Mesoporous ZnS Thin Films Prepared by a Nanocasting Route

Mesoporous metal chalcogenides (e.g., ZnS, CuS, and derived mixed sulfide or selenides) show an extremely high potential in technological areas like catalysis, sensors, environmental protection, and photovoltaics. Although chemical bath deposition methods allow obtaining stable and porous metal chalcogenide films under mild and simple conditions, the reproducible preparation of highly ordered mesoporous sulfide thin films has been challenging so far. Herein, we present a simple and efficient synthetic method to prepare ZnS mesoporous thin films using a combination of a nanocasting approach and a successive ionic layer adsorption and reaction (SILAR) process for the infiltration. A mesoporous silica thin film, prepared by evaporation induced self-assembly (EISA), serves as the hard exotemplate for the formation of the mesostructured zinc sulfide. After selective etching of the silica framework, a stable and porous ZnS thin film is obtained, which replicates the pore structure of the hard template. A thorough combination of characterization techniques is used to assess the exotemplating process as well as the template removal.