Design and Optimization of High-Performance Novel RbPbBr3-Based Solar Cells with Wide-Band-Gap S-Chalcogenide Electron Transport Layers (ETLs).

Inorganic cubic rubidium-lead-halide perovskites have attracted considerable attention owing to their structural, electronic, and unique optical properties. In this study, novel rubidium-lead-bromide (RbPbBr3)-based hybrid perovskite solar cells (HPSCs) with several high-band-gap chalcogenide electron transport layers (ETLs) of In2S3, WS2, and SnS2 were studied by density functional theory (DFT) and using the SCAPS-1D simulator. Initially, the band gap and optical performance were computed using DFT, and these results were utilized for the first time in the SCAPS-1D simulator. Furthermore, the impact of different major influencing parameters, that is, the thickness of the layer, bulk defect density, doping concentration, and defect density of interfaces, including the working temperature, were also investigated and unveiled. Further, a study on an optimized device with the most potential ETL (SnS2) layer was performed systematically. Finally, a comparative study of different reported heterostructures was performed to explore the benchmark of the most recent efficient RbPbBr3-based photovoltaics. The highest power conversion efficiency (PCE) was 29.75% for the SnS2 ETL with Voc of 0.9789 V, Jsc of 34.57863 mA cm-2, and fill factor (FF) of 87.91%, while the PCEs of 21.15 and 24.57% were obtained for In2S3 and WS2 ETLs, respectively. The electron-hole generation, recombination rates, and quantum efficiency (QE) characteristics were also investigated in detail. Thus, the SnS2 ETL shows strong potential for use in RbPbBr3-based hybrid perovskite high-performance photovoltaic devices.

Exploring the influence of pressure-induced semiconductor-to-metal transition on the physical properties of cubic perovskites FrXCl3 (X = Ge and Sn).

Even though lead halide perovskites have outstanding physiochemical properties and improved power conversion efficiency, most of these compounds threaten their future commercialization because of their instability and highly toxic nature. Thus, it is preferable to use stable alternative elements rather than lead to make environmentally friendly perovskite material that will have comparable optical and electronic properties to those constructed from Pb-based perovskites. However, devices constructed from lead-free perovskites typically display a lower power conversion efficiency. Applying hydrostatic pressure could be deemed an effective method to alter the physical properties of these compounds. This not only improves their performance in application but also reveals significant correlations between structure and properties. This work uses DFT to investigate the structural, electronic, optical, and elastic properties of non-toxic, francium-based halide perovskites FrXCl3 (X = Ge, Sn) at different levels of hydrostatic pressures that vary from 0 to 10 GPa. The estimated structural parameter's strong correlation with the data from earlier studies ensures the accuracy of the current findings. Pressure causes the Fr-Cl and Ge (Sn)-Cl bonds to shorten and become stronger. The electronic property calculations demonstrated that both compounds are direct band-gap semiconductors. The application of pressure leads to a linear reduction in the band gap (semiconducting to metallic state) and raises the electronic density of states around the Fermi level by forcing the valence band electrons upward, indicating that the optoelectronic device's performance can be tuned and improved. The values of the dielectric constant, absorptivity and reflectivity showed an increasing tendency with pressure. As the pressure applied to the compounds increases, the absorption spectra show a redshift. These findings suggested that the FrXCl3 (X = Ge and Sn) compound becomes more appropriate for usage in optoelectronic applications under pressure. Furthermore, our examination of the mechanical properties indicates that both FrGeCl3 and FrSnCl3 exhibit mechanically stability, and ductility. Interestingly, we observe an increase in ductility as pressure levels rise.

Creation of a boron carbide-based Ti3AlBC (312) MAX phase: a route to novel MXenes for energy storage.

A novel boron carbide (B4C)-based Ti3AlBC (312) MAX phase was predicted for the first time via density functional theory (DFT). The stability of the MAX phase was confirmed by mechanical and thermal property analyses. The computational details revealed the attractive properties of Ti3AlBC, indicating its potential as an advanced material with improved characteristics. Its thermodynamic properties are reported as a function of temperature, indicating its potential for energy storage applications.

