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Öğe Alkali metals (Na, K) doped ZnO/CuO composite films for real-time tracking of sweat loss(Elsevier Sci Ltd, 2023) Sahin, B.; Ozyilmaz, G.; Kaya, T.Real-time sweat rate monitoring provides clinically proper directives for preventive medicine and dis-ease diagnosis. This research represents an attempt to develop a semiconductor-based nanostructured sensor for monitoring sweat rate using a ZnO/CuO composite thin film. A series of alkali metals (sodium, Na; potassium, K) doped ZnO/CuO composite samples were fabricated on soda lime glass substrates by the Successive Ionic Layer Adsorption and Reaction method. The sweat solution sensing response characterization exhibited promising sensing behavior under room conditions. The Na-and K-doped samples showed a pronounced response at low and high concentrations of the sweat solution. While the undoped composite film responds to the high concentration sweat solution (117.90 mM) with a sensi-tivity of 4.10, this value increases up to 9.15 for the 2.0% Na-doped samples. In addition, the response time shortens from 6 s to 4 s for 2.0% Na substitutions. Pristine, 2.0% Na and 2.0% K-substituted ZnO/CuO composites exhibit great linearity with linear regression ranges, R2, of 0.958, 0.971, and 0.984, respec-tively. We concluded that doping of ZnO/CuO composites with alkali metals Na and K is a good candidate for real-time tracking of sweat loss as biological evidence.(c) 2023 Elsevier Ltd. All rights reserved.Öğe Bandgap variation of nanostructure tin doped CdO films via SILAR processing(Elsevier Sci Ltd, 2014) Sahin, B.; Taskopru, T.; Bayansal, F.Five series of pure and tin-doped CdO films have been grown on amorphous glass substrates by the successive ionic layer adsorption and reaction (SILAR) method. The film's structural, morphological and optical properties have been investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and UV-vis spectrophotometer. XRD results showed that all of the films are polycrystalline cubic CdO. Doping of tin enhances the film's (111) preferred orientation and causes slight shift in the (111) Bragg angle towards higher value. From the FESEM images, it was seen that tin-doping concentration affects the shapes of the nanostructures. It was found that the tin-doping concentration modify the microstructures. With UV-vis analysis at the room temperature it was seen that the optical band gap and transmission properties of the films change with increasing tin concentration in the growth bath. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Öğe A comparative study on cobalt and aluminum as a dual doping element for CdO films(Elsevier Sci Ltd, 2019) Cavusoglu, H.; Aydin, R.; Sahin, B.In the present study, we have delineated the synthesis of transparent conductive un-doped, Co doped (Co0.01Cd0.99 O) and Co:Al dual-doped CdO films [(Al-m,Co0.01Cd0.99-m) (m: 0.005, 0.01 and 0.02, respectively)] by using facile successive ionic layer adsorption and reaction (SILAR) method at room temperature. Scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopic measurements had been executed to reveal the influence of Co and Al dopants on the morphological, crystallinity and optical characteristics of CdO films. The effect of Co doping and Co:Al dual doping on the surface morphology of CdO films was identified through SEM analysis. The EDX analysis results confirmed the presence of Co2+ and Al3+ dopant ions in the CdO lattices. The XRD measurements revealed that all of the SILAR-grown CdO films were polycrystalline with a cubic structure and exhibited (111) and (200) preferred orientations. The presence of chemical bonding was verified by FT-IR spectroscopic investigation. Furthermore, the optical band gap (E-g) values of the all deposited films were evaluated from UV-Vis spectrophotometric data. The ES values of all the films were remarkably widened in proportion to the Al doping from 1.92 eV to 3.05 eV. The investigations have shown that mono doping and dual doping have a substantial impact on the physical properties of SILAR-grown CdO films.Öğe CuO nanostructures grown by the SILAR method: Influence of Pb-doping on the morphological, structural and optical properties(Elsevier Science Sa, 2015) Bayansal, F.; Gulen, Y.; Sahin, B.; Kahraman, S.; Cetinkara, H. A.CuO nanostructures with and without Pb were synthesized by the Successive Ionic Layer Adsorption and Reaction method. The films were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and ultraviolet-visible spectrophotometry. Scanning electron microscopy results showed that the morphology of the film surface was changed from plate-like to coral-like nanostructures with increasing Pb concentration. The X-ray diffraction patterns showed the monoclinic crystal structure with preferential planes of ((1) over bar 11) and (111). Furthermore, ultraviolet-visible spectra showed that the band gap of the films was tailored by Pb doping. (C) 2014 Elsevier B.V. All rights reserved.