DFT study of electronic, optical, and thermodynamic properties of the 2D shape of Bi4O6 structure

Abstract

We investigate the electronic, optical, and thermal characteristics of the two-dimensional Bi${}_4$O${}_6$ structure using first-principles calculations. The excellent thermal stability of Bi${}_4$O${}_6$ is confirmed through molecular dynamics simulations at 300 K. The large band gap indicates that Bi${}_4$O${}_6$ behaves as a semiconductor in which the O-$p$ and Bi-$p$ states dominate in the valence band and the conduction band, respectively. The existence of a flat band indicates the localization of the O-$p$ state. The dielectric constant, refractive index, absorption, and optical conductivity are calculated among other important optical characteristics. The optical characteristics provide a robust response in the ultraviolet and edge visible spectrum, indicating the promise of Bi${}_4$O${}_6$ for advanced optical applications. We have successfully calculated the Seebeck coefficients and electrical conductivity at low temperatures, which enables the determination of the power factor value. The high Seebeck and robust power factor confirm its effectiveness in thermoelectric energy converter technology. Moreover, the rise in entropy and heat capacity plateaus at higher temperatures, pointing to a shift into a less ordered phase despite retaining effective thermal energy absorption. The Bi${}_4$O${}_6$ has an extraordinarily low lattice thermal conductivity. Based on its favorable characteristics, Bi${}_4$O${}_6$ is well-suited for future applications in energy conversion technologies and optoelectronics.