Field Emission Scanning Electron Microscopy Images Research Articles

Environmental friendly approach on biosorption of Ag nanoparticles using Aspergillus terreus BIOS PTK 6 biomass: Optimization, kinetics and characterization studies

The present study focused on the biosorption of Aspergillus terreus dead biomass for the removal of silver nanoparticles (AgNPs) from aqueous solution. For the better removal of AgNPs, pH, temperature, incubation time, initial biomass concentration and agitation speed were optimized and AgNPs treated as well as control biosorbents were characterized using Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray spectroscopy (EDX) analyses. In our study, the optimum conditions of pH, temperature, incubation time, initial biomass concentration and agitation speed for the maximum removal of AgNPs was found to be 4, 30 °C, 200 min, 1 mg/mL and 125 rpm, respectively. Interestingly, in our study, Langmuir isotherm model was best correlated with the highest regression coefficient (R2) of 0.992 and the maximum biosorption was found to be 740.63 μg/mL. FTIR results showed that carboxyl, carbonyl and secondary amine groups were involved in the biosorption of AgNPs. FESEM images of AgNPs treated biosorbent depicted rough surface and the presence of AgNPs on the surface of biosorbent was clearly observed. EDX spectrum showed Ag peak, which confirmed the successful uptake of AgNPs by A. terreus dead biomass. Thus, our study shows that A. terreus could be used as a cost-effective eco-friendly biosorbent for AgNPs removal from aqueous solution. Therefore, exploiting the same fungus for both synthesis and removal of AgNPs could be a novel approach in the context of mycoremediation practices.

An enzyme-free sensor based on La-doped CoFe-layered double hydroxide decorated on reduced graphene oxide for sensitive electrochemical detection of urea.

The successful synthesis ofLa-doped CoFe LDH@rGO nanocompositeis reported combiningthe advantages of LDH and rGO and shows promising performances in electrochemical sensors. The structure of the obtained nanocomposite was investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction pattern (XRD), and field emission scanning electron microscope images (FE-SEM). Then, it was directly utilized to construct a carbon paste electrode (CPE) for urea detection. The electrochemical performance of the sensor was evaluated by various electrochemical methods. The La-CoFe LDH@rGO electrode exhibited excellent electrocatalytic properties, including a wide linear workingrange of 0.001-23.5 mM, very high sensitivity of 1.07 ± 0.023 µA µM-1 cm-2, a low detection limit of 0.33 ± 0.11 µM, and rapid response time of 5 s towards urea detection at the working potential of 0.4 V. Furthermore, the sensor displayed a high selectivity in different matrices, appropriate reproducibility, and long shelf life without activity loss during 3 months of storage under ambient conditions. Further tests were performed on serum and milk samples to confirm the capability of the proposed sensor for practical applications, demonstrating a reasonable recovery of 94.8 to 102% with an RSD value below 3%. Consequently, the synergistic effect of each component led to the good electrocatalytic activity of the modified electrode towards urea.

The characterization of Ag-doped tin indium oxide/copper electrodes prepared by cold pressing method and their electrocatalytic efficiency in hydrogen production

In the present study, tin indium oxide (SnIn2O3) powder was synthesized by hydrothermal technique. In order to improve the structural property of SnIn2O3, a small amount of silver (Ag) nanoparticles was added into SnIn2O3 powder. Finally, the prepared Ag-doped SnIn2O3 (Ag@SnIn2O3) were embedded into copper (Cu) powder with different ratios. The electrocatalytically improved hetero-structured Ag@SnIn2O3/Cu materials were obtained by cold pressing method. The structural and morphological properties of different Ag@SnIn2O3/Cu materials were studied via X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). XRD pattern depicted In2O3 have both cubic and hexagonal crystal structures. FE-SEM images show that Ag@SnIn2O3 nanoparticles are homogeneously dispersed into Cu powder. The size of nanoparticles of Ag@SnIn2O3/Cu materials increases with increasing the ratio of Ag@SnIn2O3. Electrochemical impedance spectroscopy (EIS) and potentiodynamic (PD) polarization tests were carried out to investigate the electrocatalytic activities of the materials toward hydrogen evolution reaction (HER). Energy consumption and energy efficiency values for the HER on the materials were also calculated. Furthermore, the polarization resistances of the 1-Ag@SnIn2O3/Cu, 2.5-Ag@SnIn2O3/Cu, 5-Ag@SnIn2O3/Cu, and 10-Ag@SnIn2O3/Cu materials were determined as 127.4, 103.1, 552.4, and 558.7 Ω cm2, respectively after 5 days of electrolysis periods.

