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Showing papers in "Materials today communications in 2023"


Journal ArticleDOI
TL;DR: In this article , the potential of 1-(2,5-dimethyphenyl) piperazine tetrachlorocobaltate hydrate (C12H20N2) CoCl4·H2O as an adsorbent material for small molecules was investigated.
Abstract: Present study focuses on the synthesis, crystal structure analysis,density functional theory (DFT), and the potential of 1-(2,5-dimethyphenyl) piperazine tetrachlorocobaltate hydrate (C12H20N2) CoCl4·H2O as adsorbent material for small moleculesas: CO2, H2CO, H2S, NH3, and NO2 gas.To gain insight into the geometrical properties, Infrared spectrum, and the intermolecular interactions within the crystal structure, X-ray crystallography, Fourier transform infrared spectroscopy (FT-IR), and Hirshfeld analysis have been carried out.The calculated adsorption energies follow a decreasing pattern of Hybrid-NO2 > Hybrid-NH3 > Hybrid-H2S > Hybrid-H2CO > Hybrid-CO2. It is evident that Hybrid-NO2 reflects the highest adsorption energy of − 0.5235 eV, depicting that the hybrid will better adsorb NO2 gas as compared to other gases. In all cases,the adsorption phenomena are best described as chemisorptions owing to the negative adsorption magnitudes.In furtherance, the magnetic susceptibility measured over a range of 2 – 300 K reveals paramagnetic behavior with weak magnetic interactions between Co(II) ions. At 300 K, theχpTvalue reflects 2.461 emu K mol–1, indicating a spin-orbit coupling contribution to the spin-only value of 1.875 emu K mol–1 expected for Co(II) with 3d7 spin configuration.

14 citations



Journal ArticleDOI
TL;DR: In this paper , the structural, mechanical, optical, and thermoelectric properties of the cubic perovskite GeTiO3 were investigated using the first-principle method.
Abstract: The structural, mechanical, optical, and thermoelectric properties of the cubic perovskite GeTiO3 is investigated using the first-principle method. The full potential linearized augmented plane wave (FP-LAPW) approach is used to solve the Kohn–Sham equations. The local density approximation (LDA), generalized gradient approximation (GGA), and modified Becke-Johnson (mBJ) exchange potentials are used for exchange-correlation effects. The computed lattice constant is in accordance with the experimental results. The band structure calculations reveal that GeTiO3 has an indirect energy band gap (Γ-X) of 2.517 eV. Optical spectra computations such as the real and imaginary components of the dielectric function, reflectivity, and refractive index are performed within the region of 0–10 eV. We considered the maximum transition and absorption coefficients to be 5.8 (2.2 eV), and 4.8 (3.1 eV) respectively. Finally, using Boltzmann transport theory the Seebeck coefficient, electrical, thermal conductivity, and Power factor (PF) of the considered compound is evaluated. We analyzed the maximum PF of approximately 9 × 1011 W/K2ms and 15.9 × 1011 W/K2ms at 1200 K against temperature and chemical potential respectively. The high mobility of carriers improves the Seebeck coefficient, power factor, and electrical conductivity of GeTiO3 compound. Our findings will serve as theoretical guidelines for future experimental and industrial GeTiO3 applications.

9 citations


Journal ArticleDOI
TL;DR: In this article , the performance of an Al/ITO/CdS/FeSi2/PEDOT:PSS/Au solar cell was evaluated using SCAPS-1D software and the impact of the variation of thickness, carrier concentration, electron affinity of the HTL layer, shunt and series resistance, operating temperature, and surface recombination velocity (SRV) on the performance parameters have been studied to avail the better performance.
Abstract: Recently, most of the researchers are showing their interest on Iron di-silicide (FeSi2) based solar cell because, it is an excellent and promising light absorbing material for solar cell applications because of its remarkable characteristics. The inappropriateness of device structure, band alignment at the BSF/absorber and absorber/buffer interface, as well as carrier recombination at the rear and front contact, prevents the expected result from being achieved. The primary goal of this study is to enhance the performance of uniquely designed Al/ITO/CdS/FeSi2/PEDOT:PSS/Au solar cell and to scope out the influence of the PEDOT:PSS HTL layer on the performance parameters of open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF), and power conversion efficiency (PCE). The photovoltaic (PV) performance of the proposed photovoltaic cell has been simulated utilizing SCAPS-1D software. In this simulation, the defect densities of each layer and interface defect between HTL/absorber and absorber/buffer have been added. The impact of the variation of thickness, carrier concentration, electron affinity of the HTL layer, shunt and series resistance, operating temperature, and surface recombination velocity (SRV) on the performance parameters have been studied to avail the better performance. The PCE of 39.44 %, Voc of 938 mV, Jsc of 51.58 mA/cm2 and FF of 81.48 % of the proposed SC have been determined with FeSi2 absorber layer thickness and carrier concentration of 300 nm and 1014 cm−3, correspondingly. The results of this research recommend the guidelines for temperature stable, environment friendly, low cost, and high efficiency FeSi2-based SC.

