Thermoelectric p‐Type Iron‐Based Ethylenetetrathiolate Coordination Polymers

ABSTRACT Here we demonstrate high room‐temperature Seebeck coefficient of 95 µV K −1 in combination with ultralow thermal conductivity of 0.18 W m −1 K −1 for a novel bimetallic p‐type semiconducting coordination polymer. We synthesize the (Fe, Cu) bimetallic coordination polymer together with the single‐metal Cu and Fe counterparts using 1,3,4,6‐ tetrathiapentalene‐2,5‐dione (TPD) as the organic ligand. The resultant poly[metal‐ethylenetetrathiolate] materials are characterized by XPS (X‐ray photoelectron spectroscopy) and Mössbauer spectroscopy techniques for the copper and iron metal oxidation states and with PPMS (physical property measurement system) for electronic and thermal transport properties in the temperature range of 100–350 K. The heterobimetallic effect in poly[(Fe, Cu)‐ETT] is best appreciated regarding the enhanced Seebeck coefficient. We foresee that the present p‐type poly[(Fe, Cu)‐ETT] thermoelectrics could be a promising counterpart for the previously more widely investigated n‐type conducting polymers.