Influence of the precursor nature and deposition mode on the oxygen sensing properties of Ru(II) complex immobilized in a SiO2-based matrix

Films are deposited by dip- or spin-coating in gels produced from tetraethoxysilane (TEOS), octyltriethoxysilane (OtEOS) or mixtures of TEOS and OtEOS (mole ratio1:1) as well as TEOS and methyltriethoxysilane (MtEOS) (mole ratio 1:3). The Stern-Volmer constants and the response to oxygen of Ru(II)-tris(4,7-diphenyl-1,10-phenathroline) dichloride immobilized in the produced matrices are calculated. The oxygen sensitivity of the film depends on the chemical nature of the precursors, the Ru(II) concentration, the film deposition technology, and the film thickness. The uncertainty of the results obtained with films of different production batches varies between 1.5% and 3% of the measured value for oxygen content for gas mixtures between 10% and 90% oxygen content. The sonication of the sol has a strong positive effect on the sensitivity of the films and the linearity of the calibration curves.