Minimum Absorption Research Articles

A synergistic strategy for SiC/C nanofibers@MXene with core-sheath microstructure toward efficient electromagnetic wave absorption and photothermal conversion

A ingenious approach of synergistic strategy between MXene and one-dimensional (1D) materials have been proved for enhancing the performance of composites. However, the problem of MXene aggregation in compounding processes usually reduces their superiority. Herein, few-layered Ti3C2Tx wrapped SiC/C nanofibers (SiC/C@MXene NFs) with a core-sheath microstructure were synthesized via a method of electrostatic self-assembly. Strong electrostatic adsorption bonding anchored the Ti3C2Tx sheets on surface of the SiC/C NFs, which effectively inhibited the self-restacking and thus efficiently enhanced their electromagnetic (EM) wave absorption and photothermal conversion performances. As a result, 8.0 wt% SiC/C@MXene NFs dispersed in paraffin simultaneously exhibited a minimum reflection loss (RL, dB) and effective absorption bandwidth (EAB, RL < -10 dB) of −70.9 dB and 6.32 GHz at 2.63 mm. Besides, 0.4 wt% SiC/C@MXene NFs dispersed in waterborne polyurethane (PU) achieved strong photothermal conversion abilities, with the maximum temperatures rising to 95, 145, 183, and 201 °C at light intensities of 0.1, 0.2, 0.3, and 0.4 W cm−2, respectively. Therefore, the synergistic strategy effectively utilizes the structural advantages of the 2D Ti3C2Tx and 1D SiC/C NFs, endowing SiC/C@MXene NFs with core-sheath microstructure, and effectively improving their EM wave absorption and photothermal conversion performances.

An Optimization Method of Active Distribution Network Considering Time Variations in Load and Renewable Distributed Generation

Network optimization is one of an effective ways to enhance the performance of an active distribution network (ADN). Aiming to improve the operation and power quality of the ADN considering time variations in load and renewable distributed generation (RDG) power, a multi-time period optimization model and its dynamic solution method are proposed. Considering the real time load demand and power generation variation of RDG versus input parameters like wind speed and solar irradiance, the time variation models of load and RDG power output are developed. The minimum power loss and maximum absorption of RDG power are served as the optimization indexes to construct the dynamic muti-time period optimization model. A hybrid particle swarm optimization (HPSO) algorithm is presented based on integer coding and random coding technique, which can find the most satisfactory solutions for the proposed dynamic model. Considering the time variation of load and RDG power of ADN, the optimal network structure and RDG allocation scheme at any time interval are determined by analyzing the obtained solutions. Additionally, two ADNs with time variation in load and RDG are tested to verify the effectiveness and superiority of the proposed dynamic optimization model and HPSO algorithm. The simulation results show that the proposed method can improve the operation performance and RDG optimal utilization of the ADNs through muti-time period dynamic optimization.

Mid-infrared Frequency Modulation Detection of HCN and Its Reaction with O Atoms behind Shock Waves.

Hydrogen cyanide (HCN) is the primary cyanide species in combustion processes and plays a key role in the formation of NOx in the combustion of fossil fuels, nitrogen-containing biofuels, and blended hydrocarbon-ammonia mixtures. Robust, sensitive, and time-resolved in situ laser diagnostic methods are needed to gain insight into the combustion chemistry of HCN. Mid-infrared frequency modulation spectroscopy (MIR-FMS) has recently been established as such a quantitative technique for HCN detection behind shock waves. With a minimum detectable fractional absorption of 2 × 10-4 at a time resolution of 5 μs, an improved spectrometer design enabled the detection of HCN behind shock waves down to the ppm mole fraction level. An Allan noise analysis revealed that a further improvement toward shot-noise limited detection should be possible when fast mid-infrared photodetectors with a higher saturation limit will become available. HCN kinetic profiles in the presence of O(3P) atoms from thermal N2O decomposition have been measured in the temperature range 1448 K < T < 1954 K. The determined total rate constants for the key HCN oxidation reaction HCN + O, k/(cm3 mol-1 s-1) = 1.88 × 1014 exp(-64.5 kJ mol-1/RT)(+28%, -37%), turn out to be largely consistent with previous measurements. These data complete the set of available rate constant studies, by now covering the temperature range 450 K < T < 2500 K and relying on the detection of almost all feasible reactant and product species.

