Highly Conducting Organic-Inorganic Hybrid Copper Sulfides Cux C6 S6 (x=4 or 5.5): Ligand-Based Oxidation-Induced Chemical and Electronic Structure Modulation.

Abstract

Conductive coordination polymers (CPs) have potential in a wide range of applications because of their inherent structural and functional diversity. Three electrically conductive CPs (Cux C6 S6 , x=3, 4 or 5.5) derived from the same organic linker (benzenehexathiol) and metal node (copper(I)) were synthesized and studied. Cux C6 S6 materials are organic-inorganic hybrid copper sulfides comprising a π-π stacking structure and cooper sulfur networks. Charge-transport pathways within the network facilitate conductivity and offer control of the Fermi level through modulation of the oxidation level of the non-innocent redox-active ligand. Two Cux C6 S6 (x=4 or 5.5) CPs display high electrical conductivity and they feature a tunable structural topology and electronic structure. Cu4 C6 S6 and Cu5.5 C6 S6 act as degenerate semiconductors. Moreover, Cu5.5 C6 S6 is a p-type thermoelectric material with a ZT value of 0.12 at 390 K, which is a record-breaking performance for p-type CPs.