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In this study, we investigated the role of redox potential in the ability of nano-synthesis by plasma–liquid interactions. From redox potential, a parameter featured the standard Gibbs free energy, and the equilibrium constant of a reduction reaction can be determined. Our calculation showed that the reactions of AuCl 4 − / Au 0 with a redox potential of 1.0 V and Cu 2 + / Cu 0 of 0.34 V have equilibrium constants of approximately 10 50 and 10 11 , respectively. The results are significant to explain the failure in the copper nanoparticle synthesis in the process of nucleation through the Lamer theory. To compare these results to experimental data, the nanoparticles synthesized in a mixed solution of AuCl 4 − and Cu 2 + by AC glow discharge were characterized. The experimental results showed that there were only gold nanoparticles synthesized even though the concentration of gold ions is 200 times smaller. Other results of silver and platinum nanoparticles were also agreeable to the theory. Our findings provide a prediction to explain the ability in the nano-synthesis by plasma in contact with liquid for any noble metals. [ABSTRACT FROM AUTHOR]

In this study, we experimentally investigated the effect of charged particles generated from an alternating current glow discharge in liquids and the ability of these particles to synthesize silver nanoparticles. The measurement of the pH and electrical conductivity in liquids was performed to study the interface reactions and transfer of species from plasmas to liquids. Solutions of sodium hydroxide, de-ionized water, sodium nitrate, and silver nitrate were used in this study. We determined that the pH of de-ionized water and sodium hydroxide solutions was reduced to 4.0 during the discharge. However, the pH of nitrate salts evolved in two opposite stages, with an initial reduction within 3 min from the start of the discharge and a subsequent increase to alkaline values. The results also showed that spherical silver nanoparticles were generated in the silver nitrate solutions under the discharge. These results indicate that alternating current glow discharge generates both positive ions and free electrons when in contact with a liquid, leading to complex chemical transformations. This suggests that the proposed approach can be used for noble nanoparticle synthesis. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) and time-resolved photoluminescence (TRPL) spectra of GaN particles doped with divalent cations (Mg2+, Zn2+, and Be2+), which promote photocatalytic overall water splitting, were investigated. The PL and TRPL spectra were mainly attributed to donor-acceptor pair recombination between the divalent cation dopants and divalent anion impurities (O2- and S2-) unintentionally introduced from raw materials, which form acceptor and donor levels, respectively. These levels are likely to provide holes and electrons required for photocatalytic reactions, contributing to the photocatalytic activity of the GaN-based photocatalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

Discusses a study which detailed the effect of hydrogen on the properties of magnetron sputtering of hydrogenated amorphous silicon carbon alloy films. System in which silicon atoms are supplied into the plasma by the physical sputtering process; Importance of the contribution of hydrogen species to the deposition process in the system; Step taken in order to investigate the contribution of hydrogen species.

Presents a study which investigated the structural, optical, electrical and optoelectronic properties of magnetron sputtered hydrogenated amorphous-silicon carbon alloy films. Experiment; Results and discussion; Summary and conclusion.

Provides information on a study that investigated the radio frequency power dependence of structural, optical, electrical and optoelectronic properties of hydrogenated amorphous silicon carbon alloy films prepared by magnetron sputtering of silicon in methane-argon gas mixtures. Methodology of the study; Results and discussion on the study; Conclusions.