Band gap engineering in lead free halide cubic perovskites GaGeX3 (X = Cl, Br, and I) based on first-principles calculations.

Lead-free inorganic Ge-based perovskites GaGeX3 (X = Cl, Br, and I) are promising candidates for solar cell applications due to their structural, mechanical, electrical, and optical properties. In this work, we performed density functional theory (DFT) calculations using the CASTEP module to investigate these properties in detail. We found that the lattice parameters and cell volumes increase with the size of the halogen atoms, and that all the compounds are stable and ductile. GaGeBr3 has the highest ductility, machinability, and lowest hardness, while GaGeCl3 has the highest anisotropy. The band gap values, calculated using the GGA-PBE and HSE06 functionals, show a direct band gap at the R-R point, ranging from 0.779 eV and 1.632 eV for GaGeCl3 to 0.330 eV and 1.140 eV for GaGeI3. The optical properties, such as absorption coefficient, conductivity, reflectivity, refractive index, extinction coefficient, and dielectric function, are also computed and discussed. We observed that the optical properties improve with the redshift of the band gap as Cl is replaced by Br and I. GaGeI3 has the highest dielectric constant, indicating the lowest recombination rate of electron-hole pairs. Our results suggest that GaGeX3 (X = Cl, Br, and I) can be used as effective and non-toxic materials for multijunction solar cells and other semiconductor devices.

Effect of Low to High Pressure on the Structural, Mechanical, Electrical, and Optical Properties of Inorganic Material Ca3AsBr3: An Ab Initio Investigation.

Inorganic metal halide solar cells made from perovskite stand out for having outstanding efficiency, cheap cost, and simple production processes and recently have generated attention as a potential rival in photovoltaic technology. Particularly, lead-free Ca3AsBr3 inorganic materials have a lot of potential in the renewable industry due to their excellent qualities, including thermal, electric, optoelectronic, and elastic features. In this work, we thoroughly analyzed the stress-driven structural, mechanical, electrical, and optical properties of Ca3AsBr3 utilizing first-principles theory. The unstressed planar Ca3AsBr3 compound's bandgap results in 1.63 eV, confirming a direct bandgap. The bandgap within this compound could have changed by applying hydrostatic stress; consequently, a semiconductor-to-metallic transition transpired at 50 GPa. Simulated X-ray diffraction further demonstrated that it maintained its initial cubic form, even after external disruption. Additionally, it has been shown that an increase in compressive stress causes a change of the absorption spectra and the dielectric function with a red shift of photon energy at the lower energy region. Because of the material's mechanical durability and increased degree of ductility, demonstrated by its stress-triggered mechanical characteristics, the Ca3AsBr3 material may be suitable for solar energy applications. The mechanical and optoelectronic properties of Ca3AsBr3, which are pressure sensitive, could potentially be advantageous for future applications in optical devices and photovoltaic cell architecture.

A qualitative Design and optimization of CIGS-based Solar Cells with Sn2S3 Back Surface Field: A plan for achieving 21.83 % efficiency.

Conventional Copper Indium Gallium Di Selenide (CIGS)-based solar cells are more efficient than second-generation technology based on hydrogenated amorphous silicon (a-Si: H) or cadmium telluride (CdTe). So, herein the photovoltaic (PV) performance of CIGS-based solar cells has been investigated numerically using SCAPS-1D solar simulator with different buffer layer and less expensive tin sulfide (Sn2S3) back-surface field (BSF). At first, three buffer layer such as cadmium sulfide (CdS), zinc selenide (ZnSe) and indium-doped zinc sulfide ZnS:In have been simulated with CIGS absorber without BSF due to optimized and non-toxic buffer. Then the optimized structure of Al/FTO/ZnS:In/CIGS/Ni is modified to become Al/FTO/ZnS:In/CIGS/Sn2S3/Ni by adding a Sn2S3 BSF to enhanced efficiency. The detailed analysis have been investigated is the influence of physical properties of each absorber and buffer on photovoltaic parameters including layer thickness, carrier doping concentration, bulk defect density, interface defect density. This study emphasizes investigating the reasons for the actual devices' poor performance and illustrates how each device's might vary open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), power conversion efficiency (PCE), and quantum efficiency (QE). The optimized structure offers outstanding power conversion efficiency (PCE) of 21.83 % with only 0.80 µm thick CIGS absorber. The proposed CIGS-based solar cell performs better than the previously reported conventional designs while also reducing CIGS thickness and cost.

