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This study successfully synthesized high-performance photodetectors based on Ag-WO3 core–shell heterostructures using a simple and economical two-step pulsed laser ablation in water method and has investigated the electrical characteristics of the Ag@WO3 nanocomposite heterojunction. The Hall effect tests indicate that the synthesized Ag@WO3 exhibits n-type conduction with a Hall mobility of 1.25 × 103 cm2V-1S-1. Dark current–voltage properties indicated that the created heterojunctions displayed rectification capabilities, with the highest rectification factor of around 1.71 seen at a 5 V bias. A photodetector's responsivity reveals the existence of two response peaks, which are situated in the ultraviolet and visible region. The photodetector demonstrates a rapid response time of less than 100 ms. The detectivity values for wavelengths of 350 nm and 490 nm were 35 × 1013 Jones and 28 × 1013 Jones, respectively. The n-Ag-WO3/n-Si photodetector achieved a maximum EQE of 11.5% in the ultraviolet wavelength when subjected to 3 V and illuminated with 350 nm (26 mW/cm2) light. The devices demonstrate rapid switching behavior with a rise time of 0.32 s and a fall time of 0.33 s. The time-dependent light response of a photodetector under illumination at 26 mW/cm2 is seen at a bias of 3 V. The light exhibits a rise and decay duration of 15 s, while the photocurrent gain is measured at 9µA. The photocurrent of devices exhibited a positive correlation with the incoming light intensity, suggesting that the junction has the potential to function as a photo detector. [ABSTRACT FROM AUTHOR]

We introduce the pulsed laser ablation in liquid (PLAL) approach in this study to synthesize tungsten oxide nanoparticles suspended in double die ionized water (DDIW). Several laser fluences of a Nd:YAG laser's second harmonic (532 nm) were used for the ablation at 109, 129, 149, 169, and 189 J/cm2, respectively. X-ray pattern showed polycrystalline structure with preferred orientation at (220) plane corresponding to 58.7° diffraction angle. The optical bandgap energy was found to increase as the laser fluence increases from 2.83 to 3.21 eV, with the increase in the laser fluence up to 189 J/cm2, respectively. The calculated optical bandgaps and the results from photoluminescence are in very good agreement. This work shows that there is a laser fluence threshold beyond which the Brus equation does not take place; this means at a specific laser fluence the energy gap of the prepared nanomaterial increases with laser fluence instead of decreasing as known in all published articles. [ABSTRACT FROM AUTHOR]

In this study, silver-tungsten oxide core–shell nanoparticles (Ag–WO3 NPs) were synthesized by pulsed laser ablation in liquid employing a (1.06 µm) Q-switched Nd:YAG laser, at different Ag colloidal concentration environment (different core concentration). The produced Ag–WO3 core–shell NPs were subjected to characterization using UV–visible spectrophotometry, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive spectroscopy, electrical analysis, and photoluminescence PL. The UV–visible spectra exhibited distinct absorption peaks at around 200 and 405 nm, which attributed to the occurrence of surface Plasmon resonance of Ag NPs and WO3 NPs, respectively. The absorbance values of the Ag–WO3 core–shell NPs increased as the core concentrations rose, while the band gap decreased by 2.73–2.5 eV, The (PL) results exhibited prominent peaks with a central wavelength of 456, 458, 458, 464, and 466 nm. Additionally, the PL intensity of the Ag–WO3-NP samples increased proportionally with the concentration of the core. Furthermore, the redshift seen at the peak of the PL emission band may be attributed to the quantum confinement effect. EDX analysis can verify the creation process of the Ag–WO3 core–shell nanostructure. XRD analysis confirms the presence of Ag and WO3 (NPs). The TEM images provided a good visualization of the core-spherical shell structure of the Ag–WO3 core–shell NPs. The average size of the particles ranged from 30.5 to 89 (nm). The electrical characteristics showed an increase in electrical conductivity from (5.89 × 10−4) (Ω cm)−1 to (9.91 × 10−4) (Ω cm)−1, with a drop in average activation energy values of (0.155 eV) and (0.084 eV) at a concentration of 1.6 μg/mL of silver. [ABSTRACT FROM AUTHOR]

