Investigation of chromophore orientation of 2-docosylamino-5-nitropyridine and derivatives by nonlinear optical techniques

Bosshard, Ch.; Küpfer, M.; Flörsheimer, M.; Borer, T.; Günter, Peter; Tang, Qian; Zahir, S.

doi:10.1016/0040-6090(92)90209-t

Cited by 18 publications

(5 citation statements)

References 8 publications

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“…Docosyl homologues of hemicyanine and 2-amino-5-nitropyridine are used as amphiphile adsorbates, as they are able to give rise to LB supramolecular structures with nonlinear optical properties and, consequently, are commonly used in the preparation of waveguides − …”

Section: Introductionmentioning

confidence: 99%

SERS and Molecular Orientation in Langmuir−Blodgett Films Deposited onto Smooth Copper Surfaces

et al. 1996

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Surface-enhanced Raman spectroscopy was applied to the investigation of a hemicyanine dye and a 2-amino-5-nitropyridine derivative as Langmuir−Blodgett layers deposited onto smooth copper surfaces. Raman spectra of neat materials, thin layers, and LB films on Cu surfaces are reported. SERS enhancement was achieved by using colloidal silver. Orientation of the molecules in the LB films and interactions with the metal substrate are discussed.

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Section: Introductionmentioning

confidence: 99%

SERS and Molecular Orientation in Langmuir−Blodgett Films Deposited onto Smooth Copper Surfaces

et al. 1996

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“…The results are reported elsewhere 26 . Bossard et al examined LB films of the amino nitropyridine derivatives C m H 2m+1 -NH-C 5 H 3 N-NO 2 with alkyl chains of different length ranging from m = 18-26 29 . They concluded that maximum SHG intensity is reached for 2-docosylamino-5-nitropyridine (DCANP).…”

Section: Lb Layer Preparation and Characterisationmentioning

confidence: 99%

“…They investigated the influence of slightly different chemical "heads". Both groups used the transmission SHG method for tensor element evaluation 25,29 which is not possible to be used for non-transparent substrates (like silicon).…”

Section: Lb Layer Preparation and Characterisationmentioning

confidence: 99%

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Phase-matched second harmonic generation and nonlinear phase shift in a Langmuir-Blodgett film waveguide

Schrader

Flueraru

Motschmann

et al. 2001

Linear and Nonlinear Optics of Organic Materials

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Wave-guides have been prepared as y-type Langmuir-Blodgett multilayers from 2-docosylamino-5-nitropyridine (DCANP) on quartz glass substrates. The tensor elements of the LB-films as determined by polarisation dependent second harmonic generation (SHG) are χ (2) yyy = 18.6 pm/V, χ (2) yxx = 1.5 pm/V, χ (2) yzz = 6.4 pm/V (± 20%). The wave-guides were fabricated in a way that the second-order susceptibility changes sign at the nodal plane of the first-order wave-guide mode for spolarisation. In such wave-guides efficient second harmonic generation (SHG) was reached via mode conversion at a fundamental wavelength near 1064 nm. The conversion efficiency reached the extraordinary high value of 8%/W which corresponds to a normalised conversion efficiency of 3600 %/(W cm 2 ). In addition, interferometric measurements have been carried out to study the non-linear phase-shift which the fundamental beam experiences due to non-linear interaction in the wave-guide. From these experiments an apparent intensity-dependent refractive index n 2 SHG of 2,6 10 -13 cm 2 /W was calculated. This as about 400 times the intensity-dependent refractive as expected from third-order susceptibility of the isotropic material. From that it can be concluded that the main contribution of the intensity-dependent refractive index is connected to cascading of second-order processes.

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“…As a consequence, in an anisotropic medium, the effect of the local field is to alter the direction of the transition moments so that they do not correspond with those of an equivalent set of well-separated molecules. As pointed out by several authors, , the problem of taking into account local field effects in evaluating molecular parameters is not a simple task. − The Lorentz−Lorenz local field expressions are likely to be invalid for ordered Langmuir−Blodgett (LB) systems, where more detailed calculations are required − We show in particular, that the reflectance spectra of a thin uniaxial film lying on a substrate could be understood by considering the elements of a single tensor: the electric surface susceptibility tensor (γ), which is related simply to the density of the induced dipoles per unit area.…”

Section: Introductionmentioning

confidence: 98%

Investigation of the Molecular Organization in Langmuir−Blodgett Films Using Polarized Infrared Spectra: Comparison of Two Methods

et al. 1997

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We compare two methods for obtaining structural information on Langmuir-Blodgett films from polarized infrared spectroscopy. For sufficiently uniform films, we have already shown (refs 11 and 12) that all polarized spectroscopic properties could be characterized by a single quantity that we call the "electrical surface susceptibility tensor", γ . The imaginary parts of the susceptibility tensor could be readily obtained from reflectance measurements with the electric field parallel (Im(γ t)) and perpendicular (Im(γn)) to the plane of the film, independently of any specific properties of the film. This, in turn, could be related to the characteristics of individual molecules comprising the film, and their geometric disposition if the molecules are assumed to be interacting dipoles, which corrects, to a large extent, for the local field effects. We report the results of an infrared study performed on a dipalmitoylphosphatidylethanolamine monolayer. Attenuated total reflection spectra for both s and p polarization were recorded, and the spectra of Im(γ t) and Im(γn), as well as those of the imaginary part of the refractive index (kt and kn), are presented. Finally, the information deduced from the Im(γx) and kx (x ) s, p) are compared, and the molecular orientation is discussed both in terms of Im(γx) and kx. We show that by using this approach one obtains more truthworthy measurements of the disposition of oriented molecules at surfaces than those obtained from absorption coefficients.

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Investigation of chromophore orientation of 2-docosylamino-5-nitropyridine and derivatives by nonlinear optical techniques

Cited by 18 publications

References 8 publications

SERS and Molecular Orientation in Langmuir−Blodgett Films Deposited onto Smooth Copper Surfaces

SERS and Molecular Orientation in Langmuir−Blodgett Films Deposited onto Smooth Copper Surfaces

Phase-matched second harmonic generation and nonlinear phase shift in a Langmuir-Blodgett film waveguide

Investigation of the Molecular Organization in Langmuir−Blodgett Films Using Polarized Infrared Spectra: Comparison of Two Methods

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