Doping induced structural transformation in tungsten trioxide

Effects of dopants on structural stability of monoclinic WO3 were studied using density functional theory. Transformation from monoclinic to cubic crystal structures was obtained by gradually increasing doping concentrations of both rhenium (Re) and electrons inside the monoclinic WO3, whereas a large distortion of WO6 octahedra was observed by gradually increasing doping concentrations of both niobium (Nb) and holes inside the monoclinic WO3. It was verified that RexW1-xO3 has a cubic structure if x is larger than 0.375, and the transformation from monoclinic to cubic structure is mainly dependent on the occupancy of the W 5d orbital. The elastic characteristics of the RexW1-xO3 decrease with the increase of the content of Re in the range of 0.375 ≤ x ≤ 0.875.