Heteroatom-doping effects on high-temperature infrared emission of (LaPr)2Ce2O7 ceramics

Manipulating thermal radiation through electromagnetic waves while maximizing heat transfer efficiency is critical for energy conservation and thermal protection in high-temperature environments. In this study, a series of heteroatom-doped (LaPr)₂Ce₂O₇ ceramics are synthesized, with a defect fluorite structure, exhibiting differential infrared radiation properties over a broad spectrum. In particular, doping with low-valence transition metals (Cu and Co) introduces impurity levels and oxygen vacancies, effectively reducing the intrinsic bandgap and increasing emissivity at wavelengths below 6 μm. Meanwhile, the mismatched properties in mass and ionic radius between the dopants and host atoms increase the asymmetry of the lattice structure, which is beneficial for long-wavelength emissivity (>6 μm). The infrared emissivity of (LaPrCu)₂Ce₂O₇ reaches 0.870 across a broad wavelength range from 0.78 μm to 16 μm, surpassing that of pristine (LaPr)₂Ce₂O₇. This enhancement is attributed to the effective collaboration of impurity absorption, free carrier absorption, and lattice absorption. More importantly, the achieved near black-body thermal emissivity at 1300 °C is suitable for applications in high-temperature thermal radiation. In contrast, the introduction of rare-earth elements (Gd and Ho) has a small impact on infrared emissivity due to their similar characteristics to La³⁺ and Pr³⁺. Our findings provide a valuable reference for achieving high-performance infrared emission in rare-earth cerates through doping engineering.