Journal of Materials Science: Materials in Electronics

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Online ISSN: 1573-482X
Print ISSN: 0957-4522
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  • V. V. JadhavarV. V. Jadhavar
  • B. S. MundeB. S. Munde
We investigated the structure, optical, and dielectric properties of undoped and chromium-doped zinc sulfide (Zn1-xCrxS) nanoparticles prepared via co-precipitation at 300 K with Cr concentrations x = 0.00, 0.02, and 0.04. The X-ray diffraction patterns demonstrated that the Zn1-xCrxS nanoparticles have a cubic structure with no impurity. The average crystallite size of the nanoparticles calculated using the Scherrer equation is in the range of 1.70–1.56 nm and decreases with an increase in Cr content. The lattice constants were in the range of 5.38–5.35 Å. Field emission scanning electron microscope (FESEM) images of nanoparticles show nearly spherical morphology with agglomeration, and doping reduces agglomeration. Energy-dispersive spectroscopy (EDS) analysis confirmed the presence of Cr in doped samples. The optical band gap of undoped ZnS nanoparticles was found to be 3.35 eV, increasing slightly from 3.39 to 3.41 eV as the chromium concentration increased. Dielectric measurements show that the dielectric constant of doped samples is higher at low frequencies, whereas the dielectric losses of these samples are lower at higher frequencies. Furthermore, the AC conductivity of all samples varies with frequency and composition, increasing abruptly at higher frequencies and decreasing with the addition of Cr ion in the ZnS matrix. Optical and dielectric results indicate that Cr-doped ZnS nanoparticles are promising materials for optoelectronic and high-frequency devices.
  • K. VinothaK. Vinotha
  • B. JayasuthaB. Jayasutha
  • M. John AbelM. John Abel
  • K. VinothK. Vinoth
Semiconducting Indium-doped copper sulfide thin films were deposited on glass substrate by a simple and economical chemical bath deposition technique. The depositions were carried out for 40 min. The electrical studies namely resistivity, resistance, and sheet resistance of CuS and CuS: In were carried out using four-point probe apparatus. The structural, optical, and morphological characterization were studied and compared with those of CuS: In with the bare CuS thin films. XRD studies confirmed that all the prepared thin films have the hexagonal structure of copper sulfide without any secondary phase after doping and the crystallite size was found to be decrease from 69 to 53 nm. Optical absorption analysis of samples shows a red-shift in the band edge of In: CuS thin films relative to CuS film so that the bandgap energy was decreased from 1.95 eV to 1.86 eV. The functional groups present in the CuS and In: CuS samples were confirmed by FTIR and FT-Raman frequency assignments. Morphological studies of CuS and CuS: In are interpreted using SEM and constituents present in the prepared thin films are viewed by EDS. Further the photocatalytic properties of the prepared films were studied by degrading methylene blue (MB) and rhodamine B (RhB) textile dyes. Maximum degradation efficiency achieved by the photocatalyst is to be 95% and 93% respectively for MB and RhB.
  • Praveena PanchatcharamPraveena Panchatcharam
  • Narayanan VengidusamyNarayanan Vengidusamy
  • Stephen ArumainathanStephen Arumainathan
Incorporation of novel 2D materials with conducting polymers have attracted increasing attention in the supercapacitor applications owing to their unique properties. In the present work, novel polycarbazole (PCz)/porous boron carbon nitride (BCN) nanocomposites were prepared in different ratio (30, 50, and 70 wt%) via facile in situ chemical oxidative polymerization method. The PCz-BCN nanocomposites was synthesized at room temperature using an easy and inexpensive chemical oxidative method. The structure and formation of nanocomposites were analysed by X-ray diffraction (XRD), Fourier Transform Infra-Red (FT-IR), Raman Spectroscopy, and X-ray Photoelectron Spectroscopy (XPS) characterization techniques. Furthermore, the structural morphology of the PCz-BCN nanocomposite-50 wt% was analysed by Field Emission-Scanning Electron Microscopy (FE-SEM) and High-Resolution Transmission Electron Microscopy (HR-TEM). The thermal behaviour of the as-prepared sample was analysed using Thermo Gravimetric Analysis (TGA) technique. Cyclic Voltammetry (CV), Galvanostatic Charge–Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) studies were used to evaluate the electrochemical specific capacitive performance of the prepared electrode material at different scan rates and current density in the various potential windows. It was found that the orthorhombic crystalline nature of the polycarbazole incorporated well with the stacking layer of the sp²-hybridized graphitic BCN aromatic ring structure via the Van der Waals interaction. The PCz/BCN-50 wt% nanocomposite electrode material exhibits specific capacitance 134 F g⁻¹ at current density of 3 mA g⁻¹ in aqueous electrolyte 3 M KOH compared to the pure PCz and BCN. Furthermore, even after 800 cycles, the PCz-BCN nanocomposite electrode demonstrated excellent cyclic stability, because the improved enhancement of the specific capacitance of the conductive network of the PCz-BCN composite, as well as the synergistic effect of pure PCz and BCN, makes it a promising material for supercapacitor application. Hence, the facile in situ oxidative polymerization method of the synthesis of the porous PCZ-BCN nanocomposite is a promising route for producing electrode materials so as to fabricate high-performance supercapacitors in a cost-effective way.
  • Haihua HeHaihua He
  • Yufen ZhouYufen Zhou
  • Feiyong YangFeiyong Yang
  • [...]
  • Min JinMin Jin
Carbon dots (C-dots) have been known as a type of important luminescent materials in the lighting field due to their advantages such as low cost, environmental benign, and broad color-tuning range. However, the C-dots often face the aggregation-induced photoluminescence quenching (AIPLQ) and film-formation instability problems, thereby causing the limitations of their application. In this work, we have prepared the C-dots with branched-polyethylenimine chemically functionalized on the particles’ surfaces. The TEM results show that the diameter of the obtained C-dots is distributed mainly in the range of 4–7 nm, with the average diameter of 5.7 nm and lattice fringe spacing of 0.19 nm related to the (100) plane. The thermogravimetry analysis reveals that the C-dots experience three stages of weight losses. The UV–Visible absorption spectra results show that there are two absorption bands at 340 nm and 505 nm in the C-dots in the form of the aqueous solution and solid-state films, which are assigned to the π–π interactions and the carbogenic core of the C-dots. In addition, the PL results reveal that the C-dots can overcome the AIPLQ and show a highly efficient red luminescence in the solid-state form, with a maximum PL quantum yield of ~ 23% under 505 nm excitation. At last, we design and achieve an excellent C-dots-based film by dealing the C-dots with a solution spin-coating method, and demonstrate the potential application of the obtained C-dots for LED device.
  • Xiao LuXiao Lu
  • Liang ZhangLiang Zhang
  • Wang XiWang Xi
  • Mu-lan LiMu-lan Li
Since the high cost of Ag, current research on traditional high-Ag solders has gradually shifted to low-Ag solders. However, the microstructure tends to be coarser, and the all-around performance declines as the Ag content decreases. Fortunately, doping alloying elements or nanoparticles has proven efficient in enhancing low-Ag solders' properties. Furthermore, choosing a suitable surface treatment technique or employing magnet stirring for the molten solders also makes a significant difference. To further promote research regarding low-Ag solders, this paper mainly reviews the effects of alloying and particle reinforcement on melting characteristics, wettability, microstructure, interfacial reaction, mechanical properties, creep resistance, reliability and corrosion resistance, and the progress of modified low-Ag solders have also been systematically summarized and analyzed. Finally, the challenges and research gaps for low-Ag solders have been provided.
  • Ling LiLing Li
  • Jiyao ZhouJiyao Zhou
  • Yanwei ZhangYanwei Zhang
  • Xinbin PeiXinbin Pei
CoMoO4 material has great advantages in the application of supercapacitors, but the low conductivity and reactivity of CoMoO4 limit its capacity and energy density severely, resulting in a certain gap between the actual value and the theoretical value of specific capacitance. As an electrode material, the performance of CoMoO4 electrode material with spinel structure is directly related to the microstructure of the material. In this paper, CoMoO4 material grown in situ on nickel foam was synthesized by hydrothermal method. Through electrochemical performance tests, the best electrochemical performance belong to the materials using ammonium molybdate and cobalt nitrate as raw materials, synthesized at hydrothermal temperature of 140 °C for 10 h, and calcined at 250 °C for 1 h. The discharge capacity of the material is up to 11.112 F/cm2 at the current density of 3 mA/cm2. The XRD characterization shows that the material has good crystallinity, and it belongs to the orthorhombic structure. The SEM characterization shows that the synthesized material is in cuboid rod structure with loose folds on the periphery. According to EDS analysis, the atomic proportion of each element is close to that in the molecular formula. The positions of absorption peaks in the infrared spectrum are consistent with that of CoMoO4 material.