Light Emission in 2D Silver Phenylchalcogenolates.

Silver phenylselenolate (AgSePh, also known as "mithrene") and silver phenyltellurolate (AgTePh, also known as "tethrene") are two-dimensional (2D) van der Waals semiconductors belonging to an emerging class of hybrid organic-inorganic materials called metal-organic chalcogenolates. Despite having the same crystal structure, AgSePh and AgTePh exhibit a strikingly different excitonic behavior. Whereas AgSePh exhibits narrow, fast luminescence with a minimal Stokes shift, AgTePh exhibits comparatively slow luminescence that is significantly broadened and red-shifted from its absorption minimum. Using time-resolved and temperature-dependent absorption and emission microspectroscopy, combined with subgap photoexcitation studies, we show that exciton dynamics in AgTePh films are dominated by an intrinsic self-trapping behavior, whereas dynamics in AgSePh films are dominated by the interaction of band-edge excitons with a finite number of extrinsic defect/trap states. Density functional theory calculations reveal that AgSePh has simple parabolic band edges with a direct gap at Γ, whereas AgTePh has a saddle point at Γ with a horizontal splitting along the Γ-N1 direction. The correlation between the unique band structure of AgTePh and exciton self-trapping behavior is unclear, prompting further exploration of excitonic phenomena in this emerging class of hybrid 2D semiconductors.

Efficient hydrogen storage in KCaF3 using GGA and HSE approach

Being a renewable and sustainable energy carrier, hydrogen energy has garnered great interest having some technical barriers related to storage aspects. Hydride materials exhibit potential hydrogen storage capacities efficiently and safely. The current study has been performed in the framework of density functional theory to examine structural and optoelectronic properties of KCa F3−xHx (x = 0, 0.6, 1.2, 1.8, 2.4, and 3) compounds to understand their contribution about hydrogen storage. The mechanical stability of these compounds with elastic constants and negative formation enthalpies suggests these materials are stable and synthesizable. Insertion of impurity into pristine material led to an increase in optimized lattice parameter from 4.31 to 4.48 A˙ where no previous study is available to compare lattice constants other than pristine KCa F3 that is well consistent with existing literature. Computed and plotted results of plastic properties for different H-inclusions manifestly depict a decrease in elastic moduli, anisotropic and brittle nature of all studied materials. The density of states and band diagrams were drawn utilizing both GGA and HSE03 formalisms, where observations manifest not only an upsurge in bandgap but also shifting from indirect to direct nature. Two effects Burstein -Moss shift and bandgap renormalization were explored to investigate the shifting of absorption edge toward the valence band that results in bandgap narrowing. Optical parameters were also well explained within the photon energy range of 0–35eV. Startling results of absorption spectra reveal prominent redshift increases in the UV region. Among all H- insertions high value of the static refractive index (n (0) = 3.77) and dielectric function with minimum absorption losses possess KCa H3 only appropriate material for storage aspects. Also, enhancement in optical properties suggests a new end material (KCa H3) curious for optoelectronic devices. Moreover, H-incorporation has improved hydrogen storage characteristics up to a capacity of 3.6 wt% with the challenge of high desorption temperature whose improvement will play a vital role in hydrogen uptake mechanism and will enlighten future studies to make it useful for practical and transportation applications.

