Solution-Processed CdS/Cu2S Superlattice Nanowire with Enhanced Thermoelectric Property.

Previously, the solution-based cation exchange reaction has been extensively studied for the synthesis of the complex heteroepitaxial nanocolloidals. Here, we demonstrated that the strain induced selective phase segregation technique can also be applied to large size nanowires in a well-studied CdS/Cu2S system, leading to the formation of superlattice nanowire structure with a simple solution-based cation exchange reaction. This structural evolution is driven by the distinct interface formation energy at different CdS facets as indicated by ab initio calculation. Because of the energy filtering effect, the superlattice nanowire shows an enhanced thermopower without significant decrease of the electrical conductivity. This study provides a promising low-cost solution process to produce superlattice nanostructures for practical thermoelectric applications.