Mechanism for transmittance light tunable property of nanocrystalline Eu-doped SmB6: Experimental and first-principles study

Binary nanocrystalline rare-earth hexaboride is regarded as one of the promising optical absorption materials that possess the high transparency for visible light and the strong absorption for NIR due to the effects of localized surface plasmon resonance. In present work, we experimentally investigated the structural and optical absorption of ternary nanocrystalline Eu-doped SmB6 powder. As a result, it is found that the reaction temperature as an important factor not only refines the grain size, but also improves the powder dispersion of synthesized samples. The optical absorption results reveal that the transmittance wavelength of nanocrystalline SmB6 increases from 696 nm to exceeding 1000 nm with the Eu doping content increasing to x = 0.8. Theoretically, in order to study the transmittance wavelength tunable mechanisms of nanocrystalline Eu-doped SmB6, the electronic structure, density of states and energy loss function were calculated by first-principle calculation. It shows that the Eu2+ doping into SmB6 effectively reduces the plasma frequency excitation energy from 1.48 to 1.25 eV and leads to the transmittance wavelength redshift toward a higher wavelength. Based on above meaningful studies, present work is helpful for extension of optical applications of nanocrystalline SmB6 powder.