A novel hydrogen sulfide room temperature sensor based on copper nanocluster functionalized tin oxide thin films

A novel room temperature solid-state sensor for the detection of hydrogen sulfide is described. The sensor was fabricated by first depositing a thin film of tin oxide on to a glass substrate followed by surface functionalizing with monolayer-protected copper nanoclusters (MPCs) capped with different capping agents prepared as per the Brust synthesis. These nanoclusters enhance the sensitivity of the sensor towards hydrogen sulfide. The environment of copper clusters changes after the exposure to H2S gas, allowing the access of Cu to gas molecules. This further facilitates the electron transfer between cluster to cluster and hence enhances the conductance of the sensor element. The sensitivity of copper clusters capped with different functional groups and with different chain lengths is demonstrated in this work. Such a combined sensor is easy to prepare and needs no covalent chemistry. The response time for all the samples is smaller than 2 min.