High thermal radiation of Ca-doped lanthanum chromite

Abstract

Calcium-doped lanthanum chromite, La_1−xCa_xCrO₃, was prepared using a solid-state reaction method, and the effect of varying the Ca content (0 ≤ x ≤ 0.5) was investigated in relation to its crystalline structure, surface morphology, solar absorption and thermal radiation. This found that the crystalline structure is slightly distorted by Ca²⁺ doping, with an accompanying increase in the valence state of Cr ions and oxygen vacancies enhancing both the solar absorption and thermal emittance. Overall, the La_1−xCa_xCrO₃ system displays relatively high thermal radiation properties, with an optimal composition of La_0.5Ca_0.5CrO₃ exhibiting a solar absorption of 95% and a thermal emittance of 0.94. When used as a light absorber coupled to a thermoelectric module this proved capable of generating electricity and hot water, thereby demonstrating the suitability of this energy-saving material for use in solar thermal radiation applications.