Lead-free novel perovskite Ba3AsI3: First-principles insights into its electrical, optical, and mechanical properties.

Lead-free halide perovskites are a crucial family of materials in the fabrication of solar cells. At present, Solar cells are facing several challenges such as mechanical and thermodynamic instability, toxicity, unsuitable optical parameters, bandgap, and absorption coefficient. Ba3AsI3 is a halide perovskite which has demonstrated good efficiency and tremendous promise for usage in solar cell applications, and it offers a possible solution to these issues. In this study, the properties of the Ba3AsI3 perovskite solar cell were investigated using first-principles density functional theory (FP-DFT) calculations with the CASTEP (Cambridge serial total energy package) formulation. Most of its physical qualities, including its elasticity, electrical composition, bonding, optoelectronic characteristics, and optical characteristics have not yet been explored. In this work, these unexplored properties have been thoroughly investigated using density functional theory-based computations. The Born-Huang criterion and phonon dispersion characteristics have revealed that the material is mechanically stable. The bonding nature has been investigated using the density of states curves, Mulliken population analysis, and electronic charge density. Additionally, different elastic parameters demonstrate that Ba3AsI3 has reasonably high machinability and is mechanically isotropic. ELATE's three-dimensional visualization and optical properties also show isotropic behavior in all directions. The band structure shows that the bandgap is direct. Based on its direct bandgap, stability, large range of absorption coefficient, and suitable optical parameters, Ba3AsI3 is recommended as an absorber layer for solar cell fabrication in a near future.

Boosting efficiency above 28% using effective charge transport layer with Sr3SbI3 based novel inorganic perovskite.

Strontium antimony iodide (Sr3SbI3) is one of the emerging absorbers materials owing to its intriguing structural, electronic, and optical properties for efficient and cost-effective solar cell applications. A comprehensive investigation on the structural, optical, and electronic characterization of Sr3SbI3 and its subsequent applications in heterostructure solar cells have been studied theoretically. Initially, the optoelectronic parameters of the novel Sr3SbI3 absorber, and the possible electron transport layer (ETL) of tin sulfide (SnS2), zinc sulfide (ZnS), and indium sulfide (In2S3) including various interface layers were obtained by DFT study. Afterward, the photovoltaic (PV) performance of Sr3SbI3 absorber-based cell structures with SnS2, ZnS, and In2S3 as ETLs were systematically investigated at varying layer thickness, defect density bulk, doping density, interface density of active materials including working temperature, and thereby, optimized PV parameters were achieved using SCAPS-1D simulator. Additionally, the quantum efficiency (QE), current density-voltage (J-V), and generation and recombination rates of photocarriers were determined. The maximum power conversion efficiency (PCE) of 28.05% with JSC of 34.67 mA cm-2, FF of 87.31%, VOC of 0.93 V for SnS2 ETL was obtained with Al/FTO/SnS2/Sr3SbI3/Ni structure, while the PCE of 24.33%, and 18.40% in ZnS and In2S3 ETLs heterostructures, respectively. The findings of this study contribute to in-depth understanding of the physical, electronic, and optical properties of Sr3SbI3 absorber perovskite and SnS2, ZnS, and In2S3 ETLs. Additionally, it provides valuable insights into the potential of Sr3SbI3 in heterostructure perovskite solar cells (PSCs), paving the pathway for further experimental design of an efficient and stable PSC devices.

