The J- and H-bands of organic dye aggregates

Eisfeld, Alexander; Briggs, J S

doi:10.1016/j.chemphys.2005.11.015

Cited by 390 publications

(361 citation statements)

References 29 publications

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“…Two general types of stacked aggregates exist: H-aggregates, where porphyrins overlap face-to face and present a blue (hypsochromic) shift respect to the Soret band of the monomer, and J-aggregates, where a red (bathochromic) shift of the Soret band is observed because of staircase-type packing with partial overlapping of the porphyrins. 55 The absorption measurements of free-base porphyrins and the corresponding metalloporphyrins were initially carried out in chloroform at room temperature. The spectra of the free-base porphyrins showed a Soret band centered at 419 nm and for metalloporphyrins at 421 nm, indicating that in this solvent molecules behave as isolated chromophores surrounded by solvent.…”

Section: Self-assembly Of Porphyrins and Metalloporphyrins In Solutionmentioning

confidence: 99%

Bottom-Up Hierarchical Self-Assembly of Chiral Porphyrins through Coordination and Hydrogen Bonds

et al. 2015

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A series of chiral synthetic compounds is reported that show intricate but specific hierarchical assembly because of varying positions of coordination and hydrogen bonds. The evolution of the aggregates (followed by absorption spectroscopy and temperature-dependent circular dichroism studies in solution) reveal the influence of the proportion of stereogenic centers in the side groups connected to the chromophore ring in their optical activity and the important role of pyridyl groups in the self-assembly of these chiral macrocycles. The optical activity spans two orders of magnitude depending on composition and constitution. Two of the aggregates show very high optical activity even though the isolated chromophores barely give a circular dichroism signal. Molecular modeling of the aggregates, starting from the pyridine-zinc(II) porphyrin interaction and working up, and calculation of the circular dichroism signal confirm the origin of this optical activity as the chiral supramolecular organization of the molecules. The aggregates show a broad absorption range, between approximately 390 and 475 nm for the transitions associated with the Soret region alone, that spans wavelengths far more than the isolated chromophore. The supramolecular assemblies of the metalloporphyrins in solution were deposited onto highly oriented pyrolitic graphite in order to study their hierarchy in assembly by atomic force microscopy. Zero and one-dimensional aggregates were observed, and a clear dependence on deposition temperature was shown, indicating that the hierarchical assembly took place largely in solution. Moreover, scanning electron microscopy images of porphyrins and metalloporphyrins precipitated under out-ofequilibrium conditions showed the dependence of the number and position of chiral amide groups in the formation of a fibrillar nanomaterial. The combination of coordination and hydrogen bonding in the complicated assembly of these molecules -where there is a clear hierarchy for zinc(II)-pyridyl interaction followed by hydrogen-bonding between amide groups, and then van der Waals interactions -paves the way for the preparation of molecular materials with multiple chromophore environments.

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Section: Self-assembly Of Porphyrins and Metalloporphyrins In Solutionmentioning

confidence: 99%

Bottom-Up Hierarchical Self-Assembly of Chiral Porphyrins through Coordination and Hydrogen Bonds

et al. 2015

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“…13 correspond simply to gaussian fits of the calculated data. The good source of the information on the precise shape of the aggregate lines could be obtained with the coherent electron scattering (CES) approximation [38][39][40][41][42]. It is particularly useful in the case of the strong vibrational coupling that cannot be properly described by the simple electronic theory.…”

Section: Aggregation Influence On the Optical Absorptionmentioning

confidence: 99%

Molecular aspects of squaraine dyes aggregation and its influence on spectroscopic properties

Kaczmarek‐Kędziera

Kędziera

2016

Theor Chem Acc

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“…[13][14][15][16] As such, preventing dye aggregation is of key importance for designing fluorescent organic materials which employ FRET. 17,18 Perylene-diimides (PDIs) have found applications in light harvesting systems, organic electronic devices and LSCs due to their range of hues from red to violet, excellent solvent stability, high degree of chemical inertness, and superior thermal stability. [18][19][20] As expected for extended π-systems with a large quadrupole moment, PDIs are prone to forming excitation-quenching aggregates at high concentrations.…”

Section: Introductionmentioning

confidence: 99%

Energy transfer in pendant perylene diimide copolymers

et al. 2016

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We report the synthesis, characterisation and polymerisation of two novel asymmetric perylene diimide acrylate monomers. The novel monomers form a sensitiser-acceptor pair capable of undergoing Förster resonance energy transfer, and were incorporated as copolymers with tert-butyl acrylate. The tert-butyl acrylate units act as spacers along the polymer chain allowing high concentrations of dye while mitigating aggregate quenching, leading to persistent fluorescence in the solid state at high concentrations of up to 0.3 M. Analysis of fluorescence kinetics showed efficient energy transfer between the optically dense sensitiser and the lower concentration acceptor luminophores within the polymer. This reduced reabsorption within the material demonstrates that the copolymer-scaffold energy transfer system has potential for use in luminescent solar concentrators.

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The J- and H-bands of organic dye aggregates

Cited by 390 publications

References 29 publications

Bottom-Up Hierarchical Self-Assembly of Chiral Porphyrins through Coordination and Hydrogen Bonds

Bottom-Up Hierarchical Self-Assembly of Chiral Porphyrins through Coordination and Hydrogen Bonds

Molecular aspects of squaraine dyes aggregation and its influence on spectroscopic properties

Energy transfer in pendant perylene diimide copolymers

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