The discovery of graphene has led to a rising interest in seeking quasi two-dimensional allotropes of several elements and inorganic compounds. Boron, carbon’s neighbour in the periodic table, presents a curious case in its ability to be structured as graphene. Although it cannot independently constitute a honeycomb planar structure, it forms a graphenic arrangement in association with electron-donor elements. This is exemplified in magnesium diboride (MgB2): an inorganic layered compound comprising boron honeycomb planes alternated by Mg atoms. Till date, MgB2 has been primarily researched for its superconducting properties; it hasn’t been explored for the possibility of its exfoliation. Here we show that ultrasonication of MgB2 in water results in its exfoliation to yield few-layer-thick Mg-deficient hydroxyl-functionalized nanosheets. The hydroxyl groups enable an electrostatically stabilized aqueous dispersion and create a heterogeneity leading to an excitation wavelength dependent photoluminescence. These chemically modified MgB2 nanosheets exhibit an extremely small absorption coefficient of 2.9 ml mg−1 cm−1 compared to graphene and its analogs. This ability to exfoliate MgB2 to yield nanosheets with a chemically modified lattice and properties distinct from the parent material presents a fundamentally new perspective to the science of MgB2 and forms a first foundational step towards exfoliating metal borides.
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机译:石墨烯的发现引起了人们对寻找几种元素和无机化合物的准二维同素异形体的兴趣。硼是元素周期表中的碳原子的邻居,它被构造为石墨烯的能力令人惊讶。尽管它不能独立地构成蜂窝状平面结构,但它与电子给体元素结合形成石墨烯排列。以二硼化镁(MgB2)为例:这是一种无机层状化合物,包含被Mg原子交替排列的硼蜂窝平面。迄今为止,对MgB2的超导性能进行了主要研究。尚未发现其脱落的可能性。在这里,我们显示了水中MgB2的超声处理会导致其剥落,从而产生几层厚的缺Mg羟基官能化纳米片。羟基能够实现静电稳定的水分散体并产生异质性,从而导致激发波长依赖的光致发光。与石墨烯及其类似物相比,这些经过化学修饰的MgB2纳米片的吸收系数极低,为2.9 ml mg -1 sup> cm -1 sup>。剥落MgB2产生具有化学修饰的晶格和特性不同于母体材料的纳米片的能力为MgB2的科学提供了一个全新的观点,并形成了剥夺金属硼化物的第一步。
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