Papers by Keyword: Halides

Abstract: Fusing of silver (Ag) nanoparticles synthesized in an aqueous system was observed at room temperature using halide solutions. The as-synthesized Ag nanoparticles have an average diameter of about 24 nm. After dispersing the Ag nanoparticles in a halide solution, a significant increase in particle size to about 188-197 nm was observed. The enlargement of particle size was accompanied by the increase in conductivity of the Ag nanoparticle ink. The resistance was reduced from 110 kiloohms to 35 and 9.3 ohms for the as-prepared and sintered Ag nanoparticles using NaBr and NaCl solution, respectively.

Abstract: Nowadays, a novel solar cell based on an organolead halide perovskite structure, CH₃NH₃PbX₃ (X is a halogen), has been gained a great attraction due to its promising photovoltaic performance. However, their humidity limitation is a serious drawback, which limits practical application of perovskite-based solar cells. In this study, we investigated the improvement of humidity stability and the influence of halide radicals (I^- and Br^-) on optical and physical properties of thiocyanic-modified CH₃NH₃PbX₃ or CH₃NH₃PbX_3-x(SCN)_x films, prepared by two-step deposition method. The mixtures of CH₃NH₃I and CH₃NH₃Br solution with different molar ratios were prepared to control the I^-:Br^- ratios in perovskite films. The characterization of perovskite films was tested by XRD, UV-Vis spectrophotometer, UV-Vis DRS spectroscopy, FE-SEM, and moisture stability testing under constant relative humidity. The results showed that different molar ratios of I^- and Br^- could strongly affect the properties of perovskite films. The larger amount of Br^- promoted the complete reaction of perovskite, larger energy band gap, and higher moisture stability. However, the prepared films were likely to exhibit phase separation due to the formation of iodide-rich and bromide-rich domains.

Abstract: We report on the (electro) chemical etching behavior, surface morphology and composition of n-type Ge (100) in acidic halide solutions using various analytical and spectroscopic techniques. The use of an integrated (electro) chemical etching chamber connected to X-ray photoelectron spectroscopy instrument to exclude the effect of oxygen from atmosphere is highlighted.

Abstract: Hexaarylcyclotrisiloxanes were selectively prepared by solvent-free synthesis from diarylsilanediol. These well-known stable compounds were found to undergo palladium-catalyzed cross-coupling reaction with aryl halides in good yields. All of attached aryl groups on silicon atom could be utilized. Furthermore, base-sensitive functionality such as acetyl and nitro groups survived the reaction.

Abstract: The thermal conductivity, thermal diffusivity and volumetric heat capacity of monocrystalline AgCl and AgBr were measured simultaneously, by Advantageous Transient Plane Source method in the temperature range 77-350 K. Both thermal conductivity and thermal diffusivity follow Eucken’s law in the temperature region studied. The heat capacity at constant pressure (CP) determined from the volumetric heat capacity agrees with the calculated one at room temperature. The values of CP obtained from this experiment along with the reported data as a function of temperature are also reported. The ratio of the thermal conductivity (λ) of AgBr and AgCl calculated from the Leibfried-Schlömann (LS) formula are in excellent agreement with the ratio measured experimentally. The dielectric constant and loss factor, of these crystalline hallides, are also reported as a function of frequency in the range 100 Hz to 1 MHz at room temperature.