Vinča Institute of Nuclear Sciences
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High-pressure effects on the structural, mechanical, and optoelectronic properties of the lead-free β-CsSnX3 (X = I, Br, Cl) perovskite: Insights from first principle analyses
No full textThis study utilizes DFT to systematically examine the influence of mechanical pressure on the structural, electronic, mechanical, and optical properties of lead-free β-CsSnX3 perovskites (X = I, Br, Cl). The main differences among these 10 systems, as well as the pressure-dependent evolution of their structural and electronic properties, were elucidated through pressure-dependent analysis. Detailed analysis was conducted on the variations in structural and mechanical properties induced by changes in hydrostatic pressure. The electronic structure analysis reveals a consistent bandgap reduction of 0.3–0.5 eV, attributed to enhanced orbital hybridization induced by compression. Mechanical characterization further confirms the robust stability of most compositions, as indicated by elastic constants satisfying the Born stability criteria (C11 > |C12|, C44 > 0) and ductile behavior, evidenced by Pugh's ratios (B/G > 1.75). The optical analysis reveals a pronounced pressure-induced redshift in the absorption onset (∼0.5 eV) alongside a substantial enhancement in absorption intensity (30–50 % increase at 2 eV). Concurrently, the Debye temperatures exhibit a notable rise of 25–40 % (from 180 to 280 K), indicative of improved thermal stability. These results highlight the potential of β-CsSnX3 perovskites for strain-engineered optoelectronic applications, particularly in solar cells and photodetectors, where tunable bandgaps and pressure-resilient performance are essential. This study provides quantitative benchmarks for material optimization, offering valuable insights into the pressure regimes most conducive to maximizing device efficiency and operational stability
Disregulation of CaMKII and Nfr2/HO-1 signal patways in WKY rats exposed to chronic mild stress
No full textBelgrade Neuroscience Next Hub 2025 with international participation February 27, 2025. Belgrade, Serbia
Ca-ion storage enhancement of Ca-pillared vanadium oxide using a malonic-assisted solution combustion process and a novel aqueous AC//Ca(NO3)2//CaVO/C hybrid cell
No full textHerein, we report the pioneering electrochemical investigation of calcium vanadium oxide (CaV2O6) cathode as a pillared-structure host for Ca2+ ion storage in aqueous rechargeable batteries. CaV2O6 (CaVO) is synthesized using a malonic-assisted solution-combustion process, followed by calcination at 400 °C (CaVO400) and 700 °C (CaVO700). Once integrated with carbon, the oxide becomes highly active due to the initial irreversible Ca2+/H+ exchange, as evidenced by Cyclic Voltammetry, Chronopotentiometry and Impedance combined with ex-situ XRD as well as Raman and FTIR measurements. The removal of an accompanying CaV2O7 phase favors Ca2+ and H+/H3O+ insertion by leading to an increased proton concentration in the electrolyte and liberating active sites on the CaVO surface. As a result, a very high capacity of about 87 mAh g−1 is obtained in half-cells at 1 A g−1, which originates from an extrinsic pseudocapacitive behavior. When CaVO400/C is combined with a carbon anode in full-cells, it reaches about 90 mAh g−1, at 100 mA g−1 and exhibits very stable cycling for 100 cycles
Investigation of the interactions and electromagnetic shielding properties of graphene oxide/platinum nanoparticle composites prepared under low-dose gamma irradiation
No full textA low-dose gamma irradiation was used for the one-step synthesis of graphene oxide/platinum nanoparticle composites. Various spectroscopic and microscopic methods were employed to structurally and morphologically characterize the prepared composites, and the nature of the interactions between graphene oxide sheets and platinum clusters was investigated using density function theory (DFT). Gamma irradiation caused the reduction of hexachloroplatinic acid, resulting in the formation of Pt nanoparticles and the simultaneous partial reduction of graphene oxide (GO). Pt nanoparticles synthesized at doses of 10 and 20 kGy showed a homogeneous GO surface coverage with a high portion of particles with sizes of up to 10 nm. The DFT results indicate a difference in electrical conductivity between GO and PtNPs. This could cause charge redistribution across the contact area, creating a conductive network at the interface that should enhance the EMI shielding capabilities of the composite. The shielding efficiency of the composites measured at the X band showed a blockage of 77% of the incident electromagnetic wave at a center frequency of 10 GHz. The composite prepared at a 20 kGy dose exhibited a greater contribution from a mismatch loss component, attributed to the improved electrical conductivity induced by irradiation
NiM/β zeolites (M = Co, Cu, and Zn) as bifunctional oxygen electrocatalysts
