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In this paper, the application of gel materials in triboelectric nanogenerators (TENGs) and its performance improvement strategy are reviewed. With the increase of energy demand and environmental awareness, TENGs as a new type of self-powered system has attracted wide attention. Because of its excellent flexibility, adjustability and good electrical properties, gels have become an important choice for improving the performance of TENGs. This paper first introduces the working principle of TENGs. Then, the application of gel materials in TENGs are divided by adjusting the composition and structure of gel materials. Finally, methods to improve the gel material properties, such as optimizing the conductivity of the gel, increasing the surface roughness and improving the stability, are proposed to increase the output of the TENGs. In addition, this paper also discusses the application examples of different types of gel materials and the actual performance improvement effects. Finally, the current research challenges and future research directions are summarized in order to provide guidance for the further application of gel materials in TENGs. [ABSTRACT FROM AUTHOR]

Printed and flexible electronics have gained considerable scientific attention in recent years, driving the demand for low-energy production techniques, eco-friendly materials and flexible substrates. However, effective encapsulation is essential to protect these devices in harsh environmental conditions. Thus, sustainable encapsulant materials are critical for advancing flexible electronics. In this work, we studied three encapsulant materials—commercial plastic, polyvinyl alcohol and ethyl cellulose—applied to thermoelectric touch sensors printed on paper and fabric substrates. Ethyl cellulose demonstrated promising properties in terms of flexibility, water resistance and transparency, along with a low carbon footprint. Encapsulated substrates with ethyl cellulose exhibited high contact angles (121° on fabric and 116° on paper), indicating robust water repellency. Thermal stability tests showed minimal mass loss (10%) at 315 °C, confirming its temperature resilience. Furthermore, sensors encapsulated with ethyl cellulose retained their electric performance after water submersion for 1 min and withstood 100 bending cycles, maintaining response times below 1 s and signal output around 100 µV. These findings highlight ethyl cellulose as a viable green encapsulant material compatible with large-scale sustainable electronics manufacturing. [ABSTRACT FROM AUTHOR]

This paper presents the pioneering creation and use of a nanosensor to detect harmful food dyes, including Sunset Yellow (SY). This sensitive platform was created by adding Tin dioxide-Manganese dioxide nanocomposite onto the surface of a graphite electrode (GE). The sensing capabilities of the proposed nanosensor with Tin dioxide-Manganese dioxide (SnO2–MnO2) drop cast on GE were demonstrated through the use of electrochemical measurements, such as differential pulse voltammetry, Chronoamperometry, linear sweep voltammetry, square wave voltammetry, and cyclic voltammetry. The investigation of several factors enabled the optimization of the ideal response conditions for the target analyte. The study demonstrated that the SnO2–MnO2-GE nanocomposite significantly enhanced the signals of the chosen food dye in comparison to the unmodified GE. This improvement can be attributed to the combined effect of Tin dioxide and Manganese dioxide nanocomposite, which work together synergistically. The SnO2–MnO2-GE system can detect Sunset Yellow with a limit of detection of 0.89 µM under ideal conditions. Moreover, the exceptional stability, limit of detection and sensitivity of the suggested electrochemical platform shows its potential applicability in the real-world sample analysis. [ABSTRACT FROM AUTHOR]

