Selective acetylene detection through surface modification of metal–insulator–semiconductor sensors with alkanethiolate monolayers

Palladium-based metal–insulator–semiconductor sensors were functionalized with self-assembled monolayer coatings derived from alkanethiols with 6, 12, and 18 carbons. The functionalized sensor showed enhanced response to acetylene in a hydrogen background while showing negligible response to a similar gas, ethylene. The presence of sulfur alone on the surface resulted in a small acetylene response, suggesting that palladium–sulfur bond formation plays a role in the response. However, the response of alkanethiol SAM coated sensors was five times greater, indicating that the alkyl chain also affects acetylene detection.