Sonochemical synthesis of nanocrystalline mercury sulfide, selenide and telluride in aqueous solutions

Nanocrystalline mercury chalcogenides HgE (E = S, Se, Te) were synthesized in a single step by a convenient, simple sonochemical method. Mercury nitrate, Hg(NO₃)₂, dissolved in 0.1 M ethylenediamine tetraacetic acid (EDTA), was used as the source of mercury and elemental chalcogenes, dissolved in a NaOH solution, as the sources of chalcogenide. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDAX). The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. The results showed that the complexing agent EDTA plays a crucial role in the process.     

Synthesis of HgSe quantum dots through templates controlling and gas–liquid transport with emulsion liquid membrane system

A new synthetic method of HgSe quantum dots has been investigated through template controlling with emulsion liquid membrane system. The membrane system consists of kerosene as solvent, span80 as surfactant, N7301 as carrier, and HgCl₂ solution as internal-aqueous phase containing template of different concentrations, and uses gas–liquid transport on interface of external phase. Its optimum condition is as follows, kerosene:span80:N7301 = 74:6:20, Roi=1:1. While using inorganic KI as the template and adjusting HgCl₂ concentrations (keeping KI/HgCl₂ = 10), transmission electron microscope shows that HgSe quantum dots of different sizes can be obtained respectively, X-ray diffraction (XRD) reveals that the products have a cubic structure. The research has shown that quantum confinement effect of these HgSe quantum dots (2–3 nm) have inverted band structure (HgSe bulk) increase their effective bandgap giving rise to infrared (IR) luminescence. Its forming process is also inferred.     

Preparation of Group IIB Selenide Nanoparticles Using Soft-Hard Dual Template Method

Using a celloidin membrane as template, the uniform Group IIB selenide nanoparticles were inductively synthesized at room temperature and ambient pressure. The nanoparticles are cubic ZnSe quantum dots, hexagonal CdSe quantum dots and cubic HgSe nanoparticles with average diameters of 3.1, 2.0 and 44nm, respectively. In the ultraviolet-visible spectra, their absorption peaks are at about 360, 480 and 440nm individually, and have large blue shifts due to quantum size effect. The corresponding photoluminescence peaks individually showed at 367, 438 and 440nm. In addition, the preparation conditions and formation mechanism have been explored.     

(HgSe)_n(n=1～6)团簇结构和性质的密度泛函研究

本工作采用LANL2DZ赝势基组、B3LYP方法对(HgSe)n(n=1~6)团簇进行了结构优化、自然键原子轨道和频率计算,得到(HgSe)n(n=1~6)团簇基态的平衡几何结构、电子状态、垂直电离势、垂直电子亲和势、偶极矩、三个基本热力学函数等相关性质,并系统分析了该团簇的几何构型、原子净电荷布局、前沿分子轨道特征.结果表明:基态稳定结构(HgSe)2为平面四边形,(HgSe)n(n=3~6)为笼状结构,且稳定顺序为(HgSe)5(HgSe)4(HgSe)6(HgSe)2HgSe(HgSe)3,极性顺序为:(HgSe)4HgSe(HgSe)3(HgSe)5(HgSe)6(HgSe)2,(HgSe)6和(HgSe)2分子空间结构的对称性较好.(HgSe)n(n=1~6)团簇各体系都有较好的电子供体及受体等活性部位,随着n增大轨道离域现象明显,利于电子的转移,导电性增强.     

(HgSe)n(n=1~6)团簇结构和性质的密度泛函研究

本工作采用LANL2DZ赝势基组、B3LYP方法对(HgSe)n(n=1~6)团簇进行了结构优化、自然键原子轨道和频率计算,得到(HgSe)n(n=1~6)团簇基态的平衡几何结构、电子状态、垂直电离势、垂直电子亲和势、偶极矩、三个基本热力学函数等相关性质,并系统分析了该团簇的几何构型、原子的净电荷布局、前沿分子轨道特征。结果表明：基态稳定结构(HgSe)2为平面四边形,(HgSe)n(n=3~6)为笼状结构,且稳定顺序为(HgSe)5>(HgSe)4>(HgSe)6>(HgSe)2>HgSe>(HgSe)3,极性顺序为：(HgSe)4>HgSe>(HgSe)3>(HgSe)5>(HgSe)6>(HgSe)2,(HgSe)6、(HgSe)2分子空间结构的对称性较好。(HgSe)n(n=1~6)团簇各体系都有较好的电子供体及受体等活性部位,随着n增大轨道离域现象明显,利于电子的转移,导电性增强。     

HgSe:Fe quantum dots: growth and characterization

Mercury selenide and its ternary and quaternary modifications in the form Hg(A,B)Se with A, B magnetic ions, provide an interesting semiconductor family featuring different kinds of correlation effects. These effects manifest themselves already in three-dimensional, quasi-two-dimensional, and quasi-one-dimensional structures. We have succeeded now in fabricating HgSe:Fe quantum dots using three different growing procedures based on molecular beam epitaxy: (a) Stranski–Krastanov growth; (b) thermally activated surface reorganization; (c) pit filling. The special feature of the HgSe:Fe dots is the intrinsic population of the dot states by electrons, where a large amount of about 50–500 electrons form a many-electron system within a single dot. The formation of the dots was controlled in situ by RHEED. The morphology of the resulting structures was characterized by AFM. Subsequently, the electronic properties of the dots were investigated by megagauss magneto spectroscopy, indicating the presence of strong correlation effects as manifested in a 50% increase of the cyclotron mass in respect to that of structures with a higher dimensionality.     

Mercury selenide nanorods: Synthesis and characterization via a simple hydrothermal method

HgSe nanorods have been synthesized through a simple hydrothermal reduction approach. The nanorods formed were ≈45 nm average diameter and ≈3 μm nm in length. X-ray diffraction characterization suggested that the product consists of cubic phase pure HgSe. The as-prepared products were also characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An X-ray energy dispersive spectroscopy (EDX) study further confirmed the composition and purity of the product. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. The results showed that the capping agent CTAB (cetyltrimethylammoniumbromide) plays a crucial role in the process. Other factors, such as the reaction time, temperature, different capping agent and the reductant type also have an influence on the morphology of the final products to some extent.