Relaxation dynamics of excitons in J-aggregates revealing a two-component Davydov splitting

Scheblykin, Ivan G.; Varnavsky, O.P.; Verbouwe, Wouter; Backer, Steven De; Auweraer, Mark Van der; Vitukhnovsky, A. G.

doi:10.1016/s0009-2614(97)01290-6

Cited by 49 publications

(69 citation statements)

References 30 publications

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“…[29][30][31][32][33] The absorption spectra on the high-energy side of TTBC highly resemble the roomtemperature absorption spectrum of the THIATS aggregate in the water-ethylene glycol solution. 31 In the THIATS aggregate, the H-and J-bands are almost symmetrically split around the monomeric transition, and the H-band is more intense (about 35 times) than the J-band.…”

Section: Resultsmentioning

confidence: 99%

Controlled Formation of the Two-Dimensional TTBC J-Aggregates in an Aqueous Solution

2006

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Strong experimental and theoretical evidence was provided on the controlled formation of the two-dimensional J-aggregates that were assembled in the herringbone morphology. The exciton-band structure formation of 1,1′,3,3′-tetraethyl-5,5′,6,6′-tetrachlorobenzimidazolocarbocyanine (TTBC) J-aggregates was investigated in ionic (NaOH) aqueous solution at room temperature. The control was achieved by changing the [TTBC] at a given [NaOH], or vice versa, and was monitored through the changes in the absorption, fluorescence excitation, and emission spectra. Specific attention was paid to expose the excited-state structure and dynamics through simulations of the excitonic properties, which included diagonal energetic disorder and phononassisted exciton relaxation. Aggregates were characterized by an asymmetrically split Davydov pair, an H-band (∼500 nm, 1300 cm -1 wide, Lorentzian-like) and a J-band (∼590 nm, 235 cm -1 wide, with a band shape typical of a one-dimensional J-aggregate), whose relative intensities showed a strong dependence on the [TTBC]/ [NaOH]. The H-band is favored by high [TTBC] or high [NaOH]. An explanation of the control on the aggregate formation was given by correlating the changes in the absorption with the structural modifications and the subsequent changes in the dynamics, which were induced by variations in the dye and NaOH concentrations. The J-band shape/width was attributed to disorder and disorder-induced intraband phononassisted exciton relaxation. The intraband processes in both bands were estimated to occur in the same time scale (about a picosecond). It has been suggested that the wide energetic gap between the Davydov split bands (3000 cm -1 ) could get bridged by the excitonic states of the loosely coupled chains, in addition to the monomeric species at low [TTBC]. Phonon-assisted interband relaxation, through the band gap states and/or directly from the H-to the J-band, are suggested for accounting the difference between the bandwidths and shapes of the two bands. Energy transfer between the H-band and the monomeric species is suggested as crucial for tuning the relative strengths of the two bands.

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Section: Resultsmentioning

confidence: 99%

Controlled Formation of the Two-Dimensional TTBC J-Aggregates in an Aqueous Solution

2006

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“…1). In the H-band (the upper component of the Davydov-exciton-zone splitting [5]) and J-band (the lower component of the Davydov-exciton-zone splitting), the decrease in the optical density was about 1.5 %. At the same time, the decrease in the optical density in the absorption band of non-aF~regated monomer molecules amounted to 10 %.…”

Section: Methodsmentioning

confidence: 97%

“…If these molecules are assumed to differ little in size and shape from the dye molecules, the characteristic time of their diffusion from the solution to the macroaggregate surface is nearly I0 s (for the calculation, see below). The second interval includes short times of the order of luminescence lifetimes (6 ns [5]). Within these intervals, the diffusion of quencher molecules from the solution to the aggregates is insignificant, and therefore the phenomena occurring within such intervals take place directly inside the macroaggregate.…”

Section: Methodsmentioning

confidence: 99%

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Degradation of J-aggregates in solutions exposed to light

et al. 1999

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The degradation of J-aggregates of thiacarbocy~nlne dye (THIATS) exposed to visible radiation is experimentally investigated. A model that allows s consistent description of photodegradation of J-aggregates in s solution is proposed. L-mlnescence quencher molecules are formed with the participation of monomer dye molecules in s solution under action of the light. These molecules, when diffusing to the aggregates for a time of nearly 10 s, are adsorbed on their surface and participate in quenching of exciton luminescence of the J-aggregates.

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“…Nowadays J-aggregates continue to attract much attention as a supramolecular system which is expected to be useful in nanotechnology. J-aggregates are characterized by a narrow and intense exciton absorption band, which is red-shifted with respect to that of the monomers, resonance fluorescence and a short lifetime of the excited state which is in the ps time scale [4][5][6][7][8][9][10][11][12][13][14][15]. Another type of aggregate is H-aggregate which has a broader blue-shifted band.…”

Section: Introductionmentioning

confidence: 99%

J-aggregation of N-sulfobutyl oxacarbocyanine in binary mixtures of organic solvents

Чибисов¹,

Slavnova²,

Görner³

2010

Chemical Physics Letters

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Relaxation dynamics of excitons in J-aggregates revealing a two-component Davydov splitting

Cited by 49 publications

References 30 publications

Controlled Formation of the Two-Dimensional TTBC J-Aggregates in an Aqueous Solution

Controlled Formation of the Two-Dimensional TTBC J-Aggregates in an Aqueous Solution

Degradation of J-aggregates in solutions exposed to light

J-aggregation of N-sulfobutyl oxacarbocyanine in binary mixtures of organic solvents

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