National Institute Of Materials Physics - Romania

Publications

5793 articles found

301. Role of the Dopants in Improving the Piezoelectric Properties of Bi0.5Na0.5TiO3

Authors: Belgacem, K; Stanciu, C; Perju, S; Cernea, M

Published: 2023 APR 24 2023, JOURNAL OF ELECTRONIC MATERIALS, DOI: 10.1007/s11664-023-10407-9

Despite the high coercive field (E-c = 7.3 kV/mm) and the high conductivity (2.1 x 10(-7) (omega m)(-1)) of (Bi0.5Na0.5)TiO3 (BNT) ceramics, their microstructure and electric properties can be tailored by appropriate substitutions at the A and/or B-sites. In this paper, we offer a comprehensive review of the up-to-date advances on doped lead-free BNT ceramics, highlighting the role of the nature and concentration of dopants on the stoichiometry, microstructure, density, dielectric properties, and piezoelectric properties of the solid solutions obtained after doping. For each composition presented in this review, the synthesis method and the sintering technique of the ceramics are also given because of the well-known connection between powder processing (its morphology), ceramics densification (its density), and the macroscopic properties of the final product. A substitution mechanism for each dopant that explains the role of the dopant on the structure and electrical properties of the BNT matrix is also described in detail. Our review provides knowledge for the development of new solid solutions of BNT.

302. Surface species of the nematic mixture E7 obtained by electrochemical insertion of Li+ ions

Authors: Baibarac, M; Zgura, I; Ganea, CP; Frunza, L

Published: APR 2023, EUROPEAN PHYSICAL JOURNAL E, 46, 26, DOI: 10.1140/epje/s10189-023-00280-z

We studied here the influence of Li+ ions on the benzene rings of nematic mixture E7, which is electrochemically adsorbed onto gold electrode surface, to highlight the ability of this mixture for the applications in the field of the rechargeable Li+-ion batteries. Raman spectra support the changes observed in electrochemical analyses while contact angle measurements show that wetting properties of E7 layer were modified after deposition of this mixture onto gold support and the doping with Li+ ions.

303. Partial replacement of Pb2+ in MAPbI(2.6)Cl(0.4) perovskite films and their photovoltaic performance

Authors: Derbali, S; Nouneh, K; Leonat, LN; Stancu, V; Tomulescu, AG; Galca, AC; Touhami, ME; Pintilie, I; Florea, M

Published: APR 2023, JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, 34, 903, DOI: 10.1007/s10854-023-10318-9

Replacing lead atoms in halide perovskite materials is of significant importance for the development of environmentally friendly perovskite solar cells. In this paper, we investigated the effect of doping the MAPbI(2.6)Cl(0.4) hybrid perovskite (MA-methyl ammonium) with non-toxic elements, such as alkaline earth metal ions (Mg2+) and transition metal ions (Zn2+). The structural, morphological, and optical properties of the prepared samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV-Vis. spectroscopy. Finally, the doped films were used as photoactive layers in solar devices in order to evaluate their photovoltaic performance. Zn proved to be more appropriate to replace partially Pb and films with higher quality were obtained. As a result, the MAPb1(-x)Zn(x)I(2.6)Cl(0.4) based solar cells have demonstrated a slight improvement of the photovoltaic performances, resulting in a uniform and narrower PCEs (power conversion efficiency) range, compared to pristine MAPbI(2.6)Cl(0.4) based devices.

304. In situ Electrochemical Evaluation of the Interaction of dsDNA with the Proteasome Inhibitor Anticancer Drug Bortezomib

Authors: Bunea, MC; Enache, TA; Diculescu, VC

Published: APR 2023, MOLECULES, 28, 3277, DOI: 10.3390/molecules28073277

Bortezomib is an inhibitor of proteasomes and an anti-cancer drug. Although bortezomib is considered a safe drug, as confirmed by cytotoxicity assays, recent reports highlighted the possibility of interaction between bortezomib and cellular components, with detrimental long-term effects. The evaluation of the interaction between bortezomib and dsDNA was investigated in bulk solution and using a dsDNA electrochemical biosensor. The binding of bortezomib to dsDNA involved its electroactive centers and led to small morphological modifications in the dsDNA double helix, which were electrochemically identified through changes in the guanine and adenine residue oxidation peaks and confirmed by electrophoretic and spectrophotometric measurements. The redox product of bortezomib amino group oxidation was electrochemically generated in situ on the surface of the dsDNA electrochemical biosensor. The redox product of bortezomib was shown to interact primarily with guanine residues, preventing their oxidation and leading to the formation of bortezomib-guanine adducts, which was confirmed by control experiments with polyhomonucleotides electrochemical biosensors and mass spectrometry. An interaction mechanism between dsDNA and bortezomib is proposed, and the formation of the bortezomib redox product-guanine adduct explained.

