Experimental and theoretical investigation on tunable optical property of nanocrystalline Ca-doped CeB6

Nanocrystalline Ca-doped CeB 6 powders have been synthesized via a solid-state reaction of CaO and CeO 2 with NaBH 4 under a vacuum condition. The Ca doping effects on phase composition, grain morphology and optical absorption properties of nanocrystalline CeB 6 were investigated. As a result, all the synthesized nanocrystalline hexaborides are composed by single phase of CsCl -type structure. The grain size and morphology are very sensitive to the reaction temperature. The optical absorption result indicates that the absorption valley of nanocrystalline CeB 6 shows a red-shift from 619 nm to 685 nm with increasing Ca doping content, which means the tunable optical absorption of nanocrystalline Ca-doped CeB 6 . In addition, a first-principles calculation has been used to reveal the origin of the tunable optical properties. It is found that Ca doping reduces the total kinetic energy of the electrons of CeB 6 and leads to the absorption valleys shift to longer wavelength direction.