solvents and matrices do not give rise to EPR in contrast to NMR spectra. Thus, multifrequency EPR spectroscopy plays an important role in better understanding paramagnetic species such as organic and inorganic radicals, transition metal complexes as found in many catalysts or metalloenzymes, transient species such as light-generated spin-correlated radical pairs and triplets occurring in protein complexes of photosynthetic reaction centers, electron-transfer relays, etc. Special attention is drawn to high-field EPR experiments on photosynthetic reaction centers embedded in specific sugar matrices that enable organisms to survive extreme dryness and heat stress by adopting an anhydrobiotic state. After a more general overview on methods and applications of advanced multifrequency EPR spectroscopy, a few representative examples are reviewed to some detail in two Case Studies: (I) High-field ELDOR-detected NMR (EDNMR) as a general method for electron–nuclear hyperfine spectroscopy of nitroxide radical and transition metal containing systems; (II) High-field ENDOR and EDNMR studies of the Oxygen Evolving Complex (OEC) in Photosystem II, which performs water oxidation in photosynthesis, i.e., the light-driven splitting of water into its elemental constituents, which is one of the most important chemical reactions on Earth.

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Ultra-fast spin-mixing in a diketopyrrolopyrrole monomer/fullerene blend charge transfer state

Abstract: Transient absorption and time-resolved EPR spectroscopy show an ultra-fast spin-mixing CT state in a small diketopyrrolopyrrole-based molecule blended with fullerene.

Cited by 24 publications

References 51 publications

Singlet Fission in Thin Solid Films of Bis(thienyl)diketopyrrolopyrroles

Singlet Fission in Thin Solid Films of Bis(thienyl)diketopyrrolopyrroles

Manipulating molecules with strong coupling: harvesting triplet excitons in organic exciton microcavities

Biomolecular EPR Meets NMR at High Magnetic Fields

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