Wearable Panda-Shaped Textile Antenna with Annular Ring-Defected Ground Structure for Wireless Body Area Networks

This research presents a compact panda-shaped wearable antenna with a defected ground structure (DGS). It is fabricated using a flexible material to work at 2.4-GHz industrial scientific medical (ISM) band, confirming the wireless body area network (WBAN) application requirements. The annular ring DGS and circular and elliptical slots in the patch aid in achieving the operating frequency. Good impedance bandwidth is maintained during on-body and bending analysis. Furthermore, this antenna exhibits a peak gain of 7.3 dB and a minimum specific absorption rate (SAR) of 0.0233 W/kg for 1 g tissue and 1.02 W/kg for 10 g tissue. The investigation shows that an antenna with good robustness, compact, high flexibility, and very low SAR makes it a strong candidate for WBAN applications.

Development of sand-plastic composites as floor tiles using silica sand and recycled thermoplastics: a sustainable approach for cleaner production

Strict environmental concerns, depleting natural recourses, and rising demand for building construction materials have promoted scientific research toward alternative building materials. This research supports the idea of sustainability and a circular economy via the utilization of waste to produce value-added products. The research explored the potential of waste plastics and silica sand for developing thermoplastic composite as floor tiles. The samples were characterized by water absorption, compressive strength, flexural strength, and sliding wear. The morphological analysis of the sand-plastic interfaces was covered under the umbrella of this study. The maximum compressive and flexural strength were found to be 46.20 N/mm2 and 6.24 N/mm2, respectively, with the minimum water absorption and sliding wear rate of 0.039% and 0.143 × 10–8 kg/m, respectively. The study suggests the workability of the developed floor tiles in non-traffic areas of public places. Thus, the study provides a green building material through recycling waste plastics for sustainable development.

Doping Na+ into Polyvinyl Alcohol: Methacrylic Acid-Ethyl Acrylate (PVA/MAA:EA) Polymer Blend Electrolytes; A Way to Improve the Blend’s Thermal, Structural, Optical and Electrical Properties

Pristine and doped films of polyvinyl alcohol (PVA): poly (methacrylic acid-ethyl acrylate)(MAA-EA) (50:50) blend with various weight percentages (5, 10 and 15 wt%) of sodium chloride (NaCl) (Na+ ions) were prepared by a simple solution casting method. Exhibiting a decrease in diffraction peak intensities with increasing weight percentage of NaCl salt content, X-ray diffraction (XRD) indicated a decrease in crystallinity or less polymer blend. Thermogravimetric analysis (TGA) showed a decreasing trend in melting temperature of the doped films compared with the pure films. From the optical absorption and conductivity studies, among the prepared samples, the film with 15 wt% NaCl showed minimum absorption edge, direct band gap and indirect band gap values of 4.02, 4.52, 3.54 eV, respectively, and the maximum ionic conductivity of 9.85 × 10−8 S/cm.

Asymmetric Etalon Effect in Fold-Type Optical Feedback Cavity-Enhanced Absorption Spectroscopy

To further improve the performance of cavity-enhanced spectroscopy systems, a high-quality U-cavity system was established. In the process of the experiment, an asymmetric ripple effect, which is different from the previous etalon effect, was found, which seriously affects the performance of the spectral system. This unique phenomenon mainly manifests in the different amplitudes of the fluctuations of the spectral curves measured by the folding mirror and the end mirror in the U-cavity system. Based on multi-beam interference theory, we analyzed the characteristics of the transmission spectrum of each mirror in the presence of the etalon effect at the end mirror, and obtained the following conclusions: for the U-cavity system, the strength of the etalon effect of each mirror is inversely proportional to its transmission loss value, that is, the larger the loss, the smaller the ripple of the transmission spectrum, and vice versa. In order to eliminate this effect, the most effective way is to eliminate the etalon effect caused by the light feedback of the end mirror. After improving the system, the minimum detectable absorption coefficient of αmin=8.33×10−9cm−1 is obtained with this U-shape Optical Feedback Cavity-Enhanced Absorption Spectroscopy. These works are valuable references for the design of folded Cavity-Enhanced Absorption Spectroscopy systems and have potential for laser wavelength calibration and measurement of a mirror’s reflectance.