This paper is focused on thermoluminescence study of Mn4+-doped zinc aluminate nanophosphor with different Mn concentrations (0.5–3 mol %). The samples were chemically synthesized via microwave combustion method and annealed at 900 °C temperature. Nanoregime, single-phase spinel structure formation was confirmed by XRD and further analysed by Rietveld refinement method. The photoluminescence (PL) spectrum and PL decay curve revealed 745 nm emission under ultraviolet excitation wavelength, and afterglow decay time of the order of milliseconds. The thermoluminescence (TL) response was carried out using UV irradiation (254 nm) with different exposure time intervals. The effect of Mn concentration (0.5–3 mol %) and UV exposure time on TL glow curve of zinc aluminate was presented and discussed. A broad TL peak with 40 min UV irradiation exposure time was observed. Progression in TL intensity was observed with Mn concentration from 0.5 to 2% and above 2 mol %, and TL intensity was quenched. Also, a noticeable TL peak shifting was found for higher Mn4+ ions concentration. The optimum TL peak corresponding to 40 min exposure time (for 2 mol % Mn) was deconvoluted into two peaks at 395 K and 422 K temperature. The prepared ZnAl2O4:Mn4+ (2 mol %) nanophosphor showed linear dose response, essential property of dosimeters. The assessment of trap creation and trap depth was analysed by calculating the trap parameters. Two different methods, computerized glow curve deconvolution (CGCD) and Chen’s peak shape (CPS) method, were applied to calculate various kinetic TL parameters, e.g. order of kinetics (b), trap depth (activation energy Eav), and frequency factor (S). The measured trap depth suggested the involvement of shallow trap states for recombination process. This study will be immensely helpful in understanding the thermoluminescence behaviour of Mn4+-doped zinc aluminate nanophosphor for UV-TLD applications. [ABSTRACT FROM AUTHOR]

In this paper, alkali-free boroaluminosilicate glasses with low thermal expansion coefficient and low dielectric loss were prepared. The effect of Bi2O3 substitution for CaO on structure, thermal expansion, elastic modulus, and dielectric properties of the samples was investigated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermal dilatometer, ultrasonic thickness gauge, and impedance analyzer. The results show that the polymerization degree of the glass network structure increases first and then decreases, which reaches the highest with the substitution of 0.5 mol% Bi2O3 for CaO. The thermal expansion coefficient and dielectric constant decrease and then increase, while elastic modulus shows the opposite trend, which is attributed to the change in the glass network structure. The atomic mass of Bi much greater than that of Ca causes the obvious increase of glass density. The ionic radius of Bi3+ ions is larger than that of Ca2+ ions, making it more difficult to migrate through the glass network, reducing dielectric loss. In particular, the sample with 0.5 mol% Bi2O3 substitution shows excellent properties, such as low thermal expansion coefficient (3.07 × 10–6/K), high elastic modulus (80.58 GPa), low dielectric constant (5.52), and dielectric loss (3.15 × 10–3), which is very suitable for use as chip packaging material. [ABSTRACT FROM AUTHOR]

This paper presents an appropriate method of fabricating stable and efficient 3D (top)/2D (bottom) perovskite solar cells (PSCs). The method involves three-step spin-coating deposition, where 3D triple-cation perovskites are used as a light-absorbing material and phenyl trimethylammonium iodide (PTAI) serves to form a 2D Ruddlesden-Popper perovskite. Moisture penetration into the pores of porous structures is a significant degradation factor for perovskite porous solar cells. On the other hand, the high quality of the underlayer can play a crucial role in improving perovskite formation. In this study, different PTAI deposition processes were investigated for their effects on perovskite formation, surface morphology, optical properties, and device stability. As the results showed, a step-by-step post-annealing process after deposition was optimal for forming 2D perovskites, enhancing the device stability and efficiency. The efficiency of the optimized PSCs was improved for 24%, compared to the reference PSCs. Furthermore, this solar cell maintained 92% of its efficiency for a year. [ABSTRACT FROM AUTHOR]