We have investigated the impact of laser pulse wavelength on the quantity of ablated materials. Specifically, this study investigated the structural, optical, and morphological characteristics of tungsten trioxide (WO3) nanoparticles (NPs) that were synthesized using the technique of pulsed-laser ablation of a tungsten plate. A DD drop of water was used as the ablation environment at a fixed fluence at 76.43 J/cm2 and pulse number was 400 pulses of the laser. The first and second harmonic generation ablations were carried out, corresponding to wavelengths of 1064 and 532 nm, respectively. The Q-switched Nd: YAG laser operates at a repetition rate of 1 Hz and has a pulse width of roughly 15 ns. These parameters are applicable to both wavelengths and are maintained at room temperature. Results of the absorption spectra demonstrated that the quantity of material ablated is inversely proportional to the laser pulses' wavelength. FESEM and TEM images show that WO3-NPs, which were prepared by both samples, were spherical. They also show that the wavelength of laser pulses caused an increase in the particle size of NPs. The X-ray diffraction analysis revealed a polycrystalline structure with a preferential orientation along the (220) plane, which corresponded to a diffraction angle of 58.84°. The energy of the optical bandgap of WO3-NPs increases with a decrease in the wavelength of laser pulses, which is calculated to be 3.4 and 3.42 eV for 1064nm and 532 nm wavelengths, respectively. The photoluminescence result agrees well with the estimated optical band gaps. [ABSTRACT FROM AUTHOR]

Annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to improve their crystalline structure and other important properties. This work presents the effect of post heat treatment on optical, structural, morphological, and surface roughness of Nb2O5 thin films at different temperatures (200-700oC) which to the best of our knowledge not been extensively studied yet. A clear modification in surface morphology and other studied properties was obtained. XRD results show a significant enhancement in the film's structural properties such as a reduction in the dislocation densities and stress. The optical properties of the treated films show a clear decrease in the transmission and energy gap values which their values were found to reduce from (4.35 to 2.9) eV with heat treatment up to 600oC and re-increase at 700oC. The surface roughness was also enhanced as a result of increasing the grain size from (9.95 - 34.7) nm Finally, SEM images of the films show an obvious change in their morphology and an increase in film uniformity as a result of heat treatment. Therefore, heat treatment could be considered as a helpful method to control film characteristics. Main result should be presented quantitatively. [ABSTRACT FROM AUTHOR]

Researchers previously focused on tungsten trioxide (WO3) modified with noble metals. Different methods were used for syntheses such as pulsed laser deposition, co-sputtering metallic, colloidal chemical method, one-pot method, sol-gel, and hydrothermal methods. The photo-catalytic performance and sensing properties of WO3 were extremely enhanced. This review aimed to examine the increasing significance of WO3 based on previous studies and possible future outlook. [ABSTRACT FROM AUTHOR]

This work presents the effect of NH4OH molarities on the electrical characteristics of Nb2O5 films prepared using the precipitation method. Hall Effect measurements proved the formation of n-type Nb2O5 films. The carrier concentration was found to increase with ammonium hydroxide molarities up to 12mol/L, while the carrier mobility decreased. Resistivity-temperature measurements confirm the semiconductor behaviors of the thin films. It also shows a decrease in the resistivity and activation energy with molarity increasing reaching its minimum value in 12 mol/L then they increased again. [ABSTRACT FROM AUTHOR]

Al2O3 nanoparticles were created using laser ablation of an aluminum (Al) target in deionized water. The ablation process was carried out using three different laser fluences (12.7, 15.9, and 19.1 J/cm2). In this method, a 1064-nm Q-switched Nd:YAG laser with a 7-ns pulse width, 1-Hz repetition rate, and 100 pulses was used. The UV-visible absorption spectrum of the as-synthesized Al2O3 colloidal solution of nanoparticles showed an absorption maximum lying at 210 nm, which verified the presence of Al2O3 nanoparticles in deionized water. The bandgap of Al2O3 NPs decreased from 4.6 to 4.2 eV with the increased laser fluences. The fingerprint identification of Al2O3 colloidal nanoparticles was performed through FTIR spectroscopy analysis. The spectrum recorded several important stretch modes, including carbon, hydrogen, oxygen, and Al2O3 bands. Field emission scanning electron microscopy (SEM) was used to examine the morphology of Al2O3 nanoparticles produced at various laser fluences. It exposed the highly aggregated particles, which ranged in size from 91 nm to sub-micrometers. TEM images and size distribution of Al2O3 NPs showed that the partials size depended on laser fluence intensity. It showed that the majority of the nanoparticles produced by all of the ablated laser fluences have spherical shapes, with average particle sizes of 57, 70, and 117 nm at 12.7-, 15.9-, and 19.1-J/cm2 laser fluences, respectively. The effect of laser fluence on the photosensitivity of the Si detector based on the nanostructured Al2O3 film was studied. The photodetector showed strong responsiveness peaks at 350 and 800 nm, with values of about 1.2 AW−1 and 1.08 AW−1 corresponding to the responsiveness of the Al2O3 film and the Si substrate, respectively. It also displayed a high photo-detective value in the UV-Vis region. Therefore, nanosecond laser ablation in liquid is an efficient and adaptable approach for producing nanoparticles with customized size, shape, and properties. It is also a wonderful way to manufacture a variety of nanostructured materials that have applications in a variety of industries. [ABSTRACT FROM AUTHOR]