9 citations


Journal ArticleDOI
TL;DR: A literature review on the physical and mechanical characteristics of coral aggregates, the mechanical properties and chloride ion penetration performance of CAC, the bond performance and durability of fiber-reinforced polymer (FRP) bars in CACs, and the mechanical behavior and durability as mentioned in this paper .
Abstract: The utilizations of locally available marine resources (e.g., seawater, sea-sand or coral sand, and coral coarse aggregate) for concrete preparation on reef or island areas contribute to the reduced construction period and construction costs of offshore projects. However, the porous nature and high chloride content of coral aggregates will affect the mechanical properties and durability of seawater coral aggregate concrete (CAC) structures reinforced with fiber-reinforced polymer (FRP) composites. This paper presents a literature review on the physical and mechanical characteristics of coral aggregates, the mechanical properties and chloride ion penetration performance of CAC, the bond performance and durability of FRP bars in CAC, and the mechanical behavior and durability of FRP-reinforced CAC structures. Structural responses of FRP-reinforced CAC systems, including FRP-confined CAC tube columns, FRP-reinforced CAC beams, FRP-reinforced CAC columns, and FRP-reinforced CAC slabs, are presented and discussed. These research results can provide a reference for the service life performance and durability design methods of FRP-reinforced CAC structures.

8 citations


Journal ArticleDOI
Martin Götte1
TL;DR: In this paper , the effect of the number of layers on the electronic and optical properties of few-layer SiCNSs has been studied according to the first principles, and the results show that the more the layer number, the stronger the interlayer coupling and the smaller the band gap of FL-SiCnss.
Abstract: Silicon carbide nanosheets (SiCNSs) have a broad application prospect in the new generation of micro/nanophotonic devices. In this paper, the effect of the number of layers on the electronic and optical properties of few-layer SiCNSs (FL-SiCNSs) has been studied according to the first principles. The results show that the more the layer number, the stronger the interlayer coupling and the smaller the band gap of FL-SiCNSs. There are three absorption peaks at 4.35 eV, 7.83 eV, and 11.68 eV in the vertical direction of FL-SiCNSs. There is a strong absorption band between 2 and 10 eV in the parallel direction. As the decrease of the band gap promotes the recombination of excited carriers, this spectral band becomes narrower with the increase of layers. The dielectric response increases with the number of layers increasing in the parallel direction and decreases with the number of layers increasing in the vertical direction. It exhibits metallic properties in the range of 1000–2250 THz in the parallel direction. In the perpendicular direction, only around 2830 THz show metallic properties. It has suitable reflectance in the range of 100–580 nm and is a good material for making ultraviolet reflectors.

8 citations


Journal ArticleDOI
TL;DR: In this article , a review of recent progress on surface texturing and solid lubricants is provided, focusing on the effect of texture on the surface/interface of lubricating coating and the lubrication effect of texturing.
Abstract: This study provides a review of recent progress on designs, properties, and mechanisms of surface texturing and solid lubricants. Firstly, the design and processing of surface texture, the type of solid lubricants and the preparation method of texture combined with lubricants are mentioned in design strategy, respectively. Then, effects of surface texture and solid lubricants on tribological properties are analyzed, including antifriction, wear-resistance and other beneficial effects. Next, the synergistic effect mechanisms of surface texture and solid lubricants are discussed, focusing on the effect of texture on the surface/interface of lubricating coating and the lubrication effect of solid lubricants by texturing. Finally, this review looks forward to the problems and future development of texture and lubricants.

8 citations


Journal ArticleDOI
TL;DR: In this article , robust superhydrophobic film was fabricated on Al alloy through anodic anodization followed by chemical deposition and spin coating of TiO2/SiO2-silane composite film.
Abstract: The stable superhydrophobic coating is significant for prolonging service life, reducing maintaining cost and enhancing material performances. In this study, robust superhydrophobic film was fabricated on Al alloy through anodic anodization followed by chemical deposition and spin coating of TiO2/SiO2-silane composite film. This fabrication method is controllable, eco-friendly, available for large and irregular Al alloy with low equipment requirements. Uniquely, the as-prepared Al alloy showed uniform micro-nanoporous arrays and achieved excellent superhydrophobic performance, with static water contact angle of 165º and sliding angle of 2.92º. Moreover, the robust superhydrophobic film on Al alloy presented high adhesion strength, strong stability under ambient air, ultraviolet light irradiation and abrasion. Meanwhile, two orders of magnitude reduction in corrosion current density and anti-corrosion efficiency of 99.2% were realized. The superhydrophobic Al alloy surface further displayed superb non-sticking, water repellency, self-cleaning, and anti-icing performances, which can be applied at harsh conditions in aerospace and marine fields.