No full textA series of Ni/β and NiM/ β zeolites (where M =Co, Cu, and Zn) were synthesized by a low-cost aqueous ion
exchange procedure from hydrogen form β zeolite (SiO2/Al2O3 = 38). After calcination and morphological examination, the materials were examined for oxygen evolution (OER) and reduction reaction (ORR) in alkaline
media. Namely, all zeolites exhibited good OER and ORR activity. For OER, NiZn/β exhibited the lowest onset
potential (Eonset) of 1.63 V, followed by NiCo/β (1.66 V). Overpotentials at onset (ηonset) decreased in the order:
Ni/β (630 mV) > NiCu/β (610 mV) > NiCo/β (460 mV) > NiZn/β (430 mV). NiCo/β gave the highest OER
current density (34.2 mA cm− 2
), followed by NiZn/β (19.4 mA cm− 2
), while NiCu/β (3.0 mA cm− 2
) and Ni/β
zeolites (2.1 mA cm− 2
) gave significantly lower values. These results confirmed that NiCo/β and NiZn/β showed
the highest activity for OER. For ORR, NiZn/β and Ni/β displayed the lowest Tafel slopes, indicating favorable
kinetics. The half-wave potentials (E1/2) of 0.69, 0.68, 0.66, and 0.65 V were observed for Ni/β, NiZn/β, NiCu/β,
and NiCo/β, respectively. NiZn/β demonstrated excellent stability and gave a number of exchanged electrons
from 3.0 to 3.3, which shows mixed direct and indirect pathways of ORR, while the rest of the NiM/β zeolites
predominantly showed indirect pathways of ORR. These results confirmed that NiCo/β exhibits the best activity
for OER, while NiZn/β demonstrated similar OER activity to NiCo/β but showed the highest ORR activity
The Use of Radiation Technology for the Protection of the Archeological Site of Vinča from the Neolithic Age
No full textThe Vinča culture represents the early Neolithic culture of Europe between the fifth millennium BC and the fourth millennium BC. It was the most technologically advanced prehistoric culture in the world. The discovery of the so-called "Vinča letter" is particularly significant and interesting. Vinča script, also known as Vinčanica or Serbica, is the name for a series of symbols, i.e., letters, found at prehistoric sites in Southeastern Europe, more precisely in Serbia and Romania. Some scientists argue that it is a script of the Vinča culture. In order to gain more knowledge about perhaps the oldest script in human civilization, the Government of the Republic of Serbia decided to conduct extensive excavations in the territory of the municipality of Vinča. Excavations are scheduled to begin next year. A handful of Neolithic objects are expected to be found. The paper describes the conservation plan of excavated cultural heritage objects using gamma radiation. The radiation conditions are described. After determining the stability of the samples relative to the effect of gamma radiation and determining the appropriate dose of radiation, the conservation process will start.ICARST-2025 : 3rd International Conference on Applications of Radiation Science and Technology; 7-11 April 2025, IAEA Headquarters, Vienna, Austria
Favorable Influence of Aqueous Media on Gamma Irradiated PP
No full textPP belongs to the polymers sensitive to ionizing radiation, even for relatively small doses. Even though the basic radiation chemistry of PP is well known, and many scientific publications and reviews are available on this topic, the interest of the academic community and the need for sterilization, modification, and additional improvements in properties vital for the medical and other industries, drive further the research in this area. PP is known to undergo excessive oxidative degradation and deterioration in properties upon irradiation in air. Usually, in the absence of effective crosslinking coagent and/or crosslinking media, relatively high doses (≥ 250 kGy) are required before the dose to incipient gelation is reached, and the effects of crosslinking begin to show. In this work, changes in the structure and physical properties of stabilized isotactic polypropylene (iPP) were created by gamma irradiation of PP in air and deionized distilled (DD) water. The presence and evolution of free radicals after irradiation were followed using electron spin resonance (ESR) spectroscopy. Gel and infrared (IR) spectroscopy measurements were used to determine the changes in the degree of network formation and oxidative degradation, respectively. Sol-gel analysis was studied in detail using the Charlesby–Pinner (C–P) equation. Additional characterization was conducted by optical microscopy (OM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), dielectric relaxation spectroscopy (DRS), differential scanning calorimetry (DSC), and mechanical measurements. The results were analyzed, compared, and discussed, emphasizing the favorable influence of aqueous media on PP properties in contrast to air. Obtained results may be of interest in the practical application of ionizing radiation in polymer technologies, which involves PO medical devices, but also in cable, automotive, packaging, textile, and other industrial usesICARST-2025 : 3rd International Conference on Applications of Radiation Science and Technology; 7-11 April 2025, IAEA Headquarters, Vienna, Austria
