Temperature and Oxygen Sensing Properties of Ru(II) Covalently-Grafted Sol–Gel Derived Ormosil Hybrid Materials

Abstract

In this article, oxygen and temperature-sensing hybrid materials consisting of [Ru(Phen)3]2+ portions covalently-grafted onto the sol–gel derived ormosil network were prepared by co-condensation of tetraethoxysilane (TEOS) using n-octyltriethoxysilane as the network modifier. For comparison purposes, the hybrid materials in which [Ru(Phen)3]2+ were conventionally physically-incorporated into the matrix were also prepared. The obtained hybrid materials were characterized by Fourier transform infrared (FT-IR), luminescence intensity oxygen quenching Stern-Volmer plots, temperature quenching plots and excited-state lifetime. The near linear Stern-Volmer plots can be attributed to the approximate heterogeneous environment of the luminophore within the ormosil materials. The results reveal that the covalently-grafted sample is more sensitive to O2, and has a higher sensing sensitivity and a higher thermal activation energy compared to the physically-incorporated one, since these Ru(II) molecules are strongly covalently-grafted onto the Si–O network via the CH2–Si bonds and less –OH group.