In this study, the effect of cerium (Ce) concentration on humidity sensing performance of humidity sensors based on Ce-doped zinc oxide nanostructure was investigated. Undoped ZnO (uZnO) and Ce-doped zinc oxide (CZO) nanoparticles were synthesized by sol–gel method. X-ray diffraction analyzes revealed that all nanostructures have a hexagonal wurtzite crystal structure and preferential orientation along the (002) plane. Scanning electron microscopy micrographs showed that there are homogeneously and uniformly distributed nanosized grains and capillary-nanopores on the surfaces of nanostructures. The energy dispersive x-ray spectroscopy analyzes confirmed the presence of zinc, oxygen and Ce elements in the nanostructures. The relative humidity (RH) sensing performances of uZnO and CZO nanostructured sensors were determined by means of electrical resistance measurements in the range of 40–90% RH at room temperature. The humidity sensing performance of the zinc oxide (ZnO) nanostructured sensor was significantly increased by Ce doping. All of the CZO sensors showed very high sensitivity to humidity and very short response and recovery times were achieved. It has been determined that 3 mol% Ce-doped ZnO has the best crystallite quality, the highest humidity sensitivity with a ratio of 7490 in the range of 40–90% RH, and the fastest times with a response time of 0.8 s and a recovery time of 4.7 s. This study clearly showed that CZO nanostructures, which we produce easily and at low cost, have the ideal humidity sensor potential and therefore have a bright future for humidity sensor applications.

Herein, we report nanostructures of NiTe and NiTe2 nanorods (NRs) with stoichiometric chemical compositions grown in an efficient one-pot hydrothermal approach. In the synthesis, hydrazine hydrate played multiple roles, such as a dissolving agent, reductant, and structure-directing agent. The samples were characterized using various analytical methods, such as X-ray diffraction, high-resolution transmission electron microscopy (HR-TEM), nitrogen adsorption/desorption measurements, energy-dispersive X-ray spectrometer (EDX), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and UV–Vis diffuse reflectance spectroscopy consequently. Adjustment of the Ni:Te (1:1, 1:2) precursors molar ratio reflected the results as desirable stoichiometric crystal structures of NiTe (hexagonal, \(P{6}_{3}/\text{mmc}\)) and NiTe2 (trigonal, \(P{{\bar{3}\text{m}1}}\)); further, the FE-SEM images displayed the evolution of nanorod morphology with an intermediate of tellurium template by the influence of the Kirkendall effect. The TEM pictures are likely to show the formation of two distinguished nanorods with different particle sizes. Both NiTe NRs and NiTe2 NRs were developed along the hexagonal direction; however, NiTe NRs include relatively small particles, and NiTe2 NRs considerably larger ones. The high-resolution XPS spectra revealed the surface structure and chemical composition of the Ni–Te system under Ni 2p and Te 3d spectra with the characteristic peaks of Ni2+, Ni0, Te2−, and Te4+ assigned based on the influence of hydrazine reduction and surface oxidation, respectively. Therefore, the optical band gap value of the prepared NiTe and NiTe2 NRs phases was found to be 3.25 and 3.0 eV, showing the semiconductor properties and potential for a wide range of applications.

ZnO is a low-cost material which can be easily manipulated into different morphologies using hydrothermal synthesis. In this study, ZnO nanowires are grown using hexamethylenetetramine (HMTA) and ammonium hydroxide as bases for the hydrothermal method. The growth time and temperature are varied and the nanowires are characterised structurally and optically. Electron microscopy images of the nanowires show that ammonium hydroxide forms pointed tips whereas HMTA forms flat tips. This is attributed to the chelating properties of HMTA. X-ray diffraction patterns show strong c-axis preferred orientation exhibited by ammonium hydroxide grown nanowires with large variability in crystallinity, whereas HMTA produced nanowires that show random orientation. The optical band gap is observed to decrease with solution temperature for both types of bases, however surface oxygen vacancy defects are observed in photoluminescence measurements of the ammonium hydroxide grown nanowires.

