Ellipsometric and surface plasmon resonance effects on LB films of organic materials in controlled atmosphere.

1R. Rella, 1P. Siciliano, 2L. Valli, 2L. Vasanelli

1 Istituto per lo studio di nuovi Materiali per l’Elettronica IME – CNR via Arnesano, 73100 Lecce (Italy)

2 Dipartimento di Scienza dei materiali, Universita’ di Lecce, Via per Arnesano 73100 Lecce (Italy)

Langmuir-Blodgett (LB) films of Cu(II) tetrakis-(3,3-dimethyl-1-butoxicarbonyl)phthalocyanine have been studied as regard their optical property. In particular electronic spectra in the UV-VIS spectral range and the optical constant of the LB multilayers have been carried out. In order to use these LB films as optical gas sensors, ellipsometric and surface plasmon resonance (SPR) measurements were carried out in controlled atmosphere. SPR measurements were conducted by using a system based on the Kretschmann configuration. LB monolayers of Cu(dmbc)Pc deposited as selective layer on a metal surface show changes of the reflectance on exposure to nitrogen dioxide mixed with dry air in low concentration. Moreover, ellipsometric measurements carried out on LB multilayers of Cu(dmbc)Pc deposited onto silicon substrates, have shown variation at a fixed wavelength in the thickness and complex refractive index when are exposed to different concentrations of toluene and tetrachloroethene.

Keywords: Lamgmuir-Blodgett; Optical properties, Chemo-Optical Sensors