Broadband optical limiting in nanohybrids of graphene grafted peripheral (non-peripheral) pyrene substituted phthalocyanines with a low linear absorption

In nonlinear optics, nanohybrids from the functionalization of graphene and organic molecules can be an interesting area of research. In this work, nanohybrid materials consisting of pyrene conjugated peripheral phthalocyanines and non-peripheral phthalocyanines, which are non-covalently attached to the graphene exhibit broadband optical characteristics and broadband limiting optical behavior through a two-photon absorption process with a high degree of transparency. For confirming non-covalent functionalization, optical as well as spectroscopic studies like UV–vis absorption, fluorescence studies, transient absorption, FTIR, XPS, Raman, AFM techniques, etc., were employed. Distinct morphologies are observed for these nanohybrids, such as -nanohybrids with a cylindrical shape in the non-peripheral case whereas a conical shaped nanohybrids in the peripheral case. Furthermore, Raman studies reveal a shift of 8 cm−1 for the 2D peak of both nanohybrids in comparison with that of graphene confirms the strong π-π interaction, which is the maximum shift in a non-covalent interaction between pyrene attached graphene. In a major finding, a donor-acceptor combination is established in these nanohybrids, which makes them important nonlinear optical materials. The nonlinear absorption coefficients of 112 ± 7 cm/GW and 228 ± 12 cm/GW were obtained for these nanohybrids. Compared to the existing reported values, these nanohybrids with the minimum linear absorption coefficient (1.15 cm−1 and 1.25 cm−1), display broadband nonlinear optical characteristics with low optical limiting thresholds (0.9 and 0.83 Jcm−2), which is achieved through the transfer of electrons from Pc core to pyrene anchored graphene, enable them standout candidates for photonic applications.

Optimization of mechanical properties and composition of M-sand and pet particle added concrete using hybrid deep neural network-horse herd optimization algorithm

• Natural sand extraction, Granite & Basalt wastes are a problem, hence five Novel concrete design mixes are made. • Concrete performance and Durability tests are conducted and compared with the Predicted results of familiar algorithms. • Results show that the Design Mix P7.5 Containing 7.5% PET particles is the best Mix among all the Mixes made. • While Hybrid DNN-HHO proved to be the best algorithm among the other algorithms used in the investigation. Concrete is one of the broadly utilized materials due to the unavoidable nature of construction. The requirement for improvement in mechanical properties and environmental hazards with the usage of natural sand requires an alternative choice in raw materials. This research work is carried out to investigate the compressive and tensile strength properties of concrete prepared by adding manufactured sand (M-sand) sand and polyethylene terephthalate (PET) particles. Pullout test, Water Absorption (WA), Electrical Resistivity (ER), Rapid Chloride Permeability Test (RCPT), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) are also analyzed in addition to compressive and tensile strength. A suitable proportion of materials is studied from the preliminary investigation and produced five different concrete specimens for this study. New proportions of concrete mixes with cost-effective materials such as PET and M sand are contributed to enhancing the strength and tensile properties. Cylindrical-shaped concrete specimens are created with final mix proportions and their properties are studied for six different days. The results show that the final specimen has acquired a maximum compressive strength of 45.3 MPa, a maximum tensile strength of 3.77 MPa, a maximum flexural strength of 4.72 MPa, and a minimum water absorption of 8.087 were all obtained by 7.5P specimen after 90 days of synthesis. The X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analysis results taken for 7.5P specimen after 90 days indicate the presence of PET provide more strength and tensile properties. The properties of the proposed concrete composition is validated and compared with predicted values obtained from Deep Neural Network-Horse herd Optimization Algorithm (DNN-HHO) to find accurate results. The proposed concrete indicates an enhanced result in mechanical properties along with the reduction in environmental issues and can be utilized in the construction field of small applications.

