The study examines how different nitrogen doping concentrations affect hydrothermally synthesized graphene oxide’s properties using various analytical techniques. Two analytical spectroscopic techniques were used to investigate UV–visible spectroscopy in dispersed samples, namely Bromo Phenol Blue (BPB) and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The results showed that the doped graphene samples absorb most light in the visible range between 476 nm and 568 nm in the presence of BPB, and the band gap values obtained using Tauc’s formalism ranged from 2.65 to 4.03 eV. In the presence of DDQ reagent, the formation of charge transfer complexes led to sharp absorption peaks in the ultraviolet region around 310 nm wavelength and a range of energy band gap values between 3.77 and 3.98 electron volts. Empirical Relations-Based Calculation of Refractive Index (n) for Nitrogen-Doped Graphene displayed Optical Absorption Potential in the Visible and UV ranges. Pyrrolic-N Bonding Dominance in Samples as Evident by X-ray Photoelectron Spectroscopy. The VSM results demonstrated that the sample with the highest percentage of Pyrrolic-N exhibited the highest saturation magnetization (0.23 emu gm−1) and coercive field (66.6 H Oe). The improved magnetic properties and optical band gap values observed in nitrogen-doped graphene oxide make them promising materials for use in magneto-optical devices.

The BST/Si photodiode has been effectively synthesized by growth BST on the p-type Si (100) substrate utilizing the hydrothermal process. Screen printing was used to prepare TiO2 film deposited on Si substrate, then immersing TiO2 film in Ba(OH)2 and Sr(OH)2 solution to fabricate BST/Si photodiode using a hydrothermal process. The BST film was studied using XRD, FESEM, and reflection spectra. The band gap was calculated for a BT film using the reflection methods. Hall measurement confirmed the n-type conductivity of BST film. Curie temperature of the BST film was observed at 87 °C according to DC measurement. The dark and illuminated (J-V) characteristics of the BST/Si photodiode have been measured under simulated AM1 conditions using a Xenon lamp. The Shockley-Read- Hall recombination caused unequal electron and hole capture rates that dominated the I-V characteristics resulting in an absence of classic superposition phenomena. The open circuit voltage (Voc) measurement is carried out to know the recombination mechanism in an open circuit. The BST/Si film showed more conductivity after increasing illuminating power density, which qualifies it for photovoltaic applications.

The purpose of this study is to investigate the effects of Graphite (Gr)-Boron Carbide (B4C) reinforcement particles on the mechanical characteristics of an aluminium-based hybrid metal matrix composites. Hybrid metal matrix composites (MMCs) were prepared by adding different proportions of Gr and B4C (0.5–0.5, 1.0–1.0, 1.5–1.5, and 2.0–2.0 wt%) through liquid metallurgy (stir casting) route. The phase, microstructure, EDS, density, hardness, tensile strength of fabricated samples were studied. Through X-ray diffraction analysis, it was established that there was a transitional stage of development between the matrix and reinforcement particles due to interfacial bonding. Furthermore, scanning electron microscopy results indicate a consistent dispersion of reinforcement particles within the aluminium matrix up to the 1 wt% Graphite and 1 wt% B4C. As the proportion of reinforcement increased, a decrease in density was observed, with the lowest density as 2.62 g cc−1 in the sample containing 2 wt% Graphite and 2 wt% B4C. The best mechanical characteristics of the fabricated hybrid metal matrix were observed with 1 wt% Graphite and 1 wt% B4C, with a hardness of 82 HRC, impact strength of 32 Joules, and an engineering ultimate tensile strength of 134.3 MPa.

As an inhibitor for copper (Cu), Octyl hydroxamic acid (OHA) has been extensively studied through a combination of density functional theory (DFT) and experiments. Our findings indicate that using a concentration of 3 mM OHA as an inhibitor can lead to a remarkable removal rate (RR) and surface quality when the pH is at 10. Tafel analysis of potentiodynamic polarization plots was performed to demonstrate that OHA can lower the corrosion current. Further insight into the adsorption behavior of OHA on the Cu surface was obtained through a comprehensive study combining X-ray photoelectron spectroscopy (XPS), DFT calculations, and adsorption isotherm model analysis.

