Significantly Enhanced Infrared Emissivity of LaAlO3 by Co‐Doping with Ca2+ and Cr3+ for Energy‐Saving Applications

Abstract

In this study, Ca2+–Cr3+ co‐doped LaAlO3, a novel energy‐saving material with significantly enhanced infrared emissivity, was synthesized by solid‐state reaction. The experimental results demonstrated that 20 mol% Ca2+ and 10 mol% Cr3+‐doped LaAlO3, namely La0.8Ca0.2Al0.9Cr0.1O3, had an infrared emissivity as high as 0.92 in the spectral region of 1–5 μm, which was 12 times higher than that of pure LaAlO3. The first‐principles electronic structure calculations revealed that the Ca2+–Cr3+ co‐doping results in the occurrence of impurity energy levels in the forbidden band of LaAlO3, which were mainly composed of the Cr 3d orbitals. Electrons partly occupied these impurity donor states and significantly reduced the energy bandgap, thus the infrared radiation property of LaAlO3 was enhanced. This novel material with high infrared emissivity shows promising applications for energy‐saving in the field of thermal process equipment.