  • V. Jagadeesha AngadiV. Jagadeesha Angadi
  • Khalid Mujasam BatooKhalid Mujasam Batoo
  • Sajjad HussainSajjad Hussain
  • [...]
  • S. O. ManjunathaS. O. Manjunatha
Rare earth-doped ferrites are exhibiting remarkable surface phenomena. Wherein the process of adsorption is most significant. Humidity sensors are the realization of an adsorption mechanism. Therefore, rare earth-doped ferrites are suitable for humidity sensor applications. Considering this fact, in the present work, Holmium(Ho3+) Mn-Bi ferrites are prepared by the solution combustion method with the general formula Mn0.95Bi0.05Fe2-xHoxO4 (x = 0 to 0.03). The effect of holmium doping on the structural, microstructural, magnetic, and humidity properties was analyzed. The X-ray diffraction revealed the formation of a cubic spinel structure. The average crystallite size was obtained by using the Scherrer method, with a range of 7 to 13 nm. The presence of nanoparticles in samples increases the surface area required to favor adsorption mechanisms in the samples. The Scanning Electron Microscopy micrographs showed the surface morphology with the presence of pores, holes, and on their surfaces. Vibrating sample magnetometry confirmed superparamagnetic behavior. The saturation magnetization (Ms) was found to decrease with an increase of Ho+3 content in the samples. We observed the decrements of resistance with the increment of relative humidity from 11 to 97% relative humidity and the increase of sensing response with an increase in relative humidity. At 54% relative humidity, maximum humidity hysteresis is found to be 2%. The sensing response time and recovery time were recorded to be 79 s and 91 s, respectively. The difference between sensing response and recovery time is small. These kinds of samples may be used in applications of sensing material.
a–d show the nanorods reacted at 130 °C for 10, 20, 30, and 60 s, respectively, e and f show the nanorods reacted at 150 °C for 30 s and 60 s, respectively (Color figure online)
a and b 5-nm scale branched nanorods reacting at 130 °C for 10 s and their Fourier transform diffraction spots. c and d 5-nm scale branched nanorods reacting at 130 °C for 60 s and their Fourier transform diffraction spots. e and f 5-nm scale branched nanorods reacting at 150 °C for 60 s and their Fourier transform diffraction spots
a and b show the morphologies of PbSe nanocrystals with and without the addition of NH4Cl after reacting for 1 min. c and d show the low- and high-magnification TEM images indicating the morphologies of PbSe nanocrystals after reacting for 5 min
a Absorption spectrum of nanorods. b Photoluminescence of nanorods
  • Zhongxiang YaoZhongxiang Yao
  • Gang BiGang Bi
  • Juxin YinJuxin Yin
  • [...]
  • Chunfeng CaiChunfeng Cai
Due to the narrow band gap and high quantum confinement effects, Group IV–VI PbSe semiconductor materials have wide applications in infrared detectors. The morphology and size of nanomaterials affect the physical and chemical properties of PbSe semiconductor materials. Here, we developed a synthesized and grew PbSe-branched, I-shaped, and L-shaped nanorods method with uniform distribution by modulating the reaction environment. The results suggested that the arm length of the nanorods increased along the < 100 > axes with reaction time. The directional attachment of nanoparticles along the {100} plane was enhanced by appropriately increasing the reaction temperature. NH4Cl could promote the orientational attachment of PbSe nanocrystals along the {100} planes to form I-shaped and L-shaped nanorods. The PbSe-branched nanorod arms were uniformly distributed between 4.2 and 21 nm corresponding to an absorption spectrum between 1086 and 1574 nm and photoluminescence between 1301 and 1621 nm. This indicates that the optical properties are tunable in the near-infrared. Therefore, this research expands the potential applications of PbSe nanostructures in tunable infrared lasers, bioimaging, and solar cells, among others.
  • R. SuganyaR. Suganya
  • A. RevathiA. Revathi
  • D. SudhaD. Sudha
  • [...]
  • E. Ranjith KumarE. Ranjith Kumar
The presence of composite in the nanofluid resultant is essential to provide a significant methylene blue (MB) removal property in industrial waste water. Silver oxide (Ag2O) nanoparticles (NPs) placed over zinc oxide (ZnO) NPs had a significant increase in photocatalytic activity. The Ag2O NPs doped ZnO NPs were synthesised in the current study by utilising Millingtonia hortensis flower extract and a simple green synthesis procedure. The floral extract is a fantastic reducing and stabilizing agent. ZnO has been doped along with Ag2O Nanofluid (NF) (volumes of ZnO 10 ml, 15 ml, 20 ml, and 25 ml). The crystalline nature of the produced material was investigated using powder XRD analysis. To confirm the presence of silver in nanofluids, the EDAX spectrum and UV–Vis spectral analysis were employed. The EDAX spectrum established the materials’ compositions, while the FESEM analysis revealed the various surface morphologies of the generated materials. ZnO/Ag2O (NPs) catalysts degraded the organic dye MB. ZnO/Ag2O NPs (25 ml Ag2O NF) degrade at a rate of 63 percent after 120 min of irradiation, due to their large surface area. The typical particle size of synthesised nanoparticles is 16–17 nm. The photocatalytic activities are enhanced when particles from the flower are extracted, according to the characterization data.
  • Yan WangYan Wang
  • Xiaojie HuXiaojie Hu
  • Haiou WangHaiou Wang
  • [...]
  • Dexuan HuoDexuan Huo
The transport properties and magnetoresistance (MR) effect of Pr0.7Sr0.3MnO3 (PSMO) film on SrTiO3 (STO) substrate are investigated in this work. The PSMO film is grown on (001) STO substrate by pulsed laser deposition (PLD). The high-resolution X-ray diffraction (XRD) pattern suggests that the Pr0.7Sr0.3MnO3 film shows the out-of-plane single orientation. Atomic force microscopy (AFM) image shows that the surface of the film is smooth. In addition, the significant interference peaks can be found in the XRD. All these confirm the high quality of the PSMO film grown on STO substrate to some extent. The magnetotransport properties and the MR associated to the double exchange (DE) interactions of the Pr0.7Sr0.3MnO3 film have been studied by the resistivity versus temperature and resistivity versus magnetic field data. The temperature dependence of resistivity shows that the film sample undergoes a metal-to-insulator (MI) transition at MI temperature TMI. The TMI gradually increases with the increase of applied magnetic field. Under different fields of 1 T, 2 T, 4 T and 6 T, the maximum values of negative MR (MR = [ρ-ρ0/ρ0] × 100%) reveal about 47.16%, 53.16%, 86.59% and 92.22%, respectively. Compared with other reports on bulk polycrystalline PSMO compounds and polycrystalline PSMO films, the PSMO film on STO in our work has relatively large MR, which is related to the single-oriented growth of PSMO/STO film. The large MR is conducive to the practical applications in magneto-electronic devices. The applied magnetic field dependence of resistivity shows that near TMI, the resistance changes significantly with the change of the applied field. This also implies that there is a large MR at around TMI, which can be explained by the traditional DE mechanism.
  • Keiji TanakaKeiji Tanaka
  • Akira SaitohAkira Saitoh
It is known that amorphous chalcogenide materials exhibit unique optical phenomena, including high nonlinearity, photodarkening, and phase changes. Upon single or repeated, pulsed excitations, these phenomena induce changes in optical properties and/or macroscopic shapes, which are promising for applications to photonic devices and micro-fabrications. We consider comprehensively the fundamentals of such pulse-induced phenomena appearing in sulfides (and selenides), which may be contrastive to the opto-thermal phase change in telluride films. The optical nonlinearity works as refractive-index switches with fs response times, transient absorption could operate as optical switches, and photodarkening-related effects can be applied to memories. Besides, damages produced by intense pulses may be useful for micro-fabrications. These responses are feasible at the optical communication wavelength, ~ 1.55 μm, where the materials are transparent. However, roles of band-edge and -gap states remain to be explored. Pulsed excitations would also produce noticeable temperature rises, for which a simple evaluation scheme is presented.
