The Effect on the Gas Selectivity of CNT-Based Gas Sensors by Binder in SWNT/Silane Sol Solution

We investigated that CNT-based gas sensors could be sensitized selectively by changing binders contained in SWNTs/silane sol solution. To do this, we fabricated CNT-based gas sensors that consisted of a SWNTs/silane hybrid thin film deposited by multiple spray-coating, and we examined the electrical response for alcohol vapor gas from the sensor which is applicable to an alcohol breath analyzer. Generally, silane binders are mixed in CNT solution to adhere CNTs to substrates well, and they can be easily functionalized to each group on the surface of CNTs after they are hardened by way of the hydrolysis reaction. Therefore, the response property to a special gas will be changed if the binder in the solution is different. Here, we compared the effect of TEOS with MTMS as a binder. As a result, we observed that the resistance in the sensors using TEOS decreased dramatically while it decreased scarcely in the sensors using MTMS for increasing alcohol concentrations.