No abstract

Nanocrystallites of non-stoichiometric copper sul®des were synthesized via the reaction between [Cu(NH 3 ) 4 ] 2z and thiourea in sealed autoclaves at the low temperature of 60 ³C for 3 h. Thiourea played a key role in the process of Cu 9 S 8 nanocrystal formation. Through adjusting the redox atmosphere, Cu 7 S 4 and CuS were obtained from the freshly formed Cu 9 S 8 nanocrystals. The products were characterized by means of X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy and transmission electron microscopy (TEM) techniques. The Cu : S atomic ratios for Cu 9 S 8 and Cu 7 S 4 were 9 : 8.08 and 7 : 4.05, respectively, analyzed by inductively coupled plasma (ICP) spectroscopy. The possible mechanism of phase transformation among copper sul®des (Cu 9 S 8 , CuS, and Cu 7 S 4 ) was discussed. The optical properties of the products were also recorded by means of UV±vis absorption, and photoluminescence spectroscopy.

Semiconductor ZnS nanowires were synthesized by a direct templating route in an inverted hexagonal liquid crystal formed by oligo(ethylene oxide)oleyl ether amphiphiles, n-hexane, n-hexanol/i-propanol (2:1), and water. The final product consists of ordered nanowires with a diameter of ca. 5 nm. Most importantly, seven or more close-packed nanowires aggregate to form a regularly shaped bundle with a width of ca. 10−30 nm, duplicating the hexagonal structure of close-packed inverted micelles formed by amphiphiles. We propose a novel simultaneous in situ formation (SISF) technique to synthesize ordered ZnS nanowires by γ-irradiation at room temperature. The reaction is worth noting in that its occurrence is homogeneous and simultaneous. The structures of the inverted hexagonal liquid crystal phase and the final product were characterized by means of polarized optical microscopy (POM), XRD, XPS, TEM and EDX techniques. UV−vis and PL spectra recorded the optical properties of the ZnS nanowires. The amount of amphiphiles passivated with ZnS nanowires is ∼3.4 wt %, as determined by thermal gravimetric analysis (TGA).

Nanocrystallites of nonstoichiometric copper selenide (Cu(2-x)Se) and stoichiometric copper selenides (beta-CuSe and Cu(3)Se(2)) were synthesized in different solutions via sonochemical irradiation at room temperature. The influence of solvents, surfactants, and ultrasonic irradiation on the morphology and phase of products has been investigated. The morphological difference of the products was mainly affected by the solvents and surfactants, which can self-aggregate into lamellar structures or microemulsions, and then these unique structures can act as both supramolecular template and microreactor to direct the growth of copper selenides. On the other hand, it was also found that the sonochemical irradiation and solvents played an important role in the formation of different phases of copper selenides. The proposed formation mechanism of copper selenides is discussed.

A novel solvent-relief-self-seeding (SRSS) process was applied to grow bulk polygonal tubular single crystals of Sb(2)E(3) (E = S, Se), using SbCl(3) and chalcogen elements E (E = S, Se) as the raw materials at 180 degrees C for 7 days in ethanol solution. The products were characterized by various techniques, including X-ray powder diffraction (XRD), scanning electronic microscope (SEM), transmission electronic microscope (TEM), electronic diffraction (ED), and X-ray photoelectron spectra (XPS). The calculated electrical resistivities of the tubular single crystals in the range 20-320 K were of the order of 10(5)-10(6) Omega cm for Sb(2)S(3) and 10(3)-10(4) Omega cm for Sb(2)Se(3), respectively. The studies of the optical properties revealed that the materials formed had a band gap of 1.72 eV for Sb(2)S(3) and 1.82 eV for Sb(2)Se(3), respectively. The optimal reaction conditions for the growth of bulk tubular single crystals were that the temperature was not lower than 180 degrees C and the reaction time was not shorter than 7 days. The possible growth mechanism of tubular crystals was also discussed.