Significantly Enhanced Infrared Emissivity of LaAlO ₃ by Co‐Doping with Ca ²⁺ and Cr ³⁺ for Energy‐Saving Applications

Abstract

In this study, Ca 2+ –Cr 3+ co‐doped LaAlO 3 , a novel energy‐saving material with significantly enhanced infrared emissivity, was synthesized by solid‐state reaction. The experimental results demonstrated that 20 mol% Ca 2+ and 10 mol% Cr 3+ ‐doped LaAlO 3 , namely La 0.8 Ca 0.2 Al 0.9 Cr 0.1 O 3 , 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 LaAlO 3 . The first‐principles electronic structure calculations revealed that the Ca 2+ –Cr 3+ co‐doping results in the occurrence of impurity energy levels in the forbidden band of LaAlO 3 , which were mainly composed of the Cr 3 d orbitals. Electrons partly occupied these impurity donor states and significantly reduced the energy bandgap, thus the infrared radiation property of LaAlO 3 was enhanced. This novel material with high infrared emissivity shows promising applications for energy‐saving in the field of thermal process equipment.