Experiment and simulation of infrared emissivity properties of doped LaAlO3

In this study, LaAlO3 doped with Sr/Co/Mn was prepared by sol-gel method, with its infrared (IR) radiative properties and variation mechanism investigated by X-ray powder diffraction, X-ray photoelectron spectroscopy, IR, scanning electron microscopy. Meanwhile, the electronic band structure was simulated by Cambridge Serial Total Energy Package. The conclusions are as follows: the order of emissivity in the near-IR band is La0.67Sr0.33Al0.67Mn0.33O3> La0.67Sr0.33Al0.67Co0.33O3> LaAl0.67Mn0.33O3> LaAl0.67Co0.33O3> LaAlO3. In 0-2.5 mu m at room temperature, the emissivity of La0.67Sr0.33Al0.67Mn0.33O3 can reach 0.9504. The emissivity increase mechanism lies in the further free carrier absorption caused by numerous small polarons formed by the Sr-Mn co-doping and increased concentration of electron-oxygen vacancies. Meanwhile, the Sr-Mn co-doping causes lattice distortion and strengthens the lattice vibration absorption. The band gap of La0.67Sr0.33Al0.67Mn0.33O3 is 0.910 eV, much smaller than 3.445 eV of LaAlO3, favorable to the valence band electron transition, generating more electron-oxygen vacancy pairs and promoting free carrier absorption. La0.67Sr0.33Al0.67Mn0.33O3 conduction band migrates to the lower energy region, while Mn3d impurity energy level appears. Thanks to the band gap reduction, dielectric function imaginary peaks, and absorption coefficient peaks are red-shifted. Due to its high emissivity, La0.67Sr0.33Al0.67Mn0.33O3 has a high utilization value and broad potential application.