Ionic conductivity of Pb and Co-substituted Bi2VO5.5 single crystal

A single crystal of Bi1.94Pb0.06V0.9Co0.1O5.32, in which the Bi and V sites of later-structured Bi2VO5.5 were substituted simultaneously, was prepared for the first time and the effects of the Pb substitution on the conductiv ities in a (b)- and c-axis directions were investigated. Any improvements o f ionic conductivity along c-axis perpendicular to the (Bi2O2)(2+) layer wa s not observed compared with that in single crystal without Pb substitution . From the results of conductivity and Rietveld refinement of XRD pattern, oxygen vacancies generated by Pb substitution were suggested to locate in t he pseudo-perovskite block, not in the (Bi2O2)(2+) layer.