Solid State Communications最新文献

Photovoltaics (PV) having perovskite material have an enormous influence on the progress in solar cell technology. Excluding the high efficiency, stability, and flexibility, the extended impact has now been given on utilizing lead-free environmentally suitable, and much cheaper materials for the PSC fabrication. The material with a volatile free, that is, cesium tin iodide (CsSnI₃), is capable for the fabrication of the Perovskite Solar Cell that creates eco-friendly as well as enhanced optical-electronic features for the low bandgap, that is 1.27eV. Sn could increase the steadiness of the lead-free perovskite. However, as widely known, Sn²⁺ always suffers from oxidation with I₂ and O₂ and induces instability issues. In the ongoing work, cesium tin iodide, is employed as the primary absorber, in so much the root-extracted naturally manufactured ZnO is used as ETM for less cost in production. Correspondingly, Spiro-OMeTAD is used as HTM for enhancement in hole collection in the device. The inclusive numerical simulation with the bio-synthesized ZnO-NP can be applied in designing the solar cell having an applicable thickness of CsSnI₃, suitable temperature, total defect density, and the influence of the resistance, respectively. The current simulation of PSC offers the extraordinary power conversion efficiency (η) of 26.40 % considering CsSnI₃ as the absorber. The results described in this investigation may confirm an effective approach to design and the expansion of the lead-free PSC.

Nanocrystalline rare-earth (R) and transition metal (T) alloys are known for their outstanding magnetic properties, which are driven by the combination of (R) and (T) magnetic moments. Adding carbon (C) has been proven to alter these magnetic properties. In the present work, we use X-ray diffraction, transmission electron microscopy, and atom probe tomography to investigate and characterize the impact of carbon addition on the crystalline structure, morphology, and chemical distribution of Pr₅Co₁₉ and its carbides Pr₅Co₁₉C_x. The nanocrystalline Pr₅Co₁₉ compound was synthesized by high-energy ball milling and the addition of carbon was performed by a solid-solid reaction between Pr₅Co₁₉ and C₁₀H₁₄. TEM study revealed that after carbonation the microstructure is refined, and the mean grain size decreases from 126 nm in Pr₅Co₁₉ to 65 nm with a carbon of content 1.5. Three-dimensional APT was performed to characterize the chemical composition of Pr-Co binary systems. The analyzed Pr₅Co₁₉C_1.5 sample reveals an irregular nano-lamella structure decorated by carbon atoms, the distance between the lamellas varying from 8 to 20 nm. An under-stoichiometry of Co was found in the C-rich lamellas. Fundamental magnetic properties such as saturation magnetization M_s, exchange field H_ex and magnetic susceptibility $\chi$ of the Pr₅Co₁₉ and its carbides were calculated using the random magnetic anisotropy (RMA) method.

Structural, electronic, optical, mechanical, thermoelectric and dielectric properties of binary Bi₂A₃ (A = S, Se, Te) chalcogenide semiconductors are studied by first-principles approach. Bismuth sulfide (Bi₂S₃) is found to be structurally stable in orthorhombic structure while bismuth selenide (Bi₂Se₃) and bismuth telluride (Bi₂Te₃) are stable in trigonal structure. Calculated mechanical properties reveal that all three Bi₂A₃ (A = S, Se, Te) compounds fulfil the mechanical stability criteria. Band structure calculations reveal that the Bi₂S₃ exhibits direct optical band gap (E_g = 1. 58 eV) which lies in the near-infrared (NIR) region, while the calculated E_g of Bi₂Se₃ and Bi₂Te₃ are found to be 0.53 eV and 0.35 eV, respectively lying in the far-infrared region. For Bi₂S₃ and Bi₂Se₃ compounds, the calculated dielectric properties show strong anisotropic behavior, while negligible anisotropic dielectric behavior is observed for Bi₂Te₃. Calculated optical properties show that all three Bi₂A₃ compounds possess high absorption coefficient (> 10⁴ cm⁻¹). For all three Bi₂A₃ (A = S, Se, Te) compounds, the calculated optical conductivity show prominent peak corresponding to the occurrence of optical conduction at energies 3.36 eV, 2.65 eV and 2.02 eV respectively. Calculated optical results support the results deduced from band structures and density of states spectra. Optical properties and dielectric behavior suggest that the Bi₂S₃ compound has suitable band gap and has potential to use for photovoltaic applications while Bi₂A₃ (A = Se, Te) compounds could be used in infrared detectors and other optical devices. Calculated thermal properties reveal that the Bi₂A₃ (A = S, Se, Te) chalcogenides could be potential materials for thermoelectric applications.

Preadsorbing suitable gas molecule on the substrate can effectively improve the adsorption strength of the system. The adsorption properties of preadsorping NH₃ on SO₂-adsorbed Hf₂CO₂ monolayer are explored by first-principles calculation. All possible adsorption sites are considered. SO₂ molecule cannot be adsorbed by Hf₂CO₂ monolayer, while preadsorbing NH₃ can increase the adsorption strength of SO₂-adsorbed Hf₂CO₂ monolayer. The adsorption system has the direct semiconductor character and is the reusable SO₂ gas sensor because of short recovery time and the appropriate adsorption strength. Preadsorbing NH₃ can decrease the carrier mobility in conduction band, but has little impact on the carrier mobility in valence band. The charge transfer of the co-adsorption system is also investigated.

