Disentangling the Effects of Inter- and Intra-octahedral Distortions on the Electronic Structure in Binary Metal Trioxides

Recently,
a subclass of binary perovskite-structured metal trioxides,
such as WO3 and MoO3, have been propounded for
many key optoelectronic applications due to their proper band edge
positions and appropriate band gap sizes. Unlike their superclass
perovskites, the structure–property relationship for these
binary metal trioxides is less apparent, given that they suffer from
much larger structural deformities within the octahedra. In this work,
by using first-principles density-functional theory calculations and
atomistic scale models, we examine the internal and external distortions of WO3 and
MoO3 polymorphs. We then compare our results with conventional
polyhedral distortion descriptors and finally use a refined data set
of different perovskite-structured oxides to establish and demonstrate
how these binary metal trioxides operate with a different structure–property
relationship from the conventional oxide perovskites.