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Öğe A straightforward approach for the synthesis of nanostructured Y2O3 particles: synthesis, morphology, microstructure and crystal imperfection(Elsevier, 2020) Emil Kaya, Elif; Gürmen, SebahattinA facile and straightforward approach has been implemented for the synthesis of nanostructured Y2O3 particles via sol-gel method from yttrium nitrate solution. The individual effects of calcination temperature, precipitation-chelating agent and precursor concentration on microstructural parameters, crystal defects and morphology of Y2O3 were investigated in detail. The morphology of synthesized nanostructured Y2O3 particles was revealed by scanning electron microscopy (SEM). X-ray diffraction (XRD) and Williamson Hall analysis were used to find out how Y2O3 crystallite size, lattice strain-stress, dislocation density and morphology affect the sol-gel process parameters. Comparative studies for determining crystallite size of particles were carried out by Modified Debye-Scherer and Williamson Hall analysis. A more detailed microstructural analysis and investigation of crystallographic imperfections were conducted by Williamson- Hall (W-H) method. W-H analysis was carried out on Y2O3 particles with spherical shape and sponge morphology for the first time. Results reveal that as calcination temperature is increased from 700 degrees C to 900 degrees C, the crystallite size increases from 37.15 nm to 49.49 nm while lattice strain increases from 8.154 x 10(-4) to 8.696 x 10(-4). It is also found that, an increment in solution concentration from 0.1 mol/L to 0.2 mol/L results in crystallite size decrement from 47.27 nm to 44.37 nm. A further increment from 0.2 mol to 0.4 mol/L leads to crystallize size increase from 44.37 nm to 49.67 nm.Öğe Estimation of yttrium oxide microstructural parameters using the Williamson-Hall analysis(Taylor & Francis Ltd, 2018) Emil Kaya, Elif; Gürmen, SebahattinYttrium oxide (Y2O3) particles were synthesised from a yttrium nitrate solution via ultrasonic spray pyrolysis (USP) method. The effects of temperature and precursor concentration on morphology and microstructural parameters were investigated. Y2O3 particles were characterised by scanning-electron-microscope energy-dispersive spectroscopy, Raman spectroscopy and X-ray diffraction analysis. Based on X-ray peak broadening, the crystallite size was calculated using the modified Debye-Scherrer (MDS) method. Furthermore, the crystallite size, crystal strain and the energy density of the crystal were evaluated using the Williamson-Hall (W-H) analysis integrated with the uniform deformation model, the uniform stress deformation model and the uniform deformation energy density model. A comparative evaluation of Y2O3 crystallite size using the MDS and W-H methods was carried out.Öğe Fabrication and characterization of Yb-doped Y2O3 powders and thin films(Carl Hanser Verlag, 2020) Emil Kaya, Elif; Ünal, Fatma; Kazmanlı, Kürşat; Gürmen, SebahattinYttrium oxide (Y2O3) and ytterbium (Yb)-doped Y2O3 particles were synthesized via the sol-gel method from the aqueous solution of their nitrate salts. The synthesized powders were then deposited on Corning glass substrates using an electron beam evaporation technique to examine the growth morphology of the thin films. The effect of the Yb dopant concentration on the microstructure and morphology of the Y2O3 powders and thin films was investigated using various characterization techniques. The synthesized powders and fabricated thin films have body-centered cubic structures with space group Ia-3. Based on the X-ray peak broadening, crystallite size and lattice parameters were evaluated with the Williamsom-Hall and Cohen-Wagner methods. The lattice parameter and crystallite size decrease with increasing Yb concentration. The intensities of the Raman peaks decrease due to microstructural disorder caused by the increase in the Yb dopant concentration. The band gap values of the powders also decrease depending on the dopant concentration, similar to the lattice parameter and crystallite size. While the synthesized powders have a sponge-like morphology, they exhibit different morphological structures depending on the dopant concentration when converted into thin films.