Effects of nitrogen dioxide on surface plasmon resonance of copper phthalocyanine langmuir-blodgett films

摘要

Surface Plasmon Resonance (SPR) measurements were conducted by using a system based on the Kretschmann configuration of the apparatus. Langmuir-Blodgett monolayers of Copper (Ⅱ) [tetrakis(3,3-dimethyl-butoxycarbonyl)] phthalocyanine deposited as the selective layer on a metal surface show changes of the reflectance on exposure of the LB films to nitrogen dioxide mixed with dry air in low concentration. This is the basis for any sensor exploiting SPR methodology. Exposure to nitrogen dioxide results in a partially reversible shift in the resonance depth and position of the SPR curves at room temperature. This is connected to the interaction of the NO_2 gas molecules with the LB layer that modifies the mean refractive index (real part) or the thickness of the film. The experimental set-up is described and preliminary results are presented together with the deposition details and optical parameters of the active layer.