Direct Band Gap Energy Research Articles

Impact of bismuth oxide on structural, optical and gamma-ray shielding properties of calcium-sodium-borate glasses.

In the present study, we have prepared six glass samples of bismuth borate using the melt-quenching method with the composition (70-x)B2O3-10CaO-20Na2O-xBi2O3; x=0, 3, 6, 9, 12 and 15mol%. The density of the prepared glasses was determined using Archimedes principle. The X-ray diffraction patterns provide confirmation of the amorphous nature of the prepared samples, whereas the Fourier transform infrared measurements pointed to the existence of structural units like BO3, BO4, BiO3 and BiO6 within the glass network. An assessment of the optical absorption spectra unveiled that with the increase in the bismuth oxide content, there was a decrease observed in both the direct and indirect band gap energies. Specifically, they decreased from 3.40 to 2.79eV and from 3.10 to 2.46eV, respectively. The properties related to gamma ray attenuation, including the mass attenuation coefficient (μm), effective atomic number (Zeff), half-value layer (HVL) and mean free path (MFP), were examined for all the glass samples. This investigation was carried out using the Phy-X/PSD software, covering the energy range from 0.511 to 1.332MeV. Out of all the samples, Bi-15, featuring the highest Bi2O3 content, demonstrated the highest μm, Zeff, the smallest HVL and MFP. These results suggest that the glass with 15mol% of Bi2O3 offers the most effective gamma radiation shielding performance. Moreover, the glasses examined in this study exhibit superior radiation shielding characteristics compared with specific concrete types, namely, ordinary concrete, Hematite serpentine concrete and barite concrete, as well as commercial glasses such as RS-360 and RS-253.

Elaboration, Structural and Optical Characterization of the New Ternary Chalcogenide SnSb<sub>2</sub>S<sub>5</sub>

In this study, -antimony sulfide (SnSb2S5) thin films with 200 nm, 312 nm, and 431 nm thicknesses were successfully fabricated using thermal evaporation. These films' structural, optical, and photoanode properties were meticulously characterized to assess their suitability for photovoltaic applications. X-ray diffraction (XRD) analysis confirmed the presence of an orthorhombic symmetry phase within the <em>Pnma</em> space group, ensuring the crystalline quality of the films. Raman spectroscopy further validated the crystal structure and provided detailed identification of the vibrational active modes specific to this pseudo-binary chalcogenide compound. Optical characterization revealed that the SnSb<sub>2</sub>S<sub>5</sub> thin films possess direct optical bandgap energies ranging from 1.91 to 1.99 eV, making them ideal for efficient light absorption in photovoltaic devices. The refractive index (n) displayed minimal variation within the absorption region, indicating stable optical properties. At the same time, it increased proportionally with film thickness outside the absorption region, suggesting enhanced optical behavior with thicker films. This characteristic is particularly advantageous for improving the efficiency of photoanode materials. The combination of favorable structural properties, optimal bandgap energies, and tunable optical responses positions SnSb<sub>2</sub>S<sub>5</sub> thin films as promising candidates for advanced photovoltaic and optoelectronic applications. These findings highlight the potential of SnSb<sub>2</sub>S<sub>5</sub> in developing high-performance photoanodes, contributing to the advancement of solar energy conversion technologies.

Effect of Sm3+ concentration on reddish orange photoluminescence and electrochemical properties of copper aluminate nanoparticles for display and supercapacitor applications

In this report, a novel synthesis method for Sm3+-doped copper aluminate nanoparticles (1–9 mol %) is presented, utilizing Ocimumsanctum leaves extract as a reducing agent through the solution combustion method, followed by calcination at 600 °C for 3 h. The resulting cubic spinel structure, validated by Bragg reflections, demonstrates a decrease in crystallite size and a direct energy band gap correlated with increasing dopant concentration. The morphology exhibits irregularly shaped nanoparticles and hexagonal shaped nanoplates. On deconvolution, three peaks situated at 579, 590 and 600 nm. The emission peak observed at 579 and 590/600 nm can be attributed to transitions from excited level G5/24 to its lower lying levels, H5/26, H7/26 respectively, with noticeable concentration quenching at 7 mol %. CIE and CCT coordinates affirm the red emission of Sm3+ within the host lattice, suggesting potential applications in residential and hospital settings. Cyclic voltammetry analysis provides insights into redox reactions, electrode kinetics, and electrochemical behavior. Electrochemical Impedance Spectroscopy (EIS) elucidates ion transport kinetics, while Galvanostatic Charge–Discharge (GCD) analysis determines supercapacitance values ranging from 53.89 F/g with increasing dopant concentrations. This material exhibits promise for applications in energy storage and display technology.

PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers: Improved the physical properties for energy storage devices and optoelectronic applications

The current investigation aims to enhance the optical and dielectric properties of poly (vinyl alcohol) (PVA)/polyethylene glycol (PEG) blended polymers via loading with copper cobaltite (CuCo2O4), polyaniline (PANi), and x wt% multi-walled carbon nanotubes (MWCNTs) for potential applications in optoelectronics and capacitive storage. The fabrication of PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers was carried out via casting and hydrothermal methods. Characterization of the blended polymer's structure and morphology was conducted using X-ray diffraction and scanning electron microscopy techniques. The impact of various fillers on the linear and nonlinear optical properties of the host blend was analyzed. The loaded blends demonstrated efficacy in blocking UVA, UVB, and UVC spectra, making them suitable absorbers for solar cells. The lowest values for direct and indirect optical band gap energy (Eg), of 5.34 eV and 4.44 eV were attained at x = 0.02. The blend with x = 0.01 displays the highest refractive index at λ = 600 nm. The optical conductivity exhibited nonmonotonically growth until peaking at x = 0.01. Analysis of chromaticity diagrams in CIE 1931 color space reveals that all blends emit blue-violet hues with slight variations in intensity. The fluorescence (FL) intensity of the doped blend is notably lower compared to the undoped counterparts. The doped blend (x = 0.03) showcases superior dielectric constants and ac conductivity values. The maximum energy density was achieved at 1 kHz for the host blend incorporating CuCo2O4/PANi. Overall, the observed characteristics indicate that PVA/PEG/CuCo2O4/PANi/x wt% MWCNTs blended polymers represent promising hybrid nanomaterials suitable for diverse applications.

Effects of Rapid Heat Treatments on the Properties of Cu2O Thin Films Deposited at Room Temperature Using an Ammonia-Free SILAR Technique

We report herein the analysis of the properties of copper(I) oxide thin films deposited by an optimized ammonium-free successive ion layer adsorption and reaction (SILAR) technique. The Cu2O thin film deposition process was carried out at room temperature using copper acetate monohydrate, sodium citrate as complexing agent, and hydrogen peroxide as precursors of copper and oxygen ions, respectively. The harmless and easy-to-handle sodium citrate replaces the volatile NH4OH commonly employed as complexing agent in the SILAR technique for the deposition of metal oxide thin films. The optical, structural, morphological, and electrical properties of the as-deposited Cu2O thin films were studied as a function of the number of cycles during deposition, as well as their modifications produced by the effect of rapid thermal annealing (RTA) in vacuum in a temperature range of 200–250°C for 1 min, 3 min, and 5 min. The as-deposited thin films had cubic crystalline structure corresponding to the Cu2O phase as determined by x-ray diffraction (XRD), with a direct energy bandgap of 2.43–2.51 eV depending on the number of cycles, and electrical resistivity of the order of 103 Ω cm. The XRD and x-ray photoelectron spectroscopy (XPS) analysis of the Cu2O thin films treated by RTA demonstrated an increase of the crystal size with time and temperature of the RTA and reduction effects from Cu2+ to Cu1+ oxidation states. On the other hand, the RTA treatments also decreased their energy bandgap to 2.38 eV and electrical resistivity to 102 Ω cm. The high energy bandgap values of the Cu2O thin films were attributed to quantum confinement effects produced by their small crystal size in the range of 3.6–8.6 nm.Graphical

Theoretical insights into the structural and optoelectronic properties of the ternary cesium tetrafluoridobromate semiconductor CsBrF4

This work deals with the first theoretical study of structural, electronic, and optical properties of CsBrF4 ternary compound by using first-principle calculations. The calculated structural parameters and atomic positions are in accordance with the experimental ones declared in the literature. The obtained electronic properties signalize that this compound is a semiconductor material with a direct energy band gap. According to the investigated optical properties, the vast optical absorption range in the ultraviolet region indicates that CsBrF4 semiconductor could be useful for specific applications in ultraviolet optoelectronic devices; consequently, this theoretical study is the potential to support future experimental research.