Double layer metal selenides growing on Ni-plated carbon fibers toward high efficiency electromagnetic wave absorption

A growing body of research has shown that microcosmic three-dimensional (3D) hierarchical structural design is an effective method to synthesis composites with excellent performance to electromagnetic wave. This strategy helps give play to the advantages of each component and generate synergistic effects by the specific structures simultaneously. In this study, a simple hydrothermal reaction was performed to grow a NixSey intermediary and MoSe2 sheath on the surface of Ni-plated CFs (CN). Finally, CFs@NixSey @MoSe2 (CNMS) composites with core-sheath structure were synthesized. The surface morphology and electromagnetic parameters of the prepared composites were adjusted by the added amount of sodium molybdate, which led to a difference in the minimum reflection loss (RL) and effective absorption bandwidth (EAB) among the products. For electromagnetic wave absorption performance, CNMS-2 exhibited an EAB (RL ≤ −10 dB) of 6.7 GHz, which completely covered the Ku-band. In addition, CNMS-2 had an absorption peak of − 46.4 dB at approximately 14 GHz. The double layer of transition metal selenides not only effectively decreases the conductivity of CFs and avoids skin effects but also generates more interfaces and defects that can provide multi-polarization losses.

Grow defect-rich bamboo-like carbon nanotubes on carbon black for enhanced microwave absorption properties in X band

• By in-situ growing bamboo-like CNTs on CB, a developed conductive network was constructed and plentiful CB/CNT interfaces were introduced to improve the electromagnetic wave loss ability. • Defect-rich CNTs with open atomic edges can endow nanocarbons with a better balance between good impedance matching and strong loss capacity, causing an effective microwave absorption. • The minimum reflection loss and effective absorption bandwidth of CB-CNT with the CNTs growth time of 40 min reach to −53.6 dB and 4.1 GHz with the matching thickness of 2.7 mm, respectively. Due to the limited electromagnetic wave (EMW) loss capacity and agglomeration, carbon black (CB) gradually fails to meet the increasingly harsh demanding conditions. Herein, defect-rich bamboo-like carbon nanotubes (CNTs) were grown on CB by the process of chemical vapor deposition. CNTs prepared in situ on CB can assist it to build a developed multilevel conductive network and introduce plentiful CB/CNTs nano-interfaces. What's more, the defects that accompany the growth of CNTs endow CNTs with a moderate conductivity and good impedance matching, thereby causing an effective microwave absorption (MA). Meanwhile, the high-density defects on CNTs can induce dipole polarization to further strengthen the EMW loss ability. The influence of CNTs with different growth time on MA performance has been explored. Profiting from the structural merits, the synthesized CB-CNT with CNTs growth time of 40 min exhibits the optimal absorbing property, which has the minimum reflection loss of -53.6 dB and maximum effective absorption bandwidth of 4.1 GHz with the thickness of 2.7 mm, covering almost the entire X band. The introduction of defect-rich CNTs significantly enhances the EMW loss ability of CB, which provides a rational strategy for the design of high-efficient microwave absorption materials.

Heterointerface engineering in quaternary magnetic structures for high-efficiency and thermal stable microwave absorption

High-efficiency and thermal stability are two important factors of ideal microwave absorption materials (MAMs), which are becoming desired because of the more complex modern service environment. Herein, a novel quaternary magnetic core-shell-shell structure FeCo-Co@Fe3O4 @SiO2 (FCSF) has been fabricated by a facile and generic route. In this structure, the incipient oxidation temperature of magnetic core can be greatly increased from 523 K to 773 K by the Fe3O4/SiO2 double shells, and the multiple magnetic heterointerfaces can generate electron transfer and spin-orbit interaction based on DFT calculations. The minimum reflection loss (RLmin) and efficient absorption band (RL<−10 dB, feff) of FCSF composites can reach up to −42.8 dB and 7.3 GHz with the thickness of 2 mm, due to the emerged electromagnetic loss mechanisms of interface polarization and exchange resonance. Moreover, owing to the optimized impedance matching and enhanced electromagnetic loss at elevated temperature, the RLmin values of FCSF at 673 K and 773 K increase by 15.4% and 41.2% compared with that at 298 K, respectively. The results demonstrate that the FCSF composite can act as a promising candidate for high-efficiency MAMs in thermal environment, and the synthetic strategy of heterostructures in this work can also be applied to design other MAM systems.

