Increasing Precursor Concentration Research Articles

Carya Illinoinensis-mediated Green Synthesis and Antimicrobial Screening of Zirconium Oxide Nanoparticles: The Promising Antimicrobial Agent

Background: The synthesis of metal-based nanoparticles through conventional methods involves harsh conditions, high costs, and severe environmental threats. To overcome these issues, researchers are nowadays focusing on eco-friendly and low-cost methods for the synthesis of nanoparticles. Finally, several plant-mediated synthesis techniques have been developed, which have various advantages, such as low-cost, environmentally friendly, and easy application. The plant extract not only serves as a reducing agent but also plays a role as a stabilizing agent. The plantmediated synthesis provides new opportunities for cost-effective, environmentally-friendly nanoparticle synthesis with high dispersity and stability. Besides, bio-generated nanoparticles derived from plant extract have promising pharmacological applications, making them potential candidates for future medicines. Aims and Objectives: The current study aimed to synthesize zirconium oxide nanoparticles using Carya illinoinensis extract and examine their physicochemical properties. Additionally, the antimicrobial efficacy of these nanoparticles was evaluated against various pathogens, exploring their potential as potent antimicrobial agents. Method: The synthesized nanoparticles were analyzed and characterized by various techniques like UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive X-ray spectroscopy (EDX). The UV-visible peak at 216 nm confirmed the formation of ZrO2 nanoparticles. The SEM images clearly showed that nanoparticles were spherical and relatively dispersed, with few agglomerations. The EDX spectra confirmed the existence of zirconium and oxygen as the basic constituents of the sample. TEM images demonstrated nanoparticles as spherical and uniformly dispersed but agglomerated with increasing precursor concentrations and decreasing nanoparticle dispersion. Fluconazole and gentamicin were used as standards in determining the antibacterial and antifungal activities of nanoparticles. Results: Considering the antifungal activity, a maximum zone of inhibition of 16 μg/ml was demonstrated in the case of 2 mM as compared to 4 mM and 6 mM concentrations. The Carya illinoinensismediated ZrO2 nanoparticles were screened against Gram-positive (S. aureus and P. aeruginosa) and Gram-negative (S. typhi and E. coli) bacterial strains. The fabricated nanoparticles exhibited promising action against all microorganisms. Conclusion: In the current study, zirconium oxide nanoparticles were synthesized by using Carya illinoinensis leaves extract as a reducing agent. The antifungal and antibacterial potential of the synthesized nanoparticles were evaluated. The green synthesis method used in this study is preferable to the others as it is more affordable, environmentally benign, and widely accessible.

One-Dimensional ZnO Nanorod Array Grown on Ag Nanowire Mesh/ZnO Composite Seed Layer for H2 Gas Sensing and UV Detection Applications.

Photodetectors and gas sensors are vital in modern technology, spanning from environmental monitoring to biomedical diagnostics. This paper explores the UV detection and gas sensing properties of a zinc oxide (ZnO) nanorod array (ZNA) grown on silver nanowire mesh (AgNM) using a hydrothermal method. We examined the impact of different zinc acetate precursor concentrations on their properties. Results show the AgNM forms a network with high transparency (79%) and low sheet resistance (7.23 Ω/□). A sol-gel ZnO thin film was coated on this mesh, providing a seed layer with a hexagonal wurtzite structure. Increasing the precursor concentration alters the diameter, length, and area density of ZNAs, affecting their performance. The ZNA-AgNM-based photodetector shows enhanced dark current and photocurrent with increasing precursor concentration, achieving a maximum photoresponsivity of 114 A/W at 374 nm and a detectivity of 6.37 × 1014 Jones at 0.05 M zinc acetate. For gas sensing, the resistance of ZNA-AgNM-based sensors decreases with temperature, with the best hydrogen response (2.71) at 300 °C and 0.04 M precursor concentration. These findings highlight the potential of ZNA-AgNM for high-performance UV photodetectors and hydrogen gas sensors, offering an alternative way for the development of future sensing devices with enhanced performance and functionality.

