Cambridge Serial Total Energy Package Research Articles

Electrospun Lithium Porous Nanosorbent Fibers for Enhanced Lithium Adsorption and Sustainable Applications.

Electrospun nanosorbent fibers specifically designed for efficient lithium extraction were developed, exhibiting superior physicochemical properties. These fibers were fabricated using a polyacrylonitrile/dimethylformamide matrix, with viscosity and dynamic mechanical analysis showing that optimal interactions were achieved at lower contents of layered double hydroxide. This meticulous adjustment in formulation led to the creation of lithium porous nanosorbent fibers (Li-PNFs-1). Li-PNFs-1 exhibited outstanding mechanical attributes, including a yield stress of 0.09 MPa, a tensile strength of 2.48 MPa, and an elongation at a break of 19.7%. Additionally, they demonstrated pronounced hydrophilicity and hierarchical porous architecture, which greatly favor rapid wetting kinetics and lithium adsorption. Morphologically, they exhibited uniform smoothness with a diameter averaging 546 nm, indicative of orderly crystalline growth and a dense molecular arrangement. X-ray photoelectron spectroscopy and density functional theory using Cambridge Serial Total Energy Package revealed modifications in the spatial and electronic configurations of polyacrylonitrile due to hydrogen bonding, facilitating lithium adsorption capacity up to 13.45 mg/g under optimal conditions. Besides, kinetics and isotherm showed rapid equilibrium within 60 min and confirmed the chemical and selective nature of Li+ uptake. These fibers demonstrated consistent adsorption performance across multiple cycles, highlighting their potential for sustainable use in industrial applications.

Theoretical investigation of structural, mechanical, electronic, optical, and thermal properties of ternary compounds of heusler alloy ANiSn (A= TI, TH, U) using first principles calculations

In this study, we investigated the ANiSn (A = Ti, Th, U) half-Heusler materials for various properties, including structural, electronic, mechanical, elastic anisotropic, optical, and thermal properties, using Density Functional Theory (DFT) with the Cambridge Serial Total Energy Package (CASTEP) code. The elastic constants satisfied Born's criteria, confirming the thermodynamic and mechanical stability of the ANiSn compounds. Mechanical stability was further assessed through bulk modulus, shear modulus, and Poisson's ratio. Our analysis revealed that TiNiSn and ThNiSn exhibit ductile behaviour, whereas UNiSn is brittle. The calculated elastic modulus indicated that the compounds we studied are elastically anisotropic. The electronic and optical properties confirmed the semiconducting nature of these materials, with significant absorption and conductivity observed in the ultraviolet region. ANiSn is suitable for manufacturing various optoelectronic devices, such as laser diodes (LDs), photodetectors, LEDs, and UV sensors, due to its high absorption coefficient in the IR to UV regions. Additionally, measured Debye and melting temperatures confirmed that TiNiSn is more thermally conductive and can be used in high-temperature structural substances. The low minimum thermal conductivity suggests that UNiSn may be a more efficient material for thermal barrier coatings (TBC) compared to TiNiSn and ThNiSn.

Investigation of structural, electronic, optical, and mechanical properties of perovskite CsPbBr3 material through induced pressure for photovoltaic applications: A DFT Insights

Herein, perovskite CsPbBr3 material was computationally explored at pressure limits from 0.0 to 8.0 GPa using a 5-step (2GPa gap) calculation. CASTEP (Cambridge Serial Total Energy Package) program is used which is based on density functional theory (DFT), with an ultra-soft (US) pseudo-potential (SP) plane wave and the GGA-PBE exchange–correlation functional. When the pressure increases from 0.0 to 8.0 GPa, the bandgap decreases from 1.84 to 0.60 eV. In comparison to higher pressures, the bandgap decreases significantly until 8.0 GPa. The mechanical properties of the compound at various pressures are also investigated, which indicates that the compound is mechanically ductile and stable in nature. Various optical characteristics, such as the refractive index, loss function, absorption coefficient, and reflectivity, have been determined under pressure limits from 0.0 to 8.0 GPa. For solar cell applications, a compound with high absorption, refractive index, and optical conductivity is optimal.