Synthesis of nano-selenium and its effects on germination and early seedling growth of four crop plants

In this work, nano-selenium (NSe) with different shapes (wires, rods, and spherical particles) was synthesized by a wet chemical method. These synthesized products were characterized by x-ray powder diffraction (XRD) analysis, a field emission scanning electron microscope (FE-SEM) with an energy dispersive x-ray analyzer, and Raman spectroscopy. FE-SEM images revealed that nanowires with an average diameter of 30–50 nm and length of 3–5 µm, nanorods with lengths of 400–800 nm and diameters of about 20–50 nm, and spherical-shaped nanoparticles (NPs) with diameters ranging from 40 to 60 nm were successfully synthesized. The XRD and Raman analysis confirmed that all the produced NSe samples exhibited hexagonal single-phase crystalline structure with no impurity phase. All three NSe products (SeNWs, SeNRs, and SeNPs) with a concentration range of 25–150 mg/l were used to investigate the impact of shape and concentration on seed germination and seedling vigor of four different crop species, namely, green bean, okra, wheat, and radish. The results revealed that NSe at low concentrations (≤50 mg/l for SeNWs and ≤100 mg/l for SeNRs and SeNPs) can promote seed germination, plant growth, and development of all the studied crop species. However, NSe can adversely affect the growth of plants at higher concentrations (≥75 mg/l for SeNWs).

EFFECT OF DEPOSITION PARAMETER ON EXTERIOR MORPHOLOGY, STRUCTURAL AND OPTICAL CHARACTERISTICS OF CHEMICAL BATH-DEPOSITED ZINC OXIDE THIN FILMS

In this research, Zinc Oxide thin films (ZOTF) have been placed onto a glass substrate at different times of deposition via chemical bath deposition (CBD) technique. The influence of deposition time (DT) on the exterior morphology, elemental, structural and optical behaviors of the prepared thin films has been studied through various characterization techniques for example field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD) analysis and UV-Vis spectroscopic analysis, respectively. According to FESEM images, the thin film surface existing on a dense and flower-like surface morphology was changed to flake-like structure due to increase of DT. EDX analysis exhibited the mass % and atomic % of Zn which is extant in greater proportion but O is lesser in the prepared ZOTF. The XRD pattern exposed the hexagonal wurtzite structure of ZOTF. The UV-V is results exhibited a decrease in transmittance and the optical band gap was significantly influenced by the alteration of DT. The observed high transparency of these thin films in the visible region makes them appropriate for utilization as transparent windows in numerous optical device applications.

Solution‐based fabrication of copper oxide thin film influence of cobalt doping on structural, morphological, electrical, and optical properties

In this study, Cobalt (Co) doped Copper Oxide (CuO) films at different concentrations were deposited on glass substrates, using the Chemical Bath Deposition (CBD) method. The films were characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Ultra Violet-Visible Spectroscopy (UV-Vis.) and two-point contact method. The FESEM images showed that nanoplates formed increased in size and voids on the films surface decreased with increasing Co concentration. The XRD patterns revealed an increase in crystallite size with increasing (from 14.40 to 18.60 nm) Co concentration and no secondary phase was formed. The Energy-dispersive X-ray spectroscopy (EDS) spectra showed the presence of Co in the film composition with increasing concentration. The results of UV-Vis. spectroscopy showed that band gap values could be changed with Co doping and thus the CuO band gap could be adjusted with the Co doping. The temperature-dependent current-voltage measurement results obtained with the two-point contact method showed that activation energy levels increased (from 0.134 to 0.232 eV) with increasing Co concentration. It was also observed that the conductivity increased with increasing temperature.

Biosynthesis of ZnO, Bi2O3 and ZnO-Bi2O3 bimetallic nanoparticles and their cytotoxic and antibacterial effects.