Photoluminescence spectroscopy is a powerful technique for investigating carrier dynamics in semiconductor materials and photovoltaic devices. In this short review, we present our recent luminescence spectroscopic studies on halide perovskites, including thin films and solar cell devices, and discuss their photocarrier dynamics with relevance to photovoltaic performance.

In this work, a ferroelectric tunnel thin-film transistor (FeT-TFT) with polycrystalline-silicon (poly-Si) channel and ferroelectric HfZrOx gate dielectric is demonstrated with analog memory characteristics for the application of synaptic devices. The FeT-TFT exhibits a much lower conduction current of ∼0.032 times in transfer characteristics and maximum conductance (Gd) of ∼ 0.14 to 0.2 times in potentiation and depression operation than the FeTFT due to FeT-TFT’s carrier transport mechanism: interband tunneling. This work employed pulse widths of 75, 150, and 300 ns to modulate Gd, and it was found that using a pulse width of 75 ns could achieve low asymmetry ∼ 1 and high Gd ratio ∼ 20.63 under the consideration of operation speed. When the pulse time is increased, the potentiation and depression voltages can be significantly decreased to maintain the low asymmetry, but the Gd ratio is also reduced. In addition, the endurance characteristic of poly-Si FeT-TFT is found to be strongly related to the degradation effect of subthreshold swing due to the dynamic stress effect in the endurance measurement. This result reveals that the reliability of ferroelectric devices is not only owing to the degradation of the remanent polarization.

Zinc substituted nickel-cobalt ferrites, i.e., ZnxNi0.8−xCo0.2Fe2O4 (x = 0.0, 0.05, 0.10 and 0.20) with average crystallite size 100 nm were synthesized by citrate-gel auto-combustion method to investigate effects of Zn2+ substitution on the structural and dielectric properties. Both X-ray diffraction (XRD) and IR spectroscopy studies confirms the formation of pure cubic spinel structure. Variation of lattice parameter infers Vegard’s law linear dependence with the addition of Zn2+ concentration. The temperature-dependent behavior of dielectric and modulus spectra has been studied within the frequency range 100 Hz-100 kHz for different temperatures between 100 K and 400 K. It was concluded that the dielectric responses of ZnxNi0.8−xCo0.2Fe2O4 are found to be frequency dependent and thermally activated. Also, In the Zn doped ferrites variations of dielectric loss (tan δ) and the imaginary part of electric modulus (M") show the presence of the non-Debye type of dielectric relaxation. Rise in Zinc concentration leads to a decrease in dielectric constant (ε r) due to the declining of Fe3+–O–M2+ conducting network (M is Co or Ni). Here, we report a low loss tangent factor of the order of 8×10−3 for the sample Ni0.6Zn0.2Co0.2Fe2O4 make this composition suitable for high frequency-applications at room temperature. The activation energy is calculated from electric modulus formalism and DC electrical conductivity and found to increase with further substitution of Zn2+ concentration.

In this research we have proposed a high selectivity Isopropanol gas sensor. The sensor shows significant resistance change only to Isopropanol gas. The synthesis method of flower-like SnO2 nanostructures, the electrode material and design, and the optimized working temperature provide the high selectivity and high response of the sensor. The SnO2 nanoflowers (NFs) have been synthesized in a two-step process as the gas sensitive layer. The sensor shows its best performance on Au interdigitated electrodes. The optimized working temperature is obtained at 150 °C. The proposed sensor has a high sensitivity, good repeatability, long-term stability and remarkable selectivity. The responses of the sensor to 100 ppm of isopropanol at 150 °C is 71 and the sensor is capable of keeping almost 96% of the initial response in a 40 d period.

