One-dimensional CuO–SnO2 p–n heterojunctions for enhanced detection of H2S

Abstract

Highly crystalline SnO2 nanowires were synthesized and functionalized with copper particles in a CVD using Sn(OBut)4 and [CuII((C5H4N)(CHCOCF3))2]2 (1) as precursors respectively. Controlled oxidation of Cu to CuO led to the formation of CuO@SnO2 p–n heterojunctions, which were found to be highly sensitive and selective towards the detection of H2S gas. The change in the conductance upon exposure to H2S gas was attributed to the formation of CuS resulting in the shrinkage of the space charge region along the SnO2 nanowire and a concomitant increase of the conductivity channel in an individual nanowire.