Functionalization of APTES modified tin dioxide gas sensor

Summary In the present work, commercial SnO2 powder was used for sensor thick film fabrication. The film was produced using screen printing technology. The SnO2 functionalization was done with 3-aminopropyltriethoxysilane (APTES) in liquid phase as an intermediate step, followed by functionalization using hexanoyl chloride exhibiting an alkyl end functional (CH3) group. The SnO2 sensor modified with alkyl end group was found to be sensitive to ammonia gas at 100°C. The advantages are the reduction of the power consumption by decreasing the operating temperature, and the enhancement of the selectivity and sensitivity to the gas with respect to pure SnO2 sensor. Motivation Molecularly modified metal oxide gas sensors have shown to be promising devices for selective gas sensor related to disease diagnosis. Those sensors can be used to detect the gas emanated from the human body for breath analysis application. Tin dioxide sensors have lack of selectivity and work at high temperature (350-500°C). The need of selective sensors with high sensitivity at low gases concentration pushes us to modify SnO2 sensing element in order to change its interactions with gas. The modification with organic functional groups with different polarities change the sensor response to specific gases depending on their polarity. A SnO2 functionalization based on APTES combined with hexanoyl chloride was investigated. Another objective is to reduce the power consumption by decreasing the operating temperature.