Hybrid CdTe solar cells including the organic polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) in the typical structure were fabricated. PEDOT:PSS was added as a p+ region in the structure of solar cells after CdTe deposition and before the processing of the Cu–Mo back contact and was compared with a CdTe reference solar cells without polymer. The PEDOT:PSS was deposited at different rotational speeds of 3000 to 6000 rpm for 30 s, by spin coating technique. The obtained thicknesses were around 20–40 nm. Adequate coverage of the CdTe surface and grain morphology was obtained, when the polymer was deposited at 5000 rpm of rotational speed this according to Scanning Electron Microscope measurements. The final structure of the solar cells was SnO2:F/ZnO+CdS-TT/CdTe+CdCl2-TT/PEDOT:PSS/Cu-Mo. In our results was clear that the solar cells with PEDOT:PSS processed at different rotational speeds had higher fill factor and thus higher photovoltaic efficiencies. A high photovoltaic efficiency of around 13% was obtained when PEDOT:PSS was deposited at 5000 rpm and the Cu–Mo back contact was processed with a substrate temperature of 200 °C. A particular increment in the photovoltaic efficiency of solar cells close to 8% was achieved, when the Cu–Mo back contact was processed at room temperature.

Alkali tetraborate glasses 10RO-30ZnO-xLi2B4O7-(60-x) K2B4O7 (R = Mg, Ca) with x varying from 0 mole% to 60 mole% were synthesized by melt quenching approach at around 1150 °C. Broad and peak less X-ray diffraction spectra confirmed the amorphous nature of synthesized glass samples. Physical and optical properties namely density, molar volume, refractive index, optical band gaps, molar refractivity and Urbach energy values have been reported. The density of the present glass samples improved with increasing x mole% except at the presence of equal amounts of alkali oxides in the glass system. The molar volume decreased continuously with x mole%. Oxygen packing density (OPD) increased with increasing x mole%. The optical energy band gap Eopt values with increasing lithium tetraborate in the glass composition have shown a downward trend, where are refractive index values shown upward. FTIR and Raman studies revealed the variation of BO3 and BO4 units in the glasses with composition is marginal. EPR spectra of copper ions confirmed the existence of Cu2+ ions in the ground state dx 2–y 2 orbital (2B1g). The observed non-linear variations of various properties are attributed to the structural changes caused by mixed alkali effect.

A comparative study of Eu3+ ion luminescence in YXO4 (X=P, As, V) with the tetragonal zircon structure is conducted in relation to the intensity of the hypersensitivity 5D0 → 7F2 ΔJ=2 transition. Both the asymmetry ratio, R=I5D0−7F2I5D0−7F1, and the Judd-Ofelt Ω2 intensity parameter increases in the order YPO4 < YAsO4 < YVO4. This correlation is interpreted qualitatively in terms of the covalency and polarizability of (XO4)3−, which increases in the order (PO4)3− < (AsO4)3− < (VO4)3−. The trend is supported by the results of electronic band structure calculations of the three compounds which establish the strength of hybridization between the X cation and the oxygen 2p states. The electronic structure of YAsO4 is calculated to probe the covalence of As–O bonding. The increasing oscillator strength of the Eu3+5D0 → 7F2 transition in going from YPO4 to YAsO4 to YVO4 is consistent with the expectation of ligand dipolar polarization model for hypersensitivity which states that the oscillator strength of the 5D0 → 7F2 transition is proportional to the square of the ligand dipolar polarizability. The connection between the mechanism of hypersensitivity and second harmonic generation (SHG) is presented.

By employing a 355-nm nanosecond (ns) ultraviolet (UV) laser annealing, the impact of fluorine (F) co-doping on the formation of a highly activated N-type shallow junction in germanium (Ge) is investigated. Secondary ion mass spectrometry (SIMS) depth profiling of phosphorus (P) demonstrated that an ultra high P concentration of 9 × 1020 cm−3 at a shallow junction of 55 nm with less dopant diffusion can be obtained using ns laser annealing. F co-doping was confirmed to be an efficient way to improve the activation of the P dopants, but show less influence on the redistribution of P dopants within the NLA melted region. However, the activation level of the shallow junction could be increased to approximately 1 × 1020 cm−3 in the presence of F at an optimized concentration.