Inorganic novel cubic halide perovskite Sr3AsI3: Strain-activated electronic and optical properties.

In recent years, inorganic perovskite materials have attracted a lot of attention in the field of solar technology due to their exceptional structural, optical, and electronic properties. This study thoroughly investigated, using first-principles density-functional theory (FP-DFT), the impact of compressive and tensile strain on the structural, optical, and electrical properties of the inorganic cubic perovskite Sr3AsI3. The unstrained planar Sr3AsI3 molecule exhibits a direct bandgap of 1.265 eV value at Γ point. The bandgap of the Sr3AsI3 perovskite is lowered to 1.212 eV when the relativistic spin-orbital coupling (SOC) effect is subjected in the observations. In addition, the structure's bandgap exhibits a falling prevalence due to compressive strain and a slight rise due to tensile strain. The optical indicators such as dielectric functions, absorption coefficient, reflectivity, and electron loss function show that this component has a great ability to absorb in the visible range in accordance with band characteristics. When compressive strain is raised, it is discovered that the spikes of the dielectric constant of Sr3AsI3 move to lower photon energy (redshift), and conversely, while growing tensile strain, it exhibits increased photon energy changing behavior (blueshift). As a result, the Sr3AsI3 perovskite is regarded as being ideal for use in solar cells for the production of electricity and light management.

Achieving above 24% efficiency with non-toxic CsSnI3 perovskite solar cells by harnessing the potential of the absorber and charge transport layers.

Lead toxicity is a barrier to the widespread commercial manufacture of lead halide perovskites and their use in solar photovoltaic (PV) devices. Eco-friendly lead-free perovskite solar cells (PSCs) have been developed using certain unique non- or low-toxic perovskite materials. In this context, Sn-based perovskites have been identified as promising substitutes for Pb-based perovskites due to their similar characteristics. However, Sn-based perovskites suffer from chemical instability, which affects their performance in PSCs. This study employs theoretical simulations to identify ways to improve the efficiency of Sn-based PSCs. The simulations were conducted using the SCAPS-1D software, and a lead-free, non-toxic, and inorganic perovskite absorber layer (PAL), i.e. CsSnI3 was used in the PSC design. The properties of the hole transport layer (HTL) and electron transport layer (ETL) were tuned to optimize the performance of the device. Apart from this, seven different combinations of HTLs were studied, and the best-performing combination was found to be ITO/PCBM/CsSnI3/CFTS/Se, which achieved a power conversion efficiency (PCE) of 24.73%, an open-circuit voltage (VOC) of 0.872 V, a short-circuit current density (JSC) of 33.99 mA cm-2 and a fill factor (FF) of 83.46%. The second highest PCE of 18.41% was achieved by the ITO/PCBM/CsSnI3/CuSCN/Se structure. In addition to optimizing the structure of the PSC, this study also analyzes the current density-voltage (J-V) along with quantum efficiency (QE), as well as the impact of series resistance, shunt resistance, and working temperature, on PV performance. The results demonstrate the potential of the optimized structure identified in this study to enhance the standard PCE of PSCs. Overall, this study provides important insights into the development of lead-free absorber materials and highlights the potential of using CsSnI3 as the PAL in PSCs. The optimized structure identified in this study can be used as a base for further research to improve the efficiency of Sn-based PSCs.

Deep Insights into the Coupled Optoelectronic and Photovoltaic Analysis of Lead-Free CsSnI3 Perovskite-Based Solar Cell Using DFT Calculations and SCAPS-1D Simulations.