This work introduces an easy method for producing Bi2O3, ZnO, ZnO-Bi2O3 nanoparticles (NPs) by Biebersteinia Multifida extract. Our products have been characterized through the outcomes which recorded with using powder X-ray diffractometry (PXRD), Raman, energy dispersive X-ray (EDX), field emission-scanning electron microscopy (FE-SEM), and Fourier-transform infrared (FT-IR) techniques. The finding of SEM presented porous structure and spherical morphology for Bi2O3 and ZnO NPs, respectively. While FE-SEM image of bimetallic nanoparticles showed both porous and spherical morphologies for them; so that spherical particles of ZnO have sat on the porous structure of Bi2O3 NPs. According to the PXRD results, the crystallite sizes of Bi2O3, ZnO and ZnO-Bi2O3 NPs have been obtained 57.69, 21.93, and 43.42 nm, respectively. Antibacterial performance of NPs has been studied on Staphylococcus epidermidis and Pseudomonas aeruginosa bacteria, to distinguish the minimum microbial inhibitory concentration (MIC). Antimicrobial outcomes have showed a better effect for ZnO-Bi2O3 NPs. Besides, wondering about the cytotoxic action against cancer cell lines, the MTT results have verified the intense cytotoxic function versus breast cancer cells (MCF-7). According to these observations, obtained products can prosper medical and biological applications.

Development and characterization of nano-magnesia-based refractories filled with graphite nanosheets

Thermo-mechanical and mechanical properties of Magnesia-Carbon (MgO–C) refractories are of great importance in industrial furnace applications and are greatly influenced by the amount of carbon in the MgO Matrix. In this research work, the effect of exfoliated graphite nanosheets (EGS) content on mechanical behavior and thermal shock resistance of MgO-based refractories was examined. MgO nanoparticles were synthesized by the co-precipitation method and micro-MgO particles were used as received. EGS was added in both micro and nano-MgO in variable amounts ranging from 0.5 to 2.5 wt % to study its effect on fracture strength and thermal shock resistance. The morphology of synthesized MgO nanoparticles and the fractured surfaces of the resultant composites were analyzed by field emission scanning electron microscopy (FESEM) coupled with energy dispersive x-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and compression testing. The synthesized nano-MgO and as received micro-MgO particles were found to be of spherical morphology with no impurity elements as observed by FESEM and EDX mapping. XRD analysis did not show any phase change after the sintering of the composites. The FESEM and TEM images of the fractured surfaces of MgO-EGS refractory samples displayed the fine distribution of EGS. EGS were embedded in MgO particles, enhancing the composite-refractory samples' fractured strength. Fracture strength and thermal shock resistance were increased with the increasing amount of EGS in MgO. However, the highest fracture strength and thermal shock resistance values were achieved for nano-MgO with 2.5 wt% EGS. The resulting refractory samples can be used as furnace linings having a lower carbon content and enhanced thermo-mechanical properties.

A novel method for examining the influence of molecular and structural properties of the asphaltene fraction on the wettability change of the calcite surface

Asphaltene deposition in the porous media of the reservoir during the production life causes serious challenges with significant economic cost. From the point of view of proactive action to prevent the formation of such precipitates, today asphaltene inhibitors are widely used in the oil industry. The successful performance of inhibitors strongly depends on molecular structure of asphaltene. This study investigates the effect of molecular-structural properties of asphaltene in four crude oil samples on calcite surface wettability. The wettability of the calcite surface is evaluated with contact angle test and micromodel. The crude oil properties are determined using DHA (Detailed Hydrocarbon Analysis) and FTIR (Fourier Transform Infrared Spectroscopy) tests, while the molecular-structural properties of asphaltene are assessed using elemental analysis, FESEM (Field Emission Scanning Electron Microscopy), NMR (Nuclear Magnetic Resonance), and FTIR techniques. Based on FTIR analysis of oil samples, the higher polarity of samples B and G compared to samples F and A can be attributed to the presence of C = O carboxylic acid stretches. In addition, DHA analysis indicates that sample B, which contains heavier compounds comprising 27.4220 % of the C14+ compounds by weight, exhibits distinct characteristics. The FESEM images demonstrate a uniform and smooth spread surface morphology of the asphaltene samples. However, the elemental analysis does not establish a correlation between the heteroelement ratios of N/C, O/C, and S/C and asphaltene adsorption tendency. FTIR and NMR analyses suggest that the wetting properties observed on the surface are mainly attributed to the high aromatic and aliphatic compounds present in the asphaltene of sample B, while the polar compounds are less influential. The results reveal that crude oil sample B exhibits the highest percentage of damage to the porous medium caused by asphaltene deposition, with a rate of 36.18 % and a contact angle of 163.53 degrees. This indicates a wetter surface of the oil compared to other samples. Samples G and A follow with contact angles of 157.34° and 153.60°, respectively. On the other hand, sample F shows the lowest wettability change on the calcite surface with a contact angle of 144.77° and only 0.08 % damage to the porous medium.

