Electronic, optical and photocatalytic properties of three-layer perovskite Dion–Jacobson phase CsBa₂M₃O₁₀(M = Ta, Nb): a DFT study

Abstract

The structure, electronic and optical properties have been studied to consider photocatalytic activity of three-layer perovskite Dion-Jacobson phase CsBa 2 M 3 O 10 (M = Ta, Nb) using the density functional theory (DFT) method with the plane-wave pseudo-potential in the frame of the GGA proposed by Perdew, Burke, and Ernzerhof (PBE). CsBa 2 Ta 3 O 10 and CsBa 2 Nb 3 O 10 are indirect band gap semiconductors with different type of M-O bonds from pure covalent to pure ionic. According to the symmetry breaking of MO 6 octahedra from O h point group to centrosymmetric (D 4h ) and non-centrosymmetric (C 4v ) point groups, the generation of local internal fields, the promotion of electron-hole pairs separation in the very initial process of photo-oxidation and the improvement in photocatalytic activity are suggested. Site and angular projected density of states for CsBa 2 M 3 O 10 show that the valence and conduction bands are made mainly of O and M orbitals, therefore the presence of dipole moment at the MO 6 octahedra will play an important role in separating of electrons and holes. According to the optical properties simulation the origin of interband transitions for CsBa 2 Ta 3 O 10 and CsBa 2 Nb 3 O 10 are from O-p and M-d orbitals. CsBa 2 Ta 3 O 10 and CsBa 2 Nb 3 O 10 are UV-light-responsive photocatalysts with plasmon energies 13.16 and 12.07 eV, respectively, which can possibly oxidize/decompose organic pollutants and generate hydrogen from water splitting.

First-principles study on ZnV2O6 and Zn2V2O7: Two new photoanode candidates for photoelectrochemical water oxidation

“…The calculated equilibrium lattice constants are satisfactory consistent with the experimental data indicating the reliability of our DFT-based calculations. The existing discrepancy between the experimental values and the present theoretical values are usually caused by intrinsic approximations in the exchange-correlation functional and differences in the conditions of experimental (at room temperature) and theoretical (at 0 K) measurements [34].…”

First-Principles Investigations of the Structure, Electronic, and Optical Properties of Mullite-Type Orthorhombic Bi2M4O9 (M = Al3+, Ga3+)

“…Differences between the theoretical and experimental values are caused by intrinsic approximations in the exchange−correlation functional and differences in the conditions of experimental (at 300 K) and theoretical (at 0 K) measurements. 26 Structural results show that the computational method and parameters used in this work are reasonable. It should be noted that the results of the GGA-PBE method have been acceptable for the prediction of structural and electronic properties of another member of mullite-type orthorhombic Bi 2 M 4 O 9 (Bi 2 Fe 4 O 9 ).…”

“…The calculated equilibrium lattice parameters are satisfactory in comparison with the experimental data. ,, The maximum and minimum deviation of lattice parameters are 2.7% and 0.2%, respectively. Differences between the theoretical and experimental values are caused by intrinsic approximations in the exchange–correlation functional and differences in the conditions of experimental (at 300 K) and theoretical (at 0 K) measurements . Structural results show that the computational method and parameters used in this work are reasonable.…”

“…The real part of the dielectric function at zero frequency shows that the static dielectric constant for Bi 2 Al 4 O 9 and Bi 2 Ga 4 O 9 is 3.17 and 3.36, respectively. The negative values of the real part of the dielectric function in the energy range from 6.65 to 11.31 eV for Bi 2 Al 4 O 9 and 6.04 to 10.92 eV for Bi 2 Ga 4 O 9 are due to destruction of the electromagnetic wave, and zero values show that longitudinally polarized waves are possible. , In the imaginary part of the dielectric function there are two peaks located at 5.72 and 13.68 eV for Bi 2 Al 4 O 9 , whereas the positions of these peaks for Bi 2 Ga 4 O 9 are at 5.07 and 13.57 eV. The main peak for Bi 2 Al 4 O 9 and Bi 2 Ga 4 O 9 corresponds mainly to the interband electronic transition from O 2p­(VB) to Bi 6s­(CB).…”

Effective masses, electronic and optical properties of (111)-layered B-site deficient hexagonal perovskite Ba5M4O15(M = Ta, Nb): a DFT study using HSE06

“…The real part of dielectric function in the energy range from 7 to 12 eV is negative because of damping of electromagnetic wave 46. Color legends: total DOS in black, s orbitals in blue, p orbitals in red, and d orbitals in green.…”