CsSnI3 is considered to be a viable alternative to lead (Pb)-based perovskite solar cells (PSCs) due to its suitable optoelectronic properties. The photovoltaic (PV) potential of CsSnI3 has not yet been fully explored due to its inherent difficulties in realizing defect-free device construction owing to the nonoptimized alignment of the electron transport layer (ETL), hole transport layer (HTL), efficient device architecture, and stability issues. In this work, initially, the structural, optical, and electronic properties of the CsSnI3 perovskite absorber layer were evaluated using the CASTEP program within the framework of the density functional theory (DFT) approach. The band structure analysis revealed that CsSnI3 is a direct band gap semiconductor with a band gap of 0.95 eV, whose band edges are dominated by Sn 5s/5p electrons After performing the DFT analysis, we investigated the PV performance of a variety of CsSnI3-based solar cell configurations utilizing a one-dimensional solar cell capacitance simulator (SCAPS-1D) with different competent ETLs such as IGZO, WS2, CeO2, TiO2, ZnO, PCBM, and C60. Simulation results revealed that the device architecture comprising ITO/ETL/CsSnI3/CuI/Au exhibited better photoconversion efficiency among more than 70 different configurations. The effect of the variation in the absorber, ETL, and HTL thickness on PV performance was analyzed for the above-mentioned configuration thoroughly. Additionally, the impact of series and shunt resistance, operating temperature, capacitance, Mott-Schottky, generation, and recombination rate on the six superior configurations were evaluated. The J-V characteristics and the quantum efficiency plots for these devices are systematically investigated for in-depth analysis. Consequently, this extensive simulation with validation results established the true potential of CsSnI3 absorber with suitable ETLs including ZnO, IGZO, WS2, PCBM, CeO2, and C60 ETLs and CuI as HTL, paving a constructive research path for the photovoltaic industry to fabricate cost-effective, high-efficiency, and nontoxic CsSnI3 PSCs.

Harnessing the potential of CsPbBr3-based perovskite solar cells using efficient charge transport materials and global optimization.

Perovskite solar cells (PSCs) have become a possible alternative to traditional photovoltaic devices for their high performance, low cost, and ease of fabrication. Here in this study, the SCAPS-1D simulator numerically simulates and optimizes CsPbBr3-based PSCs under the optimum illumination situation. We explore the impact of different back metal contacts (BMCs), including Cu, Ag, Fe, C, Au, W, Pt, Se, Ni, and Pd combined with the TiO2 electron transport layer (ETL) and CFTS hole transport layer (HTL), on the performance of the devices. After optimization, the ITO/TiO2/CsPbBr3/CFTS/Ni structure showed a maximum power conversion efficiency (PCE or η) of 13.86%, with Ni as a more cost-effective alternative to Au. After the optimization of the BMC the rest of the investigation is conducted both with and without HTL mode. We investigate the impact of changing the thickness and the comparison with acceptor and defect densities (with and without HTL) of the CsPbBr3 perovskite absorber layer on the PSC performance. Finally, we optimized the thickness, charge carrier densities, and defect densities of the absorber, ETL, and HTL, along with the interfacial defect densities at HTL/absorber and absorber/ETL interfaces to improve the PCE of the device; and the effect of variation of these parameters is also investigated both with and without HTL connected. The final optimized configuration achieved a VOC of 0.87 V, JSC of 27.57 mA cm-2, FF of 85.93%, and PCE of 20.73%. To further investigate the performance of the optimized device, we explore the impact of the temperature, shunt resistance, series resistance, capacitance, generation rate, recombination rate, Mott-Schottky, JV, and QE features of both with and without HTL connected. The optimized device offers the best thermal stability at a temperature of 300 K. Our study highlights the potential of CsPbBr3-based PSCs and provides valuable insights for their optimization and future development.

First-Principles Calculations to Investigate the Stability and Thermodynamic Properties of a Newly Exposed Lithium-Gallium-Iridium-Based Full-Heusler Compound.

