Electronic properties, optical transparency and transport properties of the p-type transparent conductive oxide family Sn2−xPbxNb2O7 (x = 0, 0.5, 1.0, 1.5, and 2.0): a density functional theory study

Abstract

Based on density functional theory, we introduce a novel family of p-type transparent conductive oxides, Sn_2−xPb_xNb₂O₇ (x = 0, 0.5, 1.0, 1.5, and 2.0), and confirm their thermodynamic and mechanical stabilities through detailed calculations of free energy, mixing enthalpy and elastic constant. We discuss how Pb atom substitution affects the lattice structure, band structure, electronic properties, optical properties, and transport properties of materials in this family and reveal the regulatory mechanisms. The antibonding coupling of Sn–O1 and Pb–O1 contributes to the formation of p-type characteristics. The highly dispersive Sn(Pb)5s(6s) band is formed when the O2–Sn(Pb)–O2 bonding angle is close to 180°, and the large elastic constant and small deformation potential energy all contribute to the high mobility in the system. Based on the evaluation of three empirical criteria, and incorporating the computational analysis of optical and transport properties, we determined that compounds with x = 1.0 and 1.5 are excellent intrinsic p-type transparent conductive materials with high valence band maximum (VBM) positions. The elevated VBM positions in these materials pave the way for significant enhancements in p-type conductivity via acceptor doping techniques.