Free cortisol and free 21-deoxycortisol in the clinical evaluation of congenital adrenal hyperplasia.

Some patients with classic congenital adrenal hyperplasia (CAH) survive without glucocorticoid treatment. Increased precursor concentrations in these patients might lead to higher free (biological active) cortisol concentrations by influencing the cortisol-protein binding. In 21-hydroxylase deficiency (21OHD), the most common CAH form, accumulated 21-deoxycortisol (21DF) may further increase glucocorticoid activity. Both mechanisms could explain the low occurrence of symptoms in some untreated classic CAH patients. Develop and validate an LC-MS/MS method for free cortisol and free 21DF to quantify these steroids in untreated patients with classic CAH (n=29), non-classic CAH (NCCAH, n=5), other forms of adrenal insufficiency (AI, n=3), and controls (n=11) before and 60 minutes after Synacthen® administration. Unstimulated total cortisol concentrations of untreated classic CAH patients (median 109 nmol/L) were lower than in untreated NCCAH patients (249 nmol/L, p=0.010) and controls (202 nmol/L, p=0.016), but free cortisol concentrations were similar. Basal free 21DF concentrations were high in 21OHD patients (median 5.32 nmol/L) and undetectable in AI patients and controls (<0.19 nmol/L). After Synacthen® administration, free 21DF concentrations increased in 21OHD patients, while free cortisol concentrations did not change. Free cortisol concentrations in classic CAH patients were similar to those in controls and NCCAH patients, indicating comparable cortisol availability. Additionally, 21OHD patients produce high concentrations of 21DF, possibly explaining the low occurrence of symptoms in some classic 21OHD patients. Free cortisol and 21DF levels should be considered in evaluating adrenal insufficiency in patients with CAH.

Raman Study of Novel Nanostructured WO3 Thin Films Grown by Spray Deposition.

The present communication reports on the effect of the sprayed solution volume variation (as a thickness variation element) on the detailed Raman spectroscopy for WO3 thin films with different thicknesses grown from precursor solutions with two different concentrations. Walls-like structured monoclinic WO3 thin films were obtained by the spray deposition method for further integration in gas sensors. A detailed analysis of the two series of samples shows that the increase in thickness strongly affects the films' morphology, while their crystalline structure is only slightly affected. The Raman analysis contributes to refining the structural feature clarifications. It was observed that, for 0.05 M precursor concentration series, thinner films (lower volume) show less intense peaks, indicating more defects and lower crystallinity, while thicker films (higher volume) exhibit sharper and more intense peaks, suggesting improved crystallinity and structural order. For higher precursor concentration 0.1 M series, films at higher precursor concentrations show overall more intense and sharper peaks across all thicknesses, indicating higher crystallinity and fewer defects. Differences in peak intensity and presence reflect variations in film morphology and structural properties due to increased precursor concentration. Further studies are ongoing.

Photoelectrochemical properties of self-powered corundum-structured Ga2O3 nanorod array/fluorine-doped SnO2 photodetectors modulated by precursor concentrations

Herein, corundum-structured Ga2O3 (α-Ga2O3) nanorod array/fluorine-doped SnO2 (FTO) structures have been fabricated by hydrothermal and thermal annealing processes with different precursor concentrations from 0.01 to 0.06 M. The diameter and length of the nanorod arrays are much larger with increasing precursor concentrations due to more nucleation sites and precursor ions participating in the reaction procedures. The optical bandgap decreases from 4.75 to 4.47 eV because of the tensile stress relieving with increasing the precursor concentrations. Based on self-powered photoelectrochemical (PEC) photodetectors, the peak responsivity is improved from ∼0.33 mA W−1 for 0.06 M to ∼1.51 mA W−1 for 0.02 M. Schottky junctions can be formed in PEC cells. More photogenerated carriers can be produced in wider depletion region. From Mott–Schottky plots, the depletion regions become much wider with decreasing the precursor concentrations. Therefore, the enhance responsivity is owing to the wider depletion regions. Due to the reduced possibility of photogenerated holes captured by traps ascribed from fewer green and yellow luminescence defects, smaller charge transfer resistance, and shorter transportation route, the decay time becomes much faster through decreasing the precursor concentrations. Compared with the other self-powered α-Ga2O3-nanorod-array-based PEC photodetectors, it shows the fastest response time (decay time of 0.005 s/0.026 s) simply modulated by precursor concentrations for the first time without employing complex precursors, seed layers or special device designs. Compared with other high-responsivity monoclinic Ga2O3 (β-Ga2O3) self-powered photodetectors, our devices also show comparable response speed with simple control and design. This work provides the realization of fast-speed self-powered Ga2O3 based solar-blind ultraviolet photodetectors by simple modulation processes and design, which is a significant guidance for their applications in warnings, imaging, computing, communication and logic circuit, in the future.

Effect of molar concentration on optoelectronic properties of NiO nanoparticles for p-n junction diode application

In this work, fine nickel oxide nanoparticles (NiO NPs) were successfully made utilizing a straightforward co-precipitation approach at low temperature. The effects of precursor concentration on the structural, optical, and electrical characteristics of NiO nanoparticles were investigated. All indexed diffraction peaks in XRD demonstrate the production of NiO with cubic structure. An increase in NiO crystallite size above 16.8 nm was observed when the precursor concentration exceeds 2 M, suggesting the presence of nanostructure in the final product. In FT-Raman spectra, the band centered at ∼ 500 cm–1 is due to Ni-O stretching (LO) mode, and two-magnon (2 M) scattering mode causes the band at 1514 cm–1. The synthesized product is composed of almost rod-shaped particles with a size range of 10–20 nm, according to FESEM pictures. The UV absorption studies showed a high absorption at the fundamental absorption edges originating at 332 nm, which gradually shifted to a lower energy region up to 400 nm with increasing precursor concentration, which means a reduction in bandgap values. The effect of precursor concentration associated with the electrical characteristics of the produced NiO nanoparticles has been investigated for the temperature range 30 to 130 °C. The I-V characterization was used to compute the different photo-diode parameters including n, ФB, Io, PS, R, QE, and D* . The remarkable high photosensitivity of 1100% and specific detectivity of 4.324 × 10−10 Jones for the diode evaluated at 120 mW/cm2 was observed in a 2 M fabricated diode. These findings imply that all the fabricated diodes are exceptionally light-sensitive and are well-suited for upcoming UV photodetector applications.

Optimization of Reaction Parameters during the Synthesis of Hexagonal Hexadecylamine Capped ZnS Nanoparticles

Zinc sulphide nanoparticles capped with hexadecylamine (ZnS-HDA) have been synthesized through thermal decomposition of (Z)-2- (pyrrolidin-2-ylidene)thiourea zinc(II) complex. The effects of temperature, time and concentration of the precursor on the properties of ZnS-HDA capped nanoparticles were investigated. The values of the optical band edges were increasing when the temperature, reaction tim and the amount of the precursor were elevated. X-ray diffraction patterns of all the synthesized nanoparticles mainly exhibited hexagonal phase structures. The morphologies of the particles were increasing with the increase in temperature, time and precursor concentration.

Rational Design of the Electronic Structure of CdS Nanopowders.

In this study, various techniques, such as energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and spectrophotometry, were used to analyze the properties of nanometric CdS particles synthesized with varying precursor concentrations. EDX analysis revealed the nonstoichiometric composition manifested by an increase in the Cd/S ratio from 1.02 up to 1.43 with increasing precursor concentration. The growth of lattice parameters and unit cell volume accompanying preferential crystallization of the hexagonal phase along with an increasing Cd/S ratio was confirmed by XRD analysis. This indicated the presence of interstitial cadmium in nonstoichiometric Cd1+xS. The formation of shallow Cdi donor levels below the bottom edge of the conduction band impacts the bang-gap energy; a decrease from 2.56 to 2.21 eV along with increasing nonstoichiometry was observed. This is accompanied by a widening of the range of absorption of light, which creates conditions that can lead to an increase in the efficiency of redox reactions in photochemical processes.

Formation mechanism, precursor sensitivity and control strategies of summertime ozone on the Fenwei Plain, China

As one of the most polluted regions in China, the Fenwei Plain has suffered severe summertime ozone (O3) pollution in recent years. However, related studies in this region are still scarce. In this study, a comprehensive observation campaign was conducted in a typical city on the Fenwei Plain. An observation-based model (OBM) was used to investigate the summer O3 formation mechanism, precursor sensitivity and control strategies during O3-polluted and clean periods. Our results showed that O3 pollution was accompanied by increased O3 precursor concentrations (∼15% higher) and unfavorable meteorological conditions. In situ O3 production played a dominant role in the daytime O3 concentration increment in both polluted (+6.0 ppbv/h) and clean (+3.5 ppbv/h) periods. HO2 + NO (65.9%–66.7%) was the most dominant pathway of daytime O3 formation, and OH + NO2 (41.3%–63.1%) was the most dominant pathway of O3 destruction. Regional transport has a certain contribution to the occurrence of polluted days, as well as a diluting effect on clean days. Regional transport had a certain contribution effect on polluted days and a dilution effect on clean days. The southeastern regions were potential source regions of high O3, and the northwestern regions were potential source regions of low O3. When pollution occurred, the O3 formation control regimes transformed from a volatile organic compound (VOC)-limited regime to a transition regime, corresponding to an increase in precursor concentrations and stronger local O3 production. A 30% reduction in VOCs and a 20% reduction in NOx (VOCs/NOx ≈ 1.5) were determined to be the optimal control strategies to achieve the O3 control target (82 ppbv) in summer. VOC reductions should target reactive and O3-sensitive species (Oxygened VOCs, alkenes, aromatics) to effectively alleviate O3 pollution. This study could provide scientific support for local O3 pollution control on the Fenwei Plain.

Hydrodynamic radius dictates sensitivity of x-ray detectors based on the radiomicrofluidic synthesis of colloidal silver

A radiolytic synthesis of silver nanoparticles was carried out in combination with a microfluidic method to produce liquid radiation detectors. The detector response was analyzed by correlating the absorbed dose with the dispersion’s absorbance and with the hydrodynamic radius (HR). Samples were irradiated with x-rays of varying beam energies and dose rates and the data were discussed to elucidate how nucleation and growth processes are affected by the radiation quantities. Results reveal that HR does not change with the absorbed dose, but can be well controlled by varying the precursors concentration, beam energy, and dose rate. Increased precursor concentrations or dose rates favor nucleation, leading to the formation of smaller HR particles and increased detector sensitivity. Upon increasing the x-ray energy, growth is favored, leading to larger HR and decreased detector sensitivity. It is shown that HR and detector sensitivity are strongly correlated so that HR dictates detection sensitivity: the smaller the HR, the higher the sensitivity. Therefore, the dependence of the HR on the dose rate and on the x-ray energy establishes a new method for the controlled growth of colloidal silver, besides opening new possibilities for ionizing radiation detection.

Precursor concentration-dependent structural, optical and electrical properties of titanium dioxide nanostructures

Titanium dioxide (TiO2) is a widely used material in many industries due to its unique properties, such as high refractive index, high chemical stability, and excellent photocatalytic as well as antimicrobial activity. The anatase phase of TiO2 is particularly important because it exhibits the highest photocatalytic activity among all TiO2 phases. The anatase phase TiO2 nanostructures are synthesized by the Sol-Gel route at a fixed calcination temperature of 600 °C and varying precursor concentrations i.e. the number of moles of TTIP and its influence on the structural, optical and electrical properties is investigated. The most prominent peak in XRD spectra is (101) which corresponds to anatase TiO2 with average crystallite size ranging from 20 nm to 37 nm at a TTIP concentration varying from 6.75 mmol to 16.9 mmol. With the increase of precursor concentration, the dislocation density decreases gradually. The SEM micrograph reveals the formation of nanosheets at lower concentrations and both nanosheets and nanoparticles at higher concentrations. From the UV–visible spectroscopy and four probe resistivity measurements, the energy band gaps and resistivity of the nanostructures are found to decrease with the increase of concentration. For making the theoretical prediction of our experimental results, the DFT was employed to simulate and calculate the structural and electronic properties of the synthesized materials which revealed the indirect band-gap of 1.94 eV for the anatase phase. The XRD spectra generated from the simulated anatase phase also matched the experimental XRD data.

Preparation of Cu2O/Au Composite Nanomaterials for Effective Reduction of 4‐Nitrophenol

AbstractThe conversion of nitroaromatics to aminobenzene plays an important role in the synthesis of medicines or fine chemicals. In this work, we successfully prepared Cu2O/Au nanocubes with different Au content for the reduction of 4‐nitrophenol. With the increase of gold precursor concentration or reaction time, the density of Au nanoparticles (NPs)on Cu2O surface increases, which results in the stronger electron transfer between Au and Cu2O, and thus the better synergistic catalytic performance of Cu2O/Au nanoparticles toward 4‐Nitrophenol (4‐NP). In this work, we found the Au component in the nanoparticles played an important role in charge redistribution and transfer, as well as the adsorption and reduction of 4‐NP. Therefore, the degradation performance of Cu2O/Au composite is better than that of pure Cu2O, and the degradation rate of 4‐NP can reach almost 90 % in 10 min, therefore providing a new idea for the rational design of effective nanocatalysts.

Effect of precursor concentration on stoichiometry and optical properties of spray pyrolyzed nanostructured NiO thin films

In this study, spray pyrolysis was used to produce nanostructured NiO thin films from high purity nickel acetate (Ni(CH3COO)2.3H2O) precursors on pre-heated ultrasonically cleaned soda-lime glass substrates. The metallic constituent concentrations in the films were varied, and the precursors were produced in distilled water at various molarities ranging from 0.1 to 0.4 M. In the study, the field-emission scanning electron microscope (FESEM) results strongly confirmed adherence of the films to the glass substrate at 350 °C. The presence of Ni and O in the samples was confirmed using Rutherford backscattering spectroscopy (RBS), X-ray diffractometry (XRD) and energy dispersive X-ray spectroscopy (EDX). For the 0.1 M NiO thin films, the thickness was approximately 43 nm, and for the 0.2 M, 0.3 M, and 0.4 M films, the thickness was 46 nm, 47 nm, and 49 nm, respectively. The XRD findings were supported by the increased Raman intensity peaks with increased precursor concentration, which confirmed the films' improved crystallinity. For the same number of passes of films deposition, as the molar concentration increases, the films thickness increases. The amount of nickel in NiO thin films increases as the molarity increases, but the amount of oxygen in NiO thin films decreases as the molarity increases. It was discovered that as molarity increases, the optical transmittance decreases and the optical band gap narrows. The qualities of NiO discovered in this study suggest the films’ potentials for usage as window layer and buffer material in thin film solar cells.

Tuning Growth of ZnO Nano-Arrays by the Dewetting of Gel Layer

The classical two-step sol-gel hydrothermal method enables the growth of nanoarrays on various substrates via a seed layer. The morphology of the nanoarrays is often tuned by changing the composition ratio of the seed solution. It is taken for granted that the number density and size of seeds will increase with the proportion of precursors. However, in this work, we found novel two-stage dependencies between the concentration of the precursor (ZnAC) and the geometric parameters (number density and diameter) of ZnO seed particles. The completely opposite dependencies illustrate the existence of two different mechanisms. Especially when the proportion of precursors is low (ϕZnAC:ϕPVA&lt;0.22), the seed number density and diameter decrease with the increasing precursor concentration. This counterintuitive phenomenon should be caused by the destabilization and dewetting process of the thin film layers during annealing. Based on this new mechanism, we demonstrate the tuning growth of the ZnO seed layer and the nanowire array by annealing time. The number density of the nanorod array can be changed by 10 times, and the diameter of the nanorods can be changed by more than 8 times. The new mechanism we proposed can not only help people deepen their understanding of the formation and evolution of the seed layer but also provide a new way for the controllable growth of nanomaterials.

Numerical analysis on burning and particle formation of a single ethanol-based droplet in flame spray pyrolysis

Ethanol is a common inexpensive solvent for industrial flame spray pyrolysis. This work presents a numerical study of a single ethanol-based droplet burning with different precursor concentrations under both dry and wet air conditions. The evaporation and decomposition of precursors, the deposition of water vapor and its diffusion and transport in the liquid phase are considered. The micro-explosion behavior and droplet burning constant were well predicted as compared to existing experimental data in literature. The results show that surface condensation, dissolution, and re-evaporation of water were controlled by the disparity of mass transfer and evaporation priorities of different components in the droplet at different temperatures. Water in the ethanol droplet increases first during the initial burning stage and then decreases with increasing temperature as water preferentially vaporized than the formed less-volatile viscous layer on the droplet surface during the droplet combustion. The ratio of particle synthesis through evaporation and thermal decomposition decreases with increasing precursor concentration. It is further identified that the presence of water from either combustion products or humid air suppresses evaporation of the precursors in ethanol droplets because water dissolved in droplets evaporates preferably than the precursor, thereby potentially inhibiting the gas-to-particle route and providing another potential option for the control of flame synthesis process.

Structural, morphological and optical attributes of ZnO thin films deposited via spray pyrolysis process: Impact of molarity variation

Undoped thin films of ZnO were prepared over glass substrates using a simple chemical spray pyrolysis process. The solution of aqueous ‘Zinc acetate dehydrate’ was used as precursor and sprayed over preheated glass substrate at 400 °C. The concentration of solution changed from 0.2M to 1 M with the step of 0.2 and its impact on structural, morphological and optical properties has been studied with the help of XRD, SEM, UV-Vis Spectroscopy and four-probe technique. The films are polycrystallines, have a hexagonal wurtzite structures, and have a preferred orientation in the (002) plane. SEM analysis indicates the dependency of film morphology on precursor concentration. Optical Transmittance decreases with increasing precursor concentration. Maximum optical transmittance reaches up to 51% with film obtained from 0.2M concentration. Decreasing band gap values from 3.18 eV to 3.04 eV are noted as carrier concentration increases with precursor concentration.

Starch-capped silver oxide (Ag2O) nanoparticles: synthesis, characterization and antibacterial activity

Silver oxide nanoparticles were synthesized at room temperature using a green synthetic method and water as a solvent. Starch was used as a capping and reducing agent because it is cheap, non-toxic and environmentally friendly. The effect of precursor and capping agent concentrations were investigated. The nanoparticles have been characterized using spectroscopic and morphological techniques. The spectrum of Ag2O nanoparticles showed the maximum absorbance range at 350-366 nm. TEM analysis showed a size particle range of 2-14 nm. The increase in precursor concentration showed an increase in particle size while increasing the capping agent concentration resulting in reduced particle size. Increased capping concentration also resulted in the change to nanofibers. The nanoparticles showed antibacterial activities against both Staphylococcus aureus and Escherichia coli strains. The 2:1 Ag2O ratio showed the best activity towards both strains, 15 ± 0.19 and 14 ± 0.11 mm diameter, respectively.

Effect of Optimized Precursor Concentration, Temperature, and Doping on Optical Properties of ZnO Nanoparticles Synthesized via a Green Route Using Bush Tea (Athrixia phylicoides DC.) Leaf Extracts.