The structural, optical, electrical, thermodynamic, superconducting, and mechanical characteristics of LiGa2Ir full-Heusler alloys with the MnCu2Al configuration were comprehensively examined in this work using the first-principles computation approach premised upon density functional analysis. This theoretical approach is the first to investigate the influence of pressure on the mechanical and optical characteristics of LiGa2Ir. The structural and chemical bonding analysis shows that hydrostatic pressure caused a decrease in the lattice constant, volume, and bond length of each cell. According to the mechanical property calculations, the LiGa2Ir cubic Heusler alloy exhibits mechanical stability. It also has ductility and anisotropic behavior. This metallic substance shows no band gap throughout the applied pressure range. The physical characteristics of the LiGa2Ir full-Heusler alloy are analyzed in the operating pressure range of 0-10 GPa. The quasi-harmonic Debye model is employed to analyze thermodynamic properties. The Debye temperature (291.31 K at 0 Pa) increases with hydrostatic pressure. A newly invented structure attracted a lot of attention around the globe for its superior superconductivity (Tc ∼ 2.95 K). Optical functions have also been improved after applying stress to utilize it in optoelectronic/nanoelectric devices. The optical function analysis is supported strongly by the electronic properties. Due to these reasons, LiGa2Ir imposed an essential guiding principle for relevant future research and could be a credible candidate substance for industrial settings.

An extensive study on multiple ETL and HTL layers to design and simulation of high-performance lead-free CsSnCl3-based perovskite solar cells.

Cesium tin chloride (CsSnCl3) is a potential and competitive absorber material for lead-free perovskite solar cells (PSCs). The full potential of CsSnCl3 not yet been realized owing to the possible challenges of defect-free device fabrication, non-optimized alignment of the electron transport layer (ETL), hole transport layer (HTL), and the favorable device configuration. In this work, we proposed several CsSnCl3-based solar cell (SC) configurations using one dimensional solar cell capacitance simulator (SCAPS-1D) with different competent ETLs like indium-gallium-zinc-oxide (IGZO), tin-dioxide (SnO2), tungsten disulfide (WS2), ceric dioxide (CeO2), titanium dioxide (TiO2), zinc oxide (ZnO), C60, PCBM, and HTLs of cuprous oxide (Cu2O), cupric oxide (CuO), nickel oxide (NiO), vanadium oxide (V2O5), copper iodide (CuI), CuSCN, CuSbS2, Spiro MeOTAD, CBTS, CFTS, P3HT, PEDOT:PSS. Simulation results revealed that ZnO, TiO2, IGZO, WS2, PCBM, and C60 ETLs-based halide perovskites with ITO/ETLs/CsSnCl3/CBTS/Au heterostructure exhibited outstanding photoconversion efficiency retaining nearest photovoltaic parameters values among 96 different configurations. Further, for the six best-performing configurations, the effect of the CsSnCl3 absorber and ETL thickness, series and shunt resistance, working temperature, impact of capacitance, Mott-Schottky, generation and recombination rate, current-voltage properties, and quantum efficiency on performance were assessed. We found that ETLs like TiO2, ZnO, and IGZO, with CBTS HTL can act as outstanding materials for the fabrication of CsSnCl3-based high efficiency (η ≥ 22%) heterojunction SCs with ITO/ETL/CsSnCl3/CBTS/Au structure. The simulation results obtained by the SCAPS-1D for the best six CsSnCl3-perovskites SC configurations were compared by the wxAMPS (widget provided analysis of microelectronic and photonic structures) tool for further validation. Furthermore, the structural, optical and electronic properties along with electron charge density, and Fermi surface of the CsSnCl3 perovskite absorber layer were computed and analyzed using first-principle calculations based on density functional theory. Thus, this in-depth simulation paves a constructive research avenue to fabricate cost-effective, high-efficiency, and lead-free CsSnCl3 perovskite-based high-performance SCs for a lead-free green and pollution-free environment.

Excellent photocatalytic properties in 2D ZnO/SiC van der Waals hetero-bilayers: water-splitting H2-fuel production.