In the present work, uniform Polypyrrole (PPy) films were deposited on fluorine doped tin oxide substrates by chronoamperometry technique with various electropolymerization times. They were then investigated as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). Fourier transform infrared spectroscopy and contact angle measurements confirmed PPy polymerization efficiency. Scanning electron microscopy reveals the formation of unbounded PPy chains over the cauliflower structure at higher deposition times. The electrocatalytic activity of PPy films were found to decrease with increasing in deposition time. Similarly, the performance of PPy CE based-DSSCs is dependent upon polymer deposition time. DSSCs fabricated using PPy CE with 1s polymerization time exhibited higher photocurrent and thus superior power conversion efficiency. Electrochemical Impedance Spectroscopy suggests that the lower performance of DSSC with longer PPy deposition time is due to higher ion diffusion resistance in the porous structure of the formed unbounded PPy chains which retards the reduction of the triiodide ions \({ (I}_{3}^{-}\) ) at CE.

Dielectric resonator oscillators (DRO) have been recognized as the basic energy source in microwave telecommunication, radar, and navigation systems. This paper reports fabrication and characterization of structure, microstructure and dielectric properties of (Mg0.8Zn0.2)(Ti0.99Sn0.01)3 ceramics (MZTS hereafter) as a DR, a well as characterization of key parameters of a DRO module, i.e. resonant frequency, output power, bandwidth and phase noise, when the ceramics were used as a resonator in the module. Five-mm diameter solid cylindrical MZTS ceramics were fabricated and sintered at 1100 °C for 4, 6, 8, and 10 h. XRD, SEM–EDS and Network Analyzer were used to characterize the structure, surface morphology, εr and Q factor at 3.3 GHz, and τf of the ceramics. The εr of 17.34–17.48, Q factor of 6464–6510 at 3.3 GHz, and τf of 38–59 ppm/°C measured over 25–70 °C. The DRO key parameters were measured using a Spectrum Analyzer at a transverse electric (TE)01δ resonant mode with 12 Volt dc biasing. The ceramics recorded the resonant frequency at 4.0 GHz which are stable for 1 h with large output power, narrow bandwidth, and low phase noise at 300, 500, 700 kHz, and 3 MHz offset frequencies. The best DRO characteristics was shown by the 8 h ceramic, i.e. the resonant frequency at 4.05 GHz with -6.55 dBm output power, 58.50 kHz bandwidth, and -114.56 dBc/Hz phase noise at 700 kHz offset frequency. With such performance, MZTS ceramics are promising to be used as a silent oscillator in C-band radar systems.

In this work, two different combinations of materials are prepared, and the effects on dual doping in Ca1−x−yGdxSrxMnO3 and Ca1−x−yCexSrxMnO3 (x = 0, 0.025, 0.05, y = 0, 0.025, 0.05) materials are evaluated, and its parameters are optimized and predicted by the Box-Benhken design in the RSM method. The activation energy was measured with respect to different thermoelectrical material concentrations. RSM design is validated using hybrid DBN-RSO. The results show that increasing temperature, increases the amount of doping, decreases the thermal conductivity (k) and increases the electrical conductivity (σ) and power factor (PF). A bigger number of merits was also reached by increasing the amount of doping and the temperature. At 1000 K, the Ca0.95Gd0.05Sr0.05MnO3 material has a low thermal conductivity and the highest figure of merit (ZT) value of 0.24, which is more than Ca0.95Ce0.05Sr0.05MnO3. The predicted values from the DBN-RSO method provide results that are closer to the experimental observations. The highest score (ZT) that the DBN-RSO prediction received was 0.26. Besides, the regression value of 99% is obtained from the experimented and predicted values. It shows the confidence and fitness of values. Also, the DBN-RSO achieves closer results to the experimental design with the lowest error value.

