Photocatalytic, plasma and combined plasma–photocatalytic processes were applied for the destruction of a model pollutant, Rhodamine B dye, in an aqueous solution (concentration of 40 mg/L). For this purpose TiO₂-pillared montmorillonite was used as a photocatalyst (characterized by X-ray analysis and low-temperature nitrogen adsorption/desorption). It was prepared by the method of intercalation of titanium hydroxocomplexes, including hydrothermal activation of the process and preliminary mechanical treatment of the layered substrate. The dielectric barrier discharge (DBD) plasma in the presence of photocatalysts increases the efficiency of dye degradation (100%, 8 s) compared to plasmolysis (94%) and UV photolysis (92%, 100 min of UV irradiation); in contrast to photolysis, destructive processes are more profound and lead to the formation of simple organic compounds such as carboxylic acids. The plasma–catalytic method enhances by 20% the energetic efficiency of the destruction of Rhodamine B compared to DBD plasma. The efficiency of dye destruction with the plasma–catalytic method increases with the improvement of the textural properties of the photocatalyst.

Colloidal nanoparticles, and quantum dots in particular, are a new class of materials that can significantly improve the functionality of photonics, electronics, sensor devices, etc. The main challenge addressed in the article is modification of the syntheses of colloidal NP to launch them into mass production. It is proposed to use an additive printing method of chips for microfluidic synthesis, and it is shown that our approach allows to offer a cheap, easily scalable and automated synthesis method which allows to increase the product yield up to 60% with improved optical properties of ${\mathrm{AgInS}}_2$ quantum dots.

Semiconductor colloidal nanostructures capped with chiral organic molecules are a research hotspot due to their wide range of important implications for photonic and spintronic applications. However, to date, the study of chiral ligands has been limited almost exclusively to naturally occurring chiral amino and hydroxy acids, which typically contain only one stereocenter. Here, we show the pronounced induction of chirality in atomically thin CdSe nanoplatelets (NPLs) by capping them with enantiopure menthol derivatives as multi-stereocenter molecules. L-(−)/D-(+)-menthyl thioglycolate, easily synthesized from L-(−)/D-(+)-menthol, is attached to Cd-rich (001) basal planes of 2- and 3-monolayer (ML) CdSe NPLs. We show the appearance of narrow sign-alternating bands in the circular dichroism (CD) spectra of 2 ML NPLs corresponding to heavy-hole (HH) and light-hole (LH) excitons with maximal dissymmetry g-factor up to 2.5 × 10⁻⁴. The most intense CD bands correspond to the lower-energy HH exciton, and in comparison with the N-acetyl-L-Cysteine ligand, the CD bands for L-(−)-menthyl thioglycolate have the opposite sign. The CD measurements are complemented with magnetic CD measurements and first-principles modeling. The obtained results may be of interest for designing new chiral semiconductor nanostructures and improving understanding of their chiroptical properties.

Subject of study. The spectral features of nanocrystals with ternary compositions I-V-VI₂ and I-III-VI₂ doped with the rare earth metal ytterbium are investigated and described. Purpose of the study. The aim of this work is to develop a novel synthesis method for these nanocrystals to further examine their optical and morphological properties. Method. The average sizes of AgInS₂:Yb and AgBiS₂:Yb nanocrystals are analyzed using atomic force microscopy and dynamic light scattering, and the results are compared. Spectrophotometry and spectrofluorimetry are employed to record the absorption and photoluminescence spectra, respectively. Additionally, the photoluminescence decay kinetics are recorded using a laser scanning luminescence microscope for a deeper exploration of the electronic structure of the synthesized materials. Main results. Morphological analysis reveals that single-stage synthesis produced nanocrystals based on the AgInS₂ matrix are smaller than the reference sample, while two-stage synthesis results in average nanocrystal sizes 1.5 times larger than the reference sample. The absorption spectra of the AgInS₂:Yb and AgBiS₂:Yb samples, as well as their reference samples, correspond to typical absorption spectra of semiconductor nanocrystals of ternary compounds. The absorption spectrum of AgBiS₂:Yb nanocrystals, unlike AgInS₂:Yb, spans a broad range from 300 nm to 1300 nm. In the photoluminescence spectra of AgInS₂ and AgInS₂:Yb nanocrystals, no significant shift of the band maximum is observed, and photoluminescence typical of Yb ions is absent. It is found that the weighted average photoluminescence lifetime in AgInS₂:Yb nanocrystals can be modulated by ytterbium doping. Photoluminescence in AgBiS₂ and AgBiS₂:Yb samples is not detected in the red and near-infrared regions. Practical significance. These materials may be used in the fabrication of absorber layers for solar cells, as well as sensitizers for photodynamic and photothermal therapy. Further studies of isotropic samples of these nanocrystals could not only expand their potential applications but also enhance the physical properties of nanoparticles in the long term.