Anion and Cation Co-Doping of NiO for Transparent Photovoltaics and Smart Window Applications

Materials engineering based on metal oxides for manipulating the solar spectrum and producing solar energy have been under intense investigation over the last years. In this work, we present NiO thin films double doped with niobium (Nb) and nitrogen (N) as cation and anion dopants (NiO:(Nb,N)) to be used as p-type layers in all oxide transparent solar cells. The films were grown by sputtering a composite Ni-Nb target on room-temperature substrates in plasma containing 50% Ar, 25% O2, and 25% N2gases. The existence of Nb and N dopants in the NiO structure was confirmed by the Energy Dispersive X-Ray and X-Ray Photoelectron Spectroscopy techniques. The nominally undoped NiO film, which was deposited by sputtering a Ni target and used as the reference film, was oxygen-rich, single-phase cubic NiO, having a visible transmittance of less than 20%. Upon double doping with Nb and N the visible transmittance of NiO:(Nb,N) film increased to 60%, which was further improved after thermal treatment to around 85%. The respective values of the direct band gap in the undoped and double-doped films were 3.28 eV and 3.73 eV just after deposition, and 3.67 eV and 3.76 eV after thermal treatment. The changes in the properties of the films such as structural disorder, direct and indirect energy band gaps, Urbach tail states, and resistivity were correlated with the incorporation of Nb and N in their structure. The thermally treated NiO:(Nb,N) film was used to form a diode with a spin-coated two-layer, mesoporous on top of a compact, TiO2 film. The NiO:(Nb,N)/TiO2heterojunction exhibited visible transparency of around 80%, showed rectifying characteristics and the diode’s parameters were deduced using the I-V method. The diode revealed photovoltaic behavior upon illumination with UV light exhibiting a short circuit current density of 0.2 mA/cm2 and open-circuit voltage of 500 mV. Improvements of the output characteristics of the NiO:(Nb,N)/TiO2 UV-photovoltaic by proper engineering of the individual layers and device processing procedures are addressed. Transparent NiO:(Nb,N) films can be potential candidates in all-oxide ultraviolet photovoltaics for tandem solar cells, smart windows, and other optoelectronic devices.

Synthesis and structural characterization of supramolecular cocrystals of [(4-cyano-1-methylpyridinium)2-(18-crown-6)] diiodide

Abstract This study focuses on synthesizing and characterizing supramolecular cocrystals derived from 4-cyano-1-methylpyridinium iodide and 18-crown-6. The synthesis employed a solvent evaporation technique, followed by a thorough structural analysis utilizing XRD methods. The compound’s purity is confirmed by powder XRD analysis, while single-crystal XRD confirms its triclinic system packing with a centrosymmetric space group ( P 1 ‾ $P\overline{1}$ ). The findings unveiled the emergence of unique cocrystals characterized by distinct molecular configurations supported by hydrogen bonding and ion-dipole interactions. Through diffuse reflectance spectral measurements, the direct band gap energy was assessed at 2.36 eV. Thermogravimetric analysis was utilized to evaluate the thermal properties of the compound across varying temperatures. The compound’s elemental composition and surface morphology were analyzed through investigations using EDS and SEM.