Öğe New proposal for size and size-distribution evaluation of nanoparticles synthesized via ultrasonic spray pyrolysis using search algorithm based on image-processing technique(Mdpi, 2020) Emil Kaya, Elif; Kaya, Ozan; Alkan, Gözde; Gürmen, Sebahattin; Stopic, Srecko; Friedrich, BerndNanoparticle properties are correlated to their size, size distribution, and shape; it is essential to accurately measure these features in the field of nanoscience. In this study, silver nanoparticles (AgNPs) were synthesized with the ultrasonic-spray-pyrolysis (USP) method from a water solution of silver nitrate. The synthesized AgNPs were characterized by Dynamic Light Scattering (DLS) analysis and Scanning Electron Microscopy (SEM) to reveal their size and size distribution. A search algorithm based on an image-processing technique to obtain particle size and particle-size distribution from SEM micrographs is proposed. In order to obtain more quantitative information and data with respect to the morphology of particles synthesized under different process parameters, SEM micrographs with a nonhomogeneous background contrast were examined via image-processing techniques in MATLAB. Due to the inhomogeneous contrast of SEM micrographs, defining an overall threshold value was insufficient in the detection of whole nanoparticles. Thus, subimages were directly created according to the maximum and minimum particle size specified by the user to determine local threshold values. The obtained results were automatically combined to represent both particle dimension and location in the SEM micrographs. We confirmed that the results of our DLS analysis, theoretical calculation, and image-processing technique were correlated with our expected results.Öğe Novel strategy for one-step production of attenuated Ag-containing AgCu/ZnO antibacterial-antifungal nanocomposite particles(Springer, 2020) Çakmak, Tolga; Emil Kaya, Elif; Küçük, Demet; Ebin, Burçak; Balcı, Onur; Gürmen, SebahattinNovel strategies have been developed to comply with Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulations to provide the same performances for antibacterial and antifungal materials. The strategy for producing composite materials by attenuating the silver (Ag) content and a one-step production technique without minimizing the antibacterial and antifungal performance was developed. In this study, attenuated spherical Ag containing spherical AgCu/ZnO nanocomposite particles have been synthesized from an aqueous solution of silver nitrate (AgNO3), copper nitrate (Cu(NO3)(2) center dot 3H(2)O), and zinc nitrate (Zn(NO3)(2) center dot 7H(2)O) by a facile one-step ultrasonic spray pyrolysis and hydrogen reduction (USP-HR) method. Characterization of AgCu/ZnO nanocomposite particles was carried out by various techniques such as X-ray diffraction analysis (XRD), scanning electron microscopy (FEG-SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The structural analysis showed that AgCu/ZnO nanocomposites were composed of face-centered cubic Ag, face-centered cubic Cu, and hexagonal ZnO phases. Antibacterial and antifungal properties of nanocomposite particles against Escherichia coli and Aspergillus niger were investigated by agar medium and broth medium methods. The obtained results indicate that produced nanocomposite particles possess antibacterial and antifungal properties (100%). The attenuated Ag in the AgCu/ZnO nanocomposite particles has the usage potential in different areas of the textile industry. In particular, the research on utilizing this nanocomposite in hand-made fiber production as an additive is of very high interest.Öğe Tuning the morphology of ZnO nanostructures with the ultrasonic spray pyrolysis process(Mdpi, 2018) Emil Kaya, Elif; Alkan, Gözde; Gürmen, Sebahattin; Rudolf, Rebeka; Jenko, Darja; Friedrich, BerndNanostructured zinc oxide (ZnO) particles were synthesized by the one step Ultrasonic Spray Pyrolysis (USP) process from nitrate salt solution (Zn(NO3)(2)center dot 6H(2)O). Various influential parameters, from Zn(NO3)(2)center dot 6H(2)O concentrations (0.01875-0.0375 M) in the initial solution, carrier gas (N-2) flow rates (0.5-0.75 L/min) to reaction temperature (400-800 degrees C), were tested to investigate their role on the final ZnO particles' morphology. For this purpose, Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM) and (Selected Area Electron Diffraction) SAED techniques were used to gain insight into how the ZnO morphology is dependent on the USP process. It was revealed that, by certain parameter selection, different ZnO morphology could be achieved, from spherical to sphere-like structures assembled by interwoven nanoplate and nanoplate ZnO particles. Further, a more detailed crystallographic investigation was performed by XRD and Williamson-Hall (W-H) analysis on the ZnO with unique and non-typical planar morphology that was not reported before by USP synthesis. Moreover, for the first time, a flexible USP formation model was proposed, ending up in various ZnO morphologies rather than only ideal spheres, which is highly promising to target a wide application area.