Nanoparticles possess several properties, such as antimicrobial, anti-inflammatory, wound healing, catalytic, magnetic, optical, and electronic properties, that have allowed them to be used in different fields. Among them, zinc oxide (ZnO) has received copious consideration due to its technological and medicinal applications. Plant-mediated synthesis of ZnO nanoparticles has provided a cost-effective and eco-friendly method. Therefore, the objective of the study is to assess the effect of the precursor concentration and silver and cerium doping on the optical properties of ZnO nanoparticles synthesized via a green process using bush tea leaf extract as the chelating agent. Zinc nitrate hexahydrate was used as the precursor. Quasi-spherical-shaped ZnO nanoparticles were obtained with an average crystallite size ranging between 24.53 and 63.02 nm. The crystallite size was found to decrease with the increase of precursor concentration at 43.82 nm (0.05 g), 37.25 nm (0.10 g), 26.53 nm (0.50 g), and 24.53 nm (1 g); thereafter, the size increases with an increase in precursor concentration. The optimum precursor concentration was 1 g with the smallest grain size and a high purity level. The increase in annealing temperature induced an increase in the crystallite size of ZnO nanoparticles from 24.53 nm (600 °C) to 34.24 nm (800 °C), however, increasing the level of purity of the nanopowders. The band gap energies were 2.75 and 3.17 eV as calculated using the Tauc plot with variations due to the precursor concentrations. Doping with both silver and cerium increased the band gap of ZnO nanoparticles up to 3.19 eV and the increase in annealing temperature slightly augmented the band gap energy from 3.00 and 3.16 eV, respectively. Hence, doping with Ag and Ce induced the formation of nanorods at higher concentrations. This study successfully demonstrated that the natural plant extract of bush tea can be used in the bioreduction of zinc nitrate hexahydrate to prepare pure ZnO nanoparticles, thus extending the use of this plant to the nano producing industry.

Structural characterization and antibacterial activity of silver nanoparticles synthesized using a low-molecular-weight Royal Jelly extract

In recent years silver nanoparticles (Ag NPs) gained increased and widespread applications in various fields of industry, technology, and medicine. This study describes the green synthesis of silver nanoparticles (Ag NPs) applying a low-molecular-weight fraction (LMF) of Royal Jelly, the nanoparticle characterization, and particularly their antibacterial activity. The optical properties of NPs, characterized by UV–Vis absorption spectroscopy, showed a peak at ~ 430 nm. The hydrodynamic radius and concentration were determined by complementary dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The particle morphology was investigated using transmission electron microscopy (TEM), and the crystallinity of the silver was confirmed by X-ray diffraction (XRD). The antibacterial activities were evaluated utilizing Gram-negative and Gram-positive bacteria and colony counting assays. The growth inhibition curve method was applied to obtain information about the corresponding minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) required. Obtained results showed that (i) the sizes of Ag NPs are increasing within the increase of silver ion precursor concentration, (ii) DLS, in agreement with NTA, showed that most particles have dimensions in the range of 50–100 nm; (iii) E. coli was more susceptible to all Ag NP samples compared to B. subtilis.

Precursor concentration effect on the physical properties of transparent titania (Anatase-TiO2) thin films grown by ultrasonic spray process for optoelectronics application

Titanium oxide TiO2 thin films have been deposited on heated glass substrates at 0.02, 0.05, 0.1and 0.2 M of precursor concentration by ultrasonic spray process, using the titanium tetra iso-prop-oxide (TTIP) as Ti source. The present study focuses on the physical properties of TiO2 thin film as a function of precursor concentration. Furthermore, deposited thin films were systematically investigated using X-ray diffraction (XRD), scanning electron microscope, energy-dispersive X-ray (EDX) spectra, Fourier transform infrared spectroscopy (FTIR), UV–Vis spectrophotometer and four-point probe measurement. The X-ray diffraction analysis shows that TiO2 films have the tetragonal structure of anatase with a preferential growth along the (101) direction. The crystallite size of TiO2 films increases from 30 to 47 nm with increasing precursor concentration. The SEM images reveal uniform, homogenous and dense film with good adhesion to the substrate surface. In addition, EDX analysis confirms the presence of all elements forming TiO2 material. The films optical transmittance attains 86% in the visible region, while the optical band gap of the films decreases from 3.47 to 3.32 eV (the red-shifted absorption edge). Finally, the electric resistivity of the prepared films decreases from 158 to 56 Ω cm with increasing the precursor concentration.