Synthesis, structural characterisation and thermoelectric properties of Bi_1-xPb_xOCuSe

The effect of Pb2+ doping on the structure and thermoelectric properties of BiOCuSe (also known as BiCuSeO or BiCuOSe) is described. With increasing Pb2+ content, the expansion of the unit cell results in a weakening of the bonding between the [Bi(2(1-x))Pb(2)xO(2)](2(1-x)+) and the [Cu2Se2](2(1-x)-) layers. The electrical resistivity and Seebeck coefficient decrease in a systematic way with growing Pb2+ levels. The thermal conductivity rises due to the increase of the electronic contribution with doping. The power factor of materials with a 4- 5% Pb2+ content takes values of ca. 8 mu W cm(-1) K-2 over a wide temperature range. ZT at 673 K is enhanced by ca. 50% when compared to values found for other dopants, such as Sr2+ or Mg2+.