物理学报Issue(9)：1-6,6.DOI:10.7498/aps.64.096104
稀土硼化物LaxCe1-xB6亚微米粉的制备及光吸收研究∗
Synthesis and optical absorption prop erties of LaxCe1-xB6 submicron powders
摘要
Abstract
According to original knowledge, lanthanum hexaboride (LaB6) as an excellent thermionic electron emitter is char-acterized by a low work function, a high emission density, and a high brightness. Recently, much attention has been drawn to its another excellent optical properties: strong light absorption in near infrared rays (NIR), and transparency in visible light (VL), which result from the free electron plasmon resonance. However, up to now the optical properties and syntheses of ternary rare-earth hexaborides have been very rarely reported in the literature. In this paper, ternary LaxCe1−xB6 submicron crystallines are successfully synthesized using a solid-state reaction, in which La2O3 and CeO2 are used as rare-earth sources and NaBH4 as boron sources in a continuous vacuum condition. Effects of La doping content on the LaxCe1−xB6 phase composition, microstructure, and optical absorption properties are investigated by X-ray diffraction, scanning electron microscope (SEM), and transmission electron microscope (TEM). It is found that all the synthesized samples are composed of CaB6-type single-phase alloy with a space group P m¯3m at the reaction temperature of 1200 ◦C held by 2 h. The SEM results indicate that the cubic-shaped ternary LaxCe1−xB6 crystals with a mean size of 200 nm are obtained and the energy dispersive spectrometer results confirm that the La atoms are randomly distributed at the lattice sites of CeB6. High resolution transmission electron microscope images reveal the single-crystalline nature, and the FFT pattern indicates the lattice fringe d = 0.42 nm which agrees well with the (100) crystal plane. EDS analysis of TEM also indicates the La element has been doped into CeB6. And the optical absorption result shows that the absorption valley of CeB6 is 62 nm. With increasing La doping content to x = 0.6 and 0.8, the absorption valleys of La0.6Ce0.4B6 and La0.8Ce0.2B6 decrease to 613 and 610 nm respectively indicating the blueshifts of the wavelength of absorption valley From the view point of practical application, the tunable characteristic of LaxCe1−xB6 may extend the optical applications in improving the efficiency of organic photovoltaics, replacing the expensive gold and silver nanoparticles, which may have a good usage in optical filters.关键词
稀土六硼化物/纳米粉末/光吸收Key words
rare-earth hexaborides/nanocrystalline/optical absorption引用本文复制引用
包黎红,朝洛蒙,伟伟,特古斯..稀土硼化物LaxCe1-xB6亚微米粉的制备及光吸收研究∗[J].物理学报,2015,(9):1-6,6.基金项目
国家自然科学基金(批准号:51302129)、内蒙古自治区重大基础研究开放课题(批准号:20130902)和内蒙古师范大学高层次人才科研启动经费项目(批准号:2013YJRC017)资助的课题.* Project supported by the National Natural Science Foundation of China (Grant No.51302129), the Open Major Basic Project of Inner Mongolia, China (Grant No.20130902), and the High Level Talents Scientific Foundation of Inner Mongolia Normal University, China (Grant No.2013YJRC017) （批准号:51302129）
