Thermoelectric power studies of bismuth oxide and mixed oxides based on bismuth oxide

This paper reports a thermoelectric power study of pure bismuth oxide (BiO3), and preliminary measurements for two novel materials which have been reported as good oxygen ion conductors, namely bismuth vanadium oxide (Bi4V2O11) and copper-doped bismuth vanadium oxide (Bi2V0.925Cu0.075O.3875). The measurements for delta-Bi2O3 allowed a reliable estimate to be made of the heat of transport for oxygen ions which provide evidence for a complex mechanism of ionic migration in this system. For the other two materials the work suggests that reducing the oxygen partial pressure modifies the defect and/or electronic structures and merits further investigation.