Crystallochromy of perylene pigments: Influence of an enlarged polyaromatic core region

Gisslén, L.; Scholz, Reinhard

doi:10.1103/physrevb.83.155311

Cited by 25 publications

(64 citation statements)

References 40 publications

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“…12, 13,20,25,33 When |J k=0 − U| ≫ |t e + t h | (Figure 3a), the diabatic FE and CTE bands are energetically well separated, limiting the FE/ CTE mixing. In this regime, FE/CTE mixing is dominated by the first-order processes described by eq 12; only CT states characterized by p = π/N, 3π/N, ... appreciably mix with the FE, as very little second-order mixing between CT states occurs via indirect coupling through the FE state.…”

Section: Journal Of the American Chemical Societymentioning

confidence: 99%

“…12, 13 Mixing of the k = 0 CTE states in eq 12 with the k = 0 FE (referred to from here on simply as the FE and CTE states) results in a distribution of oscillator strength over a broad range of mixed FE/CTE states. Figure 3 illustrates how such FE/CTE mixing depends on the system parameters t e , t h , J k , and U, where we have taken V CT (s) = 0 to reflect the high dielectric medium and have temporarily ignored vibronic coupling.…”

Section: Absorption Signatures Of Fe/cte Mixingmentioning

confidence: 99%

“…Coupling between the CT states and the optically allowed FE depends on the sum |t e + t h |, in agreement with previous works. 12, 13,[20][21][22][23][24][25]33 Importantly, this sum also determines the coupling between CT states of different electron/hole radii (see eq 7) and thus the k = 0 CT bandwidth (see Figure 6a−c). 33 Hence, the relative phases of the CT integrals determine not only the probability of the excitation existing in a charge-separated state after absorption but also the extent to which the electron and hole are separated in such states.…”

Section: Journal Of the American Chemical Societymentioning

confidence: 99%

“…12, 13,[20][21][22][23][24][25]33 In previous works, some of us showed that the relative phase between t e and t h has a strong impact on the absorption and emission spectral profiles and can tune the short-range CT-induced coupling between J-and H-aggregate behavior (as determined by the sign of the CT-induced coupling), even in the absence of the exciton (dipole−dipole) coupling. 22,23,34 This relative phase can further modulate the exciton mobility in tightly packed molecular π-stacks 32 and was recently shown to strongly impact electron/hole recombination rates.…”

Section: Introductionmentioning

confidence: 99%

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Extended-Charge-Transfer Excitons in Crystalline Supramolecular Photocatalytic Scaffolds

Hestand

Kazantsev²,

Weingarten³

et al. 2016

J. Am. Chem. Soc.

158

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Coupling among chromophores in molecular assemblies is responsible for phenomena such as resonant energy transfer and intermolecular charge transfer. These processes are central to the fields of organic photovoltaics and photocatalysis, where it is necessary to funnel energy or charge to specific regions within the system. As such, a fundamental understanding of these transport processes is essential for developing new materials for photovoltaic and photocatalytic applications. Recently, photocatalytic systems based on photosensitizing perylene monomimide (PMI) chromophore amphiphiles were found to show variation in hydrogen gas (H 2 ) production as a function of nanostructure crystallinity. The 2D crystalline systems form in aqueous electrolyte solution, which provides a high dielectric environment where the Coulomb potential between charges is mitigated. This results in relatively weakly bound excitons that are ideal for reducing protons. In order to understand how variations in crystalline structure affect H 2 generation, two representative PMI systems are investigated theoretically using a modified Holstein Hamiltonian. The Hamiltonian includes both molecular Frenkel excitations (FE) and charge-transfer excitations (CTE) coupled nonadiabatically to local intramolecular vibrations. Signatures of FE/CTE mixing and the extent of electron/hole separation are identified in the optical absorption spectrum and are found to correlate strongly to the observed H 2 production rates. The absorption spectral signatures are found to sensitively depend on the relative phase between the electron and hole transfer integrals, as well as the diabatic energy difference between the Frenkel and CT exciton bands. Our analysis provides design rules for artificial photosynthetic systems based on organic chromophore arrays.