305. Copper-/Zinc-Doped TiO2 Nanopowders Synthesized by Microwave-Assisted Sol-Gel Method

Authors: Predoana, L; Petcu, G; Preda, S; Pandele-Cusu, J; Petrescu, SV; Baran, A; Apostol, NG; Costescu, RM; Surdu, VA; Vasile, BS; Ianculescu, AC

Published: APR 2023, GELS, 9, 267, DOI: 10.3390/gels9040267

Using the microwave-assisted sol-gel method, Zn- and Cu-doped TiO2 nanoparticles with an anatase crystalline structure were prepared. Titanium (IV) butoxide was used as a TiO2 precursor, with parental alcohol as a solvent and ammonia water as a catalyst. Based on the TG/DTA results, the powders were thermally treated at 500 degrees C. XRD and XRF revealed the presence of a single-phase anatase and dopants in the thermally treated nanoparticles. The surface of the nanoparticles and the oxidation states of the elements were studied using XPS, which confirmed the presence of Ti, O, Zn, and Cu. The photocatalytic activity of the doped TiO2 nanopowders was tested for the degradation of methyl-orange (MO) dye. The results indicate that Cu doping increases the photoactivity of TiO2 in the visible-light range by narrowing the band-gap energy.

306. Surface species of the nematic mixture E7 obtained by electrochemical insertion of Li⁺ ions

Authors: Baibarac, M; Zgura, I; Ganea, CP; Frunza, L

Published: APR 2023, EUROPEAN PHYSICAL JOURNAL E, 46, 26, DOI: 10.1140/epje/s10189-023-00280-z

307. Partial replacement of Pb²⁺ in MAPbI_2.6Cl_0.4 perovskite films and their photovoltaic performance

Authors: Derbali, S; Nouneh, K; Leonat, LN; Stancu, V; Tomulescu, AG; Galca, AC; Touhami, ME; Pintilie, I; Florea, M

Published: APR 2023, JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, 34, 903, DOI: 10.1007/s10854-023-10318-9

308. Bio-Entities Based on Albumin Nanoparticles and Biomimetic Cell Membranes: Design, Characterization and Biophysical Evaluation

Authors: Barbinta-Patrascu, ME; Iftimie, S; Cazacu, N; Stan, DL; Costas, A; Balan, AE; Chilom, CG

Published: APR 2023, COATINGS, 13, 671, DOI: 10.3390/coatings13040671

Protein-based particles are one of the most important research topics in nanomedicine, being used especially as drug delivery systems. From the wide variety of proteins, albumins offer several advantages in biomedical applications due to their special properties. Albumin nanoparticles play an important role as carriers in the drug delivery of chemical and biomolecular drugs, such as anticancer drugs; offer many advantages, such as biocompatibility and biodegradability; and are well-tolerated, without any side effects. In this work, various types of bovine serum albumin nanoparticles (BSA NPs), with or without ascorbic acid or glucose, were prepared via different nanoprecipitation methods. The obtained BSA NPs were characterized by UV-Vis absorption spectroscopy. Their size and morphology were studied by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The stability in time of the developed BSA NPs was spectrally monitored. Three types of bio-entities containing BSA NPs and chlorophyll-labeled artificial cell membranes were "green" developed. The designed biohybrids were characterized by UV-Vis absorption and fluorescence emission spectroscopy, and their three-dimensional topography was investigated by AFM. Both the size and shape of the developed bio-entities were monitored through SEM analysis. These results could be exploited in the development of novel drug carrier systems or as bio-coatings to be used in the biomedical field.

309. MRC-5 Human Lung Fibroblasts Alleviate the Genotoxic Effect of Fe-N Co-Doped Titanium Dioxide Nanoparticles through an OGG1/2-Dependent Reparatory Mechanism

Authors: Miu, BA; Voinea, IC; Diamandescu, L; Dinischiotu, A

Published: APR 2023, INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 24, 6401, DOI: 10.3390/ijms24076401

The current study was focused on the potential of pure P25 TiO2 nanoparticles (NPs) and Fe(1%)-N co-doped P25 TiO2 NPs to induce cyto- and genotoxic effects in MRC-5 human pulmonary fibroblasts. The oxidative lesions of P25 NPs were reflected in the amount of 8-hydroxydeoxyguanosine accumulated in DNA and the lysosomal damage produced, but iron-doping partially suppressed these effects. However, neither P25 nor Fe(1%)-N co-doped P25 NPs had such a serious effect of inducing DNA fragmentation or activating apoptosis signaling. Moreover, oxo-guanine glycosylase 1/2, a key enzyme of the base excision repair mechanism, was overexpressed in response to the oxidative DNA deterioration induced by P25 and P25-Fe(1%)-N NPs.

310. Sub-Stochiometric Nickel Oxide Hole-Selective Contacts in Solar Cells: Comparison of Simulations and Experiments with Sputtered Films

Authors: Nayak, M; Bergum, K; Stan, GE; Lee, IH; Kuznetsov, A

Published: APR 2023, PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, DOI: 10.1002/pssa.202200651

Sub-stochiometric nickel oxide (NiOx) films were investigated as a hole selective contact option in silicon (Si) heterojunction solar cells. Numerical simulations were carried out to evaluate the impacts of the NiOx electronic properties variations and the NiOx/Si interface defect density (D-it) on device performance. Simulation data suggest that the best performance is achievable for wide bandgaps (E-g) and corresponding high valence band edge (E-VB) positions in the NiOx films. Overall, in simulations, the performance remains practically unchanged for the nickel vacancy concentrations [V-Ni] = 10(17)-10(21 )cm(-3), assuming high E-VB and low D-it. The experimental data measured using NiOx films prepared by radio-frequency magnetron sputtering reveal that the increase in [V-Ni] lifts the conductivity, concurrently decreasing E-g and E-VB. As a result, we concluded that the performance of the fabricated sputtered NiOx/Si heterojunction solar cell is limited by high D-it as well as narrow E-g and low E-VB.