Sol-Gel for Gas Sensing Applications

Francioso L, Russo M, Taurino AM, Siciliano P (2006) Micrometric patterning process of sol-gel SnO, In Oj and WO thin film for gas sensing applications towards silicon technology integration. Sens Actuators B Chem 119 159-166... 

The use by Avnir and co-workers (21) of excited-state dynamics of pyrene-doped sol-gel materials to probe the interior of the sol-gel environment has helped pave the way for similar smdies with luminescent probes such as [Ru(bpy)3] (14). From an applications standpoint, the attributes of [Ru(bpy)3] (Section lll.D.2.b) make this metal complex a particularly good O2 sensor. The matrix can have an enormous effect on O2 diffusibility to the doped sensor depending on the conditions of synthesis. The sensing ability of [Ru(bpy)3] " is probably best suited for gas-phase O2 as the molecule has been shown to leach from sol-gels under solution conditions (146). A typical optically based O2 sensing device using such a system is shown in Fig. 23 (143). 

Experiments have shown that other types of gas sensors can also use mesoporous silicas as the sensing layer. For example, selective sensing of nitric oxide has been accomplished in the presence of carbon monoxide through the application of quartz crystal microbalance technology employing a cobalt phthalocyanine-modified sol-gel thin film (Palaniappan et al. 2006,2008). Electrochemical detection of nitrite has been accomplished using a metalloporphyrin-modified silicate material... 

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