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Section: Journal Of the American Chemical Societymentioning

confidence: 99%

Section: Absorption Signatures Of Fe/cte Mixingmentioning

confidence: 99%

Section: Journal Of the American Chemical Societymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Extended-Charge-Transfer Excitons in Crystalline Supramolecular Photocatalytic Scaffolds

Hestand

Kazantsev²,

Weingarten³

et al. 2016

J. Am. Chem. Soc.

158

View full text Add to dashboard Cite

show abstract

“…It is well known that the electron and hole bandwidths, as well as the optical bandgap in perylene dyes, are very sensitive to sub-Å shifts ("slips") in the relative orientations of neighboring molecules, leading to the remarkable range of colors displayed by such dyes in the crystalline phase. This effect, known as crystallochromy [9][10][11][12][13] , is attributed to the changing registry of the frontier molecular orbitals of nearest neighbor molecules. Small changes in the slip-stacking distance are also thought to play a strong role in the efficiency of singlet exciton fission.…”

Section: Introductionmentioning

confidence: 99%

Exciton mobility control throughsub−Åpacking modifications in molecular crystals

et al. 2015

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Exciton mobility in π-stacks of organic chromophores is shown to be highly sensitive to the interference between long-range Coulomb coupling and a short-range coupling due to wave function overlap. A destructive interference which leads to a compromised exciton bandwidth can be converted to constructive interference (and an enhanced bandwidth) upon sub-Å transverse displacements between neighboring chromophores. The feasibility of the control scheme is demonstrated theoretically on a derivative of terrylene, where the exciton is essentially immobile despite strong Coulombic coupling. A transverse slip of only 0.5 Å along either the short or long molecular axis boosts the exciton velocity to 4 2 10 × m/sec. Changes in the mobility are correlated to changes in the absorption spectrum, allowing the latter to be used as a screen for high-mobility aggregates.

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A model hamiltonian tuned toward high level ab initio calculations to describe the character of excitonic states in perylenebisimide aggregates

et al. 2018

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On the example of an aggregate of two perylenebisimide (PBI) molecules the character of the lowest excited electronic states in terms of charge transfer (CT) and Frenkel exciton (FE) configurations is investigated as a function of the intermolecular arrangement. A minimal model Hamiltonian based on two FE and two CT configurations at the frontier‐orbitals CIS (FOCIS) level is shown to represent a simple and comprehensible approach providing insight into the physical significance of the model Hamiltonian matrix elements. The recently introduced analysis and diabatization procedure (Liu et al., J. Chem. Phys. 2015, 143, 084106 ) method is used to extract the energies of the configurations and their interactions (the model Hamiltonian parameters) also from the accurate CC2 approach. An analysis in terms of diabatic energy profiles and their interactions shows that the FOCIS parameters give a qualitatively correct description of the adiabatic excited state energy profiles. Comparison with CC2 reveals, however, the presence of avoided crossings at FOCIS level, associated with a large character change (CT/FE) of the excited states as a function of the aggregate structure, which represents the major drawback of FOCIS results. We show that proper amendment of the FOCIS‐derived parameters allows to accurately represent the potential energy surfaces and crossings of the excited dimer states as a function of the aggregate structure. © 2018 Wiley Periodicals, Inc.

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Crystallochromy of perylene pigments: Influence of an enlarged polyaromatic core region

Cited by 25 publications

References 40 publications

Extended-Charge-Transfer Excitons in Crystalline Supramolecular Photocatalytic Scaffolds

Extended-Charge-Transfer Excitons in Crystalline Supramolecular Photocatalytic Scaffolds

Exciton mobility control throughsub−Åpacking modifications in molecular crystals

A model hamiltonian tuned toward high level ab initio calculations to describe the character of excitonic states in perylenebisimide aggregates

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