Smart Ag/P(HEMA/IA) Nanocomposite Hydrogels for Wound Dressing Obtained by Different Radiation Approaches
No full textFollowing two distinct radiolytic synthesis approaches - one-step and two-step method, two types of smart silver nanocomposite hydrogels were prepared. In a two-step process, P(HEMA/IA) copolymeric hydrogels, synthesized via gamma radiation during the first phase, were used as a matrix for the synthesis of silver nanoparticles which also employed a gamma radiolytic method during the second phase. The one-step approach integrates both phases of the two-step synthesis - silver nanocomposites were obtained by irradiating water/ethanol solutions containing HEMA, IA and AgNO3 resulting in the simultaneous formation of AgNPs and P(HEMA/IA) hydrogels. Ag/P(HEMA/IA) nanocomposite hydrogel libraries obtained using these two different fabrication methodologies were characterized through UV-Vis spectroscopy, swelling behavior studies, scanning electron microscopy, and energy dispersive spectroscopy. To assess their antimicrobial properties, the nanocomposites were tested against E. Coli, S. Aureus, and C. Albicans. Both types of synthesized copolymeric silver nanocomposite hydrogels demonstrated good antimicrobial activity, even at low silver concentrations, making them suitable for wound dressing applications. Combining this with the fact that one-step synthesis can provide the sterilized final product in one step, with a significant reduction in production time and cost compared to two-step synthesis, results in a useful synergistic combination for efficient hydrogel wound dressing production.ICARST-2025 : 3rd International Conference on Applications of Radiation Science and Technology; 7-11 April 2025, IAEA Headquarters, Vienna, Austria
Time-Resolved Photoacoustic Response of Thin Semiconductors Measured with Minimal Volume Cell: Influence of Photoinduced Charge Carriers
No full textWhen a semiconducting sample is illuminated by an intensity-modulated monochromatic light beam with photon energy exceeding the band gap, part of the absorbed energy is directly converted into heat through photon–lattice interactions. This gives rise to a heat source that closely follows the temporal profile of the optical excitation, known as the fast heat source. Simultaneously, another portion of the absorbed energy is used to generate electron-hole pairs. These charge carriers diffuse together and recombine via electron–electron and electron–hole interactions, transferring their kinetic energy to the lattice and producing additional heating of the sample. This indirect heating mechanism, associated with carrier recombination, is referred to as the slow heat source. In this study, we develop a model describing surface temperature variations on the non-illuminated side of a thermally thin semiconductor exposed to a rectangular optical pulse, explicitly accounting for the contribution of surface charge carrier recombinations. Using this model, we investigate the influence of surface recombination velocity and the material’s plasma properties on the time-domain temperature response for both plasma-opaque and plasma-transparent samples. Our results demonstrate that charge carrier recombinations can significantly affect the transient photoacoustic signal recorded using a minimum volume cell, highlighting the potential of time-resolved photoacoustic techniques for probing the electronic properties of semiconductors. © 2025 by the authors
Green solution for lead pollution: phytoremediation with Festuca rubra and brushite-aluminosilicate geopolymer material
No full textAluminosilicate materials are known for their high removal efficiency of lead (Pb) ions from aqueous solutions, whereas in Pb-contaminated soils they can immobilise lead ions and improve soil quality, contributing to more efficient remediation. Brushite-aluminosilicate geopolymer materials synthesised from an abandoned, raw kaolinite clay with the addition of 2, 4, and 6 wt% of brushite, were tested for their efficiency in removing Pb ions with Festuca rubra, which is known to tolerate its high concentration in soil. The highest efficiency for Pb immobilisation in the soil was observed with the addition of brushite-metakaolin-based geopolymer GPB2% and GPB6%, whereas physiological and biochemical parameters indicate a reduction in metal stress with increasing brushite content, as the concentrations of proline, total phenolic content and antioxidant activity in the shoots of the plants to which GPB6% was added were even lower than in some samples grown on uncontaminated soil. Moreover, in this sample the highest concentrations of photosynthetic pigments were found. This study suggests that the brushite-metakaolin geopolymer material improves the potential of F. rubra in remediation, whereas its stability and harmlessness to the environment, further recommend its use in the field. © 2025 Societá Botanica Italiana.Peer-reviewed article available at: [https://vinar.vin.bg.ac.rs/handle/123456789/14801