The
anisotropy in semiconductor nanoplatelets (NPLs) is reflected
in the anisotropy of their crystal structure and organic ligand shell,
which can be used for creating new semiconductor heterostructures.
This work demonstrates the synthesis of core/shell NPLs containing
zero-dimensional (0D) Cd
x
Hg1–x
Se domains embedded in CdSe NPLs via cation exchange.
The strategy is based on the different accessibility of definite regions
of the NPLs for incoming cations upon time-limited reaction conditions.
The obtained heterostructures were successfully overcoated with a
Cd
y
Zn1–y
S shell preserving their two-dimensional (2D) morphology. The NPLs
exhibit bright photoluminescence in the range of 700–1100 nm
with quantum yields up to 55%, thus making them a prospective material
for light-emitting applications in the near-infrared spectral range.
Continuous advancements in science
and technology in
the field
of flexible devices encourage researchers to dedicate themselves to
seeking candidates for new flexible transparent conductive films (FTCFs).
Our recently developed two-dimensional (2D) metal aerogels are considered
as a new class of FTCFs. Here, we describe a new large-scale self-assembly
synthesis of bimetallic Pt–Ni 2D metal aerogels with controllable
morphology during the synthesis. The obtained 2D aerogels require
only a low quantity of precursors for the synthesis of percolating
nanoscale networks with areas of up to 6 cm2 without the
need of an additional drying step. Stacks of the obtained monolayer
structures display low sheet resistances (down to 270 Ω/sq),
while decreasing the optical transparency. In perspective, the 2D
bimetallic Pt–Ni aerogels not only enrich the structural diversity
of metal aerogels but also bring forth new materials for further applications
in flexible electronics and electrocatalysis with reduced costs of
production.
A series of hybrid organic–inorganic perovskites, based on naphthalene ammonium cations have been investigated. All materials exhibit edge- or face-sharing 1D chain structures and broadband light emission arising from the self-trapped excitons.
In the current work, the microstructure, hydrogen permeability, and properties of chromium nitride (CrN x ) thin films deposited on the Inconel 718 superalloy using direct current reactive sputtering are investigated. The influence of the substrate bias voltage on the crystal structure, mechanical, and tribological properties before and after hydrogen exposure was studied. It was found that increasing the substrate bias voltage leads to densification of the coating. X-ray diffraction (XRD) results reveal a change from mixed fcc-CrN + hcp-Cr 2 N to the approximately stoichiometric hcp-Cr 2 N phase with increasing substrate bias confirmed by wavelength-dispersive X-ray spectroscopy (WDS). The texture coefficients of (113), (110), and (111) planes vary significantly with increasing substrate bias voltage. The hydrogen permeability was measured by gas-phase hydrogenation. The CrN coating deposited at 60 V with mixed c-CrN and (113) textured hcp-Cr 2 N phases exhibits the lowest hydrogen absorption at 873 K. It is suggested that the crystal orientation is only one parameter influencing the permeation resistance of the CrN x coating together with the film structure, the presence of mixing phases, and the packing density of the structure. After hydrogenation, the hardness increased for all coatings, which could be related to the formation of a Cr 2 O 3 oxide film on the surface, as well as the defect formation after hydrogen loading. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient by up to 40%. The lowest value of 0.25 ± 0.02 was reached for the CrN x coating deposited at 60 V after hydrogenation.
This article presents new possibilities of using thin
films of
lanthanide stearates as sorbent materials. Modification of the Q-sense
device resonator with monolayers of lanthanide stearates by the Langmuir–Schaeffer
method made it possible to study the process of insulin protein adsorption
on the surface of new thin-film sorbents. The resulting films were
also characterized by compression isotherms, chemical analysis, scanning
electron microscopy, and mass spectrometry. The transition of stearic
acid to salt was recorded by IR spectroscopy. Using the LDI MS method,
the main component of thin films, lanthanide distearate, was established.
The presence of Eu
2+
in thin films was revealed. In the
case of europium stearate, the maximum value of insulin adsorption
was obtained, −1.67·10
−10
mole/cm
2
. The findings suggest the possibility of using thin films
of lanthanide stearates as a sorption material for the proteomics
determination of the quantitative protein content in complex fluid
systems by specific adsorption on modified surfaces and isolation
of such proteins from complex mixtures.
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) requires a matrix, and traditionally small organic matrices (SOMs) carrying acidic or basic functional groups are used. However, the analyte ionization via secondary processes in the gas-phase seems to be more important than primary processes. For conjugated polymeric matrices, an even more complicated picture emerges due to their apolar and aprotic nature, high molecular weight, and low tendency to desorb. Poly(3-dodecylthiophene-2,5-diyl) (P3DDT), a good matrix for low-molecular weight (LMW) analytes, does not give matrix-related peaks in the LMW area. Here, carboxylic acid (-COOH) side-chains are introduced via postpolymerization modification. The polymers are characterized by NMR, FT-IR, CV, MALDI MS, and, when possible, GPC. The electron withdrawing side-chains serve three functions; i) raising the ionization potential (IP), ii) improving the absorption maximum, and iii) acting as a source of protons. When measuring basic amines, this results in the occurrence of additional [Analyte + H + ] + signals compared to polymers without acidic groups, where only radical cations [Analyte] +• are detected. Similarly, estradiol and testosterone, compounds with high IPs, are not detected by polythiophenes without acidic groups, while P3DDT-COOH enables detection as protonated species.
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