Green synthesis of CuO/MgO/ZnO nanoparticles using Costus pictus leaf extract for effective antibacterial applications

In recent years, environmentally friendly methods have garnered significant attention in developing novel nanoparticles (NPs). This study focuses on the green synthesis and characterisation of CuO/MgO/ZnO NPs using Costus pictus D. Don Plant extract as a green reducing and capping agent. X-ray diffraction (XRD) analysis was employed to assess the purity of NPs, whereas Fourier-transform infrared (FTIR) and UV–Vis spectroscopy were employed to study the chemical composition and absorption peaks of the synthesised NPs. The Field-emission scanning electron microscopy (FE-SEM) images revealed a distinctive flower-like morphology of NPs, and their stability and dispersion were supported by a negative zeta potential of −14.8 mV. The significant surface area (87.742 m2/g) of CuO/MgO/ZnO NPs was obtained from Brunauer-Emmett-Teller (BET) analysis. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) analysis confirmed that the particle size of NPs is nearly 50 nm and is poly-crystalline. Finally, the synthesised NPs were tested against the bacteria using the agar-well diffusion method. Notably, CuO/MgO/ZnO NPs exhibited better antibacterial activity against Pseudomonas aeruginosa, yielding a substantial inhibition zone of 23.33 ± 2.08 mm.

Photocatalytic and antimicrobial studies of green synthesized Dy3+doped ZnO nanoparticles prepared from Rhododendron arboreum petal extract

In this study, the primary focus revolves around the synthesis of zinc oxide (ZnO) and dysprosium-doped zinc oxide (Dy-doped ZnO) nanoparticles utilizing a green chemistry approach, employing Rhododendron arboreum petal extract as a key component. A thorough characterization of nanoparticles has been carried out, involving a range of analytical techniques including UV–visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), and fluorescence emission spectroscopy. The structural examination confirmed the persistent hexagonal wurtzite structure of ZnO nanoparticles, which remained unaltered even with Dy doping. The XPS analysis corroborated the presence of lattice oxygen in addition to confirming the presence of Dy3+ and Zn2+. The results indicated that the incorporation of Dy3+ ions replaces Zn2+ ions in host ZnO leading to an increase in the defects inside ZnO. Based on HRTEM images, the particle size was determined to be 31 nm for ZnO nanoparticles and 39 nm for Dy-doped ZnO nanoparticles. FESEM imaging unveils a morphology reminiscent of pebbles, and EDX spectra provide additional evidence of the presence of Zn, Dy, and O elements within the nanoparticles, which aligns with the findings from XPS. Subsequently, these synthesized nanoparticles were harnessed for the remediation of novacron brown, a textile dye. Additionally, nanoparticles were explored for their antibacterial and antifungal properties which highlight the considerable potential of these nanoparticles in these specific domains.

The Influence of the Various PH Value on Structural and Magnetic Properties of Cobalt Ferrite Nanostructure

In this work, CoFe2O4 nanostructure was synthesized from Cobalt and ferric nitrates and sodium hydroxide (NaOH) by hydrothermal method. Effect of PH on the structural and magnetic properties of the resulting powder was studied at calcination 400°C and 600°C. The resulted products were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Fourier transformed infrared (FTIR), and vibrating sample magnetometer (VSM) technique as synthesis , when calcination at 400°C and 600°C with different PH . The reduction in crystallite size that their average crystallite size is found (13.98-22.17) nm crystallite size at PH=9 higher than when PH=3. The FE-SEM images indicated that particles were agglomerated and spherical shape and size between (23.6 - 57.9) nm for PH=9 and (23.3 – 114.6) nm for PH=3. The created CoFe2O4 nanostructure have demonstrated ferromagnetic behavior for all the samples behavior which was found in VSM results examination.

Think before throw: waste chili stalk powder for facile scavenging of cationic dyes from water.

