Selectivity enhancement using mesoporous silica thin films for single walled carbon nanotube based vapour sensors

Vapour sensors based on single walled carbon nanotubes (SWCNT) networks offer a high sensitivity but poor selectivity. Different works were undertaken, with varying degrees of success, to overcome this drawback. In this context, we develop a new selective sensor architecture based on a SWCNT network covered with a mesoporous silica film elaborated by sol–gel process. The topological and chemical characteristics of this sensor are obtained by TEM, SEM, EDX, contact angle and electrical measurements. We demonstrate that highly polarised molecules are stopped by the silica layer while other molecules like NO2 can diffuse easily in the mesoporous silica layer to reach the SWCNT network without increasing the response time.