XRD patterns of InSe thin films: as-deposited and annealed at different temperatures (150 °C, 200 °C and 250 °C)
a The cross-sectional view of as-deposited InSe thin film. b EDS color mapping of In and Se in InSe thin film. FE-SEM images of InSe thin films c as-deposited, d annealed at 150 °C e annealed at 200 °C, and f annealed at 250 °C
Transmission spectra of InSe thin films: as-deposited and annealed at different temperature (150 °C, 200 °C and 250 °C)
(αhν\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\alpha }{} \textit{h}{\nu }$$\end{document})0.5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{0.5}$$\end{document} vs (hν\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\textit{h}{\nu }$$\end{document}) plots for optical band gap of InSe thin films: as-deposited and annealed at different temperatures (150 °C, 200 °C and 250 °C)
Variation of ln(α\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document}) with (hν\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\textit{h}{\nu }$$\end{document}) for InSe thin films, and dashed lines are the linear fit of experimental data. The inset shows the variation of Urbach energy (EU\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E_{U}$$\end{document}) with annealing temperatures, and solid line is the guide for eyes
Indium selenide (InSe), a member of chalcogenide semiconductors, has attracted immense attention due to its wide range of technological applications in solar cells, data storage, switching devices and diodes. In the present study, InSe thin films are deposited using thermal evaporation method, and post-annealing treatment has been performed in vacuum at different temperatures (150 °C, 200 °C, and 250 °C) to induce changes in structural, morphological and optical properties. As-deposited InSe thin film has monoclinic phase, and the crystallinity is found to increase with annealing at 150 °C and 200 °C. The phase transition from crystalline to amorphous phase is achieved with annealing at higher temperature (250 °C). The drastic change in the morphology with annealing temperature is clearly visible in field emission scanning electron microscope (FE-SEM) images. With annealing, the average transmission in the wavelength range of 900–2400 nm increases, and also the value of optical band gap increases from 1.12 to 1.42 eV. The observed change in the transmission and optical band gap is due to change in density of localized and/or delocalized defect states in the forbidden gap with post-annealing treatment. These results show that the post-annealing treatment has significant impact on structural, morphological and optical properties of InSe thin films.
  • Dulce K. Becerra-PaniaguaDulce K. Becerra-Paniagua
  • Evelyn B. Díaz-CruzEvelyn B. Díaz-Cruz
  • Alejandro Baray-CalderónAlejandro Baray-Calderón
  • [...]
  • Claudia Martínez-AlonsoClaudia Martínez-Alonso
In recent decades, nanostructured metal sulphides (MSs) have gained great interest due to their extensive applications ranging from optoelectronic devices to biomedical applications. Significant efforts are being focused on low toxicity MSs in response to the notable interest of the scientific community in pursuing more environmentally friendly alternatives. The controlled synthesis of MS nanostructures is crucial for providing control of their optoelectronic properties and potential applications. Among the various methods for synthesis of MSs, the microwave-assisted heating approach seems to be a viable option to conventional heating techniques for producing nanostructures using green routes, because of its homogeneous heating, greatly reduced synthesis time, as well as uniform morphology and higher phase purity of the produced materials. In this review, we provide a comprehensive overview of microwave-assisted heating and highlight its utility in the synthesis of MSs nanostructures. We address the synthesis of six environmentally friendly binary MSs that have been obtained by microwave-assisted heating: ZnS, SnSx (x = 1,2), CuS, Fe2S, Bi2S3, and Sb2S3. Herein, the most relevant findings related to the impact of microwaves on the morphology, dimensions, and properties of MS nanostructures have been summarised, emphasising the role of the dielectric constant. We conclude that materials with a large dielectric constant tend to grow in all directions with a proclivity towards a spherical shape, while materials with a small dielectric constant often grow unidirectionally, forming rod-like crystals. Finally, we evaluate the limitations, advantages, and prospects of microwave-assisted heating for the synthesis of nanostructures.
This paper presents a depth study of structural, magnetic, magnetocaloric effects, and critical behavior of the La0.67Ba0.22Sr0.11Mn0.95Ni0.05O3 manganite compound. This material was synthesized using the solid–solid method. The crystallographic study shows that our compound crystallizes in a Pnma orthorhombic structure. The magnetic measurements M (T) show that our material has a transition from the ferromagnetic (FM) state to the paramagnetic (PM) state with increasing the temperature. Arrott plots (μ0HM\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu_{0} \frac{H}{M}$$\end{document} vs. M²) show that our compound presents a second-order transition. The magnetic entropy change (−∆SM) was determined by Relying on the Maxwell relation. The obtained results prove that our compound is a promising material which can be used in magnetic refrigeration application, operating over a wide range of temperatures. In addition, the magnetocaloric properties have been investigated using a phenomenological model. Finally, the estimated critical exponents values β, γ, and δ using through various techniques are comparable to those predicted by the mean-field model. The magnetic interaction nature in our samples is described by the calculation of exchange distance J(r).
  • V. VidhyaV. Vidhya
  • P. AnbarasuP. Anbarasu
  • D. GeethaD. Geetha
Gas detected with nanosized oxide materials attracts consideration due to its promising capability of identifying different poisonous gases in atmosphere. In this study, the Cu-doped SnO2–TiO2 nanostructures were synthesized by co-precipitation and hydrothermal method using stannic chloride, titanium isopropoxide and copper nitrate as precursors. Structural characterization revealed that the items correspond to nanostructures of Cu particles deposited on SnO2–TiO2 surface. The characterizations studies of hybrid nanocomposites were determined by X-ray diffractrogram, scanning electron microscopy, FTIR and UV–Vis spectroscopy analyses. Optimized nanocomposite was fabricated into high sensitive gas thick film to sense gas molecules. The prepared sensor device using the films exhibits higher responses (sensitivities) to reducing group of gases. The improved sensitivity of this nanocomposite propagates the gas diffusivity of the sensing film comprising Cu-doped SnO2–TiO2. This sensing film will also increase the sensor response due to its catalytic and electrical sensitization effects of Cu and titanium oxide.
  • R. AydınR. Aydın
  • A. AkkayaA. Akkaya
  • B. ŞahinB. Şahin
Products based on nanostructured flexible thin films, which are anticipated to make their way into our lifetimes in the near future. Therefore, nanostructured metal-oxide thin-film materials grown on flexible substrates are anticipated to meet emerging technological requests. In this article, we present a promising light-weight and flexible thin-film material using un-doped and Ni-doped CuO samples. Ni:CuO flexible thin-film materials were fabricated by using the cost-effective SILAR method on cellulose acetate substrates and the effects of both Ni doping and bending on the change in electrical and optoelectronic performances were investigated. It is observed that Ni doping has a great impact on the main physical properties of flexible CuO samples. The optical bandgap value of the un-doped CuO film improves with increasing Ni ratio in the growth bath. Also, sheet resistance values of the un-doped and Ni:CuO samples are a little affected due to bending of samples for bending radius ~ 20 mm. These flexible all solution-processed nanostructured CuO samples are promising candidates for use in future optoelectronic applications.
  • Neelam RaniNeelam Rani
  • Bindiya GoswamiBindiya Goswami
  • Rachna AhlawatRachna Ahlawat
The present work embodies the effect of Nb2O5 on morphology and luminescence outcomes of Er³⁺-doped SiO2. Various modified structural parameters were evaluated for prepared samples due to gradual changes in the annealing temperature 300–900 °C range. The crystalline Er³⁺: SiO2/Nb2O5 powder was synthesized by a reliable sol–gel process with a 20–23 nm nanoparticle range. Proper annealing allowed to avoid the existence of various defects, chemical reactions, and impurity phases; consequently, the structural and optical properties have improved significantly in all prepared samples. In absorption spectra, the excitonic edge has been shifted toward the lower wavelength owing to the quantum size effect. A significant luminescence in the visible region is reported for Er³⁺: SiO2/Nb2O5 nanopowder at 260 nm. The International de I’Eclairage chromaticity graphs were drawn nearly in the white region, and full width half maxima was estimated at ~ 134 nm for most prominent IR signals. The observed strong luminescence has been correlated to the lifetime decay constant also. These characteristics enforced the utilization of prepared nanopowder in white light-emitting diodes and in solid-state display devices. More energetic PL emission spectra were obtained in long infrared (IR) regions at 525 nm excitation. This drastic change in optical behavior is noticed in Er³⁺: SiO2/Nb2O5 sample owing to energy transfer between Nb2O5 nanocrystals and Er³⁺ doped in amorphous silica where Nb2O5 acts as an efficient sensitizer. The reported Er³⁺: SiO2/Nb2O5 nanopowder can be implanted not only in the -S, -L, but also in the -C band of optical communication.
