Amphiphilic dyes for nonlinear optics: Dependence of second harmonic generation on functional group substitution

Bubeck, Christoph; Laschewsky, André; Lupo, Donald; Neher, Dieter; Ottenbreit, P.; Paulus, Wolfgang; Praß, Werner; Ringsdorf, Helmut; Wegner, Gerhard

doi:10.1002/adma.19910030111

Cited by 48 publications

(27 citation statements)

References 16 publications

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“…It can be seen from Table 1 that the tilt angles Q of chromophores are 42 and 36u for BPOM and BPO LB monolayer films, respectively, relative to the normal of the substrate, which is similar to those obtained from films of the hemicyanine halides, such as PO (35u). 10,18 We can suggest that the possible orientation of BPO is as shown in Scheme 3. It is known that BPOM (or BPO) has a center of symmetry in the molecule when the two D-p-A chomophores take the trans-configuration relative to the CH 2 group (as shown in Scheme 1), and that cannot yield SHG according to the principle of second-harmonic nonlinear optics.…”

Section: Shg Properties Of the Dyes Filmsmentioning

confidence: 99%

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Huang

Jin

et al. 2001

J. Mater. Chem.

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Novel amphiphilic stilbazolium dye dimers, bis{[1-(N-methylpyridinium-4-yl)-2-(3-methoxy-4octadecyloxyphenyl)]ethenyl}methane diiodide (BPOM) and bis{[1-(N-methylpyridinium-4-yl)-2-(4octadecyloxyphenyl)]ethenyl}methane diiodide (BPO) were synthesized, and they were successfully transferred onto semiconducting transparent indium-tin oxide (ITO) as H-aggregates by Langmuir-Blodgett (LB) techniques. The photocurrent generation properties of monolayer films of these dyes were investigated in a traditional three-electrode cell. A steady cathodic photocurrent was obtained upon excitation of the dye LB monolayer films deposited on an ITO electrode. The observed photocurrent generation quantum yield strongly depended on the applied electrode potential, concentration of the redox couples in the electrolyte solution, and the chemical structure of the dye congeners. The dye monomers, (E)-N-methyl-4-[2-(3methoxy-4-octadecyloxyphenyl)ethenyl]pyridinium iodide (POM) and (E)-N-methyl-4-[2-(4octadecyloxyphenyl)ethenyl]pyridinium iodide (PO) as the standards for comparison were also studied. Datashow that the photocurrent generation quantum yields are 0.35% and 0.26% for BPOM and BPO, respectively, while those for POM and PO are 0.19% and 0.11%, respectively. From the photoelectrochemical measurement, the enhanced photocurrent generation properties in the dimer compared with those in the corresponding monomer were observed.

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Section: Shg Properties Of the Dyes Filmsmentioning

confidence: 99%

Untitled

Huang

Jin

et al. 2001

J. Mater. Chem.

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“…Much of the recent interest has focused upon LB film-forming stilbazolium dyes of general formula R-Y -C6H4-CH=CH-C5H4N+-R /X-, where R-Y is the donor group (Y = O, S, NH, or NR), X-is the counterion and either R or R' is a hydrophobic alkyl chain; their properties are dependent upon the donor (Bubeck et al 1991), the extent of aggregation (Schildkraut et al 1988;Girling et al 1987) and the counterion (Young et al 1989;Ashwell et al 1992a;Liu et al 1992). The SHG from monolayer films of stilbazolium dyes may be slightly enhanced by using iodide instead of bromide, whereas a greatly improved signal has been realized by using the amphiphilic octadecylsulphate anion (Ashwell et al 1992a), the second harmonic intensity being typically 20-30 times the signal from films of the corresponding bromide.…”

Section: Introductionmentioning

confidence: 99%

Second harmonic generation from alternate-layer LB films: quadratic enhancement with film thickness

Ashwell

Jackson

Lochun

et al. 1994

Proc. R. Soc. Lond. A

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The second harmonic generation (SHG) from alternate-layer Langmuir-Blodgett (LB) films of stilbazolium dyes and 4, 4'-dioctadecyl-3, 5, 3', 5'-tetramethyldipyrryl-methene hydrobromide increases as I 2ω(N) = l 2ω(1) N 2 for N ≥ 2 bilayers, but the equivalent monolayer signal ( I 2ω(1) ) is significantly less than the intensity from LB monolayers of the corresponding dye on glass. This is attributed, in part, to the different molecular tilts and, in part, to the position of the anion which influences the charge distribution within the chromophore. For alternate-layer films of E-N-octadecyl-4-[2-(4-dimethylaminophenyl)ethenyl]pyridinium octadecylsulphate (dye I) the second-order susceptibility and chromophore tilt angle are χ (2) zzz = 45 pm V -1 and ϕ = 30° respectively, whereas the methoxy congener, E-N-octadecyl-4-[2-(4-methoxyphenyl)ethenyl]pyridinium octadecylsulphate (dye II), has χ (2) zzz = 11 Pm V -1 and ϕ = 35°. The nonlinear optical properties of such films are dependent upon the compatibility of the dye and spacer.

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“…The average tilt angle φ is the angle between the surface normal and the dipole of the chromophore; it can be calculated from eq 1 [34][35][36] where I stands for the intensity of output light beam, subscript 2ω represents the second harmonic generation output, and superscript p-p, and s-p represent the relationship between the polarities of input and output light beams. Here, we find that the average tilt angles of the dipole of M, B5, and B12 are all about 30°, whereas the tilt angle of the dipole of B3 is about 40°, indicating that compared with the LB films of other dyes the chromophores in the B3 LB film are less perpendicular to the substrate surface.…”

Section: Molecular Design and Synthetic Proceduresmentioning

confidence: 99%

Photophysical Studies on the Mono- and Dichromophoric Hemicyanine Dyes I. Photoelectric Conversion from the Dye Modified ITO Electrodes

Huang¹,

Cheng²,

Li³

et al. 2002

J. Phys. Chem. B

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Stilbazolium dimers were designed and synthesized in which methylene groups of different lengths link the two chromophores. The second-order nonlinear optical property has been detected from their LangmuirBlodgett monolayers. Photocurrent generation as well as other photophysical properties such as absorption and fluorescence were investigated. Comparing the dimers with the stilbazolium monomer, we found strong second harmonic generation (SHG) signals and remarkable enhanced photoelectric conversion (PEC) quantum yields from 1,3-BisThe structures of the Langmuir-Blodgett films of these dyes are assumed. Although these dimers are center-symmetric (or quasi-center-symmetric) molecules, they can form the ordered non-center-symmetric (in normal direction) monolayer by the compress force and the molecular interaction between the amphiphilic dye molecules and the water molecules at the air/water interface. The influences of bias, donor/acceptor, soluble oxygen, and light intensity to photocurrent generation were studied; our results provide a new perspective to improve the performance of functional molecular material without any change of the chemical structure of the chromophore itself.

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Amphiphilic dyes for nonlinear optics: Dependence of second harmonic generation on functional group substitution

Cited by 48 publications

References 16 publications

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Second harmonic generation from alternate-layer LB films: quadratic enhancement with film thickness

Photophysical Studies on the Mono- and Dichromophoric Hemicyanine Dyes I. Photoelectric Conversion from the Dye Modified ITO Electrodes

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