Influence of SnMnO2 window layer on enhancing the performance of CIGSSe thin-film solar cell

In this paper, the thickness and doping concentrations of the double buffer cell-based conventional CIGSSe solar cells are optimized, and alignment of the energy band of the optimized solar cell (ZnMgO/CIGSSe) is carried out, thus obtaining an increase in efficiency from 23.35 % to 27.88 %. Further, a new design is proposed of low cost, low resistivity, minimum absorption coefficient, tunable energy bandgap (3.6–4.44 eV) with tin-doped manganese oxide Sn1−xMnxO2 material (x = 0.5) as a window layer in conventional solar cell design. The thin-film solar cell efficiency has improved from 23.35 % to 29.05 % by aligning the energy bandgap with an optimized thickness and doping concentration. The proposed Sn1−xMnxO2 window layer-based thin-film solar cell is more convenient in instantly absorbing the maximum blue light with reduced recombination loss, increased efficiency and external quantum efficiency. The simulated parameters of the conventional model are compared and validated with the existing conventional solar cells.

Color Transparent Monitor using Si/SiO2Core-Shell Nanoparticles: Optimum Color Selection

In this paper, core–shell nanoparticles are used to provide a transparent high-quality display. To realize this idea, Si-SiO2 core–shell nanoparticles have been used to achieve the most suitable nanoparticle composition for a transparent color display with high transparency and contrast. For color transparent monitor the superimposed QDs are used. For transparent color monitors, stacked QDs are used. In this work, we determine the ratio of nanoparticles (three QD ratios) for the three colors in the proposed monitor. Because the red, green, and blue scattering peaks are different because of the scattering physics, which is wavelength-dependent. Therefore, obtaining the optimal ratio for each color is studied. The numerical method of Finite-Difference Time-Domain is used to simulate and calculate the optical properties of the proposed transparent monitor. The effect of different combinations of nanoparticles to have the maximum dispersion at blue, green, and red wavelengths and the minimum absorption at other wavelengths has been investigated. Finally, the optimum ratio and arrangement of nanoparticles for all colors are reported and numerically evaluated.

Utilization of wrightia tinctoria nano seed fibers as a reinforcement in the preparation of epoxy-based composites

Natural seed fiber reinforced composite materials are replacing many conventional ones because of their excellent properties, less weight, easy availability, etc. Composite materials are used in many areas because of their superior features. Mechanical property is one of the vital parameters for choosing the material. The current investigation has revealed an importance of recently well-known Wrightia tinctoria nano seed fibers (WTNSFs), which are extracted physically. Wrightia tinctoria nano seed fiber reinforced composite was prepared with the epoxy resin by hand layup method. Epoxy resin is easy to handle and available at low cost. Mechanical tests are conducted reinforced composites of plain epoxy and WTNSFs to obtain strength properties like tensile, flexural, impact. Water absorption tests also performed on composites. Here, the developed composites are easy to handle, offered economically, and used primarily in marine applications due to less water absorption and good wax content. A comprehensive description of different tests and the properties of WTNSFs are studied and compared with the other existing natural fibers. This work showed that 35% combination of WTNSFs reinforced epoxy matrix offers enhanced mechanical properties with minimum water absorption compared with plain epoxy composites.

