IPC PAS Articles

Displaying 1 - 5 of 185 records

Electronic structure of rare-earth erbium-doped platinum diselenide: A density functional theory study
(Elsevier, 2024-03-20) Maleki-Ghaleh, Hossein; Moradpur-Tari, Ehsan; Shakiba, Mohammad; Paczesny, Jan; Hurley, Paul K.; Siadati, M. Hossein; Ansari, Lida; Gity, Farzan; Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland; Institute of Technology, University of Tartu, Nooruse, Tartu, Estonia; Tesla Giga Texas, Austin, TX, USA; MicroNano Systems Centre, Tyndall National Institute, University College Cork, Ireland; School of Chemistry, University College Cork, Cork, Ireland; Materials Science and Engineering Faculty, K. N. Toosi University of Technology, Tehran, Iran
The effect of rare-earth erbium (Er) doping on the electronic structure of platinum diselenide (PtSe2) as a 2D transition metal dichalcogenide was studied using density functional theory (DFT). Our DFT calculations showed that Er dopant in PtSe2 led to the formation of additional states in the valence and conduction bands, and new localized states within the band gap of PtSe2. The orbital-resolved density of states revealed that the 4f orbitals of the dopant Er atom strongly impact the electronic structure of the monolayer PtSe2 and induce spin-polarized localized states. Simultaneously, in addition to a significant increase in the PtSe2 surface energy (52-fold) due to Er doping (from 7.94 × 10^5 to 4.16 × 10^3 eV/Å2), the formation energy of the Er-doped PtSe2 (- 328.72 kJ/mol) compared to the pristine PtSe2 (- 326.52 kJ/mol) indicates that Er doping has made the PtSe2 system thermodynamically more stable. The results of this study can be used as a guide to design devices for optoelectronic applications such as sensors.
Technology and research on the influence of liquid crystal cladding doped with magnetic Fe3O4 nanoparticles on light propagation in an optical taper sensor
(Frontiers Media, 2024-07-05) Niewczas, Michał; Stasiewicz, Karol A.; Przybysz, Natalia; Pakuła, Anna; Paczesny, Jan; Zbonikowski, Rafał; Dziaduszek, Jerzy; Kula, Przemysław; Jaroszewicz, Leszek R.; Faculty of Advanced Technologies and Chemistry, Military University of Technology, Warsaw, Poland,; Institute of Micromechanics and Photonics, Warsaw University of Technology, Warsaw, Poland,; Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
The results obtained for new dual-cladding optical fiber tapers surrounded by liquid crystal (LC) doped with Fe3O4 nanoparticles in a specially developed glass cell are presented. The created structures are sensitive to changes in refractive index values in the surrounding medium caused by modifying external environment parameters. In this investigation, cells are filled with nematic LCs 6CHBT and with the same mixture doped with 0.1 wt% and 0.5 wt% of magnetic nanoparticles (Fe3O4 NPs). The taper is made on a standard single-mode telecommunication fiber, stretched out to a length of 20.0 ± 0.5 mm, and the diameter of the tapers is approximately 15.0 ± 0.3 μm, with a loss lower than 0.5 dB @ 1,550 nm. Measurements are carried out in a wide range covering the visible and infrared ranges in two setups: 1) without a magnetic field, with steering only by voltage and 2) with an applied magnetic field. The presented spectrum results are divided into two ranges according to the parameters of optical spectrum analyzers: 350–1,200 nm and 1,200–2,400 nm. For all investigations, a steering voltage is chosen from the range of 0 to 200 V, which allows for establishing the influence of dopants on transmitted power and time response at different arrangements. Due to the sensitivity of LCs to temperature changes, this paper focuses on measuring at room temperature the effect of the magnetic field on propagation in a fiber optic taper. The proposed solution demonstrates the technology for creating advanced components as a combination of fiber optic technology, LCs, and nanoparticles. The presented results show the possibility of creating new sensors of various external factors such as magnetic or electric fields in miniaturized dimensions.
Synthesis and characterization of zinc-doped hematite nanoparticles for photocatalytic applications and their electronic structure studies by density functional theory
(Elsevier, 2024-10-06) Dargahi, Ziba; Ahmadi-Arpanah, Anis; Moradpur-Tari, Ehsan; Yarahmadi, Mohadeseh; Kavanlouei, Majid; Maleki-Ghaleh, Hossein; Norouzi Arator, Danial; Emami Mehr, Masoud; Sadegh Shakeri, Mohammad; Paczesny, Jan; Siadati, M. Hossein; Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran; Institute of Technology, University of Tartu, Nooruse, Tartu, Estonia; Materials Engineering Department, Faculty of Engineering, Urmia University, Urmia, Iran; Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland; Department of Materials Engineering, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran; Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland
Hematite nanoparticles doped with 1, 3 and 5 % Zn (all % are in molar) were prepared using mechanical alloying. Morphological and phase structure studies using scanning electron microscopy and X-ray diffraction showed nanoparticles possessing a semi-spherical shape and particle size of <50 nm crystallized in rhombohedral structure. The lattice parameters of hematite increased upon Zn doping. The energy-dispersive X-ray and Fouriertransform infrared results demonstrated that Zn was successfully incorporated. The optical behavior of nanoparticles was examined by UV–Vis diffuse reflectance spectroscopy and revealed that Zn doping increased the absorption intensity in the visible light region and decreased the band gap from 1.95 (hematite) to 1.83 eV (3 % Zn). Methylene blue dye degradation by the 3 % Zn sample proved doubling of the photocatalytic activity due to electronic structure modification upon Zn doping. First principles studies using density functional theory performed to investigate the effect of Zn on the electronic band structure of hematite showed that Zn doping caused band gap reduction, causing formation of new energy states, mainly above the valence band. Eventually, the enhancement of Urbach energy and reduction of effective mass, respectively accountable for increasing the relaxation time and mobility of charge carriers, were considered the two main mechanisms regarding the increased photocatalytic behavior of hematite by Zn doping.
Langmuir and Langmuir Blodgett films of zinc oxide (ZnO) nanocrystals coated with polyhedral oligomeric silsesquioxanes (POSS)
(Elsevier, 2021-05-19) Paczesny, Jan; Wolska-Pietkiewicz, Małgorzata; Binkiewicz, Ilona; Janczuk-Richter, Marta; Institute of Physical Chemistry PAS, Warsaw, Poland; Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
Hypothesis: The type and properties of ligands capping nanoparticles affect the characteristics of corresponding Langmuir and Langmuir-Blodgett films. When ligands are firmly anchored to the surface, as in zinc oxide nanocrystallites (ZnO NCs), compression at the air/water interface might cause ligands interdigitation and then the formation of supra-structures. Here, we evaluate how the introduction of bulky ligands, namely polyhedral oligomeric silsesquioxanes (POSSs), influences the self-assembly of POSS@ZnO NCs and the properties of corresponding thin films. Experiments: ZnO NCs capped with asymmetrical POSS derivatives are prepared via a one-pot two-step self-supporting organometallic (OSSOM) method. POSS@ZnO NCs are characterized by employing STEM, DLS, TGA, NMR, IR, UV–VIS, and photoluminescence spectroscopy. Changes in surface pressure, surface potential, and morphology (using BAM) are recorded upon compression at the air/water interface. Films transferred onto solid substrates are examined utilizing XRR and AFM. Findings: All studied POSS@ZnO NCs form stable Langmuir films. POSSs prevent the interdigitation of ligands capping neighboring NCs. Thus, POSS@ZnO NCs films resemble those composed of classical amphiphiles but without any visible structural source of amphiphilicity. We suggest that the core provides enough hydrophilicity to anchor NCs at the air/water interface. POSS ligands provide enough hydrophobicity for the NCs not to disperse into the subphase upon compression.
Methylhydrazinium lead halide perovskites: effect of composition and dimensionality on their optoelectronic and photodetection properties
(2024) Prochowicz, Daniel; Mahapatra, Apurba; Anilkumar, Vishnu; Scarperi, Andrea; Kubicki, Dominik J.; Yadav, Pankaj; Mączka, Mirosław; Institute of Physical Chemistry, Polish Academy of Sciences; School of Chemistry, University of Birmingham, Birmingham, UK; Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa, Italy; Department of Solar Energy, School of Technology, Pandit Deendayal Energy University, Gandhinagar, Gujarat, India; Department of Physics, School of Technology, Pandit Deendayal Energy University, Gandhinagar, Gujarat, India; Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocław, Poland
Over the last few years, lead halide perovskites (LHPs) in the form of single crystals (SCs) have been intensively investigated for photodetection applications. Methylhydrazinium (MHy) is a new type of organic cation, which can form either 2D or 3D halide perovskite structures. Here, we study single crystals MHy2PbI4 (2D), MHy2PbBr4 (2D), MHyPbBr3 (3D) and mixed-cation MA0.725MHy0.275PbBr3 to determine for the first time how dimensionality and composition affect the photodetection properties of photoconductor-type photodetectors (PDs) fabricated using this class of solids. The results provide a reference for the researchers working in the same domain by revealing the relationship between different types and structures of LHPs and their optoelectronic properties, which is crucial for the further advancement of LHP-based optoelectronic devices.

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