Alignment of molecules in Langmuir and Langmuir-Blodgett films of binary mixtures of 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylenes with a liquid crystal

Hertmanowski, Robert; Martyński, Tomasz; Bauman, Danuta

doi:10.1016/j.molstruc.2004.10.121

Cited by 23 publications

(25 citation statements)

References 36 publications

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“…6(b) and 7(b)]. As the concentration of the dye rises, small broadening of the fluorescence band at the red side appeared, especially for the dyes with short alkyl chains (1-3), similar as it was observed for the monolayer of pure 3,4,9,10-tetra-(n-alkoxy--carbonyl)-perylenes on quartz slides [8][9][10]14,15]. Thus, taking into account the shape of the fluorescence spectrum we can suggest that Y-type emission with only small contribution of E-type emission occur for LB films made of one layer of dyes 1-6 and their mixtures with arachid acid.…”

Section: Spectroscopic Studies Of Perylene-derivatives/aa Mixtures Insupporting

confidence: 58%

“…3 that all the dyes under investigation mixed with AA show A E ¹ 0. However, the deviation from an additivity rule, in comparison with the results obtained previously for dyes 2-6 mixed with the liquid crystal 8CB [10], is relatively small. This fact, together with the lack of p C changes with the mixture composition would indicate immiscibility or at most partially miscibility in the dye/AA systems.…”

Section: Surface Pressure-mean Molecular Area Isothermsupporting

confidence: 53%

“…Absorption spectra of LB films formed of 3 layers of dye/AA mixtures, similarly as LB films of the dyes themselves [9,10,14,15], show an extensive broadening and red shift of the maxima of the long-wavelength band. Moreover, the ratio of both maxima in the band is different than in the ethanol.…”

Section: Spectroscopic Studies Of Perylene-derivatives/aa Mixtures Inmentioning

confidence: 98%

“…In these spectra we observe the structureless broad fluorescence band with the maximum around 550-600 nm and, in some cases, small shoulder at shorter wavelength (»520 nm). A shape of the band depends on the length of the alkyl In our previous papers [8][9][10]14,15] we reported about the fluorescence spectra of LB films formed of dyes 2-6, pure and mixed with two liquid crystals, and supposed that the main emitters in LB films are excimers, which originate from interaction of neighbouring molecules after one is excited. Benning et al [2] have found that the maximum of the excimer fluorescence band of 3,4,9,10-tetra-(n-alkoxy--carbonyl)-perylenes in the crystalline state appears at 582-600 nm (depending on the alkyl chain length).…”

Section: Spectroscopic Studies Of Perylene-derivatives/aa Mixtures Inmentioning

confidence: 99%

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Intermolecular interactions in Langmuir-Blodget films of liquid crystalline perylene derivatives

Hertmanowski

Martyński

Stolarski

et al. 2008

Opto-Electronics Review

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Langmuir-Blodgett (LB) films formed of some discotic liquid crystals, namely 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylenes, mixed with arachid acid have been studied. The absorption and fluorescence spectra were recorded. The results obtained have led to conclusions about formation of self-aggregates of dye molecules both in ground and excited states at the air-solid substrate interface. It was found that some fraction of J-aggregates can be created in the ground state. In the excited state, mostly excimers appear and the number of this kind of aggregates depends on the length of the alkyl chains substituted to the perylene core, as well as on the dye concentration and the number of layers in LB films.

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Section: Spectroscopic Studies Of Perylene-derivatives/aa Mixtures Insupporting

confidence: 58%

Section: Surface Pressure-mean Molecular Area Isothermsupporting

confidence: 53%

Section: Spectroscopic Studies Of Perylene-derivatives/aa Mixtures Inmentioning

confidence: 98%

Section: Spectroscopic Studies Of Perylene-derivatives/aa Mixtures Inmentioning

confidence: 99%

See 2 more Smart Citations

Intermolecular interactions in Langmuir-Blodget films of liquid crystalline perylene derivatives

Hertmanowski

Martyński

Stolarski

et al. 2008

Opto-Electronics Review

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“…Close inspection shows that the orientational angle thus obtained is actually inconsistent with other studies. 102,103,105,106 Therefore, whether the same n ′ = 1.18 value is suitable for the three groups needs to be re-examined. In a recent study in our research group, using a self-consistent approach we found that the n ′ (800nm) ∼ 1.5 and n ′ (400nm) ∼ 2.5 for the -(C 6 H 4 ) 3 -CN chromophore from the SHG data, significantly different from that of the -CH 3 or -CN group, and consistent with the large polarizability of the -(C 6 H 4 ) 3 -CN chromophore.…”