Diisopropylammonium hydrogen squarate: Synthesis and comprehensive analysis of non-linear optical co-crystal using X-ray, Hirshfeld, mechanical, optical and DFT methods

This research successfully synthesized a single co-crystal of diisopropylammonium hydrogen squarate using prolonged vaporization for crystal growth. Single-crystal X-ray spectrometry confirmed its monoclinic structure, and morphological predictions were made. UV–visible spectroscopy revealed its optical transmittance with a direct optical energy band gap of 3.45 eV. Photoluminescence studies showed a strong violet emission at 402 nm when excited by a 260 nm source. Microhardness study examined the crystal's mechanical attributes portraying the normal indentation size effect followed by a qualitative overview of half-penny crack dynamics. FTIR study aided in the discernment of varied vibrational modes with NH stretching being observed at 3078 cm−1. Thermal examination further revealed the crystal's stability up till 244 °C. Proton and carbon-13 NMR spectra were analyzed to verify the presence of functional groups and the overall molecular integrity. Intermolecular interactions were analyzed using Hirshfeld surface and fingerprint mapping. The Z-scan technique demonstrated the crystal's applicative potential in its third harmonic generation capability. Theoretical calculations with Density Functional Theory (DFT) supported the experimental findings, offering insights into optimized geometries, frontier molecular orbitals, natural population and bond orbital distributions, hyperpolarizability, molecular electrostatic potentials, IR vibrational modes, and UV absorbance profiles.

Birnessite-MnO2 nanostructures synthesized by facile hydrothermal and green method for dye degradation application

Water contamination resulting from the presence of organic dye pollutants in the ecosystem is a significant issue in the 21st century, that requires urgent resolution. Utilizing an effective nanocatalyst for the removal of dyes from water is a viable solution to address this problem. In this study, we proposed two distinct approaches for synthesizing δ-MnO2 nanostructures: an environmentally friendly, “green” method (MG) and a “cost-effective” hydrothermal method (MH). The leaf extract of Clinacanthus nutans was used for the preparation of MG, while MnSO4 was used for MH as a reducing agent, along with KMnO4, with the reaction time fixed at 90 °C. X-ray diffraction analysis confirmed that both approaches yielded δ-MnO2 nanostructures with a monoclinic Birnessite phase. The MG sample displayed a coagulated nanoflake-like morphology, as observed in FESEM images. On the other hand, the MH sample exhibited a distinct nanoflower morphology. The materials' optical properties were investigated using UV–visible spectra analysis, revealing direct bandgap energies of 2.2 eV and 2.58 eV for the MG and MH, respectively. The surface area of the MG sample was found to be higher as compared to the MH nanoflower, showcasing a mesoporous structure. XPS analysis was employed to determine the oxidation states of the elements. The effect of varying pH levels on the degradation of Methyl Orange dye by the two nanocatalysts was investigated. The results demonstrated that acidic pH led to higher decolouration efficiency, particularly notable for the MG nanocatalyst. Consequently, this study illustrates that the green δ-MnO2 nanocatalyst effectively degrades methyl orange dye under acidic conditions through photocatalysis.

An extensive investigation of structural, electronic, and optical properties of inorganic perovskite Ca3AsCl3 for photovoltaic and optoelectronic applications: A first-principles approach using Quantum ATK tool

Perovskite-based solar cells have been researched for quite some time with the highest reported values of power conversion efficiencies at around 30.9 %. However, commonly investigated materials like lead halide perovskites, mixed halide perovskites, and tin-based perovskites have challenged researchers in terms of stability, toxicity, scalability, etc. In an attempt to overcome these limitations, we have conducted in-depth studies on perovskite material, i.e. Ca3AsCl3 using the QuantumATK Tool to establish its adaptability to solar cell applications. This material's mechanical stability has been established using the Born-Huang criteria. While analyzing electronic properties, Ca3AsCl3 possessed a direct energy bandgap of 1.742 eV. At 3.2 eV, the dielectric constant values, susceptibility, optical conductivity, and polarizability are reported to be 5.06, 4.06, 1.748 × 103 AV−1cm−1, and 6.859 × 10−39 C m2V−1 respectively. Current density values calculated using the FE model for the Ca3AsCl3-based perovskite Solar Cell (PSC) designed through the LCAO Device calculator, are in excellent agreement with those obtained from the SCAPS 1D model. The obtained values of the mechanical, electrical, optical, and structural properties of Ca3AsCl3 suggest promising applications in solar cells, optoelectronic devices, and a wide range of flexible electronic devices.

