Evolution of transition metal dichalcogenide film properties during chemical vapor deposition: from monolayer islands to nanowalls.

Unique properties possessed by transition metal dichalcogenides (TMDs) attract much attention in terms of investigation of their formation and dependence of their characteristics on the production process parameters. Here, we investigate the formation of TMD films during chemical vapor deposition (CVD) in a mixture of thermally activated gaseous H2S and vaporized transition metals. Our observations of changes in morphology, Raman spectra, and photoluminescence (PL) properties in combination within situmeasurements of the electrical conductivity of the deposits formed at various precursor concentrations and CVD durations are evidence of existence of particular stages in the TMD material formation. Gradual transformation of PL spectra from trion to exciton type is detected for different stages of the material formation. The obtained results and proposed methods provide tailoring of TMD film characteristics necessary for particular applications like photodetectors, photocatalysts, and gas sensors.

Correction: Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes.

Correction for 'Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes' by A. I. Chernov et al., Nanoscale, 2018, DOI: 10.1039/c7nr07054c.

Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes.

Molecule encapsulation inside the single-walled carbon nanotube (SWCNT) core has been demonstrated to be a successful route for the modification of nanotube properties. SWCNT diameter-dependent filling results in band gap modification together with the enhancement of photoluminescence quantum yield. However, the interaction between the inner structure and the outer shell is complex. It depends on the orientation of the molecules inside, the geometry of the host nanotube and on several other mechanisms determining the resulting properties of the hybrid nanosystem. In this work we study the influence of encapsulated graphene nanoribbons on the optical properties of the host single-walled carbon nanotubes. The interplay of strain and dielectric screening caused by the internal environment of the nanotube affects its band gap. The photoluminescence of the filled nanotubes becomes enhanced when the graphene nanoribbons are polymerized inside the SWCNTs at low temperatures. We show a gradual photoluminescence quenching together with a selective signal enhancement for exact nanotube geometries, specifically (14,6) and (13,8) species. A precise adjustment of the optical properties and an enhancement of the photoluminescence quantum yield upon filling for nanotubes with specific diameters were assigned to optimal organization of the inner structures.

[A multicomponent additive intended for preparing infant milk mixtures enriched with essential and protective factors]. / Mnogokomponentnaia dobavka, prednaznachennai dlia prigotovleniia detskikh molochnykh smesei, obogashchennykh éssentsial'nymi i zashchitnymi faktorami.

Hen eggs were used for the preparation of a multicomponent additive to milk mixtures for infants. Lysozyme hydrolysate containing up to 1 mg/ml lysozyme was obtained from egg albumen according to a specially developed technology. The hydrolysate was supplemented with vitamins C and PP. The egg yolk was used for the preparation of a yolk-fatty emulsion enriched with vitamin E, copper sulfate and ferrous lactate. Characteristics of the cow milk and milk mixtures supplemented with the multicomponent additive are maximally close to those of the human milk. The clinical trials of the lactic acid mixtures enriched with the multicomponent additive showed their high effectiveness in the nutrition of normal and sick infants. The technology of the additive production is simple; it is inexpensive and can be easily transported.