Tutton salt (NH4)2Zn(SO4)2(H2O)6: thermostructural, spectroscopic, Hirshfeld surface, and DFT investigations

ContextAmmonium Tutton salts have been widely studied in recent years due to their thermostructural properties, which make them promising compounds for application in thermochemical energy storage devices. In this work, a detailed experimental study of the Tutton salt with the formula (NH4)2Zn(SO4)2(H2O)6 is carried out. Its structural, vibrational, and thermal properties are analyzed and discussed. Powder X-ray diffraction (PXRD) studies confirm that the compound crystallizes in a structure of a Tutton salt, with monoclinic symmetry and P21/a space group. The Hirshfeld surface analysis results indicate that the main contacts stabilizing the material crystal lattice are H···O/O···H, H···H, and O···O. In addition, a typical behavior of an insulating material is confirmed based on the electronic bandgap calculated from the band structure and experimental absorption coefficient. The Raman and infrared spectra calculated using DFT are in a good agreement with the respective experimental spectroscopic results. Thermal analysis in the range from 300 to 773 K reveals one exothermic and several endothermic events that are investigated using PXRD measurements as a function of temperature. With increasing temperature, two new structural phases are identified, one of which is resolved using the Le Bail method. Our findings suggest that the salt (NH4)2Zn(SO4)2(H2O)6 is a promising thermochemical material suitable for the development of heat storage systems, due to its low dehydration temperature (≈ 330 K), high enthalpy of dehydration (122.43 kJ/mol of H2O), and hydration after 24 h.MethodsComputational studies using Hirshfeld surfaces and void analysis are conducted to identify and quantify the intermolecular contacts occurring in the crystal structure. Furthermore, geometry optimization calculations are performed based on density functional theory (DFT) using the PBE functional and norm-conserving pseudopotentials implemented in the Cambridge Serial Total Energy Package (CASTEP). The primitive unit cell optimization was conducted using the Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm. The electronic properties of band structure and density of states, and vibrational modes of the optimized crystal lattice are calculated and analyzed.Graphical abstract

Hydrogen storage potential of XNiH3 (X= Sr and Ba) compounds: A comprehensive DFT analysis

The increasing need for sustainable energy solutions emphasizes the significance of effective hydrogen storage materials. This work provides a thorough analysis using density functional theory (DFT) to assess the capacity of XNiH3 (X = Sr and Ba) compounds, where X denotes strontium (Sr) and barium (Ba), for storing hydrogen. We employed the Cambridge Serial Total Energy Package (CASTEP) approach to optimize the geometries and determine the structural, electrical, optical, and mechanical properties of SrNiH3 and BaNiH3. The findings indicate that SrNiH3 demonstrates a higher gravimetric hydrogen storage capacity (2.03 %) in comparison to BaNiH3 (1.52 %). Both compounds exhibit metallic behavior, characterized by the absence of band gaps, which indicates a high level of electrical conductivity. The optical investigations reveal prominent absorption peaks at 25.32 eV for SrNiH3 and 18.82 eV for BaNiH3, accompanied by substantial energy loss functions and refractive behaviors. Based on mechanical studies, it has been determined that both compounds are mechanically stable. However, SrNiH3 exhibits a larger bulk modulus and Young's modulus compared to BaNiH3. The results highlight the potential of SrNiH3 and BaNiH3 as suitable options for storing hydrogen, which can contribute to the progress of clean energy technology.

The comparative study of the empirical and DFT theoretical properties of ZnSnO3 perovskite nanoparticles

The composites of zinc tin oxide (ZTO) are lead-free materials, categorized as piezoelectric nanoparticles, and have a variety of multifunctional applications. These materials exhibit a lot of potential for a range of uses. Therefore, to prepare the aqueous solutions of ZnSnO3 and Zn2SnO4 and investigate the experimental structural and optical properties of ZTO materials, this work employed two different chemical reaction paths. ZTO materials are created via a straightforward chemical reaction process in which chemical route (I) combines tetravalent tin chloride with divalent zinc chloride. ZTO materials are generated via the employment of divalent zinc chloride and divalent tin chloride in chemical route II. The structural characteristics and composition of the material were investigated using XRD analysis. The materials were discovered to have hexagonal perovskites and a cubic structure. Furthermore, examining the optical characteristics led to estimating the optical energy gap values (Eg = 3.6 and 3.9) eV for the hexagonal and cubic perovskite structures, respectively. The paper also compares experimental results with theoretical findings obtained with the Cambridge Serial Total Energy Package (CASTEP) software’s Density Function Theory (DFT) approximation. Theoretical and empirical results were closely analyzed and contrasted.