An Insight into the Impact of Nano CuCo2O4 Doping on the Optical and Dielectric Performance of PMMA/Carbon Nanoparticles

In the present study, novel functional properties were achieved for polymethyl methacrylate (PMMA) through loading with carbon nanoparticles (CNPs) as well as varying quantities of CuCo2O4 nanoparticles. The blends obtained were subjected to different characterization techniques. Extensive investigations of different optical properties were carried out, covering linear and nonlinear optical properties. After the incorporation of CNPs/CuCo2O4 in the host polymer matrix, the absorbance, reflectance and refractive index exhibited improvements, while continuous reductions in both direct and indirect optical band gap energies were observed. Significant improvements in the linear and nonlinear optical parameters were observed with increasing CuCo2O4 doping levels. Dielectric measurements provided insights into the impact of CuCo2O4 content on the ac conductivity, energy density, dielectric properties, and electric modulus across all blends. The sample doped with 1.5 wt% exhibited the highest dielectric constant. In conclusion, the optical and dielectric properties of the PMMA/CNPs/x wt% CuCo2O4 blends make them promising candidates in optoelectronics and photocatalysis applications.

Influence of Zinc Manganite Nano Fillers on the Optical and Dielectric Features of Poly-Methyl Methacrylate/Multi-Walled Carbon Nanotubes Nanocomposites

Poly (methyl methacrylate, PMMA)/ multi-walled carbon nanotubes (MWCNTs)/ x wt %zinc manganite (ZnMn2O4) polymers were fabricated using co-precipitation and casting techniques. The structure of the filler and all polymers was determined with X-ray diffraction. The morphology of the polymer surfaces was explored by employing scanning electron microscopy. The direct and indirect band gap energies (E g) of PMMA polymer (5.02, 4.44) eV decreased attaining minimum values (4.97, 3.41) eV upon the addition of MWCNTs and 2 wt% ZnMn2O4. The refractive index at 600 nm was increased from 1.33 (PMMA) to 1.55 (x = 2 wt% ZnMn2O4). The optical dielectric constant and optical conductivity displayed their highest values when the ZnMn2O4 doping level reached 2 wt%. The PMMA/MWCNTs/x wt% ZnMn2O4 polymers exhibited blue-violet colors on the CIE 1931 chromaticity diagram under excitation wavelength of 317 nm. The electrical dielectric constant and the AC conductivity attained their peak at the concentration of 2 wt% and 1 wt% ZnMn2O4, respectively. PMMA/MWCNTs/x wt% ZnMn2O4 polymers possess controllable optical and electrical characteristics, thus making them potentially valuable optical materials for future optoelectronic or photocatalytic application development.

A Comprehensive Density Functional Theory Analysis on Structural, Electronic, and Optical Properties of BiOF

Based on density functional theory (DFT), the electronic, structural, and optical properties of bismuth oxyfluoride (BiOF) are investigated by using various exchange–correlation functionals. The local density approximation (LDA), Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA), Perdew-Burke-Ernzerhof generalized gradient approximation for solids (PBEsol), and Wu-Cohen (WC) functionals are implemented in Wien2k software. Modified Becke-Johnson (mBJ) and unmodified Becke-Johnson (umBJ) potentials are also applied to obtain an enhanced band gap. Spin–orbit coupling effect (SOC) is also taken into consideration due to the heavy Bi atom. When employing the PBE+umBJ potential, BiOF exhibits the most enhanced band gap energy, with a direct band gap energy of 3.72 eV. Moreover, optical properties such as dielectric functions, absorption coefficients, and optical conductivities are also calculated for photon energies up to ̴̴ 14 eV. In comparison to other available theoretical and experimental findings, the calculated results are in good agreement.