The PM material was effectively synthesized in this study via electropolymerization. The electrochemical characteristics of glassy carbon electrodes (GCE)@RGO were examined after the PM was polymerized onto its surface to create PM-RGO/GCE with the support of the CV technique. Furthermore, employing this modified electrode, URA and PCM were examined by applying CV and DPV electrochemical techniques. In comparison to employing the RGO/GCE, the modified PM-RGO/GCE electrode showed good responsiveness toward URA and PCM applying the DPV technique, with LOD values of 0.040 μM for URA, and 0.025 μM for PCM. The linear concentrations ranged from 0.06 to 1 μM. These factors like Na+, SO4 2−, Ca2+, Cl−, NH4 +, NO3 − ions, ascorbic acid, dopamine, hypoxanthine and xanthine, did not interfere during the modified electrode’s operation. Within this paper, it is worth emphasizing that these analytical processes for the URA and PCM in actual sample solutions are more dependable than the HPLC method.

A one-pot hydrothermal method was used to prepare reduced graphene oxide mediated CuS/MnS (CMS/rGO) nanocomposites. The XRD result revealed that the hexagonal structure of CMS/rGO with the crystallite size is about 24 to 35 nm, respectively. The presence of rGO in the CMS structure was confirmed through Raman analysis. The chemical states of CMS3/rGO nanocomposites were confirmed by the XPS analysis. From this, the observed binding energy values are in good agreement with the presence of Cu, Mn, S, O and C, respectively. The rod-like morphology of the CMS3/rGO nanocomposites was obtained by using HR-TEM. The optical property of the product was analyzed through UV-DRS and PL. The observed absorption and emission peaks are red-shifted when CuS/MnS concentration increases. It is attributed due to the increases in crystallite size. The calculated band gap energy values are decreased with increasing crystallite size. The electrochemical properties of the products show a pseudocapacitor nature (832 Fg−1) with excellent capacitance retention of 97%. The degradation efficiency of CMS3/rGOcatalyst nanocomposite shows a good efficiency of 96% and 91% against CR and CV dyes.

The development of efficient CuSCN hole transport layers is crucially important for achieving high photovoltaic performance in inorganic perovskite devices. In this study, the effects of electrodeposition charge density on the morphological/microstructural and electrical properties and the formation mechanism of electro-deposited CuSCN films are investigated and discussed. The results indicate that the charge density is the key factor that governs not only the thickness, but also morphological, electrical, and surface properties of the electro-deposited CuSCN films. For the energy band diagram property, we found that when the charge density is 120 mC cm−2 (named as CD120), the valance band of CuSCN near ITO work function. This excellent property can efficiently improve the photovoltaic performance of inorganic perovskite devices, where ITO and CuSCN are employed, owing to the reduction of energy barrier. Among the films electro-deposited at different charge densities, the CD120 exhibits the highest mobility, possibly due to the excess amount of SCN in the thin film.

In this study, nitrogen doped graphene oxide(N-GO) and sulfur doped graphene oxide(S-GO) were produced in one step, and two of these prepared materials were converted into composite form with polyaniline(PANI). For the first time in the literature, triple composite electrode materials with two heteroatom doped graphene oxides and PANI were prepared for supercapacitors. In this context, heteroatom doped graphene oxides and PANI were characterized using spectroscopic and microscopic methods. With the ternary composites formed, anode and cathode electrode materials for coin cell type supercapacitors in asymmetrical form were characterized by electrochemical methods. The capacitive behavior of the prepared supercapacitors was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) method. The change of capacitive behavior according to the number of cycles was determined by cyclic charge-discharge tests. With the electrode materials obtained with heteroatom doped graphene oxides/PANI composites, it reached the highest areal capacitance value of 79.7 mF.cm−2 at 10 mV.s−1 scan rate. The coin cell type asymmetric supercapacitors retained more than 100% of their initial specific capacitance at the end of the 1500 cycle.