DFT-based investigation of polyetherketoneketone materials for surface modification for dental implants

BackgroundPolyetherketoneketone (PEKK) is a high-performance thermoplastic polymer with unique structural and mechanical properties that make it a promising candidate for surface modification of dental implants. This study was conducted to investigate the feasibility of PEKK for this purpose using the Cambridge Serial Total Energy Package (CASTEP) code based on density functional theory (DFT).MethodsThis study examined the ground state energy, structural properties, thermodynamic behavior, cohesive energy, refractive index, stress analysis, mechanical properties, and anisotropic behavior of PEKK.ResultsThis study found that PEKK has a complex crystal structure with an orthorhombic unit cell shape, triclinic lattice type, and a centered structure. It also has a 2D layered structure owing to the presence of carbonyl groups, which provides a large surface area for interaction with biological tissues. Thermodynamic analysis showed that PEKK exhibited bond elongation and structural changes at 380 °C, indicating thermal degradation. The cohesive energy of PEKK was calculated to be – 440 eV, indicating its stability and structural integrity. PEKK has a complex refractive index, with real and imaginary components that affect its optical properties. Stress analysis showed that PEKK is resistant to shear deformation and has high hydrostatic stress, which contributes to its stability and biocompatibility.ConclusionThe mechanical properties of PEKK, including its high stiffness, resistance to volume change under pressure, and ability to accommodate natural movements, make it suitable for surface modification of dental implants.

Computational investigation on physical properties of lead based perovskite RPbBr3 (R = Cs, Hg, and Ga) materials for photovoltaic applications

In the modern era, the major problem is solving energy production and consumption. For this purpose, perovskite materials meet these issues and fulfill energy production at a low cost. Density functional theory and the Cambridge Serial Total Energy Package (CASTEP) are used to examine the characteristics of the cubic inorganic perovskites RPbBr3 (R = Cs, Hg, and Ga). In the context of the generalized gradient approximation (GGA), the ultrasoft pseudo-potential plane wave technique and the Perdew–Burke–Ernzerhof exchange–correlation functional are used for investigations. Structural, mechanical, electronics, and optical properties are investigated using CASTEP code. According to structural properties, compounds have a cubic nature with space 221 (Pm3m). Compounds formation energy (− 3.46, − 2.21, and − 3.14 eV)of (CsPbBr3, HgPbBr3, and GaPbBr3) and phonon calculations are studied and find that compounds are stable. The results of our investigation show that the compounds have narrow bandgaps of direct kind, with 1.85 eV for CsPbBr3, 1.56 eV for HgPbBr3, and 1.71 eV for GaPbBr3, respectively, indicating that they may be used to improve conductivity. Additionally, anisotropy (2.135, 3.651, 10.602), Pugh’s ratio (1.87, 2.25, 2.14), and Poison’s ratio (0.27, 0.31, 0.29) are traits that the compounds (CsPbBr3, HgPbBr3, GaPbBr3) display a ductile nature. The CsPbBr3 compound showed significant optical conductivity and absorption in terms of their optical properties, especially in the visible region, which makes them suitable for use in solar cell applications as well as for LED applications.

Predicting the thermal decomposition temperature of energetic materials from a simple model.

The key factor in designing heat-resistant energetic materials is their thermal sensitivity. Further research and prediction of thermal sensitivity remains a great challenge for us. This study is based on first-principles calculations and establishes a theoretical model, which comprehensively considers band gap, density of states, and Young's modulus to obtain a empirical parameter Ψ. A quantitative relationship was established between the new parameter and the thermal decomposition temperature. The value of Ψ is calculated for 10 energetic materials and is found to have a strong correlation with the experimental thermal decomposition temperature. This further proves the reliability of our model. Specifically, the larger the value of Ψ, the higher the thermal decomposition temperature, and the more stable the energetic material will be. Therefore, to some extent, we can use the new parameter Ψ calculated by the model to predict thermal sensitivity. Based on first-principles, this paper used the Cambridge Serial Total Energy Package (CASTEP) module of Materials Studio (MS) for calculations. The Perdew-Burke-Ernzerhof (PBE) functionals in Generalized Gradient Approximation (GGA) method as well as the Grimme dispersion correction was used in this paper.

