In 4 Sn 3 O 12 - metastable semiconducting metal oxide for gas sensing applications

One of the main problems of semiconducting metal oxide based gas sensors in real life applications is their lack of selectivity and cross interferences from secondary analytes and background gases such as water vapor. To overcome these drawbacks one is able to employ either different/new types of materials or add small quantities of noble metals. In this case a metastable material was synthesized and characterized by means on phenomenological DC resistance measurements and complementary operando approaches such as DRIFTS and work function measurements. It is shown that the material exhibits a high sensitivity for analytes of the aldehyde family, whereas the cross sensitivity to permanent gases such as H2, CO and methane is very low. Furthermore a sensing mechanism for formaldehyde is conducted. All results are reflected to commonly used SnO2. Furthermore flame spray pyrolysis is presented as a way to be able to generate metastable materials and directly employ the method to fabricate sensors in a one single step approach, being ready for sensor mass production.