In the present work, Li MO2 (Li CoO2, Li NiO2, LiMnO2, or LiFeO2) metal oxides of the transition lithium layers were modified to serve as cathode materials for lithium-ion batteries, usually prepared by combustion reaction for better electrochemical efficiency. Li: Co: Ni: Fe: O2 (LCNFO) powder was first prepared in a weight percentages mixture of 1:0.5:0.45:0.5:1 with citric acid as fuel, and de-ionized water DIW as a binding material, and then mixed with nitrate of lithium ion (Li+) and a Fe+3 to obtain a regular blend. With some addition of citric acid and de-ionized water, a powder was obtained, which then heated up to 900 °C for 8 h. Several investigations were carried out to examine the powder properties in order to adopt it for thermal and thermo-gravimetric analysis applications. The microstructure of the powder was investigated using X-ray diffraction (XRD) analysis. A well-selected annealing temperature can produce a pure single-phase LCNFO material with good electrochemical behavior. The particle size of the LCNFO material had been approximately measured from the XRD outcome, utilizing Scherer formula. The electrochemical properties of the LCNFO layers were studied, and surface topography of LCNFO powder was examined utilizing Atomic force microscopy AFM. The results show an enhancement in the properties of the LCNFO cathode material prepared by a combustion reaction in the air, which has a larger storage capacity, and thus, it considers a promising alternative to other LiCoO2, LiNiO2, and LiMnO2 cathode materials. This preparation method is simple and effective to produce such nanostructures layers with high quality and cost-effectiveness for portable batteries application. [ABSTRACT FROM AUTHOR]

This work presents the deposition of Nb2O5 on p and n type silicon substrate. Nb2O5 thin film was deposited using precipitation method for solution preparation, and employing spin coating technique for film deposition, where optimum preparation condition were achieved in our previous published article. The electrical characteristic shows a good rectification ratio of about 46.7 for the Nb2O5/p-Si junction and 4.9 for Nb2O5/n-Si. The estimated ideality factors of n- and p-type Si found to be 5.17 and 3.84 respectively. The maximum detectivity was obtained using P-Si substrate and found to be about 6.2 × 1012 cm Hz1/2 W−1. [ABSTRACT FROM AUTHOR]

Laser ablation in liquid (LAL) in recent years has emerged as a promising approach for the synthesis of industrial and functional nanomaterials. In this study, LAL was used to synthesize Au@WO3 core–shell nanoparticles under various preparation conditions without the use of a catalyst. The optical characteristics of the resulting colloid confirmed the formation of a core–shell system, evident from the distinct absorption peaks observed in both the UV and visible regions. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm the presence of Au and WO3. This study aimed to achieve an eco-friendly synthesis of Au@WO3 core–shell nanoparticles and investigate their potential biomedical applications, including anticancer and antibacterial activity against human pathogens. Various assays were employed to assess their effectiveness, including well diffusion assay, MTT assay, LDH assay, ROS generation, and apoptosis assay. The results demonstrated that the Au@WO3 core–shell nanoparticles exhibit significant anti-proliferative activity against ovarian cancer cells (SKOV-3) via induce apoptotic cell death through ROS generation, and mitochondrial damage. Additionally, these nanoparticles showed inhibition of multidrug-resistant human pathogen bacteria, such as S. aureus and E. coli through inhibiting biofilm formation. Based on these findings, Au@WO3 core–shell nanoparticles show considerable promise as therapeutic agents for biomedical applications. [ABSTRACT FROM AUTHOR]