Semiconducting bismuth borate glasses in xBi2O3–(1 − x)B2O3 system where x = 0.25, 0.50, and 0.75 (in mol.), and ZnO-glass heterostructures are studied for humidity sensing. Glass samples are prepared using melt-quenching method, whereas pristine ZnO is synthesized by sol–gel process. Heterostructure samples are obtained by adding different weight fractions of pulverized bismuth borate glass to the ZnO sol. Conducting silver paint and graphite pencil are used to make electrodes on silicon wafer and flexible paper substrates, respectively. ZnO, glass, and ZnO-glass heterostructure thin films are deposited on both the substrates through drop-casting method. Structural and microstructural changes of heterostructure films are studied using X-ray powder diffraction (XRD), and scanning electron microscope (SEM). Pristine ZnO, glass and ZnO-glass heterostructure thin film samples are tested for humidity sensing at room temperature by monitoring changes in the resistance of the samples. ZnO-glass heterostructures have shown enhanced humidity sensitivity with the lowest response and recovery times (12 and 16 s, respectively), which indicates their promising nature for humidity sensing applications. Enhanced sensing properties are attributed to the unique microstructural features of ZnO nanoparticles which are grown on glass particles through a heterogeneous nucleation process and semiconducting ZnO/glass heterostructure mechanism. [ABSTRACT FROM AUTHOR]

As human exposure to non-ionizing electromagnetic (EM) radiation increases, concerns regarding its long-term health effects have prompted the search for effective shielding materials. Traditional shielding materials, while effective, often come with high production costs, complex processing requirements, or environmental concerns. Therefore, materials that are affordable, flexible, biocompatible, and easy to manufacture are in high demand for various applications, ranging from consumer electronics to medical devices, where both performance and safety are crucial. This paper investigates the potential of self-prepared silver cellulose-acetate composite as a shield against non-ionizing EM radiation. The composite’s effectiveness was tested at various silver-to-cellulose ratios (20, 40, 60, and 80%) against frequencies ranging from 1 to 10 GHz, encompassing common sources of radiation exposure. The results showed that by placing the silver cellulose-acetate composite in front of the fired clay, transmission can be significantly reduced, with the 60% silver composition showing the highest effectiveness. These findings highlight the potential of silver cellulose acetate composites as highly effective materials for electromagnetic shielding, possessing a range of desirable characteristics. [ABSTRACT FROM AUTHOR]

In this paper the structural, dielectric and electrical conduction behaviour of Ca6-xNa2Y2(SiO4)6(Cl)2: xGd3+ (x = 0–0.05 mol%) chlorapatites prepared via hydrothermal process based on liquid–solid solution has been reported. The emergence of a monoclinic phase with P21/c space group is confirmed by x-ray diffraction (XRD) investigation. Space charge polarization is the predominant mechanism, according to dielectric studies that depend on frequency and temperature. Grain and grain boundary contributions to the thermally induced relaxation process are demonstrated using complex impedance spectroscopy. For all compositions, resistance of grain and grain boundaries exhibited negative temperature coefficient of resistance (NTCR) behaviour i.e., it decreases as temperature rises. The Nyquist plots indicated that the synthesized compounds appear non- Debye in nature. For all prepared compounds, the electrical modulus spectroscopy demonstrates that the electrical transport phenomenon occurs through both, short-range and long-range hopping of charge carriers. As frequency increases, the a. c. conductivity also increases, indicating that the compounds obey Jonscher’s power law. [ABSTRACT FROM AUTHOR]

As a macromolecular substance, cellulose is susceptible to the formation of interaction forces between its chains, which ultimately result in the generation of crystalline regions. In this paper, the reversible dehydrogenation reaction of ascorbic acid is employed, whereby the combination of dehydroascorbic acid and the hydroxyl group on the molecular chain of methylcellulose forms hydrogen bonding with the purpose of occupying the hydroxyl group on the molecular chain and inhibiting the formation of hydrogen bonding between the chains, thus eliminating the crystalline zone of methylcellulose. The alteration of hydrogen bonding and the elimination of the crystalline region were identified through the utilization of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Concurrently, a copper paste is formulated. The addition of copper results in the intensification of the oxidation of ascorbic acid at temperatures in the range of 200 °C. This leads to the formation of oxalic acid, which subsequently forms copper oxalate with copper at high temperatures. This process then enters the ascorbic acid colloid, forming a conductive channel. In accordance with the principles, a low-temperature sintered copper paste was devised and manufactured, exhibiting a high viscosity recovery rate (75.8%), high adhesion, low resistivity (4.2*10−6Ω*cm), and objective aspect ratio (0.28) after screen printing. [ABSTRACT FROM AUTHOR]