7 citations


Journal ArticleDOI
TL;DR: In this paper , the authors presented a rapid reliable tool based on neural network modified with particle swarm optimizer to predict the wear rates and coefficient of friction of Al-TiO2 nanocomposite manufactured using accumulative roll bonding (ARB).
Abstract: The prediction of the wear rates and coefficient of friction of composite materials is relatively complex using mathematical models due to the effect of the manufacturing process on the wear properties of the composite. Therefore, this work presents a rapid reliable tool based on neural network modified with particle swarm optimizer to predict the wear rates and coefficient of friction of Al-TiO2 nanocomposite manufactured using accumulative roll bonding (ARB). The wear rates and coefficient of the produced composites were computed using pin-on-disc and correlated with the composite morphology, hardness and microstructure. Experimentally, it was demonstrated that the hardness and wear rates reduce with increasing the number of ARB passes until a plateau was achieved due to the uniform distribution of TiO2 nanoparticles inside the composite and the saturation of grain refinement in the Al matrix. The maximum hardness improvement was 153.7% for composite containing 3% TiO2 nanoparticles after 5 ARB passes. While the wear rates of the same composite tested at 5 N load reduces from 3.7 × 10−3 g/m for pure Al to 1.1 × 10−3 g/m. The proposed model was able to predict the wear rates and coefficient of friction for all the produced composites tested at four different wear loads with excellent accuracy reaching R2 equal 0.9766 and 0.9866 for the wear rates and coefficient of friction, respectively.

7 citations


Journal ArticleDOI
TL;DR: In this paper , the structural, elastic, electronic properties, thermal properties and magnetic hyperfine field and thermoelectric response of Laves phase PrFe2 and PrRu2 compounds are researched by using density functional theory via full-potential linear augmented plane waves (FP-LAPW) method within the local orbitals joining the generalized gradient approximation (GGA-PBESol) of exchange-correlation functional as applied in WIEN2k software package.
Abstract: The structural, elastic, electronic properties, thermal properties and magnetic hyperfine field and thermoelectric response of Laves phase PrFe2 and PrRu2 compounds are researched by using density functional theory via full-potential linear augmented plane waves (FP-LAPW) method within the local orbitals joining the generalized gradient approximation (GGA-PBESol) of exchange-correlation functional as applied in WIEN2k software package. Additionally, the semi-classical Boltzmann theory is utilized to investigate the stress behavior and superconductors applications on magnetic moments of each atom from 0 to 25 GPa for both materials are researched. The GGA-PBESol+U approximation is employed to address the f states of Pr atoms and d states of Fe and Ru atoms. The geometrical analysis of structural parameters is applied. The structural parameters calculated by two approximations are in a good agreement with other results. The calculated elastic constants, Young’s modulus, shear modulus, Poisson’s ratio, sound velocities and Debye temperature are investigated. The thermodynamic properties are calculated by a semi-harmonic Debye model in the pressure range, 0–25 GPa and temperature, 0–1000 K. The partial and total density of states (DOS) are investigated for PrFe2 and PrRu2 compounds. The partial DOS illustrates a hybridized strong at Fermi level. While, the hyperfine magnetic field is determined using two GGA-PBESol and GGA-PBESol+U approximations. Both PrFe2 and PrRu2 have superconducting critical temperatures; 550 K and 580 K, respectively. The comprehensive experimental characterization of PrRu2 is still absent in the literature and superconducting critical-temperature values are favorable with a similar experimental value; 530 K for PrFe2.

