Comparison of the defective pyrochlore and ilmenite polymorphs of AgSbO3 using GGA and hybrid DFT

Abstract

Silver antimonate, AgSbO3, in both its defective pyrochlore and ilmenite structural polymorphs, has been suggested as a possible candidate mixed metal oxide for use in the photocatalytic splitting of water in visible light. In this study, we report electronic-structure calculations, using both standard and hybrid density-functional-theory approaches, on both structural forms of AgSbO3 to fully characterize the band structure and composition of the valence and conduction bands. Analysis of conduction properties and optical absorption is also used to compare the predicted properties of the two materials. Results show that the valence band is dominated by O 2p and Ag 4d states, whereas the conduction band is composed mainly of Ag and Sb 5s states. Band-edge effective-mass calculations indicate the materials operate via an n-type mechanism, with conduction properties being comparable for the two materials. The fundamental and optical band gaps are also predicted to be compatible with visible light adsorption.