Using a solution technique with a long evaporation process and double-distilled water as the solvent, single crystals of sodium bromide-doped L-alanine (SBLA) were produced during a 55-day growth phase. Advanced techniques were used to evaluate the SBLA crystal, including single XRD, powder XRD analysis, FTIR Spectroscopy, UV–Vis NIR spectroscopy, fluorescence study, TG/DTA study and SHG investigation. Powder XRD and single crystal XRD analysis have been used to identify the sample's structure, space group, volume, Miller indices (hkl) and unit cell properties. This led to the discovery that the structure of the SBLA single crystal was orthorhombic. The lattice parameters of SBLA crystal found by both powder XRD and single crystal XRD methods are almost the same. Utilizing FTIR analysis, the chemical groups included in the developed crystal have been identified. The absorbance and transmittance range, energy band gap value, extinction coefficient, reflectance and refractive index value, optical and electrical conductivity, and skin depth have all been determined by optical research. As a result, a significant absorbance peak in the UV region was found, and 227 nm was found to be the cut-off wavelength and by Tauc's plot, the optical band gap of the sample was found to be 5.447 eV. When analyzing the sample's photoluminescence behavior, sodium bromide-doped L-alanine single crystal (SBLA) exhibits strong green fluorescence emission at 544 nm. The material stability and kinetic and thermodynamic parameters of the SBLA single crystal have been analyzed using TG/DTA study. The SHG efficiency of Sodium bromide-doped L-alanine material is found to be 1.57 higher than that of KDP. The results and discussion of several methods of investigation of the grown SBLA single crystal are detailed in this paper. [ABSTRACT FROM AUTHOR]

The present study represents a modern computational analysis of optoelectronic response of crystalline, nanostructured copper nitride (CuxN) semiconducting material fabricated by a simple, low-cost spray pyrolysis technique that can be adopted in places lagging high-grade fabrication infrastructure. The optical spectroscopy data of the fabricated thin film was provided as input to Oghma-Nano software for carrying out numerical simulations. The variation in photoconductive response by tuning film thickness from 50 μm to 50 nm and 50 Å at different light intensities was observed. The best photoconductive performance was observed for 50 nm film with total charge density of 3 × 1025 C m−3, cut-in voltage of 1.4 V, recombination prefactor of 1.2 × 10–24 m−6 s−1 and carrier generation rate of 2.5 × 1036 m−3 s−1, respectively. These values were compatible with those of conventional semiconductors like Si, GaAs and CdTe, respectively. The feasibility of 50 nm CuxN film in photovoltaic applications was probed by modelling a device by using it as absorber and window layers in combination with various inorganic semiconductors as mentioned in the text of this paper. The best photovoltaic characteristics and parameters were noted for the solar cell with CuxN as absorber layer and CdS as window layer. This CdS–CuxN solar cell exhibited maximum current density of 9.98 A m−2, maximum power density of 89.32 W m−2, fill factor of 0.85, photoconversion efficiency of 8.93% etc. which are compatible with experimental results of other conventional CdS-based solar cells like CdS–Cu2S, CdS–PbS, CdS–CdTe. Optoelectronic performance analysis for various device applications using present technique is simple and can be adopted in places lagging high-grade fabrication and characterization infrastructure. [ABSTRACT FROM AUTHOR]

