Dye/zeolite ensembles for optical sensing applications: Vapor detection in nanopores.

摘要

The aim of this work is to combine the shape selectivity of zeolites with the chemical sensitivity of solvatochromic dyes, which has been explored for the application of size selective vapor sensing. Solvatochromic dyes are extremely sensitive to their surrounding environment and display large wavelength shifts in visible and fluorescence spectra reflecting changes in polarity.; The solvatochromic dyes Nile Red, Copper(II)(tetramethylethylenediamine) (acetylacetonate)+ and Coumarin 153, have been included into various siliceous and conventional aluminosilicate zeolites. Approaches such as inclusion synthesis, ion exchange as well as direct adsorption into zeolite hosts have been explored for dye encapsulation. Characterization methods included IR, visible diffuse reflectance and fluorescence spectroscopy, mass spectrometry and X-ray diffraction. Dramatic, reversible shifts in the absorbance and fluorescence spectra in the presence of various analytes, in bulk zeolite powders, as well as thin film samples have been demonstrated. By restricting chromophores into zeolite hosts, specificity towards various molecules, as well as size selectivity has been demonstrated.