Öğe Downstream particle image velocimetry measurements of a circular cylinder-plate junction(Sage Publications Ltd, 2009) Ozturk, N. A.; Akcayoglu, A.; Sahin, B.In the present investigation, special attention was given to the flow characteristics downstream of a circular cylinder mounted on a flat Surface for Reynolds numbers of 4000 and 7000. A series of experiments were performed in successive end-view planes with the range of 0 <= X-L/d <= 5 using the particle image velocimetry (PIV) technique in order to demonstrate characteristics of wake flow structure and interactions between the shear layers caused by shedding vortices and tails of the horseshoe vortex system emanating from the upstream base of the cylinder. The development and growth of primary vortices in the end-view planes caused by the interactions of core flow and wake flow regions along the inner face of the shedding shear layers were examined quantitatively. Finally, it was concluded that the PIV technique was also capable of providing accurate velocity readings in the end-view planes of the wake flow regions.Öğe Effect of coumarin concentration on the physical properties of CdO nanostructures(Elsevier Sci Ltd, 2014) Sahin, B.; Bayansal, F.; Yuksel, M.; Biyikli, N.; Cetinkara, H. A.In this work, nanostructured CdO films with different coumarin contents in the growth solution were fabricated on glass substrates by the HEAR method. The effects of coumarin content in the bath on optical, structural and morphological properties were studied by means of (UV-vis) spectrophotometer, SEM and XRD analysis. The analysis showed that the band gaps, surface morphologies and XRD peak intensities of the CdO films were found to change with coumarin content. A change in the band gap energy can be attributed to the improvement in crystallinity of the samples. XRD analysis showed that, the films have poly-crystalline structures with decent crystallinity levels. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Öğe Effect of heat treatment on the properties of Cd(OH)2 and CdO films grown by chemical bath deposition(Taylor & Francis Ltd, 2013) Sahin, B.; Bayansal, F.; Cakmak, H. M.; Kahraman, S.; Cetinkara, H. A.Nanostructured cadmium hydroxide (Cd(OH)2) thin films have been fabricated on glass substrates by the chemical bath deposition method and converted into cadmium oxide (CdO) films by heat treatments. Some of the films were studied as-grown and the others were annealed in air at 150, 300 and 450 degrees C. The effects of various annealing processes on the structural, morphological and optical properties of the Cd(OH)2 and CdO films were studied. The band gaps of the films vary from 2.74eV to 2.32eV for different annealing temperatures. It was observed that there is a direct dependence of the structural, morphological and optical properties on the annealing temperature of the films. X-ray diffraction (XRD) measurements showed that as-grown and annealed film at 150 degrees C fully consist of Cd(OH)2 and the annealed films at 300 and 450 degrees C consist of CdO nanoparticles. The size of the nanoparticles, which were calculated from the scanning electron microscopy (SEM) figures by using a pixels program, was found to lie between 460 and 600nm.Öğe The effect of thymus syriacus plant extract on the main physical and antibacterial activities of ZnO nanoparticles synthesized by SILAR method(Elsevier, 2022) Sahin, B.; Aydin, R.; Soylu, Soner; Turkmen, M.; Kara, M.; Akkaya, A.; Cetin, H.This study aimed to determine the main physical properties of green synthesized ZnO nanoparticles (ZnO-NPs) using Thymus syriacus plant extract and their antibacterial activities against eight different Gram-positive and Gram-negative plant bacterial disease agents. The surface morphological, structural, optical and electrical attributes of the ZnO films were analyzed by various types of characterization techniques. The authors have observed that the microstructural and surface morphological properties considerably changed by using T. syriacus plant extract. UV-Vis. analysis showed that the bandgap values are increased from 3.17 to 3.28 eV with the T. syriacus content in the growth solution. Impedance measurements presented an increase of the semicircle diameters with the increase % of T. syriacus. The antibacterial effectiveness of ZnO-NPs was evaluated against plant pathogenic bacterial species by using the agar disc diffusion method. Established on inhibition zone diameter values, ZnO-NPs displayed varying levels of antibacterial activities against all bacterial species