Poly(nickel-ethylenetetrathiolate) and Its Analogs: Theoretical Prediction of High-Performance Doping-Free Thermoelectric Polymers.

It is generally deemed that doping is a must for polymeric materials to achieve their high thermoelectric performance. We herein present the first report that intrinsically metallic behaviors and high-performance thermoelectric power factors can coexist within doping-free linear-backbone conducting polymers, poly(nickel-ethylenetetrathiolate) and its analogs. On the basis of density functional calculations, we have corroborated that four crystalline π- d conjugated transition-metal coordination polymers, including poly(Ni-CS), poly(Ni-CSe), poly(Pd-CS) and poly(Pt-CS) exhibit intrinsically metallic behavior arising from the formation of dense intermolecular interaction networks between sulfur/selenium atoms. They show moderate carrier concentrations (10-10 cm) and decent conductivities (10-10 S cm), among which, poly(Ni-CS), poly(Ni-CSe) and poly(Pd-CS) possess high power factors (∼10 μW m K).