Effect of Octahedral Distortion on Temperature-Dependent Dynamic Emissivity Behavior in Sc-doped LaFeO3

Materials with temperature-dependent dynamic emissivity are of utmost interest in self-adaptive intelligent applications. The effects of microstructure change in the process of dynamic emissivity remains to be clarified. In this paper, temperature-dependent dynamic emissivity behavior of lanthanum ferrite (LaFeO3) is studied. The correlation between optical properties and microstructure is investigated by both experiment and calculation. The influences of Sc-doping level on the morphology, band gap, lattice vibration, emissivity properties, electronic structure and structure units of Sc-doped LaFeO3 are discussed. The emissivity change of La0.875Sc0.125FeO3 reaches 0.35 in wavelengths from 3 to 5 mu m as the temperature is increased from 25 degrees C to 270 degrees C. The interaction between band gap and lattice vibration energy, which originates in the distortion of the FeO6 octahedron, leads to temperature-dependent dynamic emissivity behavior in Sc-doped LaFeO3. The mechanism of emissivity in the aspect of microstructure will provide an insight for emissivity modulation in variable emissivity materials.