Optical characterization of sol–gel derived Nb2O5 thin films

Vapor Responsive One-Dimensional Photonic Crystals from Zeolite Nanoparticles and Metal Oxide Films for Optical Sensing

“…The Nb sol was prepared by a sonocatalytic method using NbCl 5 (99%, Aldrich, St. Louis, MO, USA) as a precursor according to the recipe in [14,21]: NbCl 5 (0.400 g) was mixed with ethanol (8.3 mL, 98%, Sigma-Aldrich) and distilled water (0.17 mL). The solution was subjected to sonication for 30 min and aged for 24 h at ambient conditions prior to spin coating [14].…”

“…The solution was subjected to sonication for 30 min and aged for 24 h at ambient conditions prior to spin coating [14]. Thin Nb 2 O 5 films were deposited by dropping of 0.3 mL of the coating solution on both the pre-cleaned Si substrates and pre-cleaned optical glass plates, then spinning at a rate of 2500 rpm for 30 s was carried out.…”

“…, 500 nm in the current case. In order to achieve the correct thicknesses of the films, the concentrations of the zeolite suspension and Nb sol were optimized by addition of appropriate amount of solvent-ethanol [10,14]. An annealing of the films at 320 °C for 30 min was applied after deposition of the MEL nanozeolite.…”

“…MEL type zeolite nanocrystals are used for both the sensing and transducing elements, while a sufficient optical contrast is ensured by sol-gel derived Nb 2 O 5 film [14]. Nb 2 O 5 is a high refractive index material and could be assembled in thin film form by simple methods [14].…”

“…MEL type zeolite nanocrystals are used for both the sensing and transducing elements, while a sufficient optical contrast is ensured by sol-gel derived Nb 2 O 5 film [14]. Nb 2 O 5 is a high refractive index material and could be assembled in thin film form by simple methods [14]. Besides, recently we have reported that Nb 2 O 5 could be successfully used as a high refractive index building block of a vapor responsive Bragg stack that comprises MFI zeolite as sensing element [15].…”