Porous Ag has good electron conductivity and is one of the typical oxygen reduction reaction(ORR) catalysts. In order to investigate the mechanism of porous Ag for ORR, the relaxed structure and detailed partial density of states are determined using density-functional theory. Among multiple possible active sites, the overpotential of porous Ag is 0.50 V, which is better than that of Ag (111) at 0.62 V. After doping Pt and Pd, the overpotentials are 0.47 V and 0.49 V, respectively. Furthermore, the introduction of a transition metal has led to changes in the charge distribution on the catalyst surface, which has resulted in improved catalytic performance. By investigating the synergistic effects between doped transition metals and ORR intermediates, this can facilitate the development of catalysts with higher activity and better stability.

This study employs molecular dynamics simulations using the embedded-atom method to investigate the structural and dynamic properties of supercooled liquid silver (Ag) metal under varying external hydrostatic pressures ranging from 0 to 70 GPa. The investigation spans various length scales, analyzing short-to-medium-range order, crystalline order, and fractal dimension to discern patterns that indicate how increased pressure affects atomic arrangements. The results suggest that increased external hydrostatic pressure triggers a shift to more ordered atomic structures characterized by relative atomic positions corresponding to the fcc lattice structure, highlighting the system's heightened sensitivity to pressure conditions. Furthermore, the study reveals pressure-dependent changes in atomic diffusion behavior and shows a reduction in atomic mobility with increasing pressure. In particular, the values of the diffusion coefficient decrease from 3.719 × 10⁻⁸ to 1.564 × 10⁻⁹ cm² s⁻¹ for 0 and 70 GPa, respectively, demonstrating the direct influence of pressure on the dynamics of supercooled liquid Ag metal.

The research findings from a thorough examination of the impact of sintering temperature are presented in this publication on structural, ferroelectric, ferromagnetic and dielectric properties of Mg-doped Bismuth Ferrite. Bi_0.88Mg_0.12FeO₃ (BMFO) was synthesized using a solid-state reaction technique and sintered at three different temperatures: 750 °C, 800 °C and 830 °C. Structural analysis was performed using Rietveld refinement of XRD data, which confirms the presence of perovskite phase with rhombohedral structure in all samples and also changes in lattice parameters that result from sintering temperature changes. The average crystalline size as well as the lattice strain are calculated using the Williamson-Hall method. The loss tangent and dielectric constant have been examined as a function of frequency revealing a considerable improvement in dielectric properties. SEM analysis was performed to identify the microstructural property of the samples. Ferroelectric properties were studied using a P-E loop which confirms the enhancement in the ferroelectric property as sintering temperature increases. The improvement in the multiferroic nature will be discussed in light of the sintering temperature effect on Mg-doped Bismuth Ferrite.

The role of electron-phonon interaction in band gap shrinkage for some II-VI bulk and low-dimensional semiconductors is investigated in this work. The variation of the energy band gap is studied as a function of temperature using Varshni's, Vina's, and Passler's relations. It is observed that the change in the energy band gap is affected due to the quantum confinement as the dimensionality of these semiconductors is decreased.

Impact of non-magnetic cationic-substitution on the evolution of structural defects and correlated ferromagnetic and electrical properties are investigated in series of pulsed laser deposited Sn_1-xIn_xO₂ (0.0 ≤ x ≤ 0.12) thin films. Beyond the nominal doping concentration of 2 at.% (i.e. x > 0.02), Indium (In)-doped SnO₂ film switches to exhibit from n-type to p-type electrical conductivity and simultaneously the magnetization (M_S) as well as the Curie temperature (T_C) of the films increase significantly. Estimated values of ‘M_S’ and ‘T_C’ are found to achieve as large as 15.21 emu/cm³ and 540 K respectively when In-doping concentration approaches towards x = 0.08 and afterwards tend to decrease abruptly. Various spectroscopic techniques including Positron Annihilation Lifetime Spectroscopy (PALS) have detected the existence of Sn vacancy (V_Sn) defects within Sn_1-xIn_xO₂ films arise as the effect of In-substitution at Sn site (In_Sn) under O-rich atmosphere. The estimated positron lifetimes and the increase of line-shape S-parameter confirm the rise of V_Sn defects which serve as the major source of magnetic moments in non-magnetic host SnO₂. Besides, In_Sn defects introduce excess holes within SnO₂ lattice and thereby the magnetic spin-spin RKKY interaction between near-by V_Sn defects are mediated ferromagetically through the localized holes. For x > 0.08, stabilization of various donor-type defects such as Sn interstitial (Sn_i), indium interstitial (In_i) actually compensates the acceptors that leads to reduce the effective hole density consequently diminishing the strength of ferromagnetism within SnO₂. Hence, tuning of such ferromagnetic and semiconducting properties through non-magnetic cationic substitution in transparent conducting oxides can be very promising in the field of next-generation spintronics.

Nowadays, double perovskites for renewable energy are emerging materials because of their interesting properties such as simple and stable crystal structure. In our study, we theoretically explored the optoelectronic along with mechanical and thermoelectric characteristics of A₂InAsO₆ (A = Sr, Ba) using density functional theory and semi-classical Boltzmann theory followed by WIEN2k code. The thermodynamic and structural stabilities are determined based on the cohesive energy, enthalpy of formation and tolerance factor. The ductile and brittle behaviour has been checked by Pugh's ratios. The measured values of narrow direct energy band gaps are 0.70 eV for Sr₂InAsO₆, and 0.18 eV for Ba₂InAsO₆ with TB-mBJ approximation. These compositions are potentially used in optoelectronic applications because their electronic characteristics are tuneable. In the energy range 0–12 eV, the compositions under consideration exhibit a single-peaked response while the replacement of cation Sr with Ba caused a shift in optical structures towards lower energies. These compositions are also suitable for thermoelectric systems as they possess high values of the figure of merits at room temperature and the measured values 0.049 eV for Sr₂InAsO₆, and 0.10 eV for Ba₂InSbO₆ are recorded.