Search results for "FUNCTIONAL"
showing 10 items of 4822 documents
An insight into the functionalisation of carbon nanotubes by diazonium chemistry: Towards a controlled decoration
2014
The derivatisation of materials including iron, gold, and carbon by addition of diazonium salts is a reliable process to tune their interfacial interaction with the surrounding media. In this regard, the functionalisation of carbon nanostructures by diazonium chemistry is a versatile strategy to obtain soluble nanomaterials with degrees of functionalisation among the highest ever reported. Starting from these premises we have studied the functionalisation of multi-walled carbon nanotubes by addition of the aryl diazonium salts generated in situ by treatment of 4-methoxyaniline with isopentylnitrite. Following a thorough purification and characterisation protocol (UV-vis, TGA, ATR-IR, cyclic…
Properties-morphology relationships in electrospun mats based on polylactic acid and graphene nanoplatelets
2018
Abstract Aligned and randomly oriented polylactic acid (PLA) biocomposite nanofiber mats filled with Graphene nanoplatelets (GnP) were prepared by electrospinning. The morphological analysis revealed the successful alignment of the fibers achieved by collecting the mats on a high-speed rotary drum. Furthermore, GnP addition on the polymeric solution leads to an increase of the viscosity with a consequent increment of the fiber diameter. Tensile tests demonstrated that the reinforcing effect of GnP when added to the PLA matrix was more than three times higher in the aligned systems if compared with the respective randomly oriented mats. DSC analysis showed that GnPs were able to slightly inc…
Energetic stability and photocatalytic activity of SrTiO3 nanowires: ab initio simulations
2015
First principles periodic calculations based on the density functional theory within the localized atomic orbital approach (DFT-LCAO) using the hybrid exchange–correlation potential PBE0 have been performed in order to simulate the structural and electronic properties of both stoichiometric and nonstoichiometric [001]-oriented four-faceted SrTiO3 (STO) nanowires (NW) of cubic structure. Their diameters have been varied from 0.3 up to 2.4 nm with a corresponding consequent change of NW cross-section from 2 � 2t o 5� 5 extension of the lattice constant in bulk. Energetic stability of STO NW (both stoichiometric and non-stoichiometric) has been found to increase with the decrease of their form…
First-principles calculations of iodine-related point defects in CsPbI3
2019
Many thanks to A. Lushchik, A. Popov and R. Merkle for numerous fruitful discussions. This study was partly supported by the Latvian Council for Science (grant LZP-2018/1-0147 to EK). R.A.E acknowledges the assistance of the University Computer Center of Saint-Petersburg State University for high-performance computations.
Geometry, electronic structure, morphology, and photoluminescence emissions of BaW1-xMoxO4 (x = 0, 0.25, 0.50, 0.75, and 1) solid solutions: Theory a…
2019
Abstract The design of a solid solution with tunable electro-optical properties and multifunctionality is a promising strategy for developing novel materials. In this work, BaW1-xMoxO4 (x = 0, 0.25, 0.5, 0.75, and 1) solid solutions have been successfully prepared for the first time by a co-precipitation method. Their crystal structure and phase composition were determined by X-ray diffraction and Rietveld refinements. Fourier transform infrared and micro Raman spectroscopy in combination with field-emission scanning electron microscopy (FE-SEM) were used to describe the microstructures and chemical compositions of the synthesized materials. The influence of chemical composition on morpholo…
Diacetylene polymerization on a bulk insulator surface
2017
| openaire: EC/FP7/610446/EU//PAMS Molecular electronics has great potential to surpass known limitations in conventional silicon-based technologies. The development of molecular electronics devices requires reliable strategies for connecting functional molecules by wire-like structures. To this end, diacetylene polymerization has been discussed as a very promising approach for contacting single molecules with a conductive polymer chain. A major challenge for future device fabrication is transferring this method to bulk insulator surfaces, which are mandatory to decouple the electronic structure of the functional molecules from the support surface. Here, we provide experimental evidence for…
Understanding the optical and bonding properties of hybrid metal-halide (C5H16NP) PbX4 (X = Cl, Br, I) perovskite: A density-functional theory study
2021
Abstract Hybrid perovskites have demonstrated high stability and a promising optoelectronic performance for solar-cells. The quest over their functionalities beyond photo-voltaic applications is currently an important challenge. In this work, we have used density-functional theory to study hybrid perovskites. In particular, we have explored how atomic substitution could be used to design their optoelectronic properties. Under this approach, we have investigated the effect of changing the halogen atom (X = Cl, Br, I) on the structural, electronic, and optical properties of (C5H16NP) PbX4 hybrid perovskites. The electronic properties have been computed using hybrid functionals including the …
Small radius electron and hole polarons in PbX2 (X = F, Cl, Br) crystals: a computational study
2021
First-principles hybrid density functional theory (DFT) calculations were performed for small radius polarons – self-trapped electrons (STELs) and holes (STHs) in PbX2 (X = F, Cl, Br) crystals, widely used as parent materials for inorganic halide perovskites (CsPbX3) and scintillators. The atomic and electronic structures, spin and charge distributions and formation energies for both types of polarons were predicted for orthorhombic PbF2 and STELs for cubic PbF2. The STH structure was identified in a controversial case of PbCl2. We also confirmed and analyzed in detail experimentally suggested configurations for other cases. It is shown how, due to a delicate balance of ionic and covalent c…
Two-dimensional hydrogenated buckled gallium arsenide: an ab initio study
2020
First-principles calculations have been carried out to investigate the stability, structural and electronic properties of two-dimensional (2D) hydrogenated GaAs with three possible geometries: chair, zigzag-line and boat configurations. The effect of van der Waals interactions on 2D H-GaAs systems has also been studied. These configurations were found to be energetic and dynamic stable, as well as having a semiconducting character. Although 2D GaAs adsorbed with H tends to form a zigzag-line configuration, the energy differences between chair, zigzag-line and boat are very small which implies the metastability of the system. Chair and boat configurations display a [Formula: see text]-[Formu…
Random Structural Modification of a Low-Band-Gap BODIPY-Based Polymer
2017
International audience; A BODIPY thiophene polymer modified by extending conjugation of the BODIPY chromophore is reported. This modification induces tunability of energy levels and therefore absorption wavelengths in order to target lower energies.