6 citations



Journal ArticleDOI
TL;DR: In this paper , a fixed composition blend of polyvinylidene fluoride (PVDF) and plexiglass polymer poly(methyl methacrylate) (PMMA) with barium titanate (BaTiO3) ceramic nanofiller of varying concentrations (x = 0, 2.5, 5, 10, and 15 wt%) were prepared via a state-of-the-art solution-cast method.
Abstract: Polymer blend nanocomposite (PBNC) films consisted of fluoropolymer poly(vinylidene fluoride) (PVDF) and plexiglass polymer poly(methyl methacrylate) (PMMA) blend host matrix (fixed composition blend of PVDF/PMMA = 80/20 wt/wt%) with barium titanate (BaTiO3) ceramic nanofiller of varying concentrations (x = 0, 2.5, 5, 10, and 15 wt%) were prepared via a state-of-the-art solution-cast method. Scanning electron microscope (SEM) images evidenced high homogeneity of these PBNC films and a huge alteration in the spherulite morphology of the PVDF with the increase in dispersed BaTiO3 concentration in the polymer blend matrix. The X-ray diffraction (XRD) patterns identified the presence of electro-active polar β- and γ-phases of the PVDF crystallites in all the composite materials which are supported by the results of Fourier transform infrared (FTIR) spectra. The differential scanning calorimeter (DSC) thermograms explained the high melting temperature of these overlapped PVDF polymorphs and the degree of crystallinity altered anomalously with the variation of nanofiller concentration. The absorbance of ultraviolet-visible (UV-Vis) radiations enhanced while the direct energy band gap of the 80PVDF/20PMMA blend matrix and also the semiconducting BaTiO3 was found to decrease with the increased concentration of nanomaterial in the host polymer matrix. The ambient temperature broadband dielectric spectra covering the frequency range from 20 Hz to 1 GHz explain that the real part of complex dielectric permittivity reduced with a huge dispersion at higher radio frequencies where the dielectric loss tangent and electric modulus spectra exhibited an intense chain segmental relaxation process. The electrical conductivity of these PBNC films increased with frequency augmented and illustrated a small variation for different concentration composites. The experimental results demonstrated that these PVDF/PMMA/BaTiO3 films could be potential candidates for frequency tunable nanodielectric, electromagnetic interference shielders, a flexible dielectric substrate, thermal insulators, and bandgap regulated materials for futuristic microelectronic, capacitive energy storage, and optoelectronic technologies.

Journal ArticleDOI
TL;DR: In this article , the microstructure, mechanical characteristics, and in vitro corrosion behavior of gradient AZ91-bioactive glass composite wire fabricated by friction stir back extrusion were investigated.
Abstract: This study investigated the microstructure, mechanical characteristics, and in vitro corrosion behavior of gradient AZ91-bioactive glass composite wire fabricated by friction stir back extrusion. The results showed that by decreasing the extrusion speed from 40 to 20 mm/min, the distribution factor of bioactive glass increased from 0.31 ± 0.04–0.45 ± 0.07, and more homogenous grain size was formed at the surface and center zone of the composite wire. Under the influence of heat and plastic deformation during friction stir back extrusion, despite the formation of the β-phase in separate islands, the α + β eutectic phase was also formed in the composite wire. In composite wire processed with a rotational speed of 800 rpm and extrusion speed of 20 mm/min, a gradient distribution of bioactive glass was formed in the cross section of the wire. Compared to an as-cast AZ91 alloy, friction stir back extrusion conducted at a rotational speed of 800 rpm and an extrusion speed of 20 mm/min resulted in a 44% increase in corrosion resistance in simulated body fluid (SBF).

Journal ArticleDOI
TL;DR: In this article , a micro measurement method combining optical microscopy (OM) and digital image correlation (DIC) is used to quantitatively study the impacts of fly ash content and aggregate types on the thickness and nominal compressive elastic modulus (ENC) of ITZ.
Abstract: The interfacial transition zone (ITZ) plays a significant role in the mechanical behavior of concrete. For the purpose of improving the strength of concrete, the influences of four kinds of fly ash content and two aggregate types on the mechanical behavior of ITZ are studied in this work. A micro measurement method combining optical microscopy (OM) and digital image correlation (DIC) is used to quantitatively study the impacts of fly ash content and aggregate types on the thickness and nominal compressive elastic modulus (ENC) of ITZ. The results show that this method can characterize the properties of ITZ very well. Besides, fly ash can improve the mechanical performance of ITZ. The ITZ of the sample with 10% fly ash content has the most negligible thickness and the largest ENC. The ITZ of sample with basalt aggregate has a smaller thickness and larger ENC than the ITZ of sample with granite aggregate.