Physico-chemical characterization of feldspars for application as fluxing agents: Experimental and ab initio computational approaches

Feldspars are tectosilicates with unique composition and structural features employed to help develop the glassy phase while firing ceramic raw materials. This promotes vitrification by lowering sintering temperatures thereby making it more energy efficient and sustainable. This study examined the physico-chemical parameters of feldspars found in Marimanti, Tharaka Nithi county in Kenya with the aim of determining their fluxing capabilities. This was achieved through the use of ab-initio theoretical computations and experimental investigation into phases, morphology and thermal stability. Experimental results showed albite and anorthite mineral phases with dominant alumina and silica content, classifying it as a plagioclase type. Further experimental results revealed four predominant phases viz: Ca-feldspar, K-feldspar, Na-feldspar and quartz with mesoporous morphology and average particle sizes of 5 μm. Thermal stability studies showed a significant derived weight loss per °C in the 400–700 °C range with a peak at 497.67 °C. Three-dimensional atomistic simulations conducted on albite, anorthite and feldspar mineral phases were computed using the Cambridge Serial Total Energy Package (CASTEP) module of Material Studio software, using generalized gradient approximation (GGA) with Perde-Burke-Ernzerhof (-PBE) correction function. Accordingly, ab initio studies showed the minerals had a 3D triclinic lattice structure with predicted bulk moduli of 45.91 GPa and 88.86 GPa for albite and anorthite, respectively. In furtherance, the computed band gap energies were 2.644 eV for albite and 2.661 eV for anorthite, indicating high insulation capacity for both mineral phases. Overall, the experimental and computational results obtained were in agreement with literature on fluxing properties. Further, the outstanding properties reported indicated high quality feldspars which can be exploited sustainably for application as fluxing agents.

First-principles calculation to investigate structural, electronic, optical, and thermodynamics properties of perovskite KXO3 (K[dbnd]Ta and Zn) alloys for photovoltaic and smart window applications

Compounds KXO3 (X = Zn and Ta) properties are explored using CASTEP (Cambridge serial total energy package) software along with Generalized Gradient Approximation (GGE) and PBE exchange-correlation functionals that have pm3m (221) symmetry with cubic. Electronic characteristics associated with the electronic band structure (phase), total density of states TDOS, partial DOS, and elemental PDOS have been calculated. KTaO3 and KZnO3 show an indirect energy bandgap of 1.61 eV and 4.53 eV, respectively; thus, KTaO3 is a semiconductor while KZnO3 is an insulator. Optical properties disclose that maximum absorption occurs in both visible and ultra-violet ranges of the electromagnetic (EM) spectrum of KTaO3 and KZnO3. The elastic properties of the compounds show that KTaO3 is ductile and KZnO3 is brittle, and the brittleness of the compound will increase the reflection of the radiation, and KTaO3 will conduct radiation more frequently in the visible region.

Insight into the Physical Properties of the Chalcogenide XZrS3 (X = Ca, Ba) Perovskites: A First-Principles Computation

This study investigates the structural, mechanical, optical, thermal, and electronic properties of the ionic semiconducting materials XZrS3 (X = Ca, Ba) within the framework of density functional theory (DFT). Here, the elastic constants, modulus (bulk, shear, Young's), ratios (Pugh, Poisson) and elastic anisotropy for XZrS3 (X = Ca, Ba) are studied. Furthermore, the electronic, optical, and thermal properties for XZrS3 (X = Ca, Ba) are regenerated and designed using the values obtained with Cambridge Serial Total Energy Package (CASTEP) software. The calculated lattice parameters show excellent agreement with theoretical and experimental values. The elastic stiffness constants confirm the mechanical stability of both compounds. Although XZrS3 (X = Ca, Ba) is elastically anisotropic, it has little optical anisotropy. The electronic band structures of the material exhibit direct-bandgap semiconducting behavior, with values of 1.3 eV (CaZrS3) and 1.1 eV (BaZrS3) using the generalized gradient approximation (GGA), respectively, which is ideal for solar cell (0.9–1.56 eV) and optoelectronic device applications. Bandgap values of 1.9 eV and 1.6 eV are found for CaZrS3 and BaZrS3, respectively, using the Heyd–Scuseria–Ernzerhof HSE06 functional, which is consistent with previous theoretical and experimental bandgap results. The optical properties including dielectric function, refractive index, absorption coefficient, reflectivity, and loss function are characterized using the GGA of Perdew–Burke–Ernzerhof (GGA-PBE) and HSE06 methods and are discussed in detail. Because of the relatively low Debye temperature (D), thermal conductivity of the lattice (kph), and minimum thermal conductivity (Kmin), the studied materials can be used as thermal barrier coating (TBC) materials. The capacity of heat, Debye temperature, and thermal coefficient of expansion are all computed.

