Lanthanum doped BaPbO₃ with consistent low infrared emissivity over diverse temperature ranges

AbstractMaintaining low infrared emissivity in materials over a broad temperature range is crucial for practical applications, yet it presents significant challenges. In this study, BaPbO₃, known for its relatively high electrical conductivity and weak positive temperature coefficient, was chosen as a candidate for low infrared emissivity material. To further reduce its infrared emissivity, Lanthanum (La3+) was doped into BaPbO₃. This doping increased conductivity by enhancing the free carrier concentration through charge compensation and electron injection into the conduction band. Additionally, La3+ doping improved the overlap between Pb and O orbitals, resulting in highly curved energy bands crossing the Fermi level, which endowed the free carriers with high mobility. The enhanced electrical conductivity induces a pronounced plasma effect, leading to low infrared emissivity. As a result, 10 mol% La3+ doped BaPbO₃ exhibits emissivity of 0.311 at room temperature and 0.309 at 600 °C in the 3–5 μm band. This study provides a theoretical basis for designing materials with low infrared emissivity and wide temperature stability.