With the rapid development of the 3rd semiconductors, the metal nanoparticles are investigated to be applied in the die-attached interconnect materials. However, the organic solvent used in the nanoparticle paste needs to be addressed. In this work, we adopted the liquid phase reduction method to synthesize Cu–Ag core–shell micro/nano-mixed particles (Cu@Ag MNPs), which achieved better anti-oxidation properties than Cu MNPs. Due to the suitable boiling point and viscosity, the electrical properties and hardness of the sintered films prepared by polyethylene glycol 400 (PEG-400) are better than those of ethylene glycol and α-terpineol. The electrical properties reach 43.82 µΩ cm and the hardness reach 61.3 HV at 300 °C. The shear strength of the joint sintered by Cu@Ag MNPs paste with PEG-400 can reach 20.14 MPa at 300 °C. Besides, the sintered Cu@Ag MNPs film exhibits a denser structure than Ag MNPs and Cu MNPs film. Therefore, Cu@Ag MNPs have great development prospects in the 3rd semiconductors.

Zirconium nitride nanofibers were synthesized by electrospinning method combined with carbon thermal reduction nitridation process, with zirconium chloride octahydrate and polyvinylpyrrolidone as raw materials. The phase composition, morphology and pore structure of the as-prepared nanofibers were analyzed by XRD, XPS, SEM, TEM and BET. In addition, the microwave absorption properties were measured using transmission line theory utilizing a vector network analyzer of zirconium nitride nanofibers/paraffin composites with different filler loadings. The results show that the as-prepared nanofibers are ZrN phase. The zirconium nitride nanofibers contain residual oxygen and carbon to form Zr(N,C,O) solid solution. The average diameter of the nanofibers is approximately 300 nm. There are particles distributed in it and the particle size ranges from 100 to 200 nm. The specific surface area of zirconium nitride nanofibers is 176.7 m2/g, and their pore volume is 0.26 cc/g. The pore sizes are mainly distributed at 3 nm. The granular structure and abundant pores of zirconium nitride nanofibers provide suitable conditions for impedance matching, interfacial polarization, multiple reflections, and scattering. These nanofibers exhibit excellent microwave absorption performance, achieving an optimum reflection loss of − 55.11 dB at a thickness of 1.55 mm with an effective absorption bandwidth of 3.51 GHz when the filler loading is 35 wt%. This study suggests that zirconium nitride nanofibers with good microwave absorption performance have the potential as novel transition metal nitride microwave absorption candidate materials.

Aiming to solve the intrinsic brittleness of Sn–Bi solder alloy, the effects of In element on the microstructure evolution, mechanical and soldering properties were systematically investigated in Sn–57Bi–1Ag-based alloy. It was found that the addition of In could fragment the reticular Bi-rich phase and increase the content of β-Sn phase in the Sn–(57 − x)Bi–1Ag–xIn alloy, which significantly improved the fracture elongation of the In-containing solder alloy. The elongation of Sn–56.0Bi–1Ag–1.0In reached 68.51%, which was 2.3 times that of Sn–57Bi–1Ag (~ 29.68%). What’s more, the fracture mechanism of the alloy changes from brittle fracture to mixed ductile-brittle fracture with the addition of In element, implying a significant progress in solving the brittleness problem of Sn–Bi solder alloy. Meanwhile, compared to Sn–57Bi–1Ag, the lower melting point and solidification temperature of the In-containing solder alloys improved the solderability, which enhances the spreading rate of alloy and results in a maximum spreading rate of 72.00% for the Sn–56.0Bi–1Ag–1.0In. This work provides a valuable guidance for industrial production of solder alloys as it simultaneously improved both the solderability and the ductility of Sn–Bi-based alloys.

