Control of solar absorbance and thermal emittance of Cr-doped Sm0.5Sr0.5CoO3

• Sm0.5Sr0.5Co1−xCrxO3 can be used as a controlled near-infrared reflective inorganic oxide.
• Sm0.5Sr0.5Co1−xCrxO3 was prepared by solid-state reaction.
• Effects of Cr3+ doping on crystal structure and electrical conductivity were found.
• Solar absorbance, infrared emittance can be controlled by Cr3+ dopant concentration to meet various demands.

A new application of Sm0.5Sr0.5Co1−xCrxO3 as a controlled near-infrared reflective inorganic oxide has been developed. Samples were prepared by a solid-state reaction to form a perovskite solid solution with an orthorhombic structure. Then, the effect of Cr3+ cation doping on the crystal structure, electrical conductivity, solar absorbance, and thermal emittance properties of the Sm0.5Sr0.5Co1−xCrxO3 was investigated. The electrical conductivity decreases upon the substitution of Cr3+ ions for Co3+/Co4+ because of the appearance of Cr3+–O2−–Cr3+ and Co3+–O2−–Cr3+ units, reducing the amount of the Co3+–O–Co4+ network. The Cr3+ ions doped into Co3+ sites were found to enhance the solar absorbance from 68.2% to 91.6% and to simultaneously increase the infrared emittance from 0.25 to 0.93. The mobility of infrared optical phonons from free electrons decreases upon Cr3+ doping, which weakens the scattering effect and enhances the absorption. Based on these properties, we can control the Cr3+ dopant concentration of Sm0.5Sr0.5Co1−xCrxO3 to meet our demands.