Structure, Electronic, Optical, Magnetic and Magnetocaloric Properties of Sm2CuMnO6 Double Perovskite Nanomaterial

This study explores the structural, microstructural, optical, and magnetic characteristics of double perovskite oxide Sm2CuMnO6. The sample is prepared in the monoclinic phase with space group P21/n using the auto-combustion method. The crystal structure exhibits distortion and tilting. First-principles calculations are conducted using the density-functional theory framework, focusing on electronic structures and density of states. The average crystallite size, particle size and grain size of the sintered sample are 34.42 nm, 36.15 nm and 475 nm respectively. The sample exhibits a direct band gap energy of 1.96 eV. Analysis of the X-ray photoelectron spectra indicates the presence of Sm3+, Cu2+, and Mn3+/Mn4+ ions in the sample. The DC magnetization study reveals a Curie temperature (Tc) of 50 K for the sample. A non-metallic state resembling a spin glass is detected below 15 K, arising from the competition between antiferromagnetic and ferromagnetic interactions. The maximum value of isothermal magnetic entropy, the relative cooling power and heat capacity are 1.4 J.kg–1.K–1, 100.2 J.kg–1, and 1.35 J.kg–1.K–1 at a field change of 70 kOe respectively. The value of Temperature Averaged Entropy Change is 1.36 J.kg−1.K−1 and 1.29 J.kg−1.K−1 for a temperature span of 10 K and 40 K at a field change of 70 kOe.

Investigation of structural and optical properties of TM-doped CuO NPs: Correlation with their photocatalytic efficiency in sunlight-induced pollutant degradation

The presence of non-biodegradable, toxic, and harmful organic pollutants in various environmental mediums poses significant threats to ecosystems and human health. This study investigates the impact of transition metal (TM) doping on the photocatalytic performance of copper oxide nanoparticles (CuO NPs) in degrading methylene blue (MB) dye under sunlight irradiation. CuO NPs are synthesized using the co-precipitation method. X-ray diffraction (XRD) analysis revealed a monoclinic structure with space group C2/c for undoped and TM–doped CuONPs, with crystalline sizes ranging from 13 nm for undoped to 36 nm for Zn-doped CuO. Based on UV–Visible Spectroscopy data, the band gap energies and the nature of electronic band transitions are determined using a new simplified calculation method. Accordingly, direct band gap energy exhibits a slight red-shift as a result of doping with Ni, Mn or Fe, from 1.427 eV for undoped to 1.402 eV for Fe-doped CuO. While Co or Zn doping, induces a trivial blue-shift to 1.468 eV and 1.434 eV respectively. The CuO particles show a heterogenous distribution size and shape. The mean grain size raised from 34.3 nm for undoped to about 100 nm for TM-doped CuONPS, excluding the Co-doped CuO for which the mean grain size reached 154.532 nm with highest standard deviation heterogeneity of 125.737 nm. Furthermore, photocatalytic experiments demonstrated that TM-doping significantly enhanced the degradation rate of MB dye under sunlight irradiation. Co-doped CuO is the most efficient catalyst. This makes TM-doping a promising pathway for the use of CuO NPs in wastewater decontamination applications.

New insights into the bonding, electronic and optical properties of fergusonite and scheelite ReNbO4 (Re = Y, La and Lu) compounds

A systematic study of the structural, bonding, electronic, and optical properties of the ReNbO4 (Re = Y, La, and Lu) compounds with the fergusonite (space group I/2a) and scheelite (space group I41/a) structure was performed using density functional theory calculations. The aim of these calculations was to resolve some doubt about these properties for the fergusonite phase and to fill the existing knowledge gap for the scheelite phase. To carry out geometry optimization, the generalized gradient approximation for solids was used. Based on these optimized crystal structures, the bonding, electronic and optical properties were determined using the modified Becke and Johnson exchange potential. An analysis of the bonds between Nb and O atoms showed that Nb atoms in the fergusonite structure of the rare-earth niobates were octahedrally coordinated to oxygen atoms, unlike in the scheelite phase, which had tetrahedral coordination. The calculated values of the direct energy band gap for the fergusonite YNbO4, LaNbO4 and LuNbO4 compounds were 4.435, 4.427 and 4.431 eV, respectively. The optical spectrum for these systems is characterized by a small exciton binding energy, which affects the experimental prediction of the energy band gap when the Tauc plot method is used. The values for the energy band gap in the scheelite phase were 4.625 eV for YNbO4, 4.844 eV for LaNbO4 and 4.611 eV for LuNbO4 and all were indirect. The real and imaginary parts of the dielectric tensor were computed up to 25 eV for both phases, and were interpreted based on their electronic structure. The lower energy regions of the optical spectra of these systems are mainly due to electronic transitions within the NbO6 polyhedron (for the fergusonite phase) and the NbO4 polyhedron (for the scheelite phase), i.e., electronic transitions from the occupied O-2p states at the top of the valence band to the unoccupied Nb-4d states at the bottom of the conduction band.