Journal ArticleDOI
TL;DR: In this paper , the effects of pegylation on the optical and structural properties of the ZnO NPs are investigated, and the results show that ZnOs are formed in both non-pegylated and pegylated conditions.
Abstract: In this paper, bare and pegylated ZnO nanoparticles with different ratios of polyethylene glycol 1000 to zinc acetate are successfully synthesized using the sol-gel method, and the effects of pegylation on the optical and structural properties of the ZnO NPs are investigated. The results show that ZnO molecules are formed in bare and pegylated nanoparticles. Also, ZnO nanorods are formed in non-pegylated conditions, while pegylation generally changes the morphology and no nanorods are observed in pegylated ZnO structures with different zinc acetate to PEG ratios. Furthermore, pegylation leads to a decrease in the NPs sizes significantly. The XRD results show the formation of the wurtzite ZnO phase and the absence of other oxide phases in the synthesized structure. Pegylation affects the optical properties of ZnO NPs significantly and the reflectance of PEG ZnO nanostructures in the Vis-NIR which is much higher than bare ZnO and it reaches approximately 100% at wavelengths greater than 400 nm. So, the PEG ZnO NPs can be established as strong reflectors in a wide range of optical applications. Furthermore, bandgap energies of the NPs experience a blue shift by pegylation. The zeta potential of bare ZnO NPs is more negative than PEG one. Also, the effect of pegylation on the photocatalytic activities of two selected ZnO NPs is studied using photodegradation of methylene blue (MB) dye under exposure LED light (power=20 W, central wavelength=380 nm, and full width at half maximum=13.2 nm) in normal and acidic solutions (pH=5.4 and 7.4). The results declare that pegylation of ZnO leads to more appreciable photodegradation of MB dye in the acidic solution than bare ZnO NPs. The kinetics of photocatalytic degradation of MB reactive dye under irradiated bare and pegylated ZnO NPs is also investigated in the paper.

Journal ArticleDOI
TL;DR: In this paper , the influence of hatch spacing, laser scan speed, and powder layer thickness on the microstructure and mechanical properties of A20X aluminum alloy was investigated and a fine equiaxed grain structure with a random crystallographic orientation was observed in the vertical section of the as-built samples.
Abstract: The processing window for laser powder bed fusion (LPBF) of A20X aluminum alloy was determined to increase the build rate and reduce the fabrication cost for this material. The influence of hatch spacing, laser scan speed, and powder layer thickness on the microstructure and mechanical properties were also systematically investigated. Over a wide processing window (40–115 J/mm3 energy density), near fully dense and crack-free components were achieved. In all cases, the as-built microstructure consisted of an aluminum matrix with TiB2 particles and Al2Cu precipitates, where volume fraction and size of both TiB2 and Al2Cu phases were found to be independent of the LPBF process parameters. A fine equiaxed grain structure with a random crystallographic orientation was observed in the vertical section (XZ-plane) of the as-built samples. This led to an isotropic elastic modulus, ultimate tensile strength, and total elongation. The yield strength, however, was found to be anisotropic, exhibiting a 16 % difference for different orientations. The average grain size decreased 54 % due to increased scan speed and reduced powder layer thickness. This resulted in a remarkable improvement in the alloy micro-hardness value from 108 HV to 124 HV, where the experimental data obeyed the Hall-Petch relationship.


Journal ArticleDOI
TL;DR: In this paper , the acoustical and mechanical characteristics of mortars mixed with silica aerogel and pineapple leaf fiber for various mixture designs in determining the optimal blends that exhibit good performance in both compressive strength, σu, and sound absorption coefficient, Sa.
Abstract: While offering good thermal insulation, silica aerogels inclusion in cementitious matrices compromises hugely the products’ compressive strength. Enhancement of the mechanical performance of concrete reinforced by fibers, on the other hand, has been well evident in existing scholarly works. Even so, natural fibers are under-exploited compared to their synthetic counterpart. Therefore, this study examines the acoustical and mechanical characteristics of mortars mixed with silica aerogel and pineapple leaf fiber for various mixture designs in determining the optimal blends that exhibit good performance in both compressive strength, σu, and sound absorption coefficient, Sa. Due to the widely reported mixing issue of silica aerogel in cement matrix, the examined samples have been fabricated through a carefully planned dry mixing method with a slow introduction of water in stages. The investigated silica aerogels are in powder form whereas pineapple leaf fibers are prepared in 10 mm length, from which their examined proportions are 0 %, 10 %, 20 %, 30 %, and 40 % as well as 0 %, 1 %, and 2 %, respectively. Scanning electron microscopy and Fourier transform infrared spectroscopy are additionally conducted to offer insight into the variation observed in σu and Sa for different mixes. The commonly reported drop in mechanical strength attributed to silica aerogel inclusion is witnessed but offset by the added pineapple leaf fiber. To circumvent laborious laboratory effort, statistical and machine learning explicit expressions are derived to generalize σu and Sa as functions of silica aerogel and pineapple leaf fiber contents. Also, the optimal constituents’ contents that exhibit good soundproofing while low in mechanical strength degradation are determined from the models for future design convenience.

