Gas Sensitivity of Some Nanoparticles Ensembles in Porous Glass

Abstract

The importance of substances’ surface development suitable for sensor technology by dispersing them to the level of nanoparticles’ ensemble within a certain matrix has been demonstrated. It has been proven that the best matrix for the formation of the specified ensemble of nanoparticles is porous silicate glass. Methods of formation of ensembles of nanoparticles of some compounds in porous glass are briefly considered. The applicability of the mentioned systems for sensors is demonstrated by the example of their luminescent response sensitivity to the presence of ammonia or HCl vapours in the environment.

Properties of silica porous glasses with the nanoparticle ensembles of some compounds

“…Residual silica gel particles in the images corresponding to A and C glasses look like white spots. In C type glass they are larger, in B type glasses they are almost imperceptible (this confirms that the leaching technique leads only to the depletion of glass by silica gel [4,11]), and in type D glasses they do not exist at all.…”

“…Therefore, substitution cannot occur at position "1", because it will destroy the molecule. The results obtained in [4] show that the dye molecules have no intramolecular bonds (at least hydrogen ones), so the tautomeric forms are invariant with respect to the reading direction of carbon atoms in the benzene ring of the hydrazide fragment. Therefore, the dyes in which the substitution took place at position "2" or at position "6" are completely equivalent and have the same photoluminescence spectra.…”

“…This etchant interacts enough quickly with finely divided silica gel and acts much more slowly on solid (at least porous) matrix walls. Due to this, most of the silica gel is removed, while the walls of the matrix skeleton are only slightly etched [4,11]. The type A glass treated in this way is conventionally called the type B glass, and the type C glass is called the type D glass.…”

“…The solvent does not affect the energy of the radiation, but, depending on the solvent absorbency, can affect its intensity. As demonstrated in [4,13], the absorption capacity of the standard organic chemistry solvent dimethylformamide (CH3)2NCO, which is usually abbreviated as DMFA, is the lowest, so it is in it that dyes based on tetravalent tin complexes glow most intensely. But the dye molecules in the solution are separated from the environment by the vessel and, with the exception of those on the surface of the solution, passivate each other.…”

“…Thus, porous silicate glass perfectly meets the requirements for the matrix, but it does not exist in nature. However, it can be obtained from two-phase sodiumboron-silicate glass by a not very sophisticate technology [4].…”