Oxygen atmosphere annealing treatment of Sm0.5Sr0.5CoO3−δ for spectrally selective absorbing applications

• Spectrally selective absorbing properties of Sm0.5Sr0.5CoO3−δ were investigated.
• Both the solar absorbance and thermal emittance of Sm0.5Sr0.5CoO3−δ could be optimized by annealing treatment.
• The photothermal conversion efficiency increases from 0.43 to 0.79 after annealing treatment.

Perovskite-type oxides Sm0.5Sr0.5CoO3−δ were prepared by the solid-state reaction method, and then annealed in oxygen atmosphere at different temperatures between 400 and 1000 °C for 6 h. We investigated the effects of annealing temperatures on the crystalline structure, surface morphology and selective absorption properties. Results demonstrate that the annealing treatment plays an important role in optimizing the solar absorbance (αS) and thermal emittance (εT). The optimum sample was annealed at 800 °C in oxygen atmosphere for 6 h, which exhibited values of αS=0.85 and εT=0.06, indicating that it is an alternative material for spectrally selective absorbing applications.