This paper researches ilmenite-type [(Mg1-xMnx)0.95Zn0.05]TiO3 dielectrics synthesized by the solid-state reaction method and the influence of Mg2⁺ by Mn2⁺ on the physical characterization, such as microstructure, crystallization, Raman spectra, and microwave dielectric properties, was investigated systematically. The microstructures and phases of the synthesized dielectrics were meticulously analyzed using EDS, SEM, XRD, XPS, and Raman spectroscopy. Optimization of the process conditions revealed that sintering temperature and time significantly impact the microwave dielectric properties, and further tuning Mn2⁺ doping concentration x can obtain the wide-range quality factor. The optimal dielectric properties for [(Mg0.8Mn0.2)0.95Zn0.05]TiO3 were achieved when sintered at 1250 °C for 3 h, including a permittivity (εr) of approximately 17.4, a quality factor (Qf) of around 180,000 GHz, and a temperature coefficient of resonance frequency (τf) of about − 58 ppm/°C. Due to its substantially reduced thermal budget and low-loss microwave dielectric properties, the proposed dielectrics demonstrate a high potential for applications in manufacturing high-quality substrates for high-frequency devices in 5G and beyond 5G communication systems. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis and characterization of tungsten oxide by anodization method for 1 h using (1 M H2SO4, 1 M Na2SO4) electrolyte solution while varying NH4F concentration. The influence of NH4F concentration on structural, morphological, optical, and photocatalytic properties is examined. Scanning electron microscopy images show the formation of a thin layer with porous nanostructure attributed to the dissolution of anodic oxide by H+ and F− ions in the electrolyte under UV radiation of 365 nm. X-ray diffraction analysis reveals a mixed-phase crystal system of WO3, consisting of both monoclinic and tetragonal phases The crystallite size is found in the range 5.5‒18.2 nm with increasing NH4F concentration. UV–Vis spectroscopy analysis indicates a narrowing in the energy bandgap from 3.06 to 2.35 eV. Cyclic voltammetry manifests a decrease in the anodic peak current density with the rise in the concentration rate of NH4F. These findings extend a better understanding of the influence of NH4F concentration on the structural and electrochemical characteristics of the anodized nanoporous WO3 film as a potential candidate for hydrogen generation by the water-splitting process. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamic behavior of printed circuit board assembly (PCBA) and the reliability of board-level solder joints under thermal–vibration combined load through modal experiments and finite element (FE) analysis. Firstly, a combination of free modal test and FE simulation was adopted to obtain the equivalent material parameters of bare printed circuit board (PCB), which were utilized in the FE modeling of PCBA, and the effectiveness of the FE model was verified by experimental modal analysis. Modal tests and simulations were performed at different temperatures (22 ℃, 60 ℃) to investigate the effect of temperature on the dynamic behavior of the PCBA. Then, narrow-band random vibration simulations with constant acceleration power spectral density (PSD) amplitude were conducted on the PCBA at different temperatures. Finally, the Steinberg model was adopted to predict the vibration lifetime of the weakest solder joint. The results indicate that modal analysis is an effective method for establishing FE models of PCBA, and the temperature change significantly affects the dynamic characteristics and vibration reliability of PCBA. As the temperature changes from 22 ℃ to 60 ℃, the natural frequencies of PCBA decrease. The stiffness of the PCBA decreases as the temperature rises, leading to increased vibration deformation of the PCBA and larger stress and strain in the solder joints and PCB. Furthermore, under vibration load, the fatigue life of the solder joints is reduced by 32% due to the increasing temperature. [ABSTRACT FROM AUTHOR]