Multiple giant eruptions and X-ray emission in the recoiling AGN/LBV candidate SDSS1133

ABSTRACT We present a comprehensive analysis of 20 yr worth of multicolour photometric light curves, multiepoch optical spectra, and X-ray data of an off-nuclear variable object SDSS1133 in Mrk 177 at z = 0.0079. The UV-optical light curves reveal that SDSS1133 experienced four outbursts in 2001, 2014, 2019, and 2021. The persistent UV-optical luminosity in the non-outbursting state is ∼1041 erg s−1 with small-scale flux variations, and peak luminosities during the outbursts reach ∼1042 erg s−1. The optical spectra exhibit enduring broad hydrogen Balmer P-Cygni profiles with the absorption minimum at ∼−2000 km s−1, indicating the presence of fast-moving ejecta. Chandra detected weak X-ray emission at a 0.3−10-keV luminosity of LX = 4 × 1038 erg s−1 after the 2019 outburst. These lines of evidence suggests that SDSS1133 is an extreme luminous blue variable (LBV) star experiencing multiple giant eruptions with interactions of the ejected shell with different shells and/or circumstellar medium (CSM), and disfavours the recoiling active galactic nuclei scenario suggested in the literature. We suggest that pulsational pair-instability may provide a viable explanation for the multiple energetic eruptions in SDSS1133. If the current activity of SDSS1133 is a precursor of a supernova explosion, we may be able to observe a few additional giant eruptions and then the terminal supernova explosion or collapse to a massive black hole in future observations.

Fabrication of benzoyl chloride treated tiger-nut fiber reinforced insect repellent hybrid composite

An insect repellent composite containing tiger nut particulate fibre, waste low density polyethene (LDPE) and castor oil alkyd resin was fabricated. Canarium schweinfurthii gum was used as insect repellent compound and maleic anhydride as compatibilizer. The tiger nut chaff was subjected to benzoylation using benzoyl chloride to increase the fibre-matrix interaction. The compound and composition was then moulded with LDPE as dual matrices for excellent physico-mechanical properties (pressed for 5 min, 130 °C and 25 bar and cured). The 10 wt.% treated composite exhibited a minimum water absorption of ~ 0.085%, optimal chemical resistance for both acids (HCl and H2SO4) and bases (NaOH and KOH) and no effect on thickness. Density measurement showed the lowest value of ~ 0.0096 g/cm3 for the treated fibre composite. However, the tensile strength, flexural stress, hardness and impact load were improved up to 35.08 Mpa, 456.3 Mpa, 95 and 730 J/m respectively with treated composites. Insect repellent tests against termites and cockroaches show repellent activity with time intervals. FTIR and SEM analysis showed fibre modification achieved.

First-principles investigations of metal chalcogenides Tl2Hg3X4(X=S,Se,Te) for advanced optoelectronic and thermoelectric applications

The crystalline metal chalcogenides materials have got great attraction due to their narrow bandgap materials for renewable energy applications. In the present work, we have broadly explored the optoelectronic and thermoelectric properties of Tl2Hg3X4(X ​= ​S, Se, Te) using first-principle calculations. The Tl2Hg3S4, Tl2Hg3Se4, and Tl2Hg3Te4 have a monoclinic crystal structure and exhibit semiconducting nature with band gaps of 2.0 ​eV, 1.5 ​eV, and 0.8 ​eV, respectively. In the visible region, a minimum absorption occurred for the S dopant, but as we replace S with Se/Te a halted absorption is seen in the visible region that confirming their nominal employment in optoelectronic applications (solar cells). Optical absorption of Se and Te dopant in Tl2Hg3X4 is found in I.R and the visible region of the radiation, making them promising candidates for optoelectronics. Further, the thermoelectric parameters versus carrier concentration are studied for these materials using the BoltzTraP code. The drifts of thermoelectric parameters for the Te dopant diverge from the tendencies of S and Se dopants at specific temperatures i.e., at 300, 500, and 700 ​K. The power factor (PF) of Tl2Hg3S4 and Tl2Hg3Se4 (Tl2Hg3Te4) favor n-type (p-type) doping, indicating higher mobility of electrons(holes) as compared with the holes (electrons). These findings suggest the practical realization of these compounds for emerging optoelectronic and renewable energy device applications.