The frequency dependent electrical and dielectric properties of the Au/P3HT/n-Si metal-polymer-semiconductor (MPS) type Schottky barrier diode (SBD) has been investigated using admittance-voltage (C/G-V) measurements over the range of 10 kHz–1 MHz at room temperature. Experimental results show that the values of both C and G/w decrease with increasing frequency confirming that the charges at interface can easily follow an ac signal and yield excess capacitance, especially, at low frequency. The frequency dependent dielectric constant (ε′), dielectric loss (ε″), and loss tangent (tan δ) are obtained using C and G/w data at various voltages. The ε′ and ε″ values are found to be strongly dependent on both frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. The ac electrical conductivity (σac) tends to increase with both increasing frequency and voltage, as in the C-V and G-V values, indicating that both the interfacial polarization and surface states (Nss) are more effective at low frequencies and so yield an excess capacitance and conductance to the real value of them. Also, the electric modulus formalism of dielectric relaxation was studied to understand the nature of conductivity relaxation in P3HT. It was found that the frequency dependent real parts, M' and imaginary parts, M", of the electric modulus strongly change with both frequency and voltages.

In the present study, single crystals of potassium dihydrogen orthophosphate and chrysoidine y doped potassium dihydrogen orthophosphate are grown by slow solvent evaporation method. The incorporation of chrysoidine y in potassium dihydrogen orthophosphate crystal lattice is confirmed from the powder xrd and energy dispersive x-ray analysis. A strong absorbance peak is present in the uv-visible transmittance spectrum confirming the chrysoidine y doping in potassium dihydrogen orthophosphate crystal. The optical bandgap energy of the doped crystal is 3.65 eV and they possess lower urbach energy. The mechanical properties confirmed that the grown crystal is a soft material having reverse indentation size effect and the doped crystal has enhanced hardness properties. The chrysoidine y doped potassium dihydrogen orthophosphate crystal has lower ac activation energy and are more thermally stable.

Transition metal oxides/carbon nanocomposites derived from metal–organic frameworks (MOFs) with enhanced electronic conductivity and high theoretical capacitance have been viewed as novel porous nanostructured electrode materials for electrochemical energy storage applications. Herein, sodium ion-intercalated MoO3/NiO/C nanostructures derived from MOFs were prepared through a facile solvothermal approach and followed by calcination at 400 °C. The as-synthesized nanocomposites were characterized using FT-IR, FESEM, EDX, XRD, TEM, and TGA. Benefitting from the synergistic effects and improved ionic transfer channels, the delivered maximum electrochemical capacitance was 548.41 F g−1 in 2-M KOH. Moreover, the electrochemical property was analyzed in terms of CV, EIS, and GCD, respectively, in a two-electrode system in an environmental-friendly aqueous electrolyte and a high energy density of 17.93 Wh kg−1 was acquired when a symmetric supercapacitor device was assembled. Besides, a remarkable retained specific capacitance and coulombic efficiency were approximately at 99.67% and 96.66% after 8000 continuous cycles. It evidently revealed the potential application of MOF-derived metal oxides/carbon composites in high-performance electrochemical energy storage devices.

Thin films of undoped and Al-doped ZnO were produced, and their surface morphology, structure, and optical characteristics were researched. The thin films were produced on glass substrates using the sol–gel spin-coating technique, with Al-doping concentrations of 1.5 and 2.5%. We observed from our structural analysis that, a decrease in grain size after adding Al dopants. Similarly increase in dislocation density (inversely proportional to Crystallinity) was observed after adding Al dopants. According to the SEM data, it is found that the undoped ZnO’s particles are spherical type in shape and agglomerated. The related histograms and distribution curve demonstrate that when Al-dopant concentration rises, the spherical shape particle becomes thinner, indicating a reduction in particle size. Based on the optical transmittance spectrum, the films’ undoped transmittance, which is 75% within the visible wavelength range, falls with rising Al-dopant concentration. Band gaps of the films were observed to decrease with increasing Al-dopant percentage.