This research unravels the photocatalytic properties of a 2D ZnO/SiC van der Waals hetero-bilayer for potential water-splitting applications by first-principles calculations. Four unique stacking patterns are considered in studying the electronic and optical properties in the presence and absence of biaxial external strain. For pattern-I and II, large negative binding energy and positive phonon frequencies are observed, denoting chemical and mechanical stabilities. Under the HSE-06 pseudo potential, the calculated bandgap value for pattern-I and II reaches 2.86 eV and 2.74 eV, respectively. 2D ZnO/SiC shows a high absorption coefficient (∼105 cm-1). The absorption peak under biaxial strain could reach ∼3.5 times the peak observed under unstrained conditions. Under strain, a shift from compressive to tensile biaxial strain (-6% to 6%) results in a bandgap decrease from 3.18 eV to 2.52 eV and 3.09 eV to 2.43 eV, for pattern-I and II, respectively. The observed strain-driven kinetic overpotential for 2D ZnO/SiC pattern-I and II easily engenders photocatalytic redox reactions. The excellent mechanical durability and strain-driven large kinetic overpotential suggest 2D ZnO/SiC heterobilayers as a prospective material for water-splitting H2-fuel production.

Investigations on the structural and optoelectronic characteristics of cadmium-substituted zinc selenide semiconductors.

A change in the composition and dopant content of selective atoms in a material leads to their new desired properties by altering the structure, which can significantly improve the performance of relevant devices. By acknowledging this, we focused on characterizing the optoelectronic and structural properties of cadmium-substituted zinc selenide (Zn1-xCdxSe; 0 ≤ X ≤ 1) semiconductors using density functional theory (DFT) within the generalized gradient approximation (GGA), EV-GGA, and mBJ approximations. The results proved the cubic symmetry of the investigated materials at all Cd concentrations (0, 0.25, 0.50, 0.75, and 1). Although a linear surge in the lattice constant is observed with the change in Cd content, the bulk modulus exhibits a reverse trend. These materials are observed to be direct bandgap semiconductors at all Cd concentrations, with a decrease in electronic bandgap from 2.76 eV to 1.87 eV, and have isotropic optical properties, showing their potential applicability as a blue-to-red display. The fundamental optical properties of the materials, such as optical conductivity, reflectance, refractive index, absorption, and extinction coefficient, are also discussed. These outcomes provide a computational understanding of the diverse applications of Zn1-xCdxSe semiconductors in optoelectronic, photonic, and photovoltaic devices, particularly for a visible-range display.

Unveiling concentration effects on the structural and optoelectronic characteristics of Zn1-x Cd x S (x = 0, 0.25, 0.50, 0.75, 1) cubic semiconductors: a theoretical study.

The structural and optoelectronic characteristics of Zn1-x Cd x S (x = 0, 0.25, 0.50, 0.75, 1) semiconductors are reported using density functional theory within GGA, EV-GGA, and mBJ functionals. These semiconductors are observed in cubic symmetry at all Cd-concentrations and the lattice constant increases linearly with Cd-concentration while the bulk modulus shows a reverse behavior. These materials are direct bandgap semiconductors at all Cd-concentrations and their bandgap energy decreases from 3.67 eV to 2.59 eV. The isotropic optical properties of these direct bandgap semiconductors vary with Cd concentration as well, with absorption coefficients decreasing and absorbed near-UV light converting to visible blue light. Optical properties like refractive index, dielectric constant, conductivity, extinction coefficient, and reflectance are also displayed and discussed. These results provide useful theoretical understanding for the application of CdZnS semiconductors in photonic, photovoltaic, and optoelectronic devices.

Synthesis and Characterization of Polyvinyl Chloride Matrix Composites with Modified Scrap Iron for Advanced Electronic, Photonic, and Optical Systems.

In this study, Fe2O3 powder was synthesized using the co-precipitation method from scrap iron, which was then treated with varying concentrations of copper. Afterwards, the modified Fe2O3 was reinforced in the PVC matrix by using the solution-casting method to synthesize PVC composite films, which were subjected to a UV-visible spectrophotometer, a Fourier transform infrared spectrophotometer, an X-ray diffractometer, and a thermal gravimetric analyzer to evaluate the optical, chemical, structural, and thermal properties. FTIR analysis reveals the formation of the composite through vibrational bands pertaining to both components present, whereas no significant changes in the XRD patterns of PVC were observed after the doping of modified iron oxide, which reveals the compatibility of fillers with the PVC matrix. The optical properties of the copper-doped iron oxide-PVC composites, including absorbance, refractive index, urbach energy, and optical as well as electrical conductivity are measured, and show an increase in optical activity when compared to the pure PVC compound. Moreover, the increased thermal stability of the synthesized composite was also observed and compared with conventional compounds, which, in accordance with all the other mentioned properties, makes the copper-dopped iron oxide-PVC composite an effective material for electronic, photonic, and optical device applications.

