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  • 1
    Electronic Resource
    Electronic Resource
    Langmuir-Blodgett films of indandione-1,3 pyridinium betaine. I: Preparation, electronic structure, optical properties (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 319-330 
    Details
    ISSN: 1057-9257
    Keywords: Amphiphilic indandione-1,3 pyridinium betaine derivatives ; Langmuir-Blodgett films ; Simulation of electronic structure ; Optical properties ; Second-harmonic generation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The synthesis of a new polar amphiphilic derivative of indandione-1,3 pyridinium betaine (IPB) with different lengths of the aliphatic tail, containing 11 (C11IPB) and 17 (C17IPB) carbon atoms respectively, is described. The electronic structure (charge distribution, energy spectra, dipole moments in ground and excited states) of the IPB molecule has been calculated in the framework of the MO CNDO methods. Studies of compression π-A isotherms of these compounds show that C17IPB forms two stable phases of monolayer on the water surface, one in the 10-30 mN m-1 and the other in the 35-50 nM m-1 surface pressure region. The corresponding areas A0 per molecule are 37 and 33 Å2 respectively. Techniques for the preparation of Langmuir-Blodgett (LB) multilayers of C17IPB in the high-pressure region (π = 40 mN m-1) on glass, quartz or sapphire substrates are described. C17IPB forms LB multilayer films of Z-type configuration with oriented dipole moments. Ellipsometric data, luminescence spectra and results of preliminary studies of second-harmonic generation in these LB films are presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860020607
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Langmuir-Blodgett films of indandione-l,3 pyridinium betaine. II: Molecular structure and properties of monolayers; simulation and optical absorption data (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 4 (1994), S. 27-41 
    Details
    ISSN: 1057-9257
    Keywords: Amphiphilic indandione-1,3 pyridinium betaine derivatives ; Langmuir-Blodgett monolayers ; Monolayer spectral characteristics ; Simulation of molecular structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The molecular structure and optical properties of a monolayer at the air/water interface of novel amphiphilic derivatives of indandione-1,3 pyridinium betaine (IPB) with different lengths of the aliphatic tail, namely C1lIPB and C17IPB, have been studied using optical absorption techniques and computer simulation approaches.The compression π-A isotherm of the C17IPB monolayer and computer simulation of its molecular structure show that there may exist two energetically stable molecular configurations, one with antiparallel orientation of the dipole moments of the C17IP ‘heads’ in the low-pressure region at π = 5-32 mN m-1 and the second (after a distinct phase transition at π = 33 mN m-1) with parallel orientation of the dipoles, with different tilt angles and areas per molecule. For C11IPB only the first structural phase is observable.The compression-induced changes in spectral characteristics of the two structural phases go in diametrically opposite directions. In the low-pressure phase compression induces a red shift and an increase in intensity of the S1 absorption band, while in the high pressure phase a blue shift and a decrease in the intensity of this band are observed. These spectral changes correlate reproducibly with the compression π-A isotherms. Measurements of absorption dichroism confirm the change in the tilt angle at the phase transition pressure. The compression-induced spectral changes have been substantiated by the results of quantum chemical calculations.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860040105
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  • 3
    Electronic Resource
    Electronic Resource
    Langmuir-Blodgett films of indandione-1,3 pyridinium betaine. III: Linear dichroism and non-linear optical properties (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 6 (1996), S. 39-50 
    Details
    ISSN: 1057-9257