This study presents a stacked process of thermal and atomic layer deposition (ALD) SiO2 that reduces the interface trap density of 4H-SiC metal-oxide-semiconductor (MOS) capacitors. The channel mobility of metal-oxide-semiconductor field effect transistors (MOSFETS) are reduced due to the high interface trap density as well as coulomb scattering mechanism. Herein, we investigate SiO2/SiC interface properties of a stacked process, which is accomplished via reducing the thickness of thermal oxidation film. Notably, MOS capacitors fabricated with thermal and ALD SiO2 stacked structures can reduce the interface states density (Dit) by twofold at 0.2 eV below the conduction band energy compared with thermally grown SiO2. Additionally, the leakage current increases at a relatively slow rate in the electric field of 5–10 MV cm−1, whereas the leakage current increases sharply when the electric field is higher than 10 MV cm−1. The resultant ALD SiO2 stacked structure provides a new approach to improving interface quality, which allows a reduction in the thermal budget involved in the fabrication of devices.

This research work successfully synthesized the MF (MgFe2O4) material at various hydrothermal temperatures. The XRD, BET, SEM and EDX characterization techniques were employed to confirm the formation of MF-190. The electrochemical characteristics of the glassy carbon electrode (GCE) were investigated after dropping MF-190 material with nanoscale particles onto its surface zone to generate the modified electrode-MF/GCE. Moreover, by applying this modified MF-190 electrode, CBT (clenbuterol) signals were detected by using two electrochemistry techniques, CV (cyclic voltammetry) and DPV (differential pulse voltammetry). The MF/GCE described the great responsiveness to CBT signals using the DPV method with a LOD (limit of detection) and LOQ (limit of quantification) of 0.45 μM and 1.56 μM, compared to the bare GCE. The linear CBT concentration ranges from 1 to 50 μM. Several interferents such as NH4NO3, CaCl2, Na2SO4, uric acid, terbutaline, salbutamol and paracetamol did not affect the CBT signals within the modified electrode’s operation. Furthermore, this work shows that the determination of CBT in real purine samples with the RSD values (not higher than 4.45%) and the recovery values (97.7%–104.3%) was suitable. In addition, compared to the previous reports, this original research work would emphasize the novel detection of CBT via the MF/GCE with the costless, simple, reliable technique.

There are numerous applications for deep UV AlGaN Light-Emitting Diodes (LEDs) in virus inactivation, air and water purification, sterilization, bioagent detection and UV polymer curing. The long-term stability of these LEDs is also of interest for long-duration space missions such as the Laser Interferometer Space Antenna (LISA), the first gravitational wave detector in space. We review the literature on long-term aging of these devices as a function of drive current, temperature and dc versus pulsed operation. The LEDs typically show a gradual decline in output power (up to 50%) over extended operating times (>100 h) and the rate of decline is mainly driven by current and temperature. Experimentally, the degradation rate is dependent on the cube of drive current density and exponentially on temperature. The main mechanism for this decline appears to be creation/migration of point defects. Pre-screening by considering the ratio of band edge-to-midgap emission and LED ideality factor is effective in identifying populations of devices that show long lifetimes (>10,000 h), defined as output power falling to 70% of the initial value.

The health sector is focusing on the wellness of the society, is advancing in the phases of diagnosis and treatment. Biosensors based devices are used to diagnose a variety of human diseases. Recently, there was a sudden hike in the human mortality rate by chronic diseases caused by mutants of SARS-COV-2, on global scale. It is important to detect these kinds of diseases on an early stage to reduce the risk of spreading. For the analysis of Covid-19 influenza, tests such as Rapid Antigen Test (RAT), True NAT, CBNAAT and the commonly done RPT PCR were utilised. This proposal describes a non-invasive, quick and practical method for sensing the at-risk or infected persons with SARS-COV-2, aiming at controlling the epidemic. The proposed method employs a breath sensing device consisting of a Graphene Field Effect Transistor biosensor which can identify disease-specific biomarkers from exhaled sniff, hence allowing speedy and precise detection. This test aids screening of large populations as it is simple and quick and emerges as a promising candidate for SARS-COV-2 tests due to a high sensitivity. This work justifies the accurate diagnosis of Severe Acute Respiratory Syndrome COV 2 from aerosol particles by GFET Biosensor.