6533b7d5fe1ef96bd1264f61

RESEARCH PRODUCT

Spectroscopic Investigations Of LB Mono- And Multilayers Of 2-docosylamino 5-nitropyridine; Promising Candidates For Non-linear And Integrated Optics

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Alkylamino-5-nitropyridineshavemently been introduced forthepreparation of a novel type of non-centrosymmetric Langmuir-Blodgett (LB) multilayer (1,2). Hitherto, second order non-linear optical investigations have been resmcted toLB-films oftwomaterialsinaltematinglayerstructureand to films of a single material with head to tail arrangement of the molecules, both of whicharedifficulttoobtain (seerefs. quotedin 1 and2.1. Incontrast,allpresent data indicate that LB-filmsof 2-aUcylamino-5-nitropyridines are head-to-head and tail-to-tail (Y-type) multilayers with a rather strong tilt-angle of the alkyl chains (Fig. I). The most effective substance for second order non-linear optical experiments is 2-docosylamino-5-nitropyridine (DCANP), where the squareroot of SH-intensity increases linearly with the layer thickness up to the micronrange (1,2). Inordertovalidate that thenon-centrosymmetry oftheLB- multilayers is a true property of the LB-film and thus of the deposition process we have investigated monolayers of DCANP on the water surface by UV/Vis- spectroscopy.