Aurivillius intergrowth multiferroic phases are inspiring to many researchers owing to their scientific and technological application point of view. We have synthesized the intergrowth of promising three-layered Bi3.25La0.75Ti3O12 (BLT) and four-layered Bi4NdTi3Fe0.7Co0.3O15 (BNTF) compounds. The X-ray diffraction (XRD) data was analyzed by comparing our data with a standard eight-layered compound (Bi9Ti6FeO27) and the lattice parameters were evaluated. Showing a shoulder peak at maximum XRD intensity peak (1 1 8) is considered to be a signature of intergrowth formation. Scanning electron microscopic images have shown non-uniform disk-like grains with no preferential orientation. In order to extract information about relaxation species, Nyquist plots (Cole–Cole plots) were drawn at different temperatures. AC activation energies were evaluated from σ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sigma$$\end{document}ac vs. 1000/T plots, drawn at 10 kHz, 50 kHz and 100 kHz. Based on the impedance studies it is concluded that the hopping mechanism prefers through the doubly ionized oxygen atom vacancies and this phenomenon is corroborated to dielectric relaxation. Room temperature magnetic measurements display a weak ferromagnetic order. The intergrowth compound (BLT–BNTF) displayed ME coefficient (= 0.123 mV/cm–Oe) at lower magnetic fields. This is the most striking factor and helpful to fabricate room temperature Magnetoelectric sensors.
  • Zainab M. AlmarhoonZainab M. Almarhoon
  • T. IndumathiT. Indumathi
  • E. Ranjith KumarE. Ranjith Kumar
In this study, leaf extracts of Aloe vera (AV), Azadirachta indica (AI), and Amaranthus dubius (AD) were used to synthesize zinc oxide nanoparticles utilizing a simple green synthesis process. The structural, optical, band energy, size, surface area, and shape of as-prepared nanoparticles were studied using analytical techniques. The hexagonal phase was revealed by XRD studies for all three samples: AV-ZnO, AI-ZnO, and AD-ZnO, with crystallite sizes of 35.8 nm, 30.83 nm, and 33.1 nm, respectively. The UV–Visible spectra of AV-ZnO, AI-ZnO, and AD-ZnO exhibit the characteristic absorption in the range of 200 to 450 nm, and the band gap energy was found to be 3.10 eV, 3.12 eV, and 3.07 eV, respectively. FESEM and TEM studies revealed that the ZnO NPs are rod-shaped with a roughly spherical appearance. EDAX analysis confirmed the presence of zinc and oxygen and indicates that the formed product is a pure phase of ZnO NPs. Increased antibacterial activity was noted for AV-ZnO, AI-ZnO, and AD-ZnO against gram-negative (Klebsiella pneumonia, Shigella dysenteriae), gram positive (Staphylococcus aureus, and Bacillus) bacterial strain.
  • Jingjun LiuJingjun Liu
  • Zhichen YuanZhichen Yuan
  • Mingliang YuanMingliang Yuan
  • [...]
  • Tangfeng XieTangfeng Xie
Zeolite has many advantages such as outstanding ion exchange performance, large specific surface area and uniform pores in the field of wastewater treatment. However, zeolites are difficult to separate from complex industrial wastewater systems. Magnetically modified zeolite (MMZ) composites with both magnetic and adsorption properties were synthesized by attaching Fe3O4 to the surface of Na-zeolite by chemical co-precipitation. MMZ can be better adsorbed from wastewater by permanent magnets for reuse. The structure, morphology and magnetic properties of MMZ were characterized. Compared with Na-zeolite, the structure of MMZ has no obvious change, Fe3O4 is evenly coated on the surface of the zeolite matrix, the specific surface area is greatly increased, and the magnetism is sufficient to attract the permanent magnet. The adsorption efficiency of MMZ for Pb²⁺, Cd²⁺, and Cu²⁺ in simulated wastewater was largely dependent on pH. According to the Langmuir and Freundlich isotherms to fit the equilibrium data, the maximum monolayer saturated adsorption capacities of the three ions are 83.20 mg/g, 30.58 mg/g and 16.16 mg/g, respectively, which are greatly improved compared with the samples before modification. Therefore, MMZ is an adsorbent with good adsorption performance and easy to be recycled and reused.
Composition and content of gases in ultra-high vacuum during high-temperature cleaning
Phase transformation models
Mulliken bond population during the phase transitions
PDOS of As (Ga) atoms involved in phase transitions
Electron density difference of adsorption models
  • Xiaohua YuXiaohua Yu
  • Zude JinZude Jin
  • Guirong ShaoGuirong Shao
In this manuscript, a high-temperature cleaning experiment was carried out, according to the measurement results of Quadrupole Mass Spectrometer (QMS), and it was concluded that 5-phase transformation reactions took place in the process of high-temperature cleaning. According to the experiment, 10 adsorbed surface models were built, using first-principles calculation method, and the energy and electronic structure of these models were researched. Gibbs free energy results showed that 5-phase transformations could take place spontaneously, and adsorption energy results showed that the phase transformations were conducive to the desorption of impurity oxides. Mulliken bond population results were used to analyze the change of bonding during the phase transformations. PDOS results showed that during the phase transformations, s state and p state of the involved As(Ga) atom changed obviously. Electron density difference was used to analyze the electron distribution during the phase transformations, and dipole moment results showed that during the phase transformation, the charge offset amount and distance were changed, causing the change of work function and the photoemission of the surface.
  • Junhui YiJunhui Yi
  • Minghao LiMinghao Li
  • Runkun XieRunkun Xie
  • [...]
  • Weili HuangWeili Huang
CuBi2O4 is widely used in photocatalytic degradation for pollutants in water due to its strong visible light response characteristics, excellent chemical stability, non-toxic, and low cost. Here, stone-shaped CuBi2O4 was prepared with CuO and Bi2O3 as raw materials by high temperature solid phase. The effect of calcined temperature and time on the product was discussed. This material was analyzed and discussed by XRD, SEM, XPS, and DRS, and the visible light activity of degradation for Orange II was explored. The results showed that the absorption edge of prepared CuBi2O4 expands to the visible region, and the band gap was about 1.77 eV. The photocatalytic degradation rate of Orange II was 42.6% under the optimal conditions. After H2O2 assisted, the degradation rate was more than 2 times, and repeated experiments verified that the prepared catalysts had high stability. Finally, a reasonable mechanism of H2O2 assisted degradation enhancement is proposed. This work gives new ideas for the preparation of new and efficient catalytic materials.
  • Suryakanta ParidaSuryakanta Parida
  • Rajasmita MalikRajasmita Malik
  • R. K. ParidaR. K. Parida
  • [...]
  • Nimai C. NayakNimai C. Nayak
The microcellular xGnP-loaded EVA/EOC ternary blend nanocomposites were fabricated via a melt blending process using a chemical blowing agent. The morphological and mechanical properties were investigated. The conductivity of the synthesized composites at room temperature was studied through a computer-controlled impedance analyzer at the frequency range of 100 Hz–5 MHz. The foam composites show high relative permittivity (εr) of 1080 and maximum tangent loss of 0.145 at 100 Hz with 4 wt% of blowing agent content. Also, DC conductivity was achieved at a maximum of 4.3110–7 S/m for a 4 wt% blowing agent loading. The mechanical characteristics such as tensile strength, tear strength, and tensile modulus increased with a rise in xGnP loading but elongation at break decreased. The studied EVA/EOC/xGnP foam composites can be utilized in potential electronic applications.