    Keywords: amphiphilic indandione-1,3 pyridinium betaine ; Langmuir-Blodgett films ; monolayers ; linear dichroism ; non-linear optical properties ; second-harmonic generation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Linear dichroism and second-harmonic generation (SHG) have been measured in Langmuir-Blodgett (LB) multilayers of Z-type structure of amphiphilic indandione-1,3 pyridinium betaine (IPB) with an aliphatic tail containing 17 carbon atoms (C17IPB). The dichroic ratio As/Ap of electronic absorption of s- and p-polarised light and the SHG intensity show that the ‘heads’ of C17IPB molecules are predominantly oriented along the deposition direction of monolayers on a quartz substrate. Orientation parameters and mean statistical azimuthal and tilt angles are evaluated as a function of the number of monolayers. The SHG efficiency has been measured in C17IPB monolayers on a water surface as a function of surface pressure. The effective hyperpolarisability β of the IPB molecule has been determined experimentally in a chloroform solution by the hyper-Rayleigh-scattering method. The obtained value of β = (138 ± 16) × 10-30 esu is in good agreement with theoretical estimates.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Visible fluorescence on IR excitation of polar dimethylaminobenzylidene 1,3-indandione crystals (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 221-232 
    Details
    ISSN: 1057-9257
    Keywords: Dimethylaminobenzylidene ; 1,3-indandione crystals ; Non-linear optical effects ; Electronic structure ; Absorption and luminescence spectra ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: A novel non-linear fluorescence (NLF) effect in polar dimethylaminobenzylidene 1,3-indandione (DMABI) crystals is presented and discussed. A single crystal or vacuum-evaporated layer of DMABI excited in the IR region at 1064 nm (by a Q-switched YAG laser) emits red light in the visible region of the spectrum at 600-740 nm depending on the DMABI crystalline modification. This anti-Stokes luminescence shows a quadratic dependence on the exciting light intensity which transforms to a linear dependence at very high excitation intensities. The observed NLF effect under IR excitation is determined by optical transitions into intermolecular charge transfer (CT) states. It has been suggested that the photoexcited singlet 1CT excitations may either interact in a quadratic singlet-singlet (1CT + 1CT) annihilation reaction or, more probably, form long-lived triplet 3CT excitons via a hyperfine interaction effect which may subsequently annihilate in a similar bimolecular fusion reaction (3CT + 3CT). In both cases the excited molecular singlet state S1 is formed and thus the NLF effect is due to singlet-singlet or triplet-triplet fusion of CT excitons. A detailed energy diagram and kinetic description of the model are presented. Quantum chemical calculations of the electronic structure of the DMABI molecule illustrate the dipolar nature of its ground and excited states.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860020503
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Charge carrier trapping states in thin evaporated and Langmuir-Blodgett organic films (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 6 (1996), S. 283-287 
    Details
    ISSN: 1057-9257
    Keywords: space-charge-limited current ; thermally modulated space-charge-limited current ; charge carrier trapping states ; organic molecular thin films ; Langmuir-Blodgett multilayers ; phthalocyanines ; indandione pyridinium betaine-1,3 ; dimethylamino-benzylidene indandione-1,3 ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Thermally modulated space-charge-limited current (TM-SCLC) and conventional SCLC methods have been used to determine the energy parameters of the local charge trapping states for three heterocyclic organic compounds in two different structural states  -  as thin vacuum-evaporated layers and Langmuir-Blodgett (LB) multilayer films. The TM-SCLC method provides higher resolution and accuracy of trap depth (Et) determination with error not greater than ± 0.02 eV. In sandwich-type samples Me/organic layer/Me of metal-free phthalocyanine (α-H2Pc), five sets of hole trapping states are determined in the energy range from 0.55 to 0.07 eV; for dimethylamino-benzylidene indandione-1,3 (DMABI) samples also, five sets of trapping states are detected in the 0.5-0.28 eV range; however, for indandione pyridinium betaine-1,3 (IPB) samples, only a very shallow set of traps at Et ≈ kT emerged. In the case of evaporated layers the conductivity activation energy (Ea) dependence on voltage energy (U), Ea = Ea(U), decreases in a step-like manner, every step giving the trap depth Et of the corresponding set of trapping states. In the case of LB multilayers of vanadyl phthalocyanine (VOPc) and IPB films the Ea = Ea(U) dependences are of complex, oscillatory-type character, possibly caused by a spatially non-uniform trap distribution in the bulk of the sample.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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