Chili stalk powder (CS), a non-conventional adsorbent, has been exercised for facile removal of cationic dyes from simulated and wastewater by batch technique. The prepared material has been characterized by Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller analysis (BET), powder X-ray diffraction (powder XRD), and pHZPC and tested best with methylene blue and crystal violet under ambient conditions. FTIR denotes the presence of carbonyl and polyphenolic groups, responsible for dye adsorption. BET surface area analysis evaluates the porous nature and specific surface area of the material, and powder XRD confirms its amorphous nature. The porous structure could be ascertained from the FESEM image, and energy dispersive X-ray analysis (EDX) confirms the elemental composition. The pH above pHzpc shows an increase in removal efficiency. The maximum adsorption capacities are 49.53 and 36.88mg/g for methylene blue (MB) and crystal violet (CV) respectively. Linear as well as non-linear plots for kinetic and isotherm models were studied. Both dye uptake fits the linear plot of Langmuir adsorption isotherm (R2 = 0.999 and 0.995) and pseudo-second-order kinetics (R2 = 0.998 and 0.999). In the non-linear plot, the adsorption process for both dyes fit Langmuir (R2 = 0.999 for MB and R2 = 0.983 for CV) as well as Freundlich adsorption (R2 = 0.999 for MB and R2 = 0.994 for CV). 75.48% crystal violet (CV) and 73.35% methylene blue (MB) regeneration were successful in 1:1 methanol medium and reused for up to three cycles. The uptake mechanism is suggested to be a union of π-π stacking, electrostatic interaction, and weak hydrogen bonding. The material was tested with industrial effluent to prove its application in real wastewater treatment. Moreover, the material shows superior adsorption capacity than contemporary phytosorbents. To conclude, a zero-cost adsorbent using green chili stalk has been demonstrated for wastewater treatment.

Cr2O3- TiO2 nanocomposite made using plant (Oats) extract via impregnation technique for photocatalytic activity of hydrogen production

In this study an efficient photocatalyst of water splitting was developed. It's discussed. The Cr2O3 with TiO2nanoparticles (Cr2O3-TNPs) nanocomposite with (Oats extract) were created using ecologically friendly methods impregnation technique such TiO2 exhibits nanospherical (TNPs) shape structure. This nanocomposite material enhanced their ability to absorb ultraviolet light while also speeding up the recombination of photogenerated electrons and holes, according to the researchers. The TNPs and prepared Cr2O3-TNPs were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy (EDX), and UV-visible absorbance. The XRD of TNPs showed a Tetragonal phase with 8.9 nm of average crystallite size,. FE-SEM images showed that the average particles size in the range of 22.5 nm and UV-VIS absorbance have energy gaps are 3.9eV while the energy gaps of Cr2O3-TNPs smaller than that 3.6 eV. It was found that the performance of photocatalysts of the nanocomposite for hydrogen generation was superior, as it gave the highest rate of hydrogen production (6.3) ml at 80 min when exposed to ultraviolet light. Moreover, the nanocomposite revealed the high H2 production rate under ultraviolt light irradiation (λ < 400 nm), The Cr2O3-TNps have a high photocatalytic effectiveness due to their wide ultraviolt light photoresponse range and excellent separation of photogenerated electrons and holes.

A mechanistic study of asphaltene formation and aggregation in presence of metallic-based nanoparticles

