A high thermoelectric figure of merit ZT > 1 in Ba heavily doped BiCuSeO oxyselenides

A high ZT value of ∼1.1 at 923 K in the BiCuSeO system is achieved via heavily doping with Ba and refining grain sizes (200–400 nm), which is higher than any thermoelectric oxide. Excellent thermal and chemical stabilities up to 923 K and high thermoelectric performance confirm that the BiCuSeO system is promising for thermoelectric power generation applications.