It was previously understood that pure BaTiO3 has a diamagnetic property, whereas ferromagnetic signature has been unfolded in BaTiO3 by doping a non-magnetic dopant. In this research work, non-magnetic Sn (Tin) is doped with BaTiO3 in various concentrations i.e. 0.1%, 0.2% and 0.3% Sn via facile sol–gel approach so as to tune the magnetic parameters for spintronic applications. The formulated structural analyses demonstrate that all the synthesized samples possess a single phase of the tetragonal (0.1%), whereas a minor secondary phase of SnTiO3 is present in 0.2% and 0.3% Sn-doped samples. Making use of the UV–Visible spectra, the calculated optical band gap (Eg) of 0.1%, 0.2% and 0.3% of Sn-doped samples is 3.11, 3.14 and 3.16 eV, respectively. Further, the ferromagnetic ordering associated to the non-magnetic Sn-doped BaTiO3 could be clarified on the basis of intrinsic defects in the BaTiO3 lattice which is authenticated by performing the X-ray photoelectron spectroscopic (XPS) measurements. The vibrating sample magnetometer (VSM) study reveals that the saturation magnetization (MS) Value is 0.17 ± 0.001 × 10–3 emu/g for 0.1% Sn and 1.43 ± 0.01 × 10–3 emu/g for 0.2% Sn whereby the ferromagnetic nature is asserted for the sample. On the other hand, the 0.3% Sn-doped sample exhibits the diamagnetic feature which is because of the lack of oxygen vacancies. The derived results could affirm that the augmented ferromagnetic nature is influenced by the created defects thereby the room-temperature ferromagnetic ordering is stabilized in 0.1% and 0.2% Sn-doped nanoparticles. Therefore, the 0.1% Sn-doped BaTiO3 sample with low saturation magnetization can be a candid candidate in the emerging sphere of spintronics applications.

A novel Fe2O3–CaSiO3 (FCS) composite microwave dielectric ceramic was prepared by a solid-state reaction method (SSR). The phase composition, microstructure and relative density of the composite ceramics were systematically investigated and their relationship with microwave dielectric properties was investigated. The phase compositions of the prepared samples were CaSiO3 and Fe2O3 in all sintering temperatures. The phase fractions and cell parameters of the FCS ceramics were analyzed by Rietveld refinement. Besides, the Q × f values of the FCS ceramics were positively correlated with the phase content of CaSiO3. The effect of microscopic morphology on the microwave dielectric properties of the FCS ceramic samples was investigated by SEM technique. EDS analysis verified that the phase composition of the ceramic samples was Fe2O3 and CaSiO3. Finally, the FCS ceramics sintered at 1180 °C for 4 h obtained excellent microwave dielectric properties of εr = 8.69, Q × f = 28,000 GHz, τf = − 24.29 ppm/°C.

In recent years, increased focus has been placed on the investigation of ferrite nanoparticles’ possible use as humidity-sensing materials. In this work we report the humidity-sensing characteristics of Dysprosium doped Mg-Rb ferrites synthesized by solution combustion synthesis route. The produced Mg0.9Rb0.1DyxFe2-xO4 powder have been examined using energy dispersive X-ray spectroscopy (EDX), field effect scanning electron microscopy (FESEM), powder X-ray diffraction (PXRD), and Fourier transform infrared (FTIR). According to the results of powder XRD, unit cell volume (590–502Ao) and crystallite size (40–26 nm) decrease when Dysprosium ion concentration increases. The nanomaterial has a single phase with the Fd3m space group, according to the PXRD. The presence of Mg, Rb, Fe, Dy, and O elements is confirmed by EDX. The samples are highly porous nature (8 to 24%) and high surface volume (0.71–0.76). The spinel ferrite structure is clearly visible in the FTIR spectra, and the bands in the high-frequency region illustrate how hygroscopic the produced materials are. The fabricated powder is employed in the creation of a humidity sensor as a sensing component. It is noted that, the composition of Dy3+ increases the enhance in the resistance and is maximum for Mg0.9Rb0.1Dy0.03Fe1.97O4 composite and is determined to have the highest average sensitivity (600 M/%RH). The composition of the Dysprosium (Dy) increases the resistance is enhanced and is maximum for the Mn0.9 Rb0.1 Dy0.03Fe2-0.03O4 composite. Hence our results are good enough for sensor applications. The manufactured thin film humidity sensor has response and recovery durations of 18 and 90 s, respectively. The discovered sensing material has outstanding stability and strong repeatability (98%).

PEDOT:PSS is a promising candidate as a p-type emitter to form a heterojunction solar cell on monocrystalline silicon (mono c-Si). This is due to its high conductivity, high transparency, effectiveness as an anti-reflective coating (ARC), besides being capable of low-temperature processing. This paper investigates optical, surface morphological and electrical properties of p-type PEDOT:PSS emitter on n-type textured mono c-Si for solar cell application. The mono c-Si wafers are textured using sodium hydroxide (NaOH) solution to form random upright pyramids on the surface. Then, PEDOT:PSS emitter is spin-coated on the textured wafers with varying coating speeds (250–1000 rpm) to form different thicknesses of the emitter layer. The PEDOT:PSS on textured wafer reduces the weighted average reflection (WAR) to 4.91% when compared to 17.87% for the textured wafer alone. In the solar cell, the optimized PEDOT:PSS emitter on the textured wafer demonstrates improved short-circuit current density (Jsc), open-circuit voltage (Voc) and power conversion efficiency (PCE) when compared to the PEDOT:PSS emitter on the reference planar wafer. The highest PCE of 5.53% is achieved for the optimized PEDOT:PSS emitter on the textured solar cell. The results demonstrate that PEDOT:PSS is a promising heterojunction emitter and ARC for the textured mono c-Si solar cell.

Electroactive materials with low costs, simplicity, eco-friendliness, and efficiency are highly desirable for a variety of applications, including energy conversion, energy storage, and non-enzymatic sensing. Through the use of garlic green leaf biomass, active molecules are extracted to enhance NiCo2O4 nanostructure electroactive properties via reducing, stabilizing, and capping agents. A NiCo2O4 nanostructure electroactive material was created using 5 mL, 10 mL, and 15 mL of garlic leaf extract heated hydrothermally. An evaluation of the material's morphology, crystallinity, and surface chemical composition, as well as the application of electrochemical tests aimed at detecting ascorbic acid (AA) without the use of enzymes in phosphate buffer solution with pH of 7.4. Pure NiCo2O4 has the morphology of nanorods which was transformed into thinner nanowires consisting of nanoparticles with the addition of garlic leaves extract. Biosensors without enzymes have the advantages of being easy to make, reproducible, and stable over those with enzymes. NiCo2O4 nanostructures fabricated with garlic leaf extract in a 10 mL volume are being developed as non-enzymatic AA sensors. The AA sensor presented here operates linearly from 0.5 to 8.5 mM with a detection limit of 0.01 mM. It was found that an AA sensor is highly selective, stable, repeatable, and capable of quantifying AA concentrations in various real-life samples.

This study presents the synthesis of zinc telluride (ZnTe) nanoflakes and their composite with reduced graphene oxide (RGO-ZnTe) through a simple hydrothermal reaction. The crystal structure of the synthesized materials was characterized using X-ray Diffraction techniques. Subsequently, the Metal-Semiconductor (MS) based Schottky devices were fabricated by depositing the ZnTe and RGO-ZnTe thin films and Aluminium electrodes via vacuum coating methods. The surface morphology and topography of the deposited films were investigated using field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) techniques, respectively, to study the formation of MS junctions. The interfacial properties of the MS junctions in the Al/ZnTe/ITO and Al/RGO-ZnTe/ITO configurations were analyzed using ac impedance spectroscopy over a frequency range of 50 Hz–10 MHz. Thereafter, the bias-dependent impedance spectrometry was also conducted within a voltage range of ± 0.6 V to establish the equivalent circuits for the fabricated MS junction Schottky diodes (SDs). The diode parameters, including on/off ratio, ideality factor, barrier height and series resistance were determined by measuring the current–voltage (I–V) characteristics of the fabricated SDs. Further, the charge transport parameters, such as dc conductivity and photosensitivity, were also estimated. The findings indicate that the Schottky devices based on the RGO-ZnTe composites exhibit enhanced device performance compared to those based on pristine ZnTe, attributed to the synergistic effects between the RGO sheets and ZnTe nanoflakes.