Journal ArticleDOI
TL;DR: In this paper , the structural, elastic, phonon, and thermodynamic features of antiperovskites RE3InN (RE = Y and La) compounds using the Full potential augmented plane wave method (FP-LAPW) within the framework of density functional theory (DFT).
Abstract: The purpose of the current work is to examine the structural, elastic, phonon, and thermodynamic features of antiperovskites RE3InN (RE = Y and La) compounds using the Full potential augmented plane wave method (FP-LAPW) within the framework of density functional theory (DFT). The generalized gradient approximation of Perdew-Burke and Ernzerhof (GGA-PBE) exchange correlation have been considered to optimize the lattice parameters. The elastic properties of the investigated antiperovskite RE3InN (RE = Y and La) compounds has been studied in terms of Young, shear, bulk modulus, Poisson ratio, Debye temperature etc. The Debye temperature for RE3InN (RE = Y and La) compounds are found to be 575 K, 450 K, respectively. The compound La3InN is ductile while Y3InN compound is brittle in nature as evidenced from Cauchy pressure, Pugh ratio etc. La3InN compound is mechanically stable according to elastic property analysis. The electronic properties analysis suggests that the studiedcompounds aremetallic that arises from Y/La-4d/5d states. Additionally, we computed the thermodynamic variables, such as the bulk modulus B, relative volume, heat capacity, thermal expansion, and relative Debye temperature at a range of temperatures (0–1200 K) and pressures (0–40 GPa). The results that have been revealed should be helpful for future antiperovskite synthesis as well as for expanding our understanding of this promising class of antiperovskite-type materials.

Journal ArticleDOI
TL;DR: The perovskite solar cells (PSCs) have progressed very quickly with exceptional performance uptake from 3.8% to > 26%, poor stability and toxicity are the major challenges preventing its commercialization as mentioned in this paper .
Abstract: Even though the perovskite solar cells (PSCs) have progressed very quickly with exceptional performance uptake from 3.8% to > 26%, poor stability and toxicity are the major challenges preventing its commercialization. To make its commercialization possible, numerous modifications and fabrications techniques were explored till date. However, all the advancements made are still not good enough to scale its production at industry level and commercial use. The current work addresses recent advancements in the large-scale production and fabrication of PSCs, the accompanying benefits and drawbacks, and techniques for increasing the effectiveness of large-area perovskite films for industrial use. The review highlights all the basics of PSCs, fabrication methods, drawbacks, strategies for improving PSC efficiency, alternative PSCs, and multidimensional application. Additionally, we effectively envisioned the future scopes and possibilities of commercial uptake. In order to encourage PSC industrialization in the long-term, we also sought to obtain insight into the functional stability of PSCs as well as useful knowledge on how to extend their functional lifespan through sensible device design and materials processing. Furthermore, this review offers a quick look at insights for upcoming research while protecting the environment, human health, and safety.

Journal ArticleDOI
TL;DR: In this paper , a simple and cost-effective method has been used for obtaining highly conductive carbon quantum dots (CQDs) by hydrothermal oxidation of spent tea leaves, which proved to be exceptional working electrodes in the three-electrode cell in H2SO4 aqueous electrolyte.
Abstract: A simple and cost-effective method has been used for obtaining highly conductive carbon quantum dots (CQDs) by hydrothermal oxidation of spent tea leaves. The obtained CQDs are characterized by various analytical techniques demonstrating a crystalline structure. CQDs proved to be exceptional working electrodes in the three-electrode cell in H2SO4 aqueous electrolyte. Based on X-ray diffraction and microscopic analysis, the synthesized CQD is crystalline, with a diameter of 2–5 nm. Electrochemical impedance spectroscopy, cyclic voltammetry and charge-discharge measurements are used to evaluate the electrochemical performance of CQDs in an aqueous electrolyte. The CQD-based supercapacitor demonstrated a superior specific capacitance of 302.0 F g1 at a current of 0.5 Ag1, cyclability with 144.4 F g1 at 20 A g1 after 5000 cycles, and rate performance of 186.4 F g1 at 20 A g1. The CQDs electrode also exhibited an enhanced energy density and power density of 41.9 Wh g1 and 250 W g1, respectively at a current rate of 0.5 A g1. In experiments, it is demonstrated that many thousands of cycles could be run consistently at near 100% efficiency and a stable capacity. This explains the possibility of using spent tea leaves as a bioresource, the ease of synthetically producing these materials, and the favourable redox reaction of CQDs for high-energy devices.