  • B. DeyB. Dey
  • S. K. SrivastavaS. K. Srivastava
In this present work, titanium dioxide (TiO2) nanoparticles were prepared by a standard solid-state reaction technique. The structural analysis by the XRD pattern confirms a single rutile phase tetragonal structure. According to scanning electron microscopy analysis, the prepared sample shows uniform morphology with a mean particle size of 120–160 nm. The elemental analyses by energy dispersive spectroscopy confirm the absence of any impurity in the prepared sample. The UV–vis absorption data reveal that the band gap value of the synthesized compound was found to be 2.94 eV. From the optical transmittance spectrum, the average transmittance of the prepared sample in the visible range was found to be 55%. The field and temperature dependence of magnetization reveals a weak ferromagnetic behavior, with saturation magnetization of 0.002 µB and coercivity of 930 Oe. Most likely, the presence of defects and/or oxygen vacancies is thought to be responsible for this particular behavior. Dielectric properties observations reveal that the sample exhibits low dielectric loss in the higher frequency region, which is compatible with the Maxwell and Wagner model.
  • Bin DengBin Deng
  • Yue YangYue Yang
  • Wensheng ChenWensheng Chen
  • [...]
  • Ruijin YuRuijin Yu
In order to develop new phosphors, a series of novel trivalent dysprosium (Dy³⁺) activated single-phase yellow-emitting La5NbMo2O16 phosphors were firstly prepared through the high-temperature solid-state reaction method. Powder X-ray diffraction (XRD) patterns were measured to check the crystalline structure of La5NbMo2O16 phosphors. The photoluminescence (PL) spectra were used to characterize the luminescence properties of the prepared La5NbMo2O16:Dy³⁺ phosphors. Under 386 nm excitation, the PL spectra of La5NbMo2O16:Dy³⁺ phosphors mainly contain three dominant sharp peaks at blue (486 nm), yellow (574 nm), and red emission (669 nm), respectively. The intense peak at 574 nm attributes to the typical ⁴F9/2-⁶H13/2 transition of Dy³⁺ ions. The optimal sample is La5NbMo2O16:10 mol%Dy³⁺ phosphor with the estimated Rc = 18.89 Å. The obtained La5NbMo2O1610 mol%Dy³⁺ product shows high thermostability with high quenching temperature (above 480 K) and good activation energy (Ea = 0.32 eV). Besides, the CIE chromaticity coordinate (0.442, 0.474) of the La5NbMo2O16:10 mol%Dy³⁺ phosphor is in the yellow region. A white light-emitting diode (w-LED) with the chromaticity coordinates of (0.322, 0.335), a correlated color temperature (CCT) of 5974 K, and a color rendering index (Ra) of 90 was successfully fabricated. All results indicate that La5NbMo2O16:Dy³⁺ phosphors have extensive application prospects for w-LEDs.
  • Tianju FanTianju Fan
  • Lingfeng JianLingfeng Jian
  • Xinwen HuangXinwen Huang
  • [...]
  • Yonggang MinYonggang Min
Graphene quantum dots, as one of the pioneering materials applied in energy storage devices, possess outstanding electrical, optical, thermal, and mechanical properties. Concerning the commercial application of dye-sensitized solar cells, it is imperative to seek materials with highly effective photocatalytic activity. Herein, a novel carbon-based material based on graphene quantum dot nanorods has been prepared via hydrothermal treatment in addition to the syntheses of graphene quantum dots (GQDs) with sizes of approximately 5 and 20 nm. Efficient photoelectrodes are fabricated based on graphene quantum dot nanorods (GQDs-NRs) decorated TiO2 and their use in dye-sensitized solar cells (DSSCs) is successfully demonstrated with the maximum short circuit current density of 18.20 ± 0.02 mA cm⁻² and an efficiency of 8.06 ± 0.01%, which are remarkably greater than even traditional DSSCs (without GQDs). Hence, incorporating GQDs-NRs and GQDs with controllable size not only enhances dye-sensitized solar cell properties but also decreases the amount of dye or colorant required, which is significant for cost reduction and environmental protection. Thus, the present work provides a practical approach for configuring the size of GQDs-NRs and original GQDs for their onward utilization in TiO2-coated electrodes. The synthesized material shows high photocatalytic activity, making it suitable for efficient and cost-effective energy transformation devices.
  • Yanjun LuYanjun Lu
  • Yajing SunYajing Sun
  • Jing LiJing Li
  • [...]
  • Jifeng GuoJifeng Guo
The development of advanced photocatalysts is crucial for efficient photocatalytic degradation of the antibiotic tetracycline (TC). In this article, a series of BiOI/Bi2WO6 (I/W) with different ratios (9:1, 7:3, 5:5, 3:7, 1:9) were synthesized by hydrothermal method and solvothermal method with BiOI as the primary material. XRD, SEM, FT-IR, XPS, and other analyses showed that the two monomers BiOI and Bi2WO6 were well combined together. The degradation experiment was considered that the 7:3I/W photocatalytic composite has the best degradation effect on TC, which can degrade 84.81% of TC within 120 min. At the same time, the 7:3I/W composite has good stability after five cycles. In the 7:3I/W composite, BiOI and Bi2WO6 were successfully recombined, and a p-n type heterojunction system was formed. This p-n type result not only greatly promoted the separation between e⁻ and h⁺, but also significantly improved its photocatalytic performances. This paper provided a novel photocatalytic material for treating TC in water, and also created theoretical support for the composite of bismuth-based photocatalytic materials.
  • Yu ZhangYu Zhang
  • Lei XiaoLei Xiao
  • Sen PengSen Peng
  • [...]
  • Yuxin SunYuxin Sun
Ba[(Zn1-xMgx)1/3Nb2/3]O3(x = 0 ~ 0.9) ceramics were prepared by the traditional solid-phase reaction sintering method. In this paper, the effects of MgO doping on the shrinkage, density, phase composition, crystal structure, microstructure, and microwave dielectric properties of Ba(Zn1/3Nb2/3)O3 (BZN) ceramics were investigated. The phase constituents, crystal structure, and microstructure of the ceramics were studied by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). The results showed that Ba(Zn1/3Nb2/3)O3 as the main phase, and the secondary phase Ba5Nb4O15 was detected with high MgO content (x > 0.3). However, the appearance of secondary Ba5Nb4O15 directly led to the deterioration of the microwave dielectric properties of the samples. Ba[(Zn1–xMgx)1/3Nb2/3]O3 (x = 0.3) ceramics sintered at 1500 °C for 4 h possessed superior dielectric properties: εr = 36.31, Q × f = 111,326 GHz, τf = + 12.1 ppm/°C. Such the ceramics could be used to make dielectric resonators and stable oscillators.
  • Sukru CavdarSukru Cavdar
  • Yesim DemirolmezYesim Demirolmez
  • Neslihan TuranNeslihan Turan
  • [...]
  • Nihat TuğluoğluNihat Tuğluoğlu
In this work, which aims to investigate the capacitance and conductance properties of ZnCo2O4-doped Gelatin, 5% ZnCo2O4-doped Gelatin film was grown on n-type silicon wafer by sol–gel spin coating with the aim of fabricating Al/ZnCo2O4:Gelatin/n-Si Schottky diode. This investigation also explores the series resistance \((R_{S} )\) and interface state \((N_{ss} )\) characteristics of a diode produced with ZnCo2O4:Gelatin interface layer. Electrical measurements were taken in the voltage range of − 5 V and + 2 V and the frequency range of 30 kHz and 1 MHz. The electrical properties of the diodes were characterized from voltage and frequency-dependent measurements. Capacitance–voltage (C-V) and conductance–voltage (G-V) characteristics yielded higher values showing the significance of the interface states. At lower frequencies, the rise in the capacitance value is signed to the interface state density. The values of \(N_{SS}\) for 30 kHz and 1 MHz frequency are 10.5 × 1011 and 4.19 × 1011 eV−1 cm−2. It is recommended to use the produced diode as an electronic device.