In this paper, foam nickel conductive substrate NiMoO4@CoMoO4 self-supporting core–shell structure composite material. The microstructure and phase structure of the sample were analyzed through characterization tests such as SEM, TEM, XRD, proving that the prepared material is a self-supporting core–shell structure composite material. The NiMoO4@CoMoO4 composite materials (131.3 m2/g) have a larger specific surface area compared to single materials NiMoO4(100.79 m2/g) and CoMoO4(99.28 m2/g). This self-supporting core–shell structure is conducive to full contact between the electrode material and the electrolyte, thereby accelerating the electrochemical reaction and storing more charges. Further electrochemical performance tests were conducted on the material using a single electrode. The research results showed that the specific capacity of the material was 1712 F/g at a current density of 5 A/g. After 10,000 cycles, the capacitance retention rate was 99.3%.In the experiment, it was also studied that NiMoO4@CoMoO4 self-supporting core–shell structure composite material as positive electrode, carbon nanotubes (CNTs) as negative electrode, matching high-performance NiMoO4@CoMoO4 //CNTs solid-state asymmetric supercapacitors. The research results indicate that the asymmetric device has a high power density (energy density of 80.6 Wh/kg) and energy density (corresponding to a power density of 8000 W/kg). At a current density of 5 A/g, the device has a specific capacitance retention rate of 97.3% after 10,000 cycles, indicating that the asymmetric device has excellent cycling stability. This article is about the synthesis of excellent-performance NiMoO4@CoMoO4 composite materials providing an efficient and convenient method. [ABSTRACT FROM AUTHOR]

The ferroelectric photovoltaic (PE-PV) effect has been extensively explored and plays a crucial role in constructing self-powered photodetectors. Ferroelectric materials have been attracting great interest in self-powered ultraviolet (UV) photodetectors due to their polarization-induced photovoltaic effect. In this paper, the ultraviolet self-powered photodetection properties of polycrystalline rare-earth Yb1-xHoxMnO3 (0 ≤ x ≤ 0.08, Δx = 0.02) ferroelectric materials have been investigated. The substitution of Ho atoms for Mn atoms has a great influence on the ferroelectric polarization, and Ho doping increases the photocurrent density. The photodetectors show excellent reproducibility responsivity (R) and detectivity (D*) under illumination at 365 nm. In addition, at the light density of 1 mW/cm2, the responsivity and detectivity of the photodetectors are as high as 0.09 W/A and 3.359 × 1011 Jones, respectively. These outstanding photodetection performances are due to the relatively high short-circuit current density (Jsc). High Jsc implies that more photogenerated carriers can be produced under illumination, which makes the device more sensitive to optical signals. This study presents a feasible method for improving the light-detection performance of the ultraviolet self-powered detector. [ABSTRACT FROM AUTHOR]

The study of the pore size characteristics of porous materials and the concretization of the loss mechanism is important for the preparation of high-performance wave-absorbing materials. Hence, the carbon materials with 3D ordered macroporous (3DOM) structure were prepared by template method in this paper. 3DOM structured carbon materials with different pore size characteristics were constructed by varying the particle size of template spheres. The amount of heterogeneous interfaces between carbon/air varies greatly among carbon materials with different pore sizes due to the difference in specific surface area, leading to different interfacial polarization, which in turn modulates the dielectric constant and impedance matching of the materials and enhances the wave-absorbing performance. The 3DOM RF-300 material with an aperture of 300 nm obtains the effective absorption bandwidth of 4.8 GHz and the strongest reflection loss of − 42.33 dB. In addition, based on the simulation level, the material loss mechanism to electromagnetic waves is investigated. Meanwhile, the practical application capability of the material is demonstrated by the radar scattering cross-sectional area simulation of 3DOM RF-300 material. The study provides a new path for designing high-performance wave absorbers based on material structure design and simulation techniques. [ABSTRACT FROM AUTHOR]

The title paper (J Mater Sci: Mater Electron 35 1265 (2024)) reports on the growth, characterization, properties of novel organic single crystals of “diglycine phthalic acid (DGP)” and Procion Red doped “diglycine phthalic acid (RDGP)”. Many points of criticism, concerning the crystal growth and experimental data are highlighted in this communication to prove that the so-called DGP and RGDP crystals are improperly characterized materials. DGP and RGDP crystals are examples, which demonstrate that characterization of new materials based on unit cell data leads to erroneous conclusions. [ABSTRACT FROM AUTHOR]