Predictions of electronic structures and optical performance of potential near infrared absorber Sn0.33WO3

Abstract

For better synthesis and development of novel WO3-based near infrared absorbing materials for smart-window applications, the structural, electronic, and optical properties of hexagonal Sn0.33WO3 were investigated through the first-principles calculation. The optimized crystal structure parameters agree well with experimental values. The electronic structure shows that when Sn ions are doped in the host hexagonal WO3, Sn0.33WO3 displays a typical n-type electronic conductivity, which leads to an upshift of the Fermi energy to the conduction band. It was found that Sn0.33WO3 exhibits low reflectivity and weak absorption in the visible region, while exhibiting strong reflectivity and absorption in the near infrared light region. Therefore, it significantly reduces the optical transmittance of infrared wavelengths (down to 3.9% for the compacted film and 25.3% for the coated film), while maintaining fair optical transparency for visible wavelengths. This research indicates that Sn0.33WO3 is a prospective near infrared absorber and it can be used as near infrared shielding filters for smart windows with high transparency for visible light.