Vacancy-Induced Thermal Transport and Tensile Mechanical Behavior of Monolayer Honeycomb BeO.

Because of the rapid shrinking trend of integrated circuits, the performances of nanodevices and nanomechanical systems are greatly affected by the joule heating and mechanical failure dilemma. In addition, structural defects are inevitable during experimental synthesis of nanomaterials, which may alter their physical properties significantly. Investigation of the thermal transport and mechanical behavior of nanostructured materials with structural defects is thus a crucial requirement. In this study, the thermal conductivity (TC) and tensile mechanical behavior of monolayer honeycomb BeO are systematically explored using molecular dynamics simulations. An infinite length bulk TC of ∼277.77 ± 8.93 W/mK was found for the pristine monolayer BeO. However, the insertion of 1% single vacancy (SV) and double vacancy (DV) defects reduces the TC by ∼36.98 and ∼33.52%, respectively. On the other hand, the uniaxial tensile loading produces asymmetrical fracture stress, elastic modulus, and fracture strain behaviors in the armchair and zigzag directions. The elastic modulus was reduced by ∼4.7 and ∼6.6% for 1% SV defects along the armchair and zigzag directions, respectively, whereas the reduction was ∼2.7 and ∼ 5.1% for 1% DV defects. Moreover, because of the strong symmetry-breaking effect, both the TC and mechanical strength were significantly lower for the SV defects than those for the DV defects. The highly softening and decreasing trends of the phonon modes with increasing vacancy concentration and temperature, respectively, were noticed for both types of defects, resulting in a reduction of the TC of the defected structures. These findings will be helpful for the understanding of the heat transport and mechanical characteristics of monolayer BeO as well as provide guidance for the design and control of BeO-based nanoelectronic and nanoelectromechanical devices.

Superior tunable photocatalytic properties for water splitting in two dimensional GeC/SiC van der Waals heterobilayers.

The photocatalytic characteristics of two-dimensional (2D) GeC-based van der Waals heterobilayers (vdW-HBL) are systematically investigated to determine the amount of hydrogen (H2) fuel generated by water splitting. We propose several vdW-HBL structures consisting of 2D-GeC and 2D-SiC with exceptional and tunable optoelectronic properties. The structures exhibit a negative interlayer binding energy and non-negative phonon frequencies, showing that the structures are dynamically stable. The electronic properties of the HBLs depend on the stacking configuration, where the HBLs exhibit direct bandgap values of 1.978 eV, 2.278 eV, and 2.686 eV. The measured absorption coefficients for the HBLs are over ~ 105 cm-1, surpassing the prevalent conversion efficiency of optoelectronic materials. In the absence of external strain, the absorption coefficient for the HBLs reaches around 1 × 106 cm-1. With applied strain, absorption peaks are increased to ~ 3.5 times greater in value than the unstrained HBLs. Furthermore, the HBLs exhibit dynamically controllable bandgaps via the application of biaxial strain. A decrease in the bandgap occurs for both the HBLs when applied biaxial strain changes from the compressive to tensile strain. For + 4% tensile strain, the structure I become unsuitable for photocatalytic water splitting. However, in the biaxial strain range of - 6% to + 6%, both structure II and structure III have a sufficiently higher kinetic potential for demonstrating photocatalytic water-splitting activity in the region of UV to the visible in the light spectrum. These promising properties obtained for the GeC/SiC vdW heterobilayers suggest an application of the structures could boost H2 fuel production via water splitting.