Quantum mechanical analysis of yttrium-stabilized zirconia and alumina: implications for mechanical performance of esthetic crowns

BackgroundYttrium-stabilized zirconia (YSZ) and alumina are the most commonly used dental esthetic crown materials. This study aimed to provide detailed information on the comparison between yttrium-stabilized zirconia (YSZ) and alumina, the two materials most often used for esthetic crowns in dentistry.MethodologyThe ground-state energy of the materials was calculated using the Cambridge Serial Total Energy Package (CASTEP) code, which employs a first-principles method based on density functional theory (DFT). The electronic exchange–correlation energy was evaluated using the generalized gradient approximation (GGA) within the Perdew (Burke) Ernzerhof scheme.ResultsOptimization of the geometries and investigation of the optical properties, dynamic stability, band structures, refractive indices, and mechanical properties of these materials contribute to a holistic understanding of these materials. Geometric optimization of YSZ provides important insights into its dynamic stability based on observations of its crystal structure and polyhedral geometry, which show stable configurations. Alumina exhibits a distinctive charge, kinetic, and potential (CKP) geometry, which contributes to its interesting structural framework and molecular-level stability. The optical properties of alumina were evaluated using pseudo-atomic computations, demonstrating its responsiveness to external stimuli. The refractive indices, reflectance, and dielectric functions indicate that the transmission of light by alumina depends on numerous factors that are essential for the optical performance of alumina as a material for esthetic crowns. The band structures of both the materials were explored, and the band gap of alumina was determined to be 5.853 eV. In addition, the band structure describes electronic transitions that influence the conductivity and optical properties of a material. The stability of alumina can be deduced from its bandgap, an essential property that determines its use as a dental material. Refractive indices are vital optical properties of esthetic crown materials. Therefore, the ability to understand their refractive-index graphs explains their transparency and color distortion through how the material responds to light..The regulated absorption characteristics exhibited by YSZ render it a highly attractive option for the development of esthetic crowns, as it guarantees minimal color distortion.ConclusionThe acceptability of materials for esthetic crowns is strongly determined by mechanical properties such as elastic stiffness constants, Young's modulus, and shear modulus. YSZ is a highly durable material for dental applications, owing to its superior mechanical strength.

Effects of Alloying Element on Hydrogen Adsorption and Diffusion on α-Fe(110) Surfaces: First Principles Study

Based on first principles density functional theory (DFT) methods, this study employed the Cambridge Serial Total Energy Package (CASTEP) module within Materials Studio (MS) software under the generalized gradient approximation to investigate the adsorption, diffusion behavior, and electronic properties of hydrogen atoms on α-Fe(110) and α-Fe(110)-Me (Mn, Cr, Ni, Mo) surfaces, including calculations of their adsorption energies and density of states (DOS). The results demonstrated that doping with alloy atoms Me increased the physical adsorption energy of H2 molecules on the surface. Specifically, Mo doping elevated the adsorption energy from −1.00825 eV to −0.70226 eV, with the largest relative change being 30.35%. After doping with Me, the chemical adsorption energy of two hydrogen atoms does not change significantly, among which doping with Cr results in a decrease in the chemical adsorption energy. Building on this, further analysis of the chemical adsorption of single atoms on the surface was conducted. By comparing the adsorption energy and the bond length between a hydrogen atom and iron/dopant metal atom, it was found that Mo doping has the greatest impact, increasing the bond length by 58.58%. Analysis of the DOS functions under different doping conditions validated the interaction between different alloy elements and H atoms. Simultaneously, simulations were carried out on the energy barrier crossed by H atoms diffusing into the metal interior. The results indicate that Ni doping facilitates the diffusion of H atoms, while Cr, Mn, and Mo hinder their diffusion, with Mo having the most significant effect, where its barrier is 21.88 times that of the undoped surface. This conclusion offers deep insights into the impact of different doping elements on hydrogen adsorption and diffusion, aiding in the design of materials resistant to hydrogen embrittlement.

