Effect of poling in Polymers Containing Azobenzene Push–Pull Chromophores on nonlinear optic of second and third order

International audienc

Features of the alkynyl ruthenium chromophore with modified anionic subsystem UV absorption

Theoretical simulation of UV–vis absorption for a new series of alkynyl ruthenium chromophores spectra and investigations the influence of anionic substituence on a spectral shift of UV absorption was presented. The MM+ molecular force field method was used for total energy minimization and for building of the molecular optimized geometry [S.J. Weiner, P.A. Kollman, D.A. Case, U.C. Ghio, G. Alagona, J.S. Profeta, P. Weiner, J. Am. Chem. Soc. 106 (1984) 765; S.J. Weiner, P.A. Kollman, D.T. Nguyen, D.A. Case, J. Comput. Chem. 7 (1986) 230]. All quantum chemical calculations were performed by semi-empirical ZINDO/1 method within a framework of the restricted Hartree–Fock approach and convergence limit up to 10−6 eV after 500 iterations was achieved. Good agreement between the theoretically calculated and experimentally measured spectra was observed. The largest spectral shift in position of absorption peaks was observed for compound containing the anionic (Cl), substituent. The theoretically calculated absorption maximum is blue shifted with respect to the experimental spectra for all compounds what is connected with the changes of the charge transfer determining the corresponding state dipole moments. Analysis of the theoretical spectra shows a substantial sensitivity to the backside groups

Photoinduced Gratings in Functionalized Azo-Carbazole Compounds in Picosecond Regime

We report results of diffraction grating inscription on thin films prepared from epoxy resin doped with azo-carbazole based dyes. Diffraction gratings were recorded at the wavelength 532 nm and monitored through intensity of first order of diffraction (632 nm). Atomic force microscope scans of the gratings show that a surface relief grating also appeared

Photoluminescence studies of selected styrylquinolinium thin films made using thermal evaporation deposition technique

In this paper we present a photoluminescence (PL) study of new styrylquinolinium dyes. We made a comparative study of the luminescent properties of thin films grown on quartz substrates using thermal evaporation deposition method. Investigated films show PL emission from the violet to near-IR region at room temperature

Nonlinear optical characterization of functionalized organometallic complexes using THG and Z-scan techniques

We report the measurements of third-order nonlinear optical (NLO) properties in picosecond regim of functionalized organometallic complexes using third harmonic generation (THG) and Z-scan techniques. We show the results obtained for solutions dissolved in dichloromethane with different concentrations. For each chromophore, we give the values of: the nonlinear absorption coefficient β, the nonlinear refractive index n2, the third-order nonlinear susceptibility χ 3 and the second-order nonlinear hyperpolarisability γ of individual molecules. This approach allowed us to determine also the electronic and rotational contributions of χ 3 by using a picosecond laser Nd:YAG at the fundamental wavelength 1064 nm

NLO properties of new stryquinolinium dye thin films deposited by pulsed laser deposition

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Large nonlinear optical properties of new styrylquinolinium dye thin films deposited by pulsed laser deposition

Date du colloque&nbsp;: 09/2011</p

Novel Styrylquinolinium Dye Thin Films Deposited by Pulsed Laser Deposition for Nonlinear Optical Applications

The nonlinear optical (NLO) properties of novel styrylquinolinium dye thin films for photonic applications have been studied by the Z-scan, second harmonic generation (SHG), and third harmonic generation (THG) techniques, providing both the second- and third-order nonlinear optical parameters. The styrylquinolinium dye (E)-1-ethyl-4-(2-(4-hydroxynaphthalen-1-yl)vinyl)quinolinium bromide was synthesized by the Knoevenagel condensation, and its structure and physicochemical properties were determined by H-1 NMR, C-13 NMR, FTIR, UV-vis spectroscopy, and elemental analysis. Functional thin films were deposited by pulsed laser deposition (PLD) using UV TEA N-2 laser onto glass substrates and KCl, NaCl monocrystals at room temperature and vacuum at 10(-3) mbar/0.1 Pa. Further characterization of the films and target from native material by FTIR spectroscopy revealed that there was no difference between the deposited films and the initial material. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements have been also performed in order to provide information about the morphology and topology of the thin films

Effect of KNO3 to remove silver interferences in the determination of mercury(II): Application in milk and breast milk samples

Mercury determination was performed at rotating silver electrode (RSE) using square wave voltammetry (SWV) in electrolytic mixture of HCl (0.1 mol L−1) and KNO3 (0.2 mol L−1). The reproducibility, sensitivity and accuracy are good, provided the proper instrumental parameters and supporting electrolyte are used. The relationship between the peak current of mercury(II) and its concentration is linear with regression equation: I(μA) = 0.784 [Hg(II)] + 49.5 (r2 = 0.9878) in the dynamic range from 1.0 × 10−7 to 8.0 × 10−4 mol L−1. The detection limit (DL,3σ) and quantification limit (QL,10σ) were 4.61 × 10−8 mol L−1 and 15.3 × 10−8 mol L−1, respectively. The relative standard deviation (RSD) for seven replicate analysis of a solution containing 5.0 × 10−5 mol L−1 was 2.19%. Possible effects of Cu, Co, Fe, MnO4, Zn, were investigated but did not cause any significant interferences. Immobilization of mercury(II) on the surface of rotating silver electrode obeyed to the Langmuir adsorption isotherm. The calculated ΔG°ads value showed that the interaction between mercury and silver electrodes is mainly controlled by a chemisorption process. This methodology was potentially applied for mercury determination in milk and breast milk samples

Electrochemical growth and physico-chemical characterization in organic medium of Nb2O5 thin films

Investigations about the energetics and the electrical properties of niobium thin film, electrochemically grown, were performed in an organic solution of acetonitrile and lithium perchlorate. The study of the energetics of the Nb O /organic solution interface was performed by means of a non-destructive optical technique, photocurrent 2 5 spectroscopy. By means of this technique, it was possible estimating the value of the flat band potential and locating conduction and valence band. A more cathodic value of flat band potential in respect with acidic solution was found in organic medium. From impedance spectra, the electrical circuit that gives best fitting values is constituted by two resistances in parallel with two constant phase elements and in series with the resistance of the electrolyte. On considering the exponential coefficient, the constant phase elements model distorted capacitances