Tuning the optical absorption and exciton bound states of germanene by chemical functionalization.

We present a comprehensive study of buckled honeycomb germanene functionalized with alternately bonded side groups hydroxyl (-H), methyl (-CH) and trifluoro methyl (-CF). By means of most modern theoretical and computational methods we determine the atomic geometries versus the functionalizing groups. The quasiparticle excitation effects on the electronic structure are taken into account by means of exchange-correlation treatment within the GW framework.

Nanoantenna structures for the detection of phonons in nanocrystals.

We report a study of the infrared response by localized surface plasmon resonance (LSPR) modes in gold micro- and nanoantenna arrays with various morphologies and surface-enhanced infrared absorption (SEIRA) by optical phonons of semiconductor nanocrystals (NCs) deposited on the arrays. The arrays of nano- and microantennas fabricated with nano- and photolithography reveal infrared-active LSPR modes of energy ranging from the mid to far-infrared that allow the IR response from very low concentrations of organic and inorganic materials deposited onto the arrays to be analyzed. The Langmuir-Blodgett technology was used for homogeneous deposition of CdSe, CdS, and PbS NC monolayers on the antenna arrays.

Synthesis and Properties of Water-Soluble Blue-Emitting Mn-Alloyed CdTe Quantum Dots.

In this work, we prepared CdTe quantum dots, and series of CdMnTe-alloyed quantum dots with narrow size distribution by an ion-exchange reaction in water solution. We found that the photoluminescence peaks are shifted to higher energies with the increasing Mn content. So far, this is the first report of blue-emitting CdTe-based quantum dots.

Impurity-Governed Modification of Optical and Structural Properties of ZrO-Based Composites Doped with Cu and Y.

The influence of calcination temperature on copper spatial localization in Y-stabilized ZrO powders was studied by attenuated total reflection, diffuse reflectance, electron paramagnetic resonance, transmission electron microscopy, electron energy loss, and energy-dispersive X-ray spectroscopies. It was found that calcination temperature rise in the range of 500-700 °C caused the increase of copper concentration in the volume of ZrO nanocrystals. This increase was due to Cu in-diffusion from surface complexes that contained copper ions linked with either water molecules or OH groups.

Luminescent and Optically Detected Magnetic Resonance Studies of CdS/PVA Nanocomposite.

A series of solid nanocomposites containing CdS nanoparticles in polymeric matrix with varied conditions on the interface particle/polymer was fabricated and studied by photoluminescence (PL) and optically detected magnetic resonance (ODMR) methods. The results revealed interface-related features in both PL and ODMR spectra. The revealed paramagnetic centers are concluded to be involved in the processes of photo-excited carriers relaxation.

The Crystal Structure of Micro- and Nanopowders of ZnS Studied by EPR of Mn and XRD.

The crystal structure of micro- and nanopowders of ZnS doped with different impurities was analyzed by the electron paramagnetic resonance (EPR) of Mn and XRD methods. The powders of ZnS:Cu, ZnS:Mn, ZnS:Co, and ZnS:Eu with the particle sizes of 5-7 μm, 50-200 nm, 7-10 μm, and 5-7 nm, respectively, were studied. Manganese was incorporated in the crystal lattice of all the samples as uncontrolled impurity or by doping.

Synthesis of Capped A(II)B(VI) Nanoparticles for Fluorescent Biomarkers.

The conditions for growing CdS nanoparticles suitable for the visualization of biological tissues were theoretically studied and experimentally checked. The optimal ranges for pH values and precursors' concentrations were determined. The applicability of the mercaptoethanol-capped nanoparticles for in vitro luminescence visualization of several cellular forms in histological specimens of human placenta has been proven.

Interfacial bonding in a CdS/PVA nanocomposite: A Raman scattering study.

Raman spectroscopy is employed to characterize the bonding between CdS nanoparticles (NPs) and a polyvinyl alcohol (PVA) as well as structural changes in the polymeric matrix caused by incorporation of NPs. It is shown that after the formation of CdS NPs the vibrations of carbonyl groups in acetate residuals of PVA and of C-O groups at the macromolecules ends disappear. Formation of NPs also leads to an increased degree of hydrogen bonding and crystallinity of the hybrid material as compared with the unloaded polymer.

Enhancement of polymer endurance to UV light by incorporation of semiconductor nanoparticles.

Improvement of polyvinyl alcohol stability against ultraviolet (UV) illumination is achieved by introducing cadmium sulfide (CdS) nanoparticles into the polymeric matrix. Enhancement of stability is analyzed by optical characterization methods. UV protection is achieved by diminishing the probability of photo-activated formation of defects in polymer.

Retardation of nanoparticles growth by doping.

The process of doping of CdS nanoparticles with Mn during colloidal synthesis is analyzed by EPR and optical studies. Analysis of EPR results demonstrated that Mn(2+) ions are successfully incorporated into the nanoparticles and occupy the crystal sites both in the bulk of a NP and near the surface of a NP. Optical absorption measurements revealed the retardation of absorption edge shift during the growth for Mn-doped CdS NPs as compared to the undoped CdS NPs.

Gilded nanoparticles for plasmonically enhanced fluorescence in TiO2:Sm3+ sol-gel films.

Unlabelled: Silica-gold core-shell nanoparticles were used for plasmonic enhancement of rare earth fluorescence in sol-gel-derived TiO2:Sm3+ films. Local enhancement of Sm3+ fluorescence in the vicinity of separate gilded nanoparticles was revealed by a combination of dark field microscopy and fluorescence spectroscopy techniques. An intensity enhancement of Sm3+ fluorescence varies from 2.