Polaron formation and transport in Bi₂WO₆ studied by DFT+U and hybrid PBE0 functional approaches

Abstract

Bi2WO6 (BWO) is considered as a promising material for photocatalytic water splitting. It is unique layered structure leads the charge separation and transport is different from other materials. However, the...

s valence electrons in cations of metal oxides serving as descriptors for electron and hole polarons

“…Consistent with the aforementioned materials, using DFT+U, the electron will form a small polaron on a single W site. In Bi 2 WO 6 , the electron polaron behavior is similar as that in WO 3 reported by Tao et al 10 When small electron polarons form in HfO 2 , 39 Ta 2 O 5 , 43 NaTaO 3 , 43 WO 3 and Bi 2 WO 6 using the DFT+U approach, the formation energies are all around À0.2 eV, which indicates a stable polaron state. However, when 2D polarons form, the formation energies are around À0.05 eV, indicating that the geometric distortion to form the 2D-like polaron is much smaller than when forming the localized small polarons.…”

“…However, when using the hybrid functional, the hole will localize on a BiO 8 dodecahedron with Bi 6s and O 2p states, as reported by Kweon, Hwang, and Liu et al [7][8][9] The last example is the electron polaron in W-based materials. Tao et al 10 studied the formation of electron polarons in WO 3 and Bi 2 WO 6 (BWO) using DFT+U and hybrid PBE0 functional approaches. They found that the electron will form a small polaron on a single W stie using the DFT+U approach with U added to the W 5d state.…”

“…Tao et al . 10 studied the formation of electron polarons in WO 3 and Bi 2 WO 6 (BWO) using DFT+ U and hybrid PBE0 functional approaches. They found that the electron will form a small polaron on a single W stie using the DFT+ U approach with U added to the W 5d state.…”

Electron and Hole Polaron Formation and Transport in Monoclinic WO3 Studied by Hybrid Functional Approach

“…In the CBM, the contribution of W 6s orbital is usually ignored. However, in our previous paper, we demonstrated that it has an important role in charge carriers localized to small polarons. s orbitals are delocalized in nature and small polarons are localized in nature, which could be the reason for the observation of a 2D-shaped polaron in experiment.…”

Unexpected Two-Dimensional Polarons Induced by Oxygen Vacancies in Layered Structure MoO3–x

“…Moreover, it is found that the 2D large polarons are critical for maintaining the structural stability of O′-MoO 3−x . Our results contribute to the basic understanding of the better performance for the carrier mobility and Li and H storage in reduced MoO 3 3,40,41 and provide a reference for optimizing the physical and chemical properties of molybdenum oxides in real applications, e.g., FET, pseudocapacitors, superconductors, 34…”