Section: 77mentioning

confidence: 99%

Microscopic molecular optics theory of surface second harmonic generation and sum-frequency generation spectroscopy based on the discrete dipole lattice model

Dong¹,

Yuan²,

Liu³

et al. 2008

International Reviews in Physical Chemistry

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Two crucial issues in the interface studies with the interface specific nonlinear spectroscopy are on how to describe the macroscopic dielectric constant of the molecularly thin layer and how to calculate the anisotropic two dimensional microscopic local field effect. In the currently accepted models of the nonlinear optics, the nonlinear radiation was treated as the result of an infinitesimally thin polarization sheet layer, and a three layer model was generally employed. The direct consequence of this approach is that an apriori dielectric constant, which still does not have a clear definition, has to be assigned to this polarization layer. Because the Second Harmonic Generation (SHG) and the Sum-Frequency Generation vibrational Spectroscopy (SFG-VS) have been proven as the sensitive probes for interfaces with the submonolayer coverage, the treatment based on the more realistic discrete induced dipole model needs to be developed. Here we show that following the molecular optics theory approach the SHG, as well as the SFG-VS, radiation from the monolayer or submonolayer at an interface can be rigorously treated as the radiation from an induced dipole lattice at the interface. In this approach, the introduction of the polarization sheet is no longer necessary. Therefore, the ambiguity of the unaccounted dielectric constant of the polarization layer is no longer an issue. Moreover, the anisotropic two dimensional microscopic local field factors can be explicitly expressed with the linear polarizability tensors of the interfacial molecules. Based on the planewise dipole sum rule in the molecular monolayer, crucial experimental tests of this microscopic treatment with SHG and SFG-VS are discussed. Many puzzles in the literature of surface SHG and SFG spectroscopy studies can also be understood or resolved in this framework. This new treatment may provide a solid basis for the quantitative analysis in the surface SHG and SFG studies.

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Orientation and Polarized Optical Emission Properties of Platinum(II) Complexes in Smectic Liquid Crystals

et al. 2013

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We have prepared a series of platinum complexes with a rodlike ligand and smectic (Sm) liquid crystals (LCs) to demonstrate polarized phosphorescence. The ligands for the Pt complexes “12F2PPyO8” [2‐(4′‐dodecyl‐5′,6′‐difluorophenyl)‐5‐octyloxypyridinato‐N,C2′] and “12F2PPyO12” [2‐(4′‐dodecyl‐5′,6′‐difluorophenyl)‐5‐dodecyloxypyridinato‐N,C2′] with long alkyl and alkoxy chains exhibited the Smectic A (SmA) phase, however no liquid crystallinity was evident in Pt complexes with LC ligands. The host LCs 1‐(4‐butyl‐2,3‐difluoro‐phenyl)‐4‐(trans‐4‐pentylcyclohexyl)benzene (4F2PPCH5) and 2‐(2,3‐difluoro‐4‐hexylphenyl)‐6‐octyloxynaphthalene (6F2PNaO8) with long flexible chains showed wide SmA phase temperature ranges. Pt complex/Sm LC mixtures were oriented on rubbed polyimide substrates or by applying a magnetic field. The orientation coefficients of the magneto‐oriented samples were recorded to be over 0.6 in the Sm LC temperature range. The oriented samples exhibited polarized optical emissions assigned to the monomer and excimer states, which were perpendicular to the orientation direction. This indicates that the transition dipole moment of the Pt complex is oriented from the ligand to the Pt atom. Pt complexes with rodlike ligands with long alkyl and alkoxy chains and host Sm LC with such chains are much more likely to obtain high order parameters and generate highly polarized optical emissions. In the mixtures, the polarization ratios of the monomer and excimer in the SmA phase were estimated to be approximately 2.5–2.9 and 4.6–5.4, respectively.

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Alignment of molecules in Langmuir and Langmuir-Blodgett films of binary mixtures of 3,4,9,10-tetra-(n-alkoxy-carbonyl)-perylenes with a liquid crystal

Cited by 23 publications

References 36 publications

Intermolecular interactions in Langmuir-Blodget films of liquid crystalline perylene derivatives

Intermolecular interactions in Langmuir-Blodget films of liquid crystalline perylene derivatives

Microscopic molecular optics theory of surface second harmonic generation and sum-frequency generation spectroscopy based on the discrete dipole lattice model

Orientation and Polarized Optical Emission Properties of Platinum(II) Complexes in Smectic Liquid Crystals

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