Structural, electronic, and optical properties of Cd‐halide‐based inorganic LiCdX3 (X = F, Cl) perovskites for photovoltaic applications: A density functional theory study

AbstractHalide base perovskite LiCdX3 (X = F, Cl) is tested by CASTEP (Cambridge Serial Total Energy Package) based on density function theory (DFT). The presented discussion is to explore the structural, electronic, and optical properties of LiCdX3 (X = F, Cl). The calculated values of the lattice parameter are found to be 3.8 Å and 5.27 Å of LiCdF3 and LiCdCl3 respectively. The ideal structure of LiCdX3 (X = F, Cl) is cubic and dynamically stable. Electronic properties show that materials are semiconductors. The results from band structure are further evaluated by the total and partial density of states. The partial and total density of states confirms the degree of localization of electrons. In optical properties, the highest absorption coefficient is observed in LiCdCl3. The material is half metallic and has a narrow indirect band gap which may be used in photovoltaic applications.

Structural, electronic, optical, and mechanical properties of cubic perovskite LaMnX3 (X = Cl, Br, I) compound for optoelectronic applications: a DFT study

Perovskite materials are used extensively in the area of material science for theoretical computations. Density functional theory (DFT) calculations are used in this study to determine the properties of the cubic halide perovskite LaMnX3 (X = Cl, Br, and I). These compounds contain PM3M-221 space groups and a cubic structure. They were created via the Cambridge serial total energy package (CASTEP) program, which also used HSE (Heyd–Scuseria–Ernzerhof) exchange–correlation functionals. The structural, electrical, optical, and mechanical characteristics of the compounds are determined.LaMnCl3, LaMnBr3, and LaMnI3all have direct bandgaps of 2.366 eV, 1.844 eV, and 1.579 eV, respectively, based on their structural characteristics. Total and partial densities of states (TDOS and PDOS) offer proof of the degree of electron localization in specific bands. Electronic studies indicate that LaMnX3 materials (X = Cl, Br, I) are semiconductors. The dielectric function’s extensive range of energy transparency can be seen in the imaginary element dispersion. LaMnCl3 compound’s absorption and conductivity are preferable to those of LaMnBr3 and LaMnI3, improving its applicability for Optoelectronic applications and work function. We found that the cubic structures of all three compounds allow them to be mechanically stable. The calculated elastic results also satisfy the compound’s mechanical strength requirements. Such materials are used in optoelectronic applications.

Investigation of structural, mechanical, electronic and optical responses of Ga doped aluminum arsenide for optoelectronic applications: By first principles

Owing to the rapidly increasing performance of ternary semiconductors; Aluminium Gallium Arsenide (Al1-xGaxAs; x = 0, 0.25, 0.50, 0.75) has been studied by first-principles calculations in Cambridge Serial Total Energy Package (CASTEP-Code). Density functional theory in the frame of full potential linear augmented plane wave (FP-LAPW) is used. The structural, electronic, and optical behavior of the Zinc Blend (ZB) structure of AlAs with Ga impurity was computed by using generalized gradient approximation (GGA) as exchange potential and Perdew-Burke-Ernzerhof (PBE) as functional. Changes in lattice parameters (a), bulk modulus (66.07–76.85), hardness (5.79–8.91) and machinability (1.36–1.46), band gap energy (Eg), and optical properties are computed and discussed in this work. Lattice parameters and elastic constants showed excellent agreement with the reported data whereas some properties were found to excel much more than the theoretical reports. Remarkable bandgap reduction from 1.7eV to 0.28eV is very encouraging in its low-energy applications in UV and visible ranges. Real (Re) and Imaginary (Img) parts of the dielectric function and refractive index shifts towards lower energy values show good agreement with those of theoretical and experimental works. We contribute to the knowledge and characterization of Al1-xGaxAs facilitating its integration into various technological advancements such as photovoltaic, laser, diodes, and high-frequency transistors.

