Thin films of titanium oxides, titanium oxynitrides and titanium nitrides were deposited on glass substrates by the methods of direct current (DC) and pulsed magnetron sputtering and cathodic arc evaporation. Phase analysis of the deposited films by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) showed the presence of phases with various Ti oxidative states, which indicated a high concentration of oxygen vacancies. The films morphology was investigated by scanning electron microscopy (SEM). Investigations of the films wettability, either with water or ethylene glycol, showed that it depends directly on the concentration of oxygen vacancies. The wettability mechanism was particularly discussed.
Sb2S3 is a promising nanomaterial for application in solar cells and in the fields of electronics and optoelectronics. Herein, Sb2S3 nanoparticles were prepared via the hot-injection approach. In contrast to earlier work, the reaction temperature was decreased to 150 °C so that the reaction was slowed down and could be stopped at defined reaction stages. Thereby, the formation mechanism of the nanomaterial and the associated kinetics could be revealed. Based on morphological and structural analyses, it is suggested that seed particles (type 0) formed immediately after injecting the antimony precursor into the sulfur precursor. These seeds fused to form amorphous nanoparticles (type I) that contained a lower percentage of sulfur than that corresponding to the expected stoichiometric ratio of Sb2S3. The reason for this possibly lies in the formation of an oxygen- or carbon-containing intermediate during the seeding process. Afterward, the type I nanoparticles aggregated into larger amorphous nanoparticles (type II) in a second hierarchical assembly process and formed superordinate structures (type III). This process was followed by the crystallization of these particles and a layer-like growth of the crystalline particles by an Ostwald ripening process at the expense of the amorphous particles. It was demonstrated that the kinetic control of the reaction allowed tuning of the optical band gap of the amorphous nanoparticles in the range of 2.2–2.0 eV. On the contrary, the optical band gap of the crystalline particles decreased to a value of 1.7 eV and remained constant when the reaction progressed. Based on the proposed formation mechanism, future syntheses for Sb2S3 particles can be developed, allowing tuning of the particle properties in a broad range. In this way, the selective use of this material in a wide range of applications will become possible.
We have studied processes of gold ion implantation in polyethylene (PE) by theoretical chemistry methods. Car–Parrinello molecular dynamics (CPMD) simulations of collisions and following chemical kinetics considerations lead to the conclusion that chemical bonds between gold atoms and PE chains are formed. We have identified and characterized by a DFT method various stable structures with C–Au, C–Au–C, C–Au–H and C–Au⋯H2 types of chemical bonds. The binding energies (BE) of C–Au bonds are as high as 227 kJ mol−1 and the bond analysis reveals a covalent bonding character. For the experimental detection of these structures in gold implanted PE, we predicted characteristic infra-red (IR) frequencies. The C–Au stretching vibrational modes lie around 500 cm−1. Other characteristic frequencies lie in a band between 730 cm−1 and 1500 cm−1.