Density functional theory study of different metal dopants influence on the structural and electronic properties of a tetragonal α-PbO

In this work, using the Quantum ESPRESSO package, density functional theory was used to study the effects of different metal dopants on the structural and electronic properties of tetragonal α-PbO. Tetragonal α-PbO has attracted attention due to its application in various optoelectronic devices. However, in order to apply it in these technologies suitably, its properties have to be improved since it has low electronic conductivity. In this study, nine different metals from alkali metals, p-block metals, and 3d-transition metals have been used as dopants to investigate its electronic properties. Moreover, the performance of four pseudopotentials was tested. Via the partial density of state and band structure calculations, an indirect bandgap was found for pristine α-PbO. The generalized gradient approximation of the Perdew–Burke–Ernzerhof exchange correlation with ultrasoft pseudopotential gives 1.75 eV for pristine α-PbO, which decreased during the incorporation of different metal dopants. Depending on the position of the Fermi level and impurity energy level in metal doping, the n- or p-type conductivity has been identified. The calculated partial density of states shows the contribution of orbital states of dopants to the partial density of states. The valence band maximum is mainly made of O-2p states whereas the conduction band minimum is dominated by Pb-6p states in undoped α-PbO. The calculated lattice constants were a = b = 3.997 Å and c = 5.220 Å, which are in best agreement with the experimental values. The computational study verified that doping various metals had a significant effect on the structural and electronic properties of α-PbO.