Rubidium zinc trioxide perovskite materials for photovoltaic solar cell applications: A first principle calculations

Perovskite materials are the well-known of solar cell applications and have excellent characteristics to study and explain the photocatalytic research. Exchange generalized gradient approximation (GGA) and Perdew-Burke-Ernzerhof-PBE correlation functionals and density functional theory (DFT)-based Cambridge Serial Total Energy Package (CASTEP) software are used to inspect the structural, electrical, mechanical, and the optical aspects of Zinc-based cubic perovskite RbZnO3. The compound is found to be in a stable cubic phase according to our study. The predicted elastic characteristics also satisfy the mechanical criterion for stability. Pugh's criterion indicates that RbZnO3 is brittle. The examination shows that the electronic band structure, RbZnO3 possesses an indirect bandgap (BG) that has 4.23eV. Findings of BG analysis agree with currently available evidence. Total and partial density of states (DOS) are used in the confirmation of degree of a localized electrons in special band. Optical transitions in compound are evaluated by adjusting damping ratio for the appropriate peaks of the notional dielectric functions. On one hand, the material is a semiconductor at absolute zero. On the other hand, the dielectric function's fictitious element dispersion illustrates the wide range of values for energy transparency. This substance might therefore be used in a solar cell to capture ultraviolet light.

Structural, mechanical, electronic and optical properties of MFe2O4(M=Zn, Cu, Si) ferrites for electrochemical, photocatalytic and optoelectronic applications

First principles density functional calculations within the Cambridge Serial Total Energy Package (CASTEP) code applied to widely explore structural, mechanical, electronic and optical properties of MFe2O4 (M = Zn, Cu, Si) ferrites at pressures 0, 5, 10, 15, 20 GPa. The computed X-ray diffraction patterns showed that the lattice parameter values for MFe2O4 (M = Zn, Cu, Si) ferrites were 8.48-8.08 Å, 8.32-8.14 Å, and 8.23-7.87Å, respectively at external pressure 0–20 GPa. The energy bandgap of the MFe2O4 (M = Zn, Si) ferrites revealed a direct nature within the range 1.24-0.0.82 eV and 3.843–3.484 eV versus 0–20 GPa external pressure, respectively. The CuFe2O4 ferrite exhibited indirect bandgaps ranging from 1.167 to 0.992 eV versus 0–20 GPa external pressure. Hence, all the computed values of the band gap showed an inverse response to applied pressure. Mulliken population and the total density of state confirmed that all the bonds Fe–O, Zn–O, Si–O, and Cu–O were covalent. The mechanical properties revealed the cubic stability of MFe2O4 (M = Zn, Cu, Si) ferrites. So, these ferrites proved potential candidates in electrochemical applications. The B/G values presented that the MFe2O4 (M = Zn, Cu) ferrites were ductile and considered suitable candidates in photocatalytic applications. In contrast, the SiFe2O4 ferrite exhibited brittle behavior at all the values of external pressure 0–20 GPa and was deemed helpful to optoelectronic devices. The optical properties showed that MFe2O4 (Zn, Cu, Si) ferrites showed excellent photosensitivity to visible light in photocatalytic, solar cells and optoelectronic applications.

A DFT study on the switching energy of multiferroic capacitor with stable single-phase multiferroic material

In spintronic technology, bismuth ferrite BiFeO3 (BFO) is a potential multiferroic material for multiferroic capacitor application. In present study, the impact of transition metals X = Co, Ni, Mn, Ti at the Fe-site and rare earth element lanthanum (La) at the Bi-site is investigated using DFT calculation in order to improve the structural stability, spin polarized electronic, and dielectric properties of bismuth ferrite for switching energy of multiferroic capacitor applications. The calculations are carried out in the Cambridge Serial Total Energy Package (CASTEP) code by using ultra-soft pseudopotential (USP). The substitution of La and X atoms alters the spin-polarizedelectronic and dielectric characteristics of BFO, leading to an increase in the density of states (DOS) around the Fermi level. The observed descending order of the structure stability of co-doped BFO is given as: LaCo > LaNi > LaMn co-doped BFO system. LaCo and LaNi co-substituted systems have shown high spin polarizations of 87.08 % and 82.20 % respectively. Low switching energies of 0.52 aJ and 0.72 aJ, respectively have been observed for LaCo and LaNi co-doped BFO systems for multiferroic RAM capacitor applications.