First-Principles Investigation of photo-induced structural change of WO₃

The visible light region accounts for approximately 40% of the energy of solar radiation. Therefore, tungsten oxide, which is the visible light-driven photocatalysts, has been receiving much attention. It is known that photoexcited tungsten oxide has long-lived photocarriers, which have an important role in photocatalytic reactions. In a recent study, the dynamics of photoelectrons and structural changes of tungsten oxide has been observed by femtosecond transient XAFS. They have found that the electronic state was the first to change followed by the local structure, which was affected within 200 ps of photoexcitation. However, little is known about how the structure changes and how it affects the photocarrier. Therefore, in this study, tungsten oxide was investigated by performing first-principles calculations based on density functional theory and many-body perturbation theory. We discuss the light absorption related by excitation, photoexcited carriers, and structural changes from electronic, optical, phonon, electron-phonon properties, et cetra.