Journal ArticleDOI
TL;DR: In this paper , a review of resistive random access memory (RRAM) devices based on various binary metal oxides is presented, and various nonvolatile memory performance parameters are discussed comprehensively.
Abstract: Semiconductor memories are essential ingredients of modern electronic devices. Resistive Random-Access Memories (RRAMs) have emerged as better alternatives for conventional charge-based flash memories due to their distinct features like high speed, ultra-low power consumption, and small footprint. RRAMs can be fabricated in a three-layer metal-insulator-metal configuration that uses various materials, viz., oxides, chalcogenides, biomaterials, ferrites, and perovskites, as an active switching layer. Among the different materials, binary metal oxides are prominently used for device fabrication, owing to their superior chemical composition, multistate switching ability, and compatibility with the complementary metal-oxide-semiconductor (CMOS) fabrication process. The present review critically discusses RRAM devices based on various binary metal oxides. In particular, we tried to review the resistive switching (RS) mechanisms of titanium oxide (TiO2), zinc oxide (ZnO), nickel oxide (NiO), tungsten trioxide (WO3) copper oxide (CuxO), tantalum oxide (TaOx or Ta2O5), and hafnium oxide (HfO2) based devices. In addition to this, various non-volatile memory performance parameters were discussed comprehensively. The review sets the tone of explorations with an introductory discussion regarding the background of RS mechanisms. After that, various materials used to develop memory devices were dealt with in-depth. Multiple aspects and factors responsible for the improved performance of memory devices based on different oxides have been deliberated critically. Lastly, the review concludes with significant vital insights regarding the mechanism, usefulness, superior materials used so far, and future scope of exploring these metal oxides in the current memory technology and bio-inspired neuromorphic computing.



Journal ArticleDOI
TL;DR: In this article , a DFT-approach was employed to investigate double perovskite's (Rb2AgInX6 (X = Cl, Br, I) structural, electronic, optical and thermoelectric properties.
Abstract: The demand for renewable and clean energy increases the significance of perovskites and attracts the substantial interest of the scientific community to further explore these materials owing to their excellent optoelectronic characteristics. In this regards, a DFT-approach was employed to investigate double perovskite’s “Rb2AgInX6 (X = Cl, Br, I)” structural, electronic, optical and thermoelectric properties. To prove the structural and thermodynamic stability, the tolerance factor (tF) and formation energy (ΔHf) were computed whose values falls within acceptable stable region. Based on the band structure (BS) calculations, the compounds demonstrate direct band gaps of the values of 2.16 eV, 1.32 eV, and 0.46 eV for anions Cl, Br, and I based-double perovskites, respectively. The band gap of 1.32 eV of Rb2AgInBr6 is ideal for exploring this compound for solar cell applications. Furthermore, to study optical characteristics, the investigated compounds were explored in terms of optical absorption, refractive index, and dielectric constants for energy range 0–6 eV which ensured the absorption among infrared, visible, and ultraviolet regions. Based on maximum absorption for visible region, the studied compound Rb2AgInCl6 is an excellent candidate to harvest solar cell applications, among others. Furthermore, the Seebeck coefficient, lattice thermal and electric conductivities, and figure of merit (ZT) addressed by Boltzmann theory also make them decent aspirants for thermoelectric applications.

Journal ArticleDOI
TL;DR: In this paper , a novel device that generates energy simply by water splitting and requires no other external energy source was reported, which is an oxygen deficient mesoporous material and is reported for the first time for this application.
Abstract: The present work reports a novel device that generates energy simply by water splitting and requires no other external energy source. Generating green energy by hydroelectric cell (HEC) from water splitting is an emerging concept in the field of energy harvesting. Efficient non-photocatalytic splitting of water molecules at room temperature produces green electricity even without sunlight. The synthesized pure and lithium (Li) substituted nickel oxide (NiO) is an oxygen deficient mesoporous material and is reported for the first time for this application. Using an electrolytic chain reaction, the reported material dissociates water into H3O+ and OH- ions, generating a potential across electrodes. The tuned ratio of 80% nickel and 20% lithium (Li20Ni80O) based HEC produced 135 mA at 1.06 volts using a pellet radius of 1.75 cm. This provides a significant peak power (Pout) of 143 mW. The material is characterized using X-ray spectroscopy and Electron Paramagnetic Resonance spectroscopy for oxygen vacancies. Photoluminescence (PL) confirms the defect states formed by Ni2+ interstitials. Mesoporosity and surface areas are observed by Brunauer Emmett Teller (BET). The ionic diffusion due to splitting of H3O+ and OH- ions is observed with Nyquist curves. Nickel oxide is a cost-effective and ecologically sustainable solution for green energy generation. The energy generated per square meter by this method is comparable to solar cell energy with the added advantage of generating energy in the dark as well. Since, byproduct of this process is the generation of hydrogen gas, this material can also be used for hydrogen production. This technology may lead to an alternative route in the power sector.