The structural, dielectric and optical properties for Ni0.4Cu0.4Co0.2Fe2O4 spinel ferrite prepared by sol–gel method have been investigated in this work. The structural analysis for the sample reveals its crystallization in the cubic spinel structure (Fd3m space group). The Z‘‘(f) curve confirms the appearance of a relaxation phenomenon in the sample which exhibits semiconductor behavior. An electrical circuit consisting of a link of grain and grain boundary elements is used to analyze the Nyquist plots. The behavior of dielectric constants is related to Koop’s phenomenological theory and Maxwell–Wagner’s interfacial polarization of dielectrics. The Non-overlapping Small Polaron Tunneling is the appropriate model to explain the conduction mechanism for the sample. The estimated activation energies from the dc conductivity and electrical impedance are close implying that the relaxation and conduction processes are caused by the same type of charge carriers. The scaling mechanisms of the conductivity data versus temperature were also investigated by Ghosh and Summerfield approaches. The random barrier model is adopted to adjust the Summerfield scaling approach for the studied sample. Electrical and optical properties show higher electrical resistivity and considerable visible light absorption which makes the prepared Ni0.4Cu0.4Co0.2Fe2O4 ferrite suitable candidate for electrical and optical applications.
Ultrathin, highly conductive, and free-standing graphene films have been seen as promising electromagnetic interference (EMI) shielding materials for portable electronic devices. However, they are still expensive. In this paper, a magnetic graphene film decorated with Fe3O4 nanoparticles was prepared through in situ wet chemical synthesis followed by catalytic graphitization. A graphitic structure was obtained at a moderate annealing temperature (1000 °C), after introducing Fe3O4 nanoparticles. This temperature is much lower than the conventional graphitization temperature, which reduces the synthesis costs of graphene film. In addition, Fe3O4 also behaved as microwave absorbers, enhancing the EMI shielding performances. The resulting ultrathin film (~ 50 μm) provided a high EMI shielding effectiveness (SE) of ~ 52.76 dB in the X-band (8.2-12.4 GHz). This is found to be higher than that of bare graphene films (~ 33.45 dB) prepared under the same temperature and sufficient to screen about 99.999% of microwave radiation. Furthermore, absorption was the dominant shielding mechanism for the prepared film owing to the contribution of Fe3O4 nanoparticles that reduced the electromagnetic pollution resulting from secondary reflections. The catalytic graphitization strategy could provide a low-cost approach for fabricating efficient graphene-based EMI shielding materials for portable electronic device applications.
Spark plasma sintering (SPS) process was employed to synthesize Ba0.5Sr0.5TiO3-Mg2SiO4-MgO composite at 1200 °C for 5 min. We systematically investigated the effect of this sintering method on the dielectric properties of the samples. Experiment results show that while the dielectric content increases, the permittivity of the composite presents a decreasing tend monotonously; however, the tunability first increases abnormally and then decreases. Most importantly, the composite ceramics exhibits higher tunability than undoped Ba0.5Sr0.5TiO3. The interdiffusion in Ba0.5Sr0.5TiO3-Mg2SiO4-MgO composite was controlled via SPS process and enables us to produce composites with lower permittivity and relatively higher tunability simultaneously, which is hard to realize through traditional solid-state reaction method. Our findings reveal that the improved tunability is derived mainly from the low sintering temperature and short sintering time in SPS, which greatly suppress the doping effects. This provides valuable insights for future development of tunable applications.
Experimental procedure for the preparation of Sn–58Bi–xCo tensile samples
SEM images of a Sn–58Bi, b Sn–58Bi–0.5Co, c Sn–58Bi–1Co, d Sn–58Bi–2Co, respectively
Tensile stress–strain curves of different cobalt concentrations
Ultimate tensile strength at different aging times
Brittle phases are responsible for crack formation and propagation in tin–bismuth (Sn–58Bi) solder material. The purpose of this work is to investigate the effects of various cobalt (Co) nanoparticle (NP) concentrations on the tensile properties of the Sn–58Bi solder matrix. Different aging times were studied to find out the effect of Co NP on ultimate tensile strength. Tin–bismuth solder joints of different Co NP concentrations of 0%, 0.5%, 1%, and 2% were prepared. The reflow process was done at 180 °C for 1 min. Scanning Electron Microscopy and Energy-Dispersive X-ray spectroscopy were used to analyze the solder joints. The tensile test was carried out for the Sn–58Bi and Sn–58Bi–xCo (x = 0.5, 1, and 2) solder joints. The tensile test was run before and after aging time. The tensile results reveal that the addition of Co NP increased the tensile strength significantly at different concentrations of Co NP. The Tensile test revealed that ductility was improved as the temperature was increased. As the aging time increased, the ultimate tensile strength of all samples decreased.
PbSx thin films (x = 1, 0.9, 0.8, 0.7, 0.6) were prepared onto glass substrates using spin coating method. The phases developed and vacancies created in the different films were explored employing θ-θ scan X-ray diffraction, grazing incidence X-ray diffraction, and Fourier transform infrared techniques. The possibility of incorporation of oxygen in PbS lattice was also examined using X-ray photoelectron spectroscopy technique. Rietveld analysis was achieved to determine the variation in the structural and microstructural parameters of different films. The morphology and thickness of the films were explored using scanning electron microscope technique. The direct band gap transition values for PbSx films with x = 1, 0.9, 0.7 and 0.6 are 2.63, 2.85, 2.95, and 3.02 eV, respectively. The refractive indices of all films demonstrated a normal dispersion. The effect of sulfur reduction in the formed films on the optical absorbance, reflectance spectra, absorption edge, extinction coefficient, dielectric constant, photoluminescence emitted colors, and nonlinear optical parameters of the PbSx films was investigated.
The crystal phase combination, relative density, microstructure, varistor properties and dielectric properties of La2O3-doped ZnO-Bi2O3-based varistor at a furnace temperature of 950 °C were investigated under the electric field of 300 V/cm within 35 s. Obtained samples were fully densified and uniform in microstructure. The effect of doping with different contents of La2O3 on flash-sintered ZnO-Bi2O3-based varistor was systematically studied. The results showed that when doping La2O3 was 0 mol%, 0.1 mol%, 0.2 mol% and 0.3 mol%, the densities of the samples were 91.5%, 90.5%, 96.1% and 95.1%, respectively. When the La2O3 doping amount was 0.2 mol%, the nonlinear coefficient was the highest of 32.9, the leakage current was the lowest of 1.1μA, and the dielectric loss was less than 0.1. Therefore, uniform microstructure and excellent electrical property can be obtained by preparing La2O3-doped ZnO varistor ceramic via flash sintering.
The present study aims to prepare a low-cost, eco-friendly, free-standing film with optimized physical properties. A PVA composite of hard-soft hybrid filler ratio 1:3 (nSiO 2 :Gl) is prepared by casting. Dynamic mechanical analyses are processed in the frequency range (0.01-9 Hz). Moreover, dielectric studies are performed in the frequency range (50 Hz-5 MHz). Herein, the modified Jon-scher equation and electric modulus formalism are used to explain the results. Transmittance and reflectance of studied samples are measured in the UV-Vis range (200-700 nm). Detailed discussions of band structure, refractive index, and optoelectronic parameters are addressed. Remarkably, the results showed that mechanical and electrical properties of PVA can be tuned by careful modulation of glycerol content, whereas optical properties are more sensitive to nSiO 2 content. Finally, FTIR and SEM structural analyses investigate the induced structural changes in PVA.
The sulfur-assisted exfoliation of graphite was done in a planetary ball milling. A detailed study with varying milling times, of the Sulfur/exfoliated composite, is presented. Raman spectroscopy was applied to study the carbon material present in the composite. Various parameters like crystallite size (L a = 33), band ratios (I 2D /I G = 0.55, I D /I G = 1.12), FWHM, etc., emphasises the successful exfoliation of graphite into few-layer exfoliated graphite material. The decon-volution of the d 002 peak into two components of the X-ray diffraction pattern solidifies the sulfur impregnation and intercalation in the composite with a high degree of the amorphous layered carbon structure. The XRD analysis is in line with the Raman spectroscopy findings (L a = 37). The sulfur present in the composite was analysed with the DSC, where various aspects of sulfur and sulfur-EG interaction were discussed. Various thermodynamic quantities (DH, DC p) were extracted from this study to fully understand the sulfur-EG interface. Three to four-layer graphene has been produced with a high amount of sulfur in it which makes it a suitable option for its application in the conversion type cathode of lithium-ion battery. The milling time is also a key factor that determines the quality of layered material and so the composite. This composite material is cost-effective and environment-friendly. We have used it as a cathode for lithium-sulfur battery and found an initial capacity of 1550 mAh/g which is discussed with its electrochemical performance.
Good quality single crystal, 2-Methylimidazolium d-tartrate (2MIMDT) (C8N2O6H12) was grown by slow evaporation solution growth method. The properties of the grown crystal were investigated using various characterization techniques. The single-crystal XRD study was carried out to confirm the structural parameters of the 2MIMDT crystal. The crystalline nature was confirmed by powder X-ray diffraction analysis. The FTIR and FT-Raman vibrational modes of the title compound were recorded to analyse the functional groups. The cut-off edge was observed to be 235 nm when the optical UV–Vis-NIR transmittance was investigated. The optical band gap energy (Eg) value of 2MIMDT single crystal is 5.1 eV. The thermal stability and decomposition point of the grown crystal were studied by thermogravimetric and differential thermal analysis (TG–DTA). It is discovered that Second Harmonic Generations efficiency is 0.7 times greater than that of KDP crystals. The calculated third order NLO susceptibility (χ⁽³⁾) values of 2MIMDT single crystal was observed to be 1.47 × 10–6 esu. Detailed computational analysis was performed by DFT study utilizing B3LYP-6-311G (d.p) method and Gaussian software package. HOMO–LUMO energy gap and related properties were also calculated. Stability of the 2MIMDT molecule hyperconjugation interaction, electron charge delocalization and hydrogen bond interactions were diagnosed using NBO analysis. The first-order hyperpolarizability was found to be βtotal = 1.49 × 10–30 esu. Mulliken atomic charge distribution of the compound was performed to obtain the charge value of biggest and minor atoms. Intermolecular interactions of 2MIMDT crystal were investigated by Hirshfeld surface analysis.
In this work, a facile approach has been adopted to synthesize zinc titanium oxide (ZnTiO3) using the solution combustion synthesis technique for resistive memory application. The synthesized ZnTiO3 has been thoroughly characterized using different analytical tools. The fabricated Al/ZnTiO3/FTO device demonstrates good bipolar resistive switching property and a non-ideal memristive effect. Furthermore, switching voltages dynamics were modeled using time series analysis based on autoregressive integrated moving average (ARIMA) and Holt-Winter’s exponential smoothing (HWES) techniques. The non-volatile memory measurements suggested that the Al/ZnTiO3/FTO memristive device can switch between 10³ endurance cycles and can retain data up to 10⁴ s. The conduction analysis and plausible filamentary type RS mechanism are investigated for the fabricated memristive device. The present work demonstrates the benefits of the solution-processable RS device for non-volatile memory application and the use of statistical time series analysis for understanding the switching voltage dynamics.
The defect structures and electrical properties of 0.75BiFeO3–0.25BaTiO3 ceramics have been modified using Li/M dopants (M = Al, Ga, In, and Er). The effects of Li/M dopants with various ionic radii and electronegativities on the crystal structure, dielectric properties, ferroelectricity, leakage, and insulation behaviors of the ceramics have been investigated. The doped ceramics displayed a typical perovskite structure with a dominant rhombohedral phase, but the impurities BaFe0.24Fe0.76O2.88 emerged and increased in concentration as doping content x increased. As x increased, the dielectric loss reduced and the ferroelectricity improved noticeably. At x = 6 mol%, leakage current and resistivity studies indicated that the ceramics showed enhanced insulating qualities, particularly high resistivity of ~ 1011 Ω cm was recorded in Li/Er-doped samples. The reduced oxygen vacancies are responsible for these results, which were evaluated by defect chemistry and validated by XPS analysis.
Porous-structured materials are potential candidates for gas sensor applications because of their large specific surface areas, high pore volumes, unblocked pores, and excellent thermal stabilities. Tin (Sn) is an excellent catalytic material for improving the active sites on the material surface and plays a crucial role in gas-sensing measurements. In this study, indium oxide (IO) and tin-doped indium oxide (ITO) films with different concentrations of Sn were deposited into In2O3 using the spray pyrolysis method. Various characterisation techniques have been used to determine the structural, morphological, optical, chemical, and gas-sensing properties. XRD studies revealed the polycrystalline cubic structure of the deposited films with a (222) crystal orientation, and the crystallite size increased with increasing Sn concentration. TEMand BET surface area investigations revealed the highly porous nanostructured nature with large pore volumes of the deposited thin films. The XPS and PL emission spectra indicated that the films' chemisorbed oxygen and oxygen vacancy defects and these were estimated using Smakula’s formula. A significant impact of Sn doping on formaldehyde sensing properties were observed. The ITO thin film deposited with 6 wt % of tin exhibited the best sensing characteristics at room temperature.
Synthesis and characterization of novel and ternary photocatalysts Ag@TiO2/NiFe2O4 for the three potential applications, such as photocatalytic H2 production, photocatalytic removal of Rhodamine B and photocatalytic reduction of Cr⁺⁶, under UV and solar light illuminations. The sol–gel method has been used for the synthesis of TiO2 and NiFe2O4 nanoparticles, and ionic liquid in the hydrothermal method has been applied for the synthesis of TiO2/NiFe2O4 nanocomposite (TNFC) as binary nanocomposite material. Ag nanoparticles were effectively doped to TNFC to acquire Ag/TNFC as ternary nanocomposite material (Ag@TiO2/NiFe2O4). The framework substitution of NiFe2O4 and Ag nanoparticles in TiO2 nanostructure was done by Powder X-ray diffraction and nanocrystalline structure reveals the presence of pure anatase TiO2, the formation of single-phase cubic nanocrystal structure NiFe2O4, and cubic phase Ag nanoparticles. Further, the presence of NiFe2O4 and Ag nanoparticles in TiO2 nanostructure was confirmed and analyzed by X-ray photoelectron and energy-dispersive X-ray spectroscopy techniques. Surface morphologies of the prepared nanocatalysts were studied using SEM, TEM, and HRTEM analyses. The optical properties of the samples were characterized by UV–Vis and PL spectroscopy methods from these studies it was found that the after-loaded Ag to the TiO2/NiFe2O4 nanocomposite has a great improvement in the photocatalytic activities. TNFC with 0.3 wt% of Ag (Ag/TNFC3) nanocomposite produced the highest H2 production rate (811 µmol g⁻¹) and improved photocatalytic degradation of dye and photocatalytic reduction of Cr⁺⁶ to Cr⁺³ than the other photocatalysts. Ag/TNFC3 nanocomposite was recycled and reused as a photocatalyst for photocatalytic activities and from these studies; it was proved that the prepared photocatalysts showed good photostability.
The instability of TiN/HfZrO/TiN ferroelectric capacitors becomes a dominant obstacle in its practical application. To improve this problem, the effects of N-plasma treatment at both top and bottom TiN interfaces are investigated on the ferroelectricity behaviors and reliability characteristics of TiN/HfZrO/TiN ferroelectric capacitors. The results show that the high remanent polarization and large dielectric constant in the capacitors can be obtained by treating at the both top and bottom TiN interfaces. The wake-up and fatigue effects can be effectively suppressed and the lower leakage current can be acquired with extending the treatment time. The XPS analyses show that the oxygen vacancies in HfZrO film can be reduced efficiently by extending treatment time. The cycling test confirms that the better ferroelectricity characteristics can be measured by treating at two interfaces than that of single interface. The N-plasma treatment at both top and bottom TiN interfaces provides a new approach for the realization of highly reliable TiN/HfZrO/TiN ferroelectric capacitors.
Due to their antibacterial effect, silver nanoparticles (AgNPs) are attracting more and more attention for various applications in biomedicine. The production of nanomaterials from organometallic precursors requires the use of a capping agent that acts as a stabilizer and provides colloidal stability while preventing agglomeration and excessive growth. In this research, we studied the optical properties and antibacterial activity of AgNPs loaded in a blend of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and chitosan, which were used as capping agents to control the shape and size of the nanoparticles and to impart stability to the synthesized Ag nanomaterials. Characterization studies showed that the blend provides a uniform and controlled distribution of AgNPs inside the polymeric matrix without the addition of any more stabilizers. The mean particle size for green and laser-ablated AgNPs was found to be ~ 50 nm according to transmission electron microscopy (TEM) studies. Fourier transform infrared (FTIR) studies showed the presence of characteristic main peaks corresponding to the vibrational groups which characterize the prepared samples. The interactions between the AgNPs and the blend were marked by changes in the intensity of vibrational peaks and spectral positions. X-ray diffraction (XRD) confirmed the crystallographic modification within the PVP/PVA/chitosan matrix because of AgNPs filling. The change in the absorbance has been studied with the help of measured ultraviolet–visible spectroscopy (UV–Vis.) and therefore the optical band gap was calculated. The filling of AgNPs in the blend shows a broad peak at 427 nm because of the phenomenon of surface plasmon resonance (SPR) and its intensity increases with increasing filler concentration. The blend and the Ag nanocomposite showed remarkable antibacterial activity and caused a significant decrease in microbial growth (Escherichia coli) in 24 h. These outcomes demonstrate the suitability and promise of the nanocomposites for various applications, including biomedical labels, sensors, and detectors.
Due to the inherent environmental and health toxicities associated with lead, the use of environmental friendly lead-free solder materials has become an unavoidable trend in the electronic packaging industry. Sn-58Bi alloy is gaining attention for its good material properties such as low melting point, reliability and high tensile strength. The presence of the bismuth-rich phase increases the brittleness of Sn-58Bi alloy. The purpose of this study is to suppress the brittleness of Sn-58Bi alloy by the addition of different wt% (0, 10, 20, 30) of Sn powder. The powder metallurgy method was used to prepare the samples. Scanning electron microscopy and energy-dispersive X-ray analysis were done to study the structural properties and a tensile test was done by a universal tensile machine to study the mechanical properties. The results reveal that the Sn particles partially dissolved in the Sn-58Bi solder matrix. The dissolution of Sn particles significantly improved the mechanical strength by 30%, suppressed the brittleness and improved the strain value by 1.3 times.
a XRD, b FTIR analysis plots of g-C3N4, MFO, and g-CN-MFO electrodes
a General image of g-CN-MFO-coated Ni foam, b high magnification view of MFO, c image of only synthesized g-C3N4, d–e high magnification view of g-CN-MFO, and f high resolution TEM images of MFO
a CV curves of MFO and g-CN-MFO, b CV curves of g-CN-MFO at different scan rate, c Randles–Sevcik graph of g-CN-MFO, d explanation of the electrochemical kinetics of g-CN-MFO, e GCD curves of MFO and g-CN-MFO, and f GCD curves of g-CN-MFO at different current
a Areal capacitance vs. current plot of g-CN-MFO, b Ragon plot of energy-power density of g-CN-MFO and c Nyquist plot of MFO and g-CN-MFO
This study aimed to improve the electrochemical performance of MgFe2O4 (MFO) by combining it with g-C3N4 (g-CN). The hydrothermal process was used to produce electrodes directly on the nickel foam surface. XRD, FTIR, SEM, and TEM analyses were made to describe the electrodes in detail. CV, GCD, and EIS measurements were performed electrochemically at various scanning rates and current densities. According to the findings, g-CN-MFO electrode was successfully synthesized in spongy structure on Ni-foams. The areal capacitance (Ca) of g-CN-MFO was measured as 600 mF/cm², which is 152% higher than MFO. At the same time, the energy and power densities of g-CN-MFO were calculated to be 13.3 mWh/cm² and 200 mW/cm² at 1 mA, respectively. EIS results showed that this increase was probably due to easier diffusion of electrolyte ions onto the electrode surface. As a result, the g-CN-MFO electrode can be considered a promising anode material for supercapacitors due to its low cost, ease of fabrication, and strong electrochemical performance.
The slow evaporation method has been used to grow hexamethylenetetraminium 3,5-Dinitrobenzoate hemihydrate (HMTNB) single crystals. The single crystal X-ray diffraction investigation confirmed the centrosymmetric space group P \(\overline{1 }\) and triclinic crystalline system of grown HMTNB crystals. The powder X-ray diffraction, 1H, 13C NMR, FTIR, and FT-Raman analysis validated the crystalline nature, molecular arrangement, and functional groups in HMTNB. The intermolecular hydrogen bonding interactions of the HMTNB system have been well understood with the help of Hirshfeld surface study. Lower cutoff wavelength (386 nm) and emission peaks (312, 438, and 482 nm) have been reported in optical absorption and photoluminescence investigations. The dielectric study has revealed that HMTNB has low values of dielectric constant and loss. The photoconductivity study showed that HMTNB has a negative photoconducting nature. The HMTNB has a negative refractive index, and the Z-scan study revealed self-defocusing nature. Optical limiting studies indicate the HMTNB crystal's optical limiting response. Quantum chemical calculations were used to establish inter- and intra-molecular charge transfer mechanisms, as well as the presence of N–H···O, O–H···O and C–H···O hydrogen bonding in HMTNB are discussed in detail.
The fabrication of p–n heterojunctions was considered as a promising strategy to improve the photocatalytic efficiency of the catalyst, because such junction can effectively promote separation of carriers and improve the catalytic performance. Herein, nanoflower like p–n heterojunction photocatalyst ZnO/BiOI (abbreviated as ZB-x) was prepared by simple solution coprecipitation. Under visible light, ZnO/BiOI p–n heterojunction photocatalyst showed enhanced degradation rate toward Rhodamine B (RhB) and formaldehyde (HCHO) photodegradation. The degradation rates of RhB and HCHO by optimized complex ZB-0.5 in 60 min were 95% and 60%, respectively. The p-type BiOI with narrow band gap can effectively enhance the visible light absorption, and its p–n heterojunction with ZnO can significantly improve the separation efficiency and transfer rate of photogenerated electron hole pairs. Meanwhile, multi-dimensional nanoflower structure is not only conducive to light reflection and improve light utilization, but also can expose more catalytic active sites. This p–n heterojunction nanocomposite has a good effect on improving environmental pollution problems.
In this study, flower sphere alumina was synthesized autonomously by hydrothermal and annealing processes. The in situ polymerization of polypyrrole on the surface of alumina at low temperatures based on the principle of component synergy has enabled the construction of a core–shell structure for Al2O3@ppy materials, resulting in excellent electromagnetic wave absorption properties. The effect of the addition of alumina and the morphology of the materials on the microwave absorption properties of Al2O3@ppy composites was also discussed. Various methods are used for the characterization of the material. The Al2O3@ppy composites were effective in matching thicknesses of 2.5 mm with a minimum reflection loss (RL) of − 65.8 dB at a frequency of 11.52 GHz and a maximum effective absorption bandwidth (EAB) of 5.6 GHz at a matched thickness of 2.0 mm. The results show that Al2O3@ppy composites can provide a reference for EMW absorber material research.
In this paper, the solid solutions of strontium molybdate-tungstate [Sr(Mo1−xWx)O4] crystals with (x = 0, 0.25, 0.50, 0.75, and 1) were synthesized by the sonochemical method. Their structure, morphology, optical, and sonophotocatalytic properties were performed in function of the replacement of Mo6+ by W6+ cations into the lattice. Their structure and elemental composition were characterized using X-ray diffraction, Rietveld refinement, micro-Raman, energy-dispersive X-ray, and Fourier-transform infrared spectroscopies proving that all samples are monophasic, crystalline, and exhibit a scheelite-type tetragonal structure. Field-emission scanning electron microscopy images revealed the octahedral and dumbbell-like morphologies for SrMoO4 and SrWO4 crystals. Moreover, it is noted to pass through spindle-like morphology for the microcrystals containing both Mo6+ and W6+ cations (x = 0.25, 0.50, and 0.75). Ultraviolet-visible diffuse reflectance spectroscopy showed a directly proportional increase in the optical band gap (Egap) values from 4.27 to 5.01 eV. These data indicate an increase in the intermediary electronic levels between valance and conduction bands with the increase in the concentration of W6+ cations in the lattice. Finally, we have obtained good sonophotocatalytic performances for SrMoO4 crystals (90%), and mainly to Sr(Mo0.25W0.75)O4 crystals (98%) in the degradation of Rhodamine B dye until 240 min under UV-C light.
Top-cited authors
Masoud Salavati-Niasari
  • University of Kashan
Mehdi Rahimi-Nasrabadi
  • Imam Hossein University
Ali sobhani-nasab
  • University of Kashan
Davood Ghanbari
Ram Naresh Prasad Choudhary
  • Institute of Technical Education and Research