Vapor Responsive One-Dimensional Photonic Crystals from Zeolite Nanoparticles and Metal Oxide Films for Optical Sensing
Résumé
The preparation of responsive multilayered structures with quarter-wave design
based on layer-by-layer deposition of sol-gel derived Nb2O5 films and spin-coated MEL
type zeolite is demonstrated. The refractive indices (n) and thicknesses (d) of the layers are
determined using non-linear curve fitting of the measured reflectance spectra. Besides, the
surface and cross-sectional features of the multilayered structures are characterized by
scanning electron microscopy (SEM). The quasi-omnidirectional photonic band for the
multilayered structures is predicted theoretically, and confirmed experimentally by
reflectance measurements at oblique incidence with polarized light. The sensing properties
of the multilayered structures toward acetone are studied by measuring transmittance
spectra prior and after vapor exposure. Furthermore, the potential of the one-dimensional
photonic crystals based on the multilayered structure consisting of Nb2O5 and MEL type
zeolite as a chemical sensor with optical read-out is discussed.
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