The Electronic Structure of Silver Oxides
Lead PI:Prof. Graeme Watson
Abstract:In the silver-oxygen system, silver is known to possess both Ag(I) and Ag(III) valence states, this giving rise to a number of different phases. Silver oxides, in particular Ag2O and AgO, have important technological applications including Zn-silver oxide batteries, fast-ion conducting glasses and a range of dermatological uses due to their bacteriostatic properties. However, a full description of the electronic structure of these oxides is lacking in the literature. In addition, all previous computational studies on these materials use a standard GGA functional. This gives rise to the band gaps of these materials being significantly underpredicted. The mixed valence oxide, AgO, also has given rise to controversy in the literature, with studies the Ag valence states to be either an Ag(I,III)O or Ag(I,II)O with synergistic holes on the oxygen atoms. This aim of this study is therefore to fully characterise the electronic structures of the dominant silver oxides, namely Ag2O, AgO and Ag2O3, using hybrid-DFT models. Initial calculations of AgO have already shown conclusively that the correct mixed valence of AgO is Ag(I,III)O. Further to this, GGA is seen to fail to correctly model the mixed valence nature, predicting a symmetric Ag(II)O structure.