Highly Conducting Organic‐inorganic Hybrid Copper Sulfides CuxC6S6(X = 4 or 5.5): Ligand‐based Oxidation Induced Chemical and Electronic Structure Modulation

Over the past few years, conductive coordination polymers (CPs) have received emerging attention as subjects in fundamental research or as prospective candidates for a wide range of applications because of their inherent structural and functional diversity and modularity. Several successful approaches have been used to construct CPs with high conductivity. However, obtaining CPs with high conductivity is considered a stepping stone in regards to the full design of a material, the next and more crucial step is to have the capability of controlling the electronic structure to fine-tune the properties of the materials for new, unique applications. Herein, taking advantage of the non-innocent nature of benzenehexathiol (BHT) ligand and the rich coordination capability of cooper(I) ions, two novel electrically conductive CPs (Cu x C 6 S 6 , x = 4 or 5.5) derived from the same organic linker and metal node (copper(I)) have been synthesized and studied. These two Cu x C 6 S 6 s materials display not only high electrical conductivity but also feature tunable structural topology and electronic structure. The high conductivity of this material originates from the presence of necessary charge transport pathways that facilitate conductivity within the material but more interestingly, offers control of the Fermi level through modulation of the oxidation level of the non-innocent redox-active ligand. As a result, both Cu 4 C 6 S 6 and Cu 5.5 C 6 S 6 act as degenerate semiconductors with desirable band structures that make Cu 5.5 C 6 S 6 a potential candidate as a p-type thermoelectric material with a ZT value of 0.12 at 390 K, a record-breaking performance for p-type CPs. These results demonstrate the flexibility of BHT for the construction of highly conductive CPs originated from the identical starting components with tunable stoichiometric composition and electrical performance.