title: Synthesis and enhanced humidity detection response of nanoscale Au-particle-decorated ZnS spheres.
abstract: We successfully prepared Au-nanoparticle-decorated ZnS (ZnS-Au) spheres by sputtering Au ultrathin films on surfaces of hydrothermally synthesized ZnS spheres and subsequently postannealed the samples in a high-vacuum atmosphere. The Au nanoparticles were distributed on ZnS surfaces without substantial aggregation. The Au nanoparticle diameter range was 5 to 10 nm. Structural information showed that the surface of the annealed ZnS-Au spheres became more irregular and rough. A humidity sensor constructed using the Au-nanoparticle-decorated ZnS spheres demonstrated a substantially improved response to the cyclic change in humidity from 11% relative humidity (RH) to 33% to 95% RH at room temperature. The improved response was associated with the enhanced efficiency of water molecule adsorption onto the surfaces of the ZnS because of the surface modification of the ZnS spheres through noble-metal nanoparticle decoration.
authors.affiliation: Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan.
authors.forename: Yuan-Chang
authors.initials: YC
authors.lastname: Liang
authors.affiliation: Institute of Materials Engineering, National Taiwan Ocean University, Keelung 20224, Taiwan.
authors.forename: Shang-Luen
authors.initials: SL
authors.lastname: Liu
keywords: Nanoparticle; Structure; Sulfide; Surface modification