Assessment of the thermoelectric performance of layered semiconductor SrFCuTe with wide band-gap

The concept of "phonon-glass, electron-crystal" promotes the development of designing thermoelectric compounds through building functional blocks. Alternately stacking insulating [Sr2F2](2+) layers and conductive [Cu2Te2](2-) layers along the c-axis can construct wide-band-gap semiconductor SrFCuTe with the ZrCuSiAs-type structure. The thermoelectric characterization reveal that this compound has considerably low p-type conductivity and thermal conductivity. Na substitution Sr can significantly improve the electrical transport properties due to the acceptor-doping effect, while it increases the electronic thermal conductivity simultaneously. The synergistic effect makes the thermoelectric figure of merit zT rise about 100% at 773 K. This work demonstrates that wide-band-gap semiconductors undergoing rational performance manipulation, worthy of reassessing for thermoelectric application.