Growth of polygonal rings and wires of CuS on structured surfaces
Stoichiometric variants of copper sulfide have attracted interest in fields as diverse as photovoltaics and chemical sensors. By manipulating stoichiometry, crystal structure, and microstructure it is possible to tune copper sulfide's band gap. Using the self-assembly CuS as a test case, Prof. Aizenberg and colleagues demonstrate the feasibility of manipulating morphology via controlled growth of covellite-type "wires" and rings on a structured surface.
Materials and Methods
The structured surfaces were substrates with epoxy micropillars (1 mm diameter, 8 mm height, and 3 mm pitch), functionalized with 1-heptanethiol atop a layer of Pt/Pd for superhydrophobicity. CuS structures were grown by immersing substrates in an aqueous solution with various concentrations of copper sulfate and sodium thiosulfate. Self-assembly of structures was initiated from the tops of the micro pillars only, resulting in the growth of distinctive hexagonal rings and "wires". Morphology/crystallinity of the resulting structures was evaluated via SEM and XRD.
For lower concentrations, the