Unveiling a New 2D Semiconductor: Biphenylene-Based InN.

The two-dimensional (2D) materials class earned a boost in 2021 with biphenylene synthesis, which is structurally formed by the fusion of four-, six-, and eight-membered carbon rings, usually named 4-6-8-biphenylene network (BPN). This research proposes a detailed study of electronic, structural, dynamic, and mechanical properties to demonstrate the potential of the novel biphenylene-like indium nitride (BPN-InN) via density functional theory and molecular dynamics simulations. The BPN-InN has a direct band gap energy transition of 2.02 eV, making it promising for optoelectronic applications. This structure exhibits maximum and minimum Young modulus of 22.716 and 22.063 N/m, Poisson ratio of 0.018 and -0.008, and Shear modulus of 11.448 and 10.860 N/m, respectively. To understand the BPN-InN behavior when subjected to mechanical deformations, biaxial and uniaxial strains in armchair and zigzag directions from -8 to 8% were applied, achieving a band gap energy modulation of 1.36 eV over tensile deformations. Our findings are expected to motivate both theorists and experimentalists to study and obtain these new 2D inorganic materials that exhibit promising semiconductor properties.

Simultaneous enhancements of UV-shielding properties and photostability of polyvinyl butyral by incorporation of MWCNTs

Polymer nanocomposites with proper reinforcement can simultaneously enhance both the UV-shielding and optical properties. Such composite materials are being investigated for many commercial applications, including automotive, window screens etc. However, the inherent challenge is maintaining transparency while using reinforcement to get better optical properties and UV resistance. In this study, Multiwall Carbon Nanotubes (MWCNTs) were reinforced for a range of content (0.5, 1.0, 1.5 and 2.0 wt%) in Polyvinyl Butyral (PVB) matrix to synthesize nanocomposite films for UV-shielding purposes. UV-shielding properties are enhanced as compared to PVB for all compositions. We were adding 0.5 wt% MWCNTs to PVB effectively improved UV wavelength blocking and slightly decreased visible light transparency. UV studies were performed in the 190–1100 nm wavelength range and the values of the absorption edge, direct and indirect bandgap energies and Urbach energy were evaluated. When 0.5 wt% MWCNTs were reinforced into the PVB, the direct and indirect bandgaps changed significantly from 4.50 to 4.91 eV–3.01 eV and 4.06 eV respectively, while the Urbach energy increased from 0.73 eV to 1.16 eV. These results show that the UV shielding and photostability of PVB nanocomposite films are significantly changed with the low dispersion of MWCNTs.

DFT+U study of TlXBr3 (X = Sn, Ge) perovskites as next-generation materials for optoelectronics applications

The lead-free perovskite has gained increasing importance in optoelectronic device applications. In this study, we investigate the structural, electronic, optical, mechanical, thermodynamic, and thermoelectric properties of cubic phase TlSnBr3 and TlGeBr3 using the plane wave pseudopotential method based on density functional theory (DFT). To overcome constraints of the GGA-PBE technique, we implemented the LDA + U technique to solve on-site self-interaction errors. The Hubbard parameter 'U' was identified as a suitable solution for considering on-site self-interactions and calculating better electronic energy band gaps. The obtained lattice parameters are consistent with previous published results. Our findings indicate that both materials have a direct energy band gap, with values of 1.75 eV and 1.94 eV for TlSnBr3 and TlGeBr3, respectively. We also observe the existence of covalent and ionic bonding. The optical properties of these materials demonstrate high absorption coefficients and conductivity in the visible region. The mechanical properties are derived using the Voigt-Reuss-Hill approximation and suggest strong evidence of ductile behavior. Finally, the thermoelectric properties are evaluated by analyzing thermal to electrical conductivity, Seebeck coefficient, and Figure of merit criteria. Our comparative study of TlXBr3 (X = Sn, Ge) suggests that these compounds are promising candidate materials for photovoltaic and optoelectronic devices.