Reinforced near-infrared compatible absorption performance of Er₄Al₂O₉ based on Sm³⁺/Dy³⁺ co-doping

The damage to human body caused by laser and ultraviolet light from electronic products and sunlight has attracted attention. In this paper, on the basis of previous work, the near-infrared absorbing powder Er₄Al₂O₉ was prepared by a more straightforward co-precipitation method, and intended to apply on laser protection. To achieve compatible absorption at 1064 and 1540 nm, the effects of doping Sm³⁺ and Dy³⁺ on the phase composition and reflectivity were inquired. The morphology, phase composition and reflectance of the fines were characterized by X-ray diffraction, Scanning Electron Microscopy and the ultraviolet-visible spectrophotometer (UV3600PC). No significant variation on the crystal structure was found of doped Sm³⁺ and Dy³⁺. While, the introduction of Sm³⁺/Dy³⁺ could greatly change the morphology of Er₄Al₂O₉ powder, which will further affect the reflectivity performance. Through the co-doping of Sm³⁺ and Dy³⁺, it is expected to further broaden the characteristic absorption peak at 1100 nm. The results show that the absorption peak of Sm³⁺ at 1100 nm could be broadened with the increase of Dy³⁺ doping amount, and the reflectivity of Er_0.8Dy_2.0Sm_1.6Al₂O₉ at 1064 and 1540 nm reaches the lowest value. Compared with the ordinary un-doped powder, the reflectivity of the co-doped powder at 1064 nm decreased by 26.41%, indicating a good application prospect.