Organic covalent modification to improve thermoelectric properties of TaS₂

Organic semiconductors are attracting considerable attention as a new thermoelectric material because of their molecular diversity, non-toxicity and easy processing. The side chains which are introduced into two-dimensional (2D) transition metal dichalcogenides (TMDs) by covalent modification lead to a significant decrease in their thermal conductivity. Here, we describe a simple approach to preparing the side chains covalent modification TaS₂ (SCCM-TaS₂) organic/inorganic hybrid structures, which is a homogeneous and non-destructive technique that does not depend on defects and boundaries. Electrical conductivity of 3,401 S cm^-1 and a power factor of 0.34 mW m^-1 K^-2 are obtained for a hybrid material of SCCM-TaS₂, with an in-plane thermal conductivity of 4.0 W m^-1 K^-1, which is 7 times smaller than the thermal conductivity of the pristine TaS₂ crystal. The power factor and low thermal conductivity contribute to a thermoelectric figure of merit (ZT) of ~0.04 at 443 K.