Journal ArticleDOI
TL;DR: In this article , the anatase and rutile phases of TiO2 NPs were obtained by calcinating them at temperatures of 400 and 700 oC, respectively, respectively.
Abstract: In this paper, TiO2 NPs has been fabricated by via microwave-assisted chemically and biologically methods. The anatase and rutile phases of TiO2 NPs were obtained by calcinating them at temperatures of 400 and 700 oC, respectively. In these two different approaches, the biomolecules like alkaloids, steroids, glycosides, etc. present in Tinospora Cordifolia (TC) and polyvinylpyrrolidone (PVP), respectively, have been reported to act as stabilizing agents for TiO2 NPs. XRD, Raman, UV-visible, SEM-EDS and TEM spectroscopic techniques were used to analyze distinct physical and chemical properties. The so-synthesized TiO2 NPs exist as tetragonal crystal lattice with spheroidal shape and sizes between 8-40 and 15-98 nm. Under the influence of UV light, the photocatalytic activity was examined against two common industrial dyes, methyl orange (MO) and methylene blue (MB) by using synthesized TiO2 NPs. Up to 98% and even 100% of MO and MB dye degradation have been seen in rare circumstances. The antioxidant potential of TiO2 NPs has been evaluated up to 91 and 74% from the biologically and chemically methods, respectively.

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TL;DR: In this paper , a low-pressure cold spraying technique was employed to fabricate two new mechanically alloyed AlCoCrFeMoW and AlCoCoCr FeMoV HEA coatings, which were systematically investigated, in order to assess their resistance to dry abrasive wear and solid particle erosion.
Abstract: Recent advances in advanced metallic alloys have enabled the development of high entropy alloys (HEAs) for extreme engineering environments. HEAs are characterized by their mixing of elements with equimolar concentrations or near to equimolar concentrations, which enables the formation of solid-solution structures due to inherent high configurational entropy. With the advancement of HEAs, the attractiveness of these alloys as cold-sprayed coatings for wear resistant surfaces has been increasing. In the present study, a low-pressure cold spraying technique was employed to fabricate two new mechanically alloyed AlCoCrFeMoW and AlCoCrFeMoV HEA coatings. The phase formations, microstructure evolutions, and average microhardness of the fabricated HEA coatings were systematically investigated, in order to assess their resistance to dry abrasive wear and solid-particle erosion. The results showed that the cold-sprayed HEA coatings exhibited refined microstructure and low porosity, with the presence of body-centered cubic (BCC1 and BCC2) structures and CrMo intermetallic phases. Microhardness results revealed that AlCoCrFeMoV HEA coatings achieved the highest average hardness of around 561±63HV, such that it was 35% and 52% higher than that of AlCoCrFeMoW and AlCoCrFeMo HEA coatings, respectively. Dry abrasive wear results showed lower wear rates were achieved for AlCoCrFeMoV HEA coatings (590×10−6mm3/Nm), followed by AlCoCrFeMoW (660×10−6mm3/Nm) and AlCoCrFeMo HEA coatings (720×10−6mm3/Nm). However, damage during solid particle erosion was found to be higher in case of AlCoCrFeMoV HEA coatings compared to the other two coatings, suggesting no apparent correlation with microhardness values. These results suggest that the existence of high weight fractions of solid-solution phases in conjunction with refined microstructure and low porosity resulted in improved resistance to abrasive loading for the AlCoCrFeMoV HEA coatings but undermine performance and resistance to solid particle erosion damage.

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TL;DR: In this article , the effect of the content of SiC added to the Ti-Al-Si system on the properties and microstructures of the original coatings was explored.
Abstract: This work prepared (Ti-Al-Si)-X (x = 1, 2, 3, 4) coatings on TC4 alloy matrix composites by laser cladding to improve their surface mechanical properties. Meanwhile, the effect of the content of SiC added to the Ti-Al-Si system on the properties and microstructures of the original coatings was explored. The results showed that the reinforced composite coatings contained matrix phases (TiAl, Ti3Al, TiAl3) and reinforcing phases (Ti5Si3 and TiC). As SiC content increased, the matrix phases formed in the coatings showed different results on the Ti-Al-Si ternary phase diagram due to the introduction of C, a stabilizer of ɑ-Ti alloy. Meanwhile, TEM results indicated the existence of Ti5Si3 phase and Ti3Al secondary phase in the Ti-Al-Si-3 layer. Compared with the TC4 matrix, the reinforced composite coatings had higher microhardness with average values of 780.9 HV0.3, 853.9 HV0.3, 985.0 HV0.3 and 943.5 HV0.3 for the four coatings, respectively. The wear resistance of the reinforced composite coatings increased first and then decreased with increasing SiC content, which was the result of the matrix phase transformation. The Ti-Al-Si-3 coating had the highest microhardness (1092HV0.3) and wear resistance (the friction coefficient, the wear scar width and wear weight loss were 0.37, ∼0.83 mm and 1.8 mg, respectively). The above analysis and results demonstrated that the Ti-Al-Si-3 layer had superior mechanical properties compared with those of other reinforced coatings.