In this work, the effects of metallic-based nanostructures including iron oxide (Fe2O3), magnesium oxide (MgO) and zinc oxide (ZnO) on asphaltene precipitation and aggregation were explored. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and Brunauer, Emmett and Teller (BET) methods. Optical microscopy and asphaltene dispersant tests (ADTs) were utilized to discover the effects of nanoparticles on asphaltene stability and the size-growth of asphaltene aggregates in crude oil medium. The interactions of the asphaltene functional groups with metal oxide nanoparticles were evaluated at molecular scale by thermogravimetric analysis (TGA/DTG), FT-IR, and field emission scanning electron microscopy (FESEM). Results of different experiments exhibited that synthesized nanostructures in general postpone the asphaltene onset of precipitation (AOP) and reduce the size of asphaltene aggregates in unstable crude oil medium. MgO nanoparticles with a concentration of 300 ppm had the greatest effect on controlling the asphaltene precipitation and aggregation. The TGA/DTG analysis showed that the oxidation of pure asphaltenes occurs at a temperature of about 425 °C, while the oxidation temperature of asphaltenes adsorbed on ZnO and Fe2O3 nanoparticles occurs at around 330 °C, and for MgO nanoparticles at about 365 °C. In addition, the spectra obtained from the FT-IR analysis for asphaltenes without and with nanoparticles at the wavelengths of 1450 and 2900 cm−1 show the medium C–H stretching bonds that play the most important role in the adsorption of asphaltene on the surfaces of the nanoparticles. Also, the recorded FESEM images of the asphaltene and nanoparticles demonstrated the proper absorption of asphaltenes in the empty spaces between the structures of nanoparticles. According to the results from different experiments and intermolecular analyses, the performance of synthesized nanoparticles for retarding asphaltene precipitation and dispersing the asphaltene aggregates was in order of MgO (300 ppm) > Fe2O3 (300 ppm) > ZnO (700 ppm). The results of intermolecular analyses established the effective adsorption of the asphaltene particles onto the surface of the nanoparticles, which is caused by strong hydrogen interactions between the active sites of the asphaltene and nanoparticles. The findings of this study prove that metal-oxide nanoparticles can be utilized as an economically and environmentally-effective agents for controlling asphaltene formation and aggregation in crude oil.

Endosperm structure and Glycemic Index of Japonica Italian rice varieties.

Given that rice serves as a crucial staple food for a significant portion of the global population and with the increasing number of individuals being diagnosed with diabetes, a primary objective in genetic improvement is to identify and cultivate low Glycemic Index (GI) varieties. This must be done while ensuring the preservation of grain quality. 25 Italian rice genotypes were characterized calculating their GI "in vivo" and, together with other 29 Italian and non-Italian genotypes they were studied to evaluate the grain inner structure through Field Emission Scanning Electron Microscopy (FESEM) technique. Using an ad-hoc developed algorithm, morphological features were extracted from the FESEM images, to be then inspected by means of multivariate data analysis methods. Large variability was observed in GI values (49 to 92 with respect to glucose), as well as in endosperm morphological features. According to the percentage of porosity is possible to distinguish approximately among rice varieties having a crystalline grain (< 1.7%), those intended for the preparation of risotto (> 5%), and a third group having intermediate characteristics. Waxy rice varieties were not united by a certain porosity level, but they shared a low starch granules eccentricity. With reference to morphological features, rice varieties with low GI (<55) seem to be characterized by large starch granules and low porosity values. Our data testify the wide variability of Italian rice cultivation giving interesting information for future breeding programs, finding that the structure of the endosperm can be regarded as a specific characteristic of each variety.

Evaluation of substrate temperature role on the structural, morphological, optical, and mechanical properties of magnetron sputtered Cu2Se thin films

Copper Selenide (Cu2Se) thin films were deposited on a float glass substrate using magnetron sputtering with a radio frequency (RF) source at a power of 70 W and by varying substrate temperatures (Tsub) from 50 °C to 400 °C with an interval of 50 °C. The influence of the Tsub on the morphological, structural, and mechanical characteristics of Cu2Se thin films was investigated using the Grazing Incidence X-ray diffraction (GIXRD), Raman spectra, Field Emission Scanning Electron Microscopy (FESEM) combined with energy-dispersive spectroscopy (EDS) and Nanoindentation. The results of the GIXRD analysis suggest that the cubic Cu2-xSe phase could be observed when the deposition took place at Tsub of 50 to 200 °C. However, for the films that were deposited at temperatures higher than this range, i.e., from 250 °C to 400 °C, the elements Cu and Se formed an intermediate phase. Raman bands assigned at 261 cm−1 confirm the cubic-Cu2Se phase. The average grain size measured from FESEM images increase with varying Tsub from 50 °C to 400 °C with a value of 230 nm to 320 nm. The variation in the Tsub results in the evolution of the microstructure and EDS shows the variation in the stoichiometric ratio of deposition. The energy of the band gap decreases with an increase in Tsub, leading to the overlapping of energy levels. The nanoindentation tests show that the hardness dropped as the Tsub increased from 50 °C to 400 °C. The Cu2Se film deposited at Tsub 50 °C had the highest hardness value of 1.91 ± 0.47 GPa.

Exploration of properties (crystallographic, morphological, optical) of nano cobalt aluminate synthesized by facile sol–gel method: Effects of sintering temperature

The present work reports on the facile sol–gel synthesis of CoAl2O4 nanoparticles using cobalt nitrate and aluminum nitrate as the metal salts and citric acid and glycerol as chelating agents. The consequence of sintering temperature on the structure, particle size, morphology, composition, zeta potential, color, and reflectance spectra at neutral pH condition were explored with various instrumental techniques. The CoAl2O4 nanoparticles were characterized with Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM), Energy dispersive spectroscopy (EDS), Nanoparticle size analyzer, Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis-DRS) and CIE-Lab colorimetric method. From the data of PXRD, the crystallite size and peak profile analysis were investigated by four different models. It was found that the average crystallite size varied in the range of 28.01–320.97 nm and single-phase cubic CoAl2O4 was formed without any impurity. The average particle size of CoAl2O4 nanoparticles was discerned from the FESEM images using ImageJ software and from a nanoparticle size analyzer. The average particle sizes were increased with the increasing sintering temperature. The values of zeta potential found in all of the samples represented high dispersion stability. From the colorimetry of CoAl2O4 nanoparticles, the CIE-La*b* output illustrated high purity and brightness and the spectra.

Enhanced photoelectrochemical performance of quantum dot-sensitized solar cell using Cu2+ co-doped CdS and CdSe nanoscrystals.

Today, nanoscrystals are researched and developed very quickly because of their advantages in many areas of life. One of the potential applications is quantum dot-sensitized solar cells. This is a green, clean, environmentally friendly cell, and has been studied by scientists since 2000. In this study, we fabricated photoanodes with Cu2+ ions co-doped into cadmium sulfide (CdS) and cadmium selenide (CdSe) nanoscrystals by successive ionic layer adsorption and reaction, and chemical bath deposition methods to improve absorption spectral intensity of films. The results showed that the absorption intensity increased by eight times compared with our previous results on Cu2+ ions doped with CdSe nanoscrystals. The CdS:Cu2+ film is optimized at 2% doping, the efficiency is 4.6819%, and the current density is 27.3501 mA.cm-2, which is higher when compared with the Cu2+ ion only doped into the CdSe quantum dot (19.915 mA.cm-2). In addition, the composition of the photoanode was determined by surface and cross-sectional field-emission scanning electron microscope images, and the structure of the film was determined by X-ray diffraction, energy-dispersive X-ray spectroscopy mapping and X-ray photoelectron spectroscopy. Finally, the film's optical properties were studied by ultraviolet-visible spectroscopy, photoluminescence spectroscopy and electrochemical properties by electrochemical impedance spectroscopy. The results obtained have been discussed and presented in great detail.

Impact of a precise pH value change on the characteristics of deposited tin monosulphide films onto a flexible substrate

The chemical bath deposition technique (CBD) is considered the cheapest and easiest compared with other deposition techniques. However, it is highly sensitive to effective parameter deposition values such as pH, temperature, and so on. The pH value of the reaction solution has a direct impact on both the nucleation and growth rate of the film. Consequently, this study presents a novel investigation into the effect of a precise change in the pH reaction solution value on the structural, morphological, and photoresponse characteristics of tin monosulphide (SnS) films. The films were grown on a flexible polyester substrate with pH values of 7.1, 7.4, and 7.7. The X-ray diffraction patterns of the grown films at pH 7.1 and 7.4 confirmed their polycrystalline nature. Additionally, an observed alteration in the crystal structure occurred as the pH value increased from 7.1 to 7.4, resulting in a transition from an orthorhombic crystal structure to a cubic crystal structure. In contrast, the XRD pattern of the grown film at pH 7.7 revealed that it was amorphous. The field-emission scanning electron microscopy images revealed a flower-like morphology for the grown film at 7.1, whereas the grown films at 7.4 and 7.7 revealed a grain morphology. The results also showed that the pH values were also having an important effect on the energy gap value (Eg) of films; the Eg values were 1.46, 1.57, and 1.65 eV for pH 7.1, 7.4, and 7.7, respectively. The photodetectors fabricated using grown films exhibited excellent photoresponse characteristics when subjected to near-infrared (750 nm) illumination. It was also demonstrated that the photodetector using the cubic structure film possessed faster response times and greater sensitivity than the photodetector using the orthorhombic structure film.