Search

Magnetoelectric coupling and switching charge density in multiferroics have gained the attention of researchers around the world for energy storage, energy harvesting, and their potential applications for pulsating devices. In multiferroics, the absence of inversion symmetry and the presence of antiferromagnetic symmetry give rise to intriguing magnetoelectric coupling. In this paper, bi-phase composites, (1–x)Bi0·9La0·1FeO3 + xSrCoO3 for x = 0.1, 0.2, 0.3 are made by a facile and time-saving sol–gel auto-combustion technique. For this, we employed lanthanum-doped BiFeO3 to avoid the volatilization of bismuth ions. The composition 0.8Bi0·9La0·1FeO3 + 0.2SrCoO3 (x = 0.2) showed the maximum polarization (Pmax = 2.45 × 10−3 μC/cm2) and effective interfacial interactions depicting symmetrical magnetoelectric coupling response with least distortion along with significant switching charge density (i.e., Qsw = – 2.124 × 10−5 μC/cm2). Whereas reduction in leakage current density is observed with the inclusion of SrCoO3 contents into pure BLFO during polarization phenomena, confirming its insulating properties. Switching charge density from the positive-up- negative-down sequence not only ensured the suitability of switching applications in pulsating devices but also displayed its reliability and long-term stability. The symmetric magnetoelectric coupling showed its potential use in piezoelectric actuators and energy harvester applications. Magnetic attributes and multidomain structures were confirmed by the vibrating sample magnetometer. The maximum value of the squareness ratio appears to be 0.1035 confirming the existence of a multidomain structure for all samples. These outcomes suggest that this particular composition seems extremely viable in developing ultra-sensitive pulsating devices attributed with significant switching charge density.

With the wide potential of organic field-effect transistors in all the modern electronic circuitries, researchers are grappling with the challenge of poor charge transport and hence lower mobility in organic polymers. Low-charge carrier mobility is mainly due to disorder in the molecular packing of organic semiconductors along with other factors, such as impurities, defects and interactions between molecules. The current research work has been conducted to align the molecular chains of poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-‌‌‌b:5,4-‌b′]‌dithiophen-2-yl)-alt-[1,2,5]thiadiazolo-[3,4-c]pyridine] (PCDTPT) using directional coating techniques such as dip coating and brush coating on nano-grooved substrates. Long-range order of polymer chains was clearly observed along the direction of brush coating and nanogrooves in optical and atomic force microscope (AFM) images while transmission spectra confirmed decreased pi–pi stacking for the polymer films deposited by this technique. By comparing the mobility performance of brush-coated devices with other techniques, we found a remarkable mobility enhancement of 90 times that of conventional spin-coated device and 24 times enhancement compared with the dip-coated device for the case when the alignment of polymer chains was parallel to the channel. All the fabrication and characterizations were performed in the ambient environment. This study demonstrates a potential approach to align the polymers on long and short ranges hence providing a route for high-performing devices in ambient conditions.

In the recent development of energy storage devices, the scientific study has demonstrated a significant interest in the applications of the magnesium iron oxide (MgFe2O4) nanoparticles. In this work, we present synthesized novel MgFe2O4 nanoparticles at different molarities (0.1–0.5 M), via hydrothermal technique. An X-ray Diffractometer was used to study the phase analysis of the prepared samples at different molarities. A pure cubic phase of the MgFe2O4 is observed at molar concentrations of 0.3 M and 0.4 M. However, the mixed phases consisting of (MgFe2O4 + γ-Fe2O3) were also observed at 0.1 M, 0.2 M, and 0.5 M. The pure cubic MgFe2O4 nanoparticles depict the large value of crystallite size, 19.5 nm, and the lowest dislocation density and strain. The vibrating Sample Magnetometer shows the ferromagnetic nature of the pure MgFe2O4 with a high saturation magnetization. The value of saturation magnetization surged from 36.88 emu/g to 55.2 emu/g at 0.4 M concentration. The dielectric response of the materials as a function of applied frequency was studied thoroughly by using an Impedance Analyzer. The highest value of dielectric constant and low tangent loss was also reported at 0.4 M. Cole-Cole plots are the affirmation of the contribution of both grains and grain boundaries in the charge mechanism. These distinctive features make the synthesized material an excellent choice for future spintronics and energy storage devices.

The mechanical, electronic, optical, and thermoelectric analyses of CuCaX3 (X = Cl, Br, I) have been done using DFT based TB-mBJ approach. The stability of CuCaX3 (X = Cl, Br, I) has been confirmed from the enthalpy of formation; values for CuCaCl3, CuCaBr3, and CuCaI3 are −1.07 eV, −1.55 eV, and −2.15 eV, respectively. The phonon spectra plot is also discussed, and the phonon dispersion analysis confirms that the CuCaX3 systems are dynamically stable since no imaginary modes are observed. The modified Becke-Johnson exchange potential is used to evaluate the opto-electronic and thermo-electric properties. By replacing anions (Cl to I), the band gap of the studied material in the visible region has been tailored, from 2.9 eV to 2.65 eV, for renewable energy devices. In addition, various optical properties such as dielectric constant, refraction, absorption, optical conductivity, and optical loss factor have been analyzed for optoelectronic applications. With the replacement of anions (Cl to I), the peaks of maximum intensities shifted to lower energy to values of 7.2 eV, 6.2 eV and 5 eV for CuCaCl3, CuCaBr3 and CuCaI3 respectively. Furthermore, the BoltzTrap code has been used to discuss thermal conductivity, power factor, Hall coefficient, specific capacitance and electron densities in detail for thermoelectric applications. The CuCaX3 family of perovskites has been found to have bandgaps falling in the visible region for light-emitting diodes (LEDs). These also exhibit high thermal efficiency, making them potential multifunctional candidates for optoelectronic and energy harvesting applications.

Research on thin films of iron oxide has gained interest in recent years because of its application in advanced spintronic and electronic devices. Technologically important iron oxide phases can be achieved by adopting novel methodologies and/or selecting suitable dopants. A cost-effective microwave assisted sol–gel approach is adopted in this work to prepare thin films of iron oxide. Undoped and doped sols (2–10 wt% of dopant concentration) are irradiated with MW power of 720 W. Maghemite phase (γ-Fe2O3) is observed to be stable up to a co-dopant concentration of 6 wt%. Further increase in dopant content leads to a phase transition to mixed (γ-Fe2O3+Al2O3) crystal phases. Values of dielectric constant (DC) and loss tangent exhibit normal dispersion response with high DC value (log f 5.5 = ∼92) observed for undoped sample. Cole–Cole plots indicate the effective grain boundary contribution for low dopant concentrations, whereas contributions from grains is observed at higher dopant concentrations. M−H curves show ferromagnetic response with high value of saturation magnetization (Ms) of ∼450 emu/cm3 witnessed at 6 wt%. (Al, Cr) co-doping results in tuning of magnetic response/parameters. MD coupling of (Al, Cr) co-doped thin films of iron oxide makes this material suitable for advanced spintronic and energy storage devices.

Thin films of cadmium telluride (CdTe) have attained the attention of researchers due to the potential application in solar cells. However, cost-effective fabrication of solar cells based on thin films along with remarkable efficiency and control over optical properties is still a challenging task. This study presents an analysis of the structural, optical and electrical properties of undoped and Cu-doped CdTe thin films fabricated on ITO coated glass substrates using an electrodeposition process with a focus on practical applications. Electrolytes of cadmium (Cd), tellurium (Te) and copper (Cu) are prepared with a low molarity of 0.1 M. Thin films are deposited by keeping current density in the range of 0.12–0.3 mA/cm2. Copper doping is varied (2-10 wt%) for the optimized sample. X-ray diffraction crystallography indicates that both undoped CdTe and Cu-doped CdTe films crystallize into a dominant hexagonal lattice. Direct energy band gap is observed for both undoped and doped conditions. The study revealed a drop in the optical band gap energy to ∼1.46 eV with the increase in doping (Cu) concentration from 2 to 10 wt%. Increase in mobility and conductivity is observed with the increase in current density of the deposited undoped CdTe thin films. Whereas, Cu doping of 6 wt% produced thin films with acceptable mobility and conductivity for the doped samples. Furthermore, photoluminescence (PL) spectroscopy unveiled a multitude of emission peaks encompassing the visible spectrum, arising from the combination of electrons and holes through both direct and indirect recombination processes. Findings of this study suggest that chemically produced CdTe thin films would be suitable for use as low-cost applications pertaining to solar cells.

Lead-free halide perovskites have been investigated as promising materials for energy harvesting and thermoelectric device applications. The current article thoroughly explains the electronic behavior, stability, optical and thermoelectric characteristics of CdKF3 and CdKCl3 halide perovskite. For structural stability, the elastic constant and phonon dispersion of both halides are investigated. Additionally, thermodynamic stability is demonstrated by the investigation of formation energy (-2.45 to −1.89 eV). The ductile nature of both halides is confirmed by calculating the Poisson ratio, and their significance for the manufacturing of devices. The direct bandgap nature (2.65 eV and 0.9 eV) of both halides is observed through electronic band structures using mBJ-GGA, which has been employed to obtain more precise results for optoelectronic applications. Both halides show remarkable optoelectronic performance, with low reflectivity, high optical absorption, and conductivity. Thermal and electrical conductivity are also used to study the thermoelectric characteristics. Both halides show the figure of merit (ZT) near unity, ZT indices highlight their importance for thermoelectric devices.

Nanoparticles, to be used in biomedical applications, have been the subject of extensive investigation in recent years. Recently, zirconia and iron have gained significant relevance to the field due to their superior mechanical and structural qualities as well as their numerous biological applications. In this research, Fe3O4-stabilized zirconia nanopowders are fabricated using a low-cost sol–gel approach. Iron oxide sol is added in 1–10 wt% increments to a 0.1 M zirconia sol. The obtained crystallite size values match well with previously reported values for the tetragonally stable (t-zirconia) phase. Hardness values of approximately 1278 HV, along with fracture toughness values of ∼ 24.48 MPa.m-1/2 are observed for stable tetragonal zirconia. Results from cell lysis experiments indicate that the synthesized nanoparticles have the potential to combat cancerous cells. An encapsulation efficacy of up to ∼ 73% is observed after a 120-minute time period. Radio labeling techniques are employed to label the as-synthesized zirconia nanoparticles using Sodium Pertechnetate (Na99mTcO4) labeled radiopharmaceuticals, allowing for biodistribution assessment. Multiple CT scans of rabbits are performed to obtain accurate results and evaluate their survival. Studies show that radiolabeled nanoparticles are highly absorbed in the animals' bladders, making them a promising choice for tumor therapy. Various physical properties of the animals are periodically examined after administration of the nanoparticle-based injection for several months, and no abnormalities are found. The results obtained through these characterizations indicate that these nanoparticles can be used as future therapeutic agents as well as drug carriers.

Spintronics is the new emerging field that recasts the modern information technology using electron spin along with its charge. Various spintronic devices have been under research for the last few years such as GMR based devices, MRAMs, etc. These devices are based on the conventional ferromagnetic materials that exhibit spin asymmetry. Half metallic ferromagnetic materials, especially Heusler alloys, are considered as most promising candidates because of high spin polarization. Previously, Heusler alloys have been investigated theoretically. Few experimental reports are available that belong to high-cost vacuum-based methods. Furthermore, detailed magnetic study at room temperature is rare to be found. In this research work, structural, electronic and magnetic properties of Co2MnSn Full Heusler alloy are investigated experimentally and through density functional theory by ADF. Theoretical results of this study predict the half metallic and asymmetric behavior of the Co2MnSn Full Heusler alloy with L21 structure. The cobalt manganese tin thin films are prepared by the electrodeposition method by varying applied reducing potential from 1 to 2 V. Mixed phases are observed at an applied potential ranging from 1 V to 1.5 V. Co2MnSn phase of full Heusler alloy is observed at an applied voltage of 1.75 V. Further increase in applied voltage to 2 V results in strengthening and stability of Co2MnSn phase. Magnetic moment μB of 4.10 is in close agreement to the one calculated by Slater-Pauling Rule for full Heusler alloys. The M−H loops of cobalt manganese tin Heusler alloy electrodeposited thin films exhibit soft ferromagnetic behavior. Arrott plots show the ferromagnetic nature of cobalt manganese tin electrodeposited thin films by exhibiting convex shape. MH curves show variation in exchange bias with varying the applied potential.

Long-standing research efforts have enabled the widespread introduction of organic field-effect transistors (OFETs) in next-generation technologies. Concurrently, environmental and operational stability is the major bottleneck in commercializing OFETs. The underpinning mechanism behind these instabilities is still elusive. Here we demonstrate the effect of ambient air on the performance of p-type polymer field-effect transistors. After exposure to ambient air, the device showed significant variations in performance parameters for around 30 days, and then relatively stable behaviour was observed. Two competing mechanisms influencing environmental stability are the diffusion of moisture and oxygen in the metal–organic interface and the active organic layer of the OFET. We measured the time-dependent contact and channel resistances to probe which mechanism is dominant. We found that the dominant role in the degradation of the device stability is the channel resistance rather than the contact resistance. Through time-dependent Fourier transform infrared (FTIR) analysis, we systematically prove that moisture and oxygen cause performance variation in OFETs. FTIR spectra revealed that water and oxygen interact with the polymer chain and perturb its conjugation, thus resulting in degraded performance of the device upon prolonged exposure to ambient air. Our results are important in addressing the environmental instability of organic devices.

This study explored the potential of Fe3O4, SnFe2O4, and CoFe2O4 nanoparticles as larvicidal and adulticidal agents against Aedes aegypti (A. aegypti) larvae and adults, which are vectors for various diseases. This research involved the synthesis of these nanoparticles using the coprecipitate method. The results indicate that CoFe2O4 nanoparticles are the most effective in both larvicidal and adulticidal activities, with complete mortality achieved after 96 h of exposure. SnFe2O4 nanoparticles also showed some larvicidal and adulticidal efficacy, although to a lesser extent than the CoFe2O4 nanoparticles. Fe3O4 nanoparticles exhibited minimal larvicidal and adulticidal effects at low concentrations but showed increased efficacy at higher concentrations. The study also revealed the superparamagnetic nature of these nanoparticles, making them potentially suitable for applications in aquatic environments, where A. aegypti larvae often thrive. Additionally, the nanoparticles induced observable damage to the gut structure of the mosquitoes and larvae, which could contribute to their mortality. Overall, this research suggests that CoFe2O4 nanoparticles, in particular, hold promise as environment-friendly and effective agents for controlling A. aegypti mosquitoes, which are responsible for the transmission of diseases such as dengue fever, Zika virus, and Chikungunya. Further studies and field trials are needed to validate their practical use in mosquito control programs.

Thin films of zinc oxide (ZnO) doped with transition metals have recently gained significant attention due to their potential applications in a wide range of optoelectronic devices. This study focuses on ZnO thin films doped with the transition metals Co, Fe, and Zr, exploring various aspects of their structural, morphological, optical, electrical, and photoluminescence properties. The thin films were produced using RF and DC co-sputtering techniques. The X-ray diffraction (XRD) analysis revealed that all the doped ZnO thin films exhibited a stable wurtzite crystal structure, showcasing a higher structural stability compared to the undoped ZnO, while the atomic force microscopy (AFM) imaging highlighted a distinctive granular arrangement. Energy-dispersive X-ray spectroscopy was employed to confirm the presence of transition metals in the thin films, and Fourier-transform infrared spectroscopy (FTIR) was utilized to investigate the presence of chemical bonding. The optical characterizations indicated that doping induced changes in the optical properties of the thin films. Specifically, the doped ZnO thin film’s bandgap experienced a significant reduction, decreasing from 3.34 to 3.30 eV. The photoluminescence (PL) analysis revealed distinguishable emission peaks within the optical spectrum, attributed to electronic transitions occurring between different bands or between a band and an impurity. Furthermore, the introduction of these transition metals resulted in decreased resistivity and increased conductivity, indicating their positive influence on the electrical conductivity of the thin films. This suggests potential applications in solar cells and light-emitting devices.

Ferromagnetic and superparamagnetic oxide nanoparticles are of particular attention because of their possible use in various fields ranging from bio-nanotechnology to spintronics. Detailed magnetic, dielectric and impedance investigations are crucial for the above-mentioned applications. This study deals with the exploration of various iron oxide phases under as-synthesized conditions by sol–gel method. pH of the sols is varied in the range of 1 to 11. X-ray diffraction (XRD) analysis indicate amorphous behavior for nanoparticles synthesized using pH 1 and 3. Nanoparticles synthesized using pH 2 and 4–6 exhibit hematite phase of iron oxide. Whereas structural transition to maghemite phase is observed for pH 7–8. Nanoparticles synthesized using high pH values, i.e. 9–11, exhibit structural transition towards magnetite phase of iron oxide. Hematite nanoparticles exhibit superparamagnetic and ferromagnetic hysteresis curves with saturation magnetization of ∼ 24 emu/g and ∼ 13–17 emu/g at pH 2 and pH 4–6, respectively. Maghemite nanoparticles exhibit superparamagnetic (pH 7) and ferromagnetic (pH 8) response with saturation magnetization of ∼ 69 and ∼ 42 emu/g, respectively. Fe3O4 nanoparticles exhibit superparamagnetic (pH 9–10) and ferromagnetic (pH 11) behavior with saturation magnetization of ∼ 88, 87 and 52 emu/g, respectively. High grain boundary resistance contributed towards high dielectric constant of ∼ 99, 109 and 154 (log f = 5.0) at pH 2, 7 and 9. Detailed impedance values indicate dominant role of grain boundaries in the conductivity of iron oxide nanoparticles. Superparamagnetic iron oxide (pH 9) exhibits strong antioxidant activity along with a very weak hemolytic response. The findings of cell lysis reveal that synthesized nanoparticles have a potential to combat dangerous cancer cells. Drug efficacy results show that after 120 min the encapsulation efficacy reaches a peak of ∼ 83 % using curcumin, a naturally existing drug. In vivo biodistribution of nanoparticles was studied in Rabbit model. Synthesized nanoparticles are labelled using Technetium-99 m. Whereas, labeling efficacy and stability was examined using =nstant thin layer chromatography (ITLC) process. In vitro and in vivo results suggest potential anti-cancer applications of as-synthesized superparamagnetic nanoparticles.

Use of microwave (MW) energy as an alternate to high temperature treatment during material synthesis is gaining much attention as it offers the advantages of being faster and economical than other heating methods. A comprehensive study of structure, magnetization, and polarization behaviour of Cobalt (Co) doped Fe3O4 thin films, prepared by means of microwave assisted sol–gel method is performed. Co doped (0-10 wt%) sols are prepared after irradiating them at MW power of 1000 W. Phase analysis is confirmed using XRD where Fe3O4 phase persisted with Co concentrations of 0-6 wt%. Higher concentration results in the appearance of cobalt oxide phase. Magnetic and transport properties are strongly affected by the presence of Co ions. Co doped Fe3O4 films show anisotropic behaviour with high saturation magnetization obtained for 6 wt% Co doped Fe3O4 thin films, i.e. ∼ 125 emu/g. Verwey transition is observed for thin films with low dopant concentration while no sharp transition in magnetization behaviour is observed for higher dopant concentration. High frequency anomaly in dielectric analysis is observed at high frequencies for Co doped Fe3O4 thin films. Negative values of magneto-dielectric coefficient show coupling of magnetic and dielectric behaviour at room temperature.

Chemical bath deposition, being an application oriented electroless technique, is used for the deposition of calcium doped barium titanate (Ba1-xCaxTiO3) thin films using glass substrate. Ca concentration is varied as x = 0.0, 0.02, 0.04, 0.06, 0.08, 0.10 and 0.12. As-deposited thin films show amorphous behavior, whereas, annealed thin films show crystalline nature. X-ray diffraction (XRD) analysis of annealed thin films shows a pure tetragonal phase of Perovskite barium calcium titanate thin films up to x = 0.08 dopant concentration, while XRD peak corresponding to CaO is observed at x = 0.10 and 0.12. Maximum optical transmission of 65% is observed under undoped and as-deposited conditions. Annealed thin films show 83% transmission under undoped condition. While decrease in transmission is observed with the increase of dopant concentration due to the presence of sub bands. High value of dielectric constant (i.e. ∼3800 at log f = 1.3) and low value of tangent loss (i.e.∼0.15 at log f = 1.3) is observed for x = 0.08 dopant concentration. Cole–Cole plots reveal the presence of two electrically active grains and grain boundary regions. Maximum value of spontaneous polarization Pmax (18.46 μC/cm2) is observed for x = 0.08 dopant concentration. Mixed para-ferromagnetic response is observed under undoped condition. S-shaped magnetic response is observed for x = 0.02–0.04 whereas, ferromagnetic curves are observed for x = 0.06–0.12. It is important to mention here that tetragonal Perovskite calcium doped barium titanate thin films with U-shaped dielectric constant and good ferroelectric properties are hard to find in literature.

Abstract Background Changing climate enhances the survival of pests and pathogens, which eventually affects crop yield and reduces its economic value. Novel approaches should be employed to ensure sustainable food security. Nano-based agri-chemicals provide a distinctive mechanism to increase productivity and manage phytopathogens, with minimal environmental distress. In vitro and in greenhouse studies were conducted to evaluate the potential of green-synthesized iron-oxide nanoparticles (IONPs) in suppressing wilt infection caused by Fusarium oxysporum f. sp. lycospersici, and improving tomato growth (Solanum lycopersicum) and fruit quality. Results Various microwave powers (100–1000 W) were used to modulate the properties of the green-synthesized IONPs, using spinach as a starting material. The IONPs stabilized with black coffee extract were substantively characterized using X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy, dielectric and impedance spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy (SEM and TEM, respectively), and magnetization analysis. XRD revealed a cubic magnetite (Fe3O4) phase with super-paramagnetic nature, detected at all microwave powers. The binding energies of Fe 2p3/2 (710.9 eV) and Fe 2p1/2 (724.5 eV) of Fe3O4 NPs were confirmed using XPS analysis at a microwave power of 1000 W. Uniform, spherical/cubical-shaped particles with an average diameter of 4 nm were confirmed using SEM and TEM analysis. A significant reduction in mycelial growth and spore germination was observed upon exposure to different IONP treatments. Malformed mycelium, DNA fragmentation, alternation in the cell membrane, and ROS production in F. oxysporum indicated the anti-microbial potential of the IONPs. The particles were applied both through the root (before transplantation) and by means of foliar application (after two weeks) to the infected seedlings. IONPs significantly reduced disease severity by an average of 47.8%, resulting in increased plant growth variables after exposure to 12.5 µg/mL of IONPs. Analysis of photosynthetic pigments, phenolic compounds, and anti-oxidant enzymes in the roots and shoots showed an increasing trend after exposure to various concentrations of IONPs. Correspondingly, lycopene, vitamin C, total flavonoids, and protein content were substantially improved in tomato fruits after treatment with IONPs. Conclusion The findings of the current investigation suggested that the synthesized IONPs display anti-fungal and nutritional properties that can help to manage Fusarium wilt disease, resulting in enhanced plant growth and fruit quality. Graphical Abstract

Green synthesis of metallic nanoparticles is an auspicious method of preparing nanoparticles using plant extracts that have lesser toxicity to animal cells and the host. In the present work, we analyzed the antibacterial activity of Citrullus colocynthis and Psidium guajava-mediated silver nanoparticles (Cc-AgNPs and Pg-AgNPs, respectively) against Aeromonas hydrophila (A. hydrophila) in an in vivo assay employing Labeo rohita (L. rohita). L. rohita were divided into six groups for both Cc-AgNPs and Pg-AgNPs treatments separately: Control, A. hydrophila infected, A. hydrophila + Ampicillin, A. hydrophila + Cc/Pg-AgNPs (25 µg/L), A. hydrophila + Cc/Pg-AgNPs (50 µg/L), and A. hydrophila + Cc/Pg-AgNPs (75 µg/L). Changes in different bio-indicators such as hematological, histological, oxidative stress, and cytokine analysis were observed. Interestingly, the infected fish treated with both types of AgNPs (Cc-AgNPs and Pg-AgNPs) exhibited a higher survival rate than the untreated infected fish and demonstrated signs of recovery from the infection, providing a compelling indication of the positive impact of phytosynthesized AgNPs. Disruptions in hematological and histological parameters were found in the infected fish. Both Cc-AgNPs and Pg-AgNPs showed recovery on the hematological and histological parameters. Analysis of oxidative stress and cytokine markers also revealed provoking evidence of the positive impact of Cc-AgNPs and Pg-AgNPs treatment against disease progression in the infected fish. The major finding of the study was that the higher concentrations of the nanoparticles (50 µg/L in the case of Cc-AgNPs and 75 µg/L in the case of Pg-AgNPs) were more effective in fighting against disease. In conclusion, our work presents novel insights for the use of green-synthesized AgNPs as economic and innocuous antibacterial candidates in aquaculture.

The present study reports the green synthesis of silver nanoparticles from leaves’ extract of Mangifera indica (M. indica) and their antibacterial efficacy against Aeromonas hydrophila (A. hydrophila) in Cirrhinus mrigala (C. mrigala). The prepared M. indica mediated silver nanoparticles (Mi-AgNPs) were found to be polycrystalline in nature, spherical in shapes with average size of 62 ± 13 nm. C. mrigala (n = ±15/group) were divided into six groups i.e., G1: control, G2: A. hydrophila challenged, G3: A. hydrophila challenged + Mi-AgNPs (0.01 mg/L), G4: A. hydrophila challenged + Mi-AgNPs (0.05 mg/L), G5: A. hydrophila challenged + Mi-AgNPs (0.1 mg/L) and G6: A. hydrophila challenged + M. indica extract (0.1 mg/L). Serum biochemical, hematological, histological and oxidative biomarkers were evaluated after 15 days of treatment. The liver enzyme activities, serum proteins, hematological parameters and oxidative stress markers were found to be altered in the challenged fish but showed retrieval effects with Mi-AgNPs treatment. The histological analysis of liver, gills and kidney of the challenged fish also showed regaining effects following Mi-AgNPs treatment. A CFU assay from muscle tissue provided quantitative data that Mi-AgNPs can hinder the bacterial proliferation in challenged fish. The findings of this work suggest that M. indica based silver nanoparticles can be promising candidates for the control and treatment of microbial infections in aquaculture.

Spinel ferrites with remarkable electrochemical performance and magnetodielectric (MD) coupling are promising candidates for energy storage and spintronic devices. This study focuses on structural phases, dielectric and magnetic polarization along with magnetodielectric (MD) coupling and electrochemical response of Fe-Cr spinels. Low cost sol–gel method is used to synthesize iron chromite nanopowders. Iron to chromium (Fe/Cr) ratio is varied in the range of 0.2–0.65 (with interval of 0.05). XRD patterns confirm the formation of phase pure FeCr2O4 at Fe/Cr ratios of 0.45, 0.6 & 0.65. Amorphous behavior is observed at Fe/Cr ratios of 0.2, 0.25, 0.5 & 0.55. Mixed phases are observed at 0.3, 0.35 & 0.4 Fe/Cr ratios. Formation of pure spinel phase at Fe/Cr ratio of 0.45 results in high saturation magnetization of 9.2 emu/g. High grain boundary resistance (189.62kΩ) and high dielectric constant (∼83.38 at log f = 5.0) along with low tangent loss (0.00423 at log f = 5) are observed at Fe/Cr ratio of 0.45. Magneto dielectric studies confirm positive magneto dielectric constant (MDC) of synthesized nanopowders at 0.45, 0.6 & 0.65 Fe/Cr ratios. Cyclic voltammetry is performed at constant potential window. Oxidation/reduction process leads to the pseudo-capacitive response of the material. The cyclic voltammetry curves show specific capacitance of 156 Fg−1, 144 Fg−1 and 152 Fg−1 at scan rate of 25 mV/s at Fe/Cr ratios of 0.45, 0.6 & 0.65 of FeCr2O4 nanopowders, respectively. The galvanostatic charging/discharging behavior shows capacitive behavior of FeCr2O4 nanopowders. The electrochemical results suggest that synthesized nanopowders have potential for energy storage system.

Iron (Fe) doped zinc sulfide (ZnS) nanoparticles were prepared by thermolysis with varying concentrations of iron. X-ray diffraction (XRD) results revealed the zinc blende cubic structure of ZnS. The effect of iron on lattice parameters such as crystallite size, micro strains, and dislocation density was examined. The defect chemistry inside the samples was analyzed by photoluminescence spectroscopy (PL). The variation in PL intensity introduced by doping can be used in optical applications. The optical parameters of nanostructures were investigated with different doping and the incorporation of Fe substitute for Zn ions using UV-Visible (UV-Vis).

Tomato plants are prone to various biotic and abiotic stresses. Fusarium wilt is one of the most devasting diseases of tomatoes caused by Fusarium oxysporum f. sp. lycopersici, causing high yield and economic losses annually. Magnetite nanoparticles (Fe3O4 NPs) are one of the potent candidates to inhibit fungal infection by improving plant growth parameters. Spinach has been used as a starting material to synthesize green-synthesized iron oxide nanoparticles (IONPs). Various extracts, i.e., pomegranate juice, white vinegar, pomegranate peel, black coffee (BC), aloe vera peel, and aspirin, had been used as reducing/stabilizing agents to tune the properties of the Fe3O4 NPs. After utilizing spinach as a precursor and BC as a reducing agent, the X-ray diffraction (XRD) pattern showed cubic magnetite (Fe3O4) phase. Spherical-shaped nanoparticles (∼20 nm) with superparamagnetic nature indicated by scanning electron microscopy (SEM) monographs, whereas energy-dispersive X-ray gives good elemental composition in Fe3O4 NPs. A characteristic band of Fe-O at ∼ 561 cm–1 was exhibited by the Fourier transform infrared (FTIR) spectrum. X-ray photoelectron spectroscopy (XPS) results confirmed the binding energies of Fe 2p3/2 (∼710.9 eV) and Fe 2p1/2 (∼724.5 eV) while, Raman bands at ∼310 cm–1 (T2g), ∼550 cm–1 (T2g), and 670 cm–1 (A1g) indicated the formation of Fe3O4 NPs synthesized using BC extract. The in vitro activity of BC-Fe3O4 NPs significantly inhibited the mycelial growth of F. oxysporum both at the third and seventh day after incubation, in a dose-dependent manner. In vivo studies also exhibited a substantial reduction in disease severity and incidence by improving plant growth parameters after treatment with different concentrations of BC-Fe3O4 NPs. The increasing tendency in enzymatic activities had been measured after treatment with different concentrations of NPs both in roots and shoot of tomato plants as compared to the control. Correspondingly, the upregulation of PR-proteins and defense genes are in line with the results of the enzymatic activities. The outcome of the present findings suggests that Fe3O4 NPs has the potential to control wilt infection by enhancing plant growth. Hence, Fe3O4 NPs, being non-phytotoxic, have impending scope in the agriculture sector to attain higher yield by managing plant diseases.

Zirconia ceramics have attained much consideration owing to the amazing mechanical strength and white color. These properties provide an opportunity for the use in biomedical applications. In the present study, an application oriented sol-gel route was adapted for synthesis of zirconia nanoparticles. ZrOCl2·8H2O was used as a precursor, iron oxide (Fe3O4) nanoparticles (pH 2 & pH 9) as a stabilizer and de-ionized water was used as a solvent. Sol-gel synthesized iron oxide stabilized zirconia nanoparticles were prepared by varying concentrations of iron oxide nanoparticles in the range of 2–10 wt%. X-ray diffraction results showed mixed phases at all wt% with acidic pH value, while pure tetragonal phase of zirconia was observed for stabilization with 6 wt% basic iron oxide. Maximum value of dielectric constant (~80 at log f = 4) and minimum value of tangent loss (~0.66 at log f = 4) were observed for zirconia stabilized with basic 6 wt% iron oxide. Maximum value of hardness (1410 ± 10 HV) along with high fracture toughness were observed with optimized stabilization. Very weak hemolytic activity and maximum scavenging (~76) antioxidant activity was observed under optimized conditions. Thus, it can be suggested that optimized nanoparticles, i.e. tetragonal zirconia stabilized with 6 wt% of basic Fe3O4, can be further useful for therapeutical and pharmaceutical applications.

Chemical bath deposition (CBD) method, being an electroless technique, is used to prepare phase pure barium titanate (BaTiO3) thin films using glass as substrate. Molarity of the solution is varied from 0.1 to 1.2 M, whereas, solution temperature is kept constant at 78 °C. XRD analyses show formation of perovskite tetragonal phase of BaTiO3 at all the molarities when films are annealed at 300 °C. Strengthening in perovskite tetragonal phase is observed with increase in solution molarity. Ellipsometric results show high transmission (∼ 83 %) in the visible region for thin films prepared with 1.2 M solution. Variation in direct band gap, 3.31–3.61 eV, is observed for annealed thin films. High dielectric constant (∼ 539.26 at log f = 3) and low tangent loss is obtained for 1.2 M based thin films. Thin films prepared under all the conditions show normal and anomalous / U-shaped frequency dependent dielectric response (i.e. ∼ 2754.24 at log f = 1.5 and ∼ 2004.73 at log f = 7.5). Maximum spontaneous polarization of ∼ 14.78 μC/cm2 and remnant polarization of ∼ 6.94 μC/cm2 are observed for 1.2 M sample. It is important to mention here that U-shaped high dielectric and good ferroelectric properties of BaTiO3 are observed in current study with no change in perovskite structure of tetragonal phase making it a potential candidate for storage devices at low and high frequencies.

Aluminum nitride (AlN) is a semiconductor material possessing a hexagonal wurtzite crystal structure with a large band gap of 6.2 eV. AlN thin films have several potential applications and areas for study, particularly in optoelectronics. This research study focused on the preparation of Ni-doped AlN thin films by using DC and RF magnetron sputtering for optoelectronic applications. Additionally, a comparative analysis was also carried out on the as-deposited and annealed thin films. Several spectroscopy and microscopy techniques were considered for the characterization of structural (X-ray diffraction), morphological (SEM), chemical bonding (FTIR), and emission (PL spectroscopy) properties. The XRD results show that the thin films have an oriented c-axis hexagonal structure. SEM analysis validated the granular-like morphology of the deposited sample, and FTIR results confirm the presence of chemical bonding in deposited thin films. The photoluminescence (PL) emission spectra exhibit different peaks in the visible region when excited at different wavelengths. A sharp and intense photoluminescence peak was observed at 426 nm in the violet-blue region, which can be attributed to inter-band transitions due to the incorporation of Ni in AlN. Most of the peaks in the PL spectra occurred due to direct-band recombination and indirect impurity-band recombination. After annealing, the intensity of all observed peaks increases drastically due to the development of new phases, resulting in a decrease in defects and a corresponding increase in the crystallinity of the thin film. The observed structural, morphological, and photoluminescence results suggest that Ni: AlN is a promising candidate to be used in optoelectronics applications, specifically in photovoltaic devices and lasers.

The present study investigated the biomedical potential of eco-friendly Citrullus colocynthis-mediated silver nanoparticles (Cc-AgNPs). The antibacterial efficacy of Cc-AgNPs was evaluated against two multidrug-resistant pathogenic bacterial strains, Escherichia coli and Pseudomonas aeruginosa. The antiproliferative and antilipidemic performance of the prepared particles was determined against the MCF7 cell line, a breast cancer cell line. The in vitro antibacterial assay revealed that Cc-AgNPs induced dose-dependent bactericidal activity, as a considerable increase in the zone of inhibition (ZOI) was noted at higher concentrations. Reduced proliferation, migration, spheroid size, and colony formation exhibited the substantial antiproliferative potential of Cc-AgNPs against MCF7 cells. Significant alterations in the expression of cell surface markers, apoptosis, and cell proliferation genes further confirmed the antiproliferative impact of Cc-AgNPs. Moreover, Cc-AgNPs exhibited antilipidemic activity by reducing cellular cholesterol and triglyceride levels and regulating key genes involved in lipogenesis. In conclusion, these results propose that Cc-AgNPs can be employed as a potent tool for future antibacterial and anticancer applications

The tenacity of the present study was to develop a material using an economical chemical route, having balance between magnetic and dielectric order parameters for maximum transmittance of electromagnetic waves in order to use them in shielding materials. In this context, Mn-Zn ferrites were prepared using a wet chemical based sol-gel auto-combustion technique. X-ray diffraction confirmed the pure phase formation of samples, while some impurity peaks were also present for the higher value of Mn substitution. Field emission scanning electron microscopy revealed a decrease in grain size with increasing Mn substitution. While energy dispersive X-ray spectroscopy confirmed the elemental composition of pure and Mn substituted samples, the dielectric constant, dielectric loss and tangent loss were decreased with increasing frequency and increasing Mn substitution. The complex electric modulus was found to be a function of frequency and values of complex electric modulus were increased with increasing frequency and Mn substitution. The complex impedance of RC series circuit and RC parallel circuit was also decreased with increasing both the parameters while AC conductivity was increased in the series. Dielectric frequency response was also studied for the prepared samples and the best match was found with expected results. The Nyquist and Cole-Cole plots revealed the semi-conductive behavior at higher frequency and Mn substitution also yielded the same results. The relative stability of the samples to be used as dielectric materials was also studied using Bode and Nichols plots, and a comparatively high gain margin was observed, well suitable for potential applications in electromagnetic shielding. Keywords: Mn substituted ZnFe2O4, Impedance spectroscopy, Dielectric frequency response, Dielectric gain margin

Thermally stable surfactant modified silica nano-matrix is synthesized by the sol–gel method at low temperature. The surfactant such as cetyltrimethylammonium bromide (CTAB) assisted silica matrix is encapsulated with bromophenol blue (BPB) for sensing activities. Prepared nano-matrix consists of numerous morphological structures such as a pseudo-spherical, hierarchal and islands. The morphology of mesoporous high surface area matrices is strongly affected by CTAB, BPB dye and the aging conditions that determine the transformation from disordered silica nano-matrix morphologies to ordered encapsulated structures. Furthermore, smooth surface matrices with low surface roughness 1.2 nm, low refractive index 1.36, large pores and small dimensions of heteroatoms contribute to the stable sensing activities. The response of coated fiber optic is determined at dynamic pH range 1–12. The prepared sensor has reversibility/repeatability, stability and fast response time of approximately 0.25 s in basic media. The accuracy of sensing device measurements in household ammonia solution and the borax solution suggested that prepared device has clear potential for daily life usage. Keywords: Silica nano-matrix, Bromophenol blue dye, Mesoporous structure, Optical properties, Evanescent field optical fiber sensors, Sensitivity

Iron cobalt nickel nitride (FeCoNiN) thin films are prepared by sol-gel spin coating route. The structural, magnetic and surface properties of the thin films are evaluated. The crystalline nature of thin films was enhanced upon annealing, leading to increased crystallite size. The X-ray diffraction shows mixed phases with crystallite size in the range of 20–26.93 nm. Thin films show ferromagnetism at room temperature. Coercivity and saturation magnetization are in the range of 642–716 Oe and 2.5–7.5 emu/cm3 respectively. Both coercivity and saturation magnetization increased with annealing of thin films. Magnetic properties are related to the crystallinity of thin films. The increase in crystallite size results into an increase of magnetic properties. Rectangular shaped particles are seen on the surface of thin films. The same type of grains can be seen on the surface of thin films which confirmed the formation of FeCoNiN as predicted by XRD. These novel thin films might be used in memory devices and optoelectronic applications. Keywords: Sol-gel: thin films, Iron cobalt nickel nitride, Structural properties, Magnetic properties, Crystallite size

Rare earth zirconates with pyrochlore type structure have shown a potential for practical applications due to their stable crystal structure with tunable lattice parameters. In this context, a series of Ce-substituted neodymium zirconates with general formula, Nd2Zr2−xCexO7 (x = 0.0, 0.4, 0.8, 1.2, 1.6, 2.0) was synthesized using wet chemical sol–gel auto-combustion technique. Structural analysis confirmed the formation of stable pyrochlore phase with space group Fd3m. The scanning electron microscopic analysis revealed that the parent compound adopted a mixed morphology (rectangular, spherical, squared etc.) with sharp grain boundaries and considerable porosity. A significant agglomeration was observed with Ce-substitution at Zr-site which improved the density of material. The stoichiometric composition of the elements present in the samples was confirmed by energy dispersive X-ray spectroscopy. The response of the material to external electric field of varying frequency was studied through impedance spectroscopy which confirmed the active contribution of grains and grain boundaries in the form of electrical response of the material. The nature of mobility of charge carriers was checked by the interaction of external varying electric field with the electric dipole moments of the material. This whole study provides valuable information about the energy storage capacity of the material and thus determines the potential of the material to be used in energy storage devices. Keywords: Ce-substituted Nd2Zr2O7, Structural tunability, Impedance spectroscopy, Energy

The present study aims to assess the induced nanotoxicity of arsenic nanoparticles (AsNPs) on different organs of fresh water fish Labeo rohita. AsNPs were synthesized by chemical reduction method using sodium arsenite as precursor, ice-cold sodium borohydride as reducing agent, and sodium hydroxide to adjust the solution pH. The synthesized AsNPs were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) for optical, structural, and morphological investigations. The UV-Vis absorption peaks occurring at around 300 nm indicated the presence of AsNPs in colloidal sample. The rhombohedral crystalline nature and metallic purity of AsNPs with crystallite size of 30 ± 1 nm were confirmed by characteristic peaks of XRD pattern. The SEM micrograph revealed the almost spherical shape and 40 ± 10 nm average size prepared AsNPs. For assessment of induced nanotoxicity, juveniles of Labeo rohita (L. rohita) were exposed to three different concentrations of AsNPs (namely, 1, 10, and 20 mg/L) for 30 days (n = 15 per group), and the control fish was kept untreated. It was observed that the routine behavior activities (such as swimming, mutual interactions, and feed intake) were affected by AsNPs. The growth of AsNPs treated fish was found retarded as compared to the control fish. Total erythrocyte count, total leukocyte count, and hemoglobin and hematocrit values were low in the AsNPs treated fish. Immunobiochemical assays revealed that protein level was altered in the AsNPs treated fish. The levels of antioxidant enzymes catalase and superoxide dismutase were low in the treated fish. The histological alteration induced by AsNPs in liver, gills, and kidneys demonstrated the damage in form of glomerulus shrinkage, vacuolation, inflammation, necrosis, lamellar disorganization, and hemorrhage in comparison with untreated fish. The results of the present study indicate that AsNPs exposure causes behavior, growth, hematology, immunobiochemical, and histological shortcomings in L. rohita.

The highest power conversion efficiency (PCE) for organic-inorganic perovskite solar cells based on lead is reported as 25.2% in 2019. Lead-based hybrid perovskite materials are used in several photovoltaics applications, but these are not highly favored due to the toxicity of lead and volatility of organic cations. On the other hand, hybrid lead-free double perovskite has no such harm. In this research study, SCAPS numerical simulation is utilized to evaluate and compare the results of perovskite solar cell based on double perovskite FA2BiCuI6 and standard perovskite CH3NH3PbI3 as an active layer. The results show that the power conversion efficiency obtained in the case of FA2BiCuI6 is 24.98%, while in the case of CH3NH3PbI3, it is reported as 26.42%. This indicates that the hybrid organic-inorganic double perovskite FA2BiCuI6 has the ability to replace hybrid organic-inorganic perovskite CH3NH3PbI3 to expand next-generation lead-free harmless materials for solar cell applications.

We report here biosynthesis of silver nanoparticles (AgNPs) using aqueous extracts of (i) Azadirachta indica leaves and (ii) Citrullus colocynthis fruit and their larvicidal activity against Aedes aegypti. The UV–Vis spectroscopy absorption peaks occurred in the range of 412–416 nm for A. indica AgNPs and 416–431 nm for C. colocynthis AgNPs indicating the silver nature of prepared colloidal samples. The scanning electron microscopy examination revealed the spherical morphology of both types of NPs with average size of 17 ± 4 nm (A. indica AgNPs) and 26 ± 5 nm (C. colocynthis AgNPs). The X-ray diffraction pattern confirmed the face-centred cubic (FCC) structure with crystallite size of 11 ± 1 nm (A. indica AgNPs) and 15 ± 1 nm (C. colocynthis AgNPs) while characteristic peaks appearing in Fourier transform infrared spectroscopy analysis indicated the attachment of different biomolecules on AgNPs. The larvicidal activity at different concentrations of synthesized AgNPs (1–20 mg l−1) and extracts (0.5–1.5%) against Aedes aegypti was examined for 24 h. A concentration-dependent larvicidal potential of both types of AgNPs was observed. The LC50 values were found to be 0.3 and 1.25 mg l−1 for C. colocynthis AgNPs and A. indica AgNPs, respectively. However, both extracts did not exhibit any notable larvicidal activity.

Controlled growth of nanostructures plays a vital role in tuning the physical and chemical properties of functional materials for advanced energy and memory storage devices. Herein, we synthesized hierarchical micro-sized flowers, built by the self-assembly of highly crystalline, two-dimensional nanoplates of Co- and Ni-doped BiFeO3, using a simple ethylene glycol-mediated solvothermal method. Pure BiFeO3 attained scattered one-dimensional nanorods-type morphology having diameter nearly 60 nm. Co-doping of Co and Ni at Fe-site in BiFeO3 does not destabilize the morphology; rather it generates three-dimensional floral patterns of self-assembled nanoplates. Unsaturated polarization loops obtained for BiFeO3 confirmed the leakage behaviour of these rhombohedrally distorted cubic perovskites. These loops were then used to determine the energy density of the BiFeO3 perovskites. Enhanced ferromagnetic behaviour with high coercivity and remanence was observed for these nanoplates. A detailed discussion about the origin of ferromagnetic behaviour based on Goodenough–Kanamori's rule is also a part of this paper. Impedance spectroscopy revealed a true Warburg capacitive behaviour of the synthesized nanoplates. High magneto-electric (ME) coefficient of 27 mV cm−1 Oe−1 at a bias field of −0.2 Oe was observed which confirmed the existence of ME coupling in these nanoplates.

These days, research in agriculture is focusing on the theme of sustainability along with protection of agriculture produce. Nanotechnology in the agriculture sector aims for the enhancement of agricultural produce and the reduction of pesticides through providing innovative agrochemical agents and their novel delivery mechanisms. The current investigation involved the green synthesis of silver nanoparticles (AgNPs) from the aqueous leaf extract of Melia azedarach by following a microwave-assisted method to control Fusarium oxysporum, the causal agent of tomato wilt. Biosynthesized Melia leaf extract (MLE)-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectrometry, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zeta potential analysis. The intensity of the peak at 434 nm in UV-vis spectra, attributed to the surface plasmon resonance of MLE-AgNPs, changes with reaction parameters. TEM exhibits spherical shaped nanoparticles with an average particle size range from 12 to 46 nm. Efficient inhibition of F. oxysporum, the causal agent of tomato wilt, was achieved after exposure to MLE-AgNPs both in vivo and in vitro. In vitro studies exhibited repressed fungal mycelial growth with 79–98% inhibition as compared to the control. Significant increases in growth parameters of tomato seedlings were observed after treatment with biosynthesized nanoparticles as compared to F. oxysporum-infected plants grown without them under greenhouse conditions. Furthermore, SEM imaging was done to reveal the prominent damage on the cell wall of hyphae and spores after MLE-AgNP treatment. Propidium iodide (PI) staining of mycelium indicated the extent of cell death, causing irretrievable damage and disintegration of cellular membranes by altering the membrane permeability. Also, 2′,7′-dichlorofluorescin diacetate (DCFH-DA) fluorescence specifies intracellular reactive oxygen species (ROS) production in F. oxysporum after treatment with MLE-AgNPs. The current investigation suggested that biosynthesized nanoparticles can revolutionize the field of plant pathology by introducing an environment-friendly approach for disease management and playing a potential part in agriculture industry. However, to date, little work has been done to integrate nanotechnology into phytopathology so, this area of research is in need of adoption and exploration for the management of plant diseases.

In-situ sol-gel procedure is used to synthesize the silica-titania nanocomposite (SiO2-TiO2) as host matrix which is doped with ZnO and heated at 300 °C for 1 h for homogeneous and stable matrix surface. The mixture of organic dyes i.e. cresol red, bromophenol blue, phenol red and phenolphthalein is encapsulated within ZnO:SiO2-TiO2 nanocomposite for the evaluation of sensing activity at dynamic pH range 1–12. Microscopic findings showed that the synthesized nanocomposites have homogeneous crack-free porous coating with low roughness value of 9.7–7.6 nm. XRD analysis shows the formation of new phase ZnSiO3 after ZnO doping and heat treatment along with anatase phase of titania and silica. TEM analysis confirmed the spherical nanoparticles. The heterogeneous bonding of synthesized Zn:SiO2-TiO2 composites is investigated by FTIR. Surface analysis confirmed that prepared nanocomposites have high surface area, large pore diameters and mesoporous nature, which is desirable for good sensing behavior. Optical studies show that low refractive index (1.33–1.39) transparent nanocomposites (92–62% transparency in the visible range) are promising for sensing applications. TGA analysis shows that SiO2-TiO2 nanocomposites after ZnO doping and heat treatment are thermally stable. The fast response 0.15 s of the ZnO:SiO2-TiO2 nanocomposite coated fiber optic sensor is optimized at pH 12. The observed sensitivity is of 15 counts/pH with repeatability of 93% at 440 nm. Keywords: Silica-titania nanocomposite, ZnO doping, Structural and optical properties, Fiber optic sensing

Al-doped NiZnO thin films were fabricated by dip coating and annealed at various temperatures (250–550 °C) and their properties were evaluated. With increasing annealing temperature, the Al contents in the thin films were continually increased, because of the rapid increase in the incorporation efficiency of the Al–O layer with respect to the NiZn–O layer. Polycrystalline nature of the thin films was confirmed by the X-ray diffraction technique. All films have a perfect wurtzite structure without any recordable variation in the ZnO lattice produced by replacing Zn with Ni and Al. The absorption edge shifted to a higher wavelength (red shift) with the increase of annealing temperature indicating that the shrinkage of the optical band gap was induced. The optical band gaps of thin films decreased from 3.5 to 2.5 eV. All films showed ferromagnetic behavior. The annealing process provided a reduced resistivity due to the improved crystal structure of films.

Magnetic cores loaded with metallic nanoparticles can be promising nano-carriers for successful drug delivery at infectious sites. We report fabrication, characteristic analysis and in vitro antibacterial performance of nanocomposites comprising cobalt cores (Co-cores) functionalized with a varied concentration of silver nanoparticles (AgNPs). A two-step polyol process synchronized with the transmetalation reduction method was used. Co-cores were synthesized with cobalt acetate, and decoration of AgNPs was carried out with silver acetate. The density of AgNPs was varied by changing the amount of silver content as 0.01, 0.1 and 0.2 g in the synthesis solution. Both AgNPs and Co-cores were spherical having a size range of 30–80 nm and 200 nm to more than 1 µm, respectively, as determined by scanning electron microscopy. The metallic nature and face-centred cubic crystalline phase of prepared nanocomposites were confirmed by X-ray diffraction. Biocompatibility analysis confirmed high cell viability of MCF7 at low concentrations of tested particles. The antibacterial performance of nanocomposites (Co@AgNPs) against Escherichia coli and Bacillus subtilis was found to be AgNPs density-dependent, and nanocomposites with the highest AgNPs density exhibited the maximum bactericidal efficacy. We therefore propose that Co@AgNPs as effective drug containers for various biomedical applications.

The fabrication, characterization, and CO2 gas detection performance of single component-based and hetero-nanostructure-based optical gas sensors are reported in the present work. Single component-based structures include (i) TiO2 thin films with varied film thickness (37.45 nm, 51.92 nm, and 99.55 nm) fabricated via the RF sputtering system for different deposition times and (ii) silver nanoparticles (AgNPs) deposited on the glass substrate by the wet chemical method. Hetero-nanostructures were achieved by decorating the AgNPs on the predeposited TiO2 thin films. The structural, morphological, and optical characteristics of prepared samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ellipsometry, respectively. XRD analysis of AgNPs confirmed the crystalline nature of prepared particles with average crystallite size of 21 nm, however, in the case of TiO2 films XRD results suggested amorphous structure of all as-deposited films. size 21 nm. The SEM micrographs confirmed the deposition of AgNPs on the TiO2 thin films. With increasing sputtering time, TiO2 films were found to be denser and more compact, indicating a reduced porosity and higher film thickness. CO2 gas-sensing properties were investigated by measuring the optical transmission spectra in alone air and in CO2 gaseous atmosphere at room temperature. It was observed that neither TiO2 thin films even with higher thickness nor alone AgNPs could demonstrate any substantial gas-sensing activity. Nevertheless, TiO2/AgNP hetero-nanostructured substrates exhibited excellent CO2 gas-sensing performance as indicated by a huge change in the transmission spectra. The enhanced sensing efficiency of TiO2/AgNP nanostructures owing to synergistic effects suggests a promising role of our manufactured sensors in practical applications.

The effect of laser irradiation with different numbers of laser shots on the microstructure, the surface, and the hardness of gun metal alloy was studied by a KrF pulsed excimer laser system, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and Vickers hardness test. The influence of 100−500 laser shots was irradiated on the surface hardness profile and on the microstructure of gunmetal alloy. XRD results showed the maximum 2θ shift, the maximum full width of half maximum FWHM, the maximum dislocation density, and the minimum crystallite size for the sample irradiated with 300 laser shots. The hardness was measured in three different regions at the laser irradiated spot, and it was found that maximum hardness was present at the heat affected zone for all samples. The hardness value of the un-irradiated sample of gun metal was 180, and the value increased up to 237 by raising the number of laser shots up to 300. The peak value of surface hardness of the laser treated sample was 32% higher than the un-irradiated sample. The Raman shift of the un-exposed sample was 605 cm−1 and shifted to a higher value of wave number at 635 cm−1 at 300 laser shots. The hardness value was decreased by further increasing the number of laser shots up to 500. The samples irradiated with 400 and 500 laser shots exhibited smaller hardness and dislocation defect density, which was assigned to possible annealing caused by irradiation.

In the present in vivo study, we provide a comparison of toxicological consequences induced by four different types of spherical nanoparticles (NPs)—silver nanoparticles (AgNPs, 40 ± 6 nm), nickel (NiNPs, 43 ± 6 nm), cobalt oxide (Co3O4NPs, 60 ± 6 nm), and chromium oxide (Cr3O4NPs, 50 ± 5 nm)—on freshwater fish Labeo rohita. Fish were exposed to NPs (25 mg/L) for 21 days. We observed a NPs type-dependent toxicity in fish. An altered behavior showing signs of stress and a substantial reduction in total leukocyte count was noticed in all NP-treated groups. A low total erythrocyte count in all NP-treated fish except for Co3O4NPs was discerned while a low survival rate in the case of Cr3O4NP-treated fish was observed. A significant decrease in growth and hemoglobin were noticed in NiNP- and Cr3O4NP-treated fish. A considerable total protein elevation was detected in NiNP-, Co3O4NP-, and Cr3O4NP-treated groups. An upgrading in albumin level was witnessed in Co3O4NP- and Cr3O4NP-treated groups while a high level of globulin was noted in NiNP- and Co3O4NP-exposed groups. In all NP-treated groups, a depleted activity of antioxidative enzymes and pathological lesions in liver and kidney were noticed.

The current study emphasizes the synthesis of iron oxide nanoparticles (IONPs) and impact of hydrophilic polymer polyvinyl alcohol (PVA) coating concentration as well as anticancer drug doxorubicin (DOX) loading on saturation magnetization for target drug delivery applications. Iron oxide nanoparticles particles were synthesized by a reformed version of the co-precipitation method. The coating of polyvinyl alcohol along with doxorubicin loading was carried out by the physical immobilization method. X-ray diffraction confirmed the magnetite (Fe3O4) structure of particles that remained unchanged before and after polyvinyl alcohol coating and drug loading. Microstructure and morphological analysis was carried out by transmission electron microscopy revealing the formation of nanoparticles with an average size of 10 nm with slight variation after coating and drug loading. Transmission electron microscopy, energy dispersive, and Fourier transform infrared spectra further confirmed the conjugation of polymer and doxorubicin with iron oxide nanoparticles. The room temperature superparamagnetic behavior of polymer-coated and drug-loaded magnetite nanoparticles were studied by vibrating sample magnetometer. The variation in saturation magnetization after coating evaluated that a sufficient amount of polyvinyl alcohol would be 3 wt. % regarding the externally controlled movement of IONPs in blood under the influence of applied magnetic field for in-vivo target drug delivery.

In this work MnxCo1−xFe2O4 nanoparticles (NPs) were synthesized using a chemical co-precipitation method. Phase purity and structural analyses of synthesized NPs were performed by X-ray diffractometer (XRD). Transmission electron microscopy (TEM) reveals the presence of highly crystalline and narrowly-dispersed NPs with average diameter of 14 nm. The Fourier transform infrared (FTIR) spectrum was measured in the range of 400–4000 cm−1 which confirmed the formation of vibrational frequency bands associated with the entire spinel structure. Temperature-dependent magnetic properties in anti-ferromagnet (AFM) and ferromagnet (FM) structure were investigated with the aid of a physical property measurement system (PPMS). It was observed that magnetic interactions between the AFM (Mn) and FM (CoFe2O4) material arise below the Neel temperature of the dopant. Furthermore, hysteresis response was clearly pronounced for the enhancement in magnetic parameters by varying temperature towards absolute zero. It is shown that magnetic properties have been tuned as a function of temperature and an externally-applied field.

Bimagnetic monodisperse CoFe2O4/Fe3O4 core/shell nanoparticles have been prepared by solution evaporation route. To demonstrate preferential coating of iron oxide onto the surface of ferrite nanoparticles X-ray diffraction (XRD), High resolution transmission electron microscope (HR-TEM) and Raman spectroscopy have been performed. XRD analysis using Rietveld refinement technique confirms single phase nanoparticles with average seed size of about 18 nm and thickness of shell is 3 nm, which corroborates with transmission electron microscopy (TEM) analysis. Low temperature magnetic hysteresis loops showed interesting behavior. We have observed large coercivity 15.8 kOe at T = 5 K, whereas maximum saturation magnetization (125 emu/g) is attained at T = 100 K for CoFe2O4/Fe3O4 core/shell nanoparticles. Saturation magnetization decreases due to structural distortions at the surface of shell below 100 K. Zero field cooled (ZFC) and Field cooled (FC) plots show that synthesized nanoparticles are ferromagnetic till room temperature and it has been noticed that core/shell sample possess high blocking temperature than Cobalt Ferrite. Results indicate that presence of iron oxide shell significantly increases magnetic parameters as compared to the simple cobalt ferrite.

Silver nanoparticles (AgNPs) of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC) and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP) was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM), UV-visible spectroscopy (UV-VIS), and X-ray diffraction (XRD) techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm. The characteristic surface plasmon resonance (SPR) peaks of different spherical silver colloids occurring in the wavelength range of 397 to 504 nm, whereas triangular particles showed two peaks, first at 392 nm and second at 789 nm as measured by UV-VIS. The XRD spectra of the prepared samples indicated the face-centered cubic crystalline structure of metallic AgNPs. The in vitro antibacterial properties of all synthesized AgNPs against two types of Gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli were examined by Kirby–Bauer disk diffusion susceptibility method. It was noticed that the smallest-sized spherical AgNPs demonstrated a better antibacterial activity against both bacterial strains as compared to the triangular and larger spherical shaped AgNPs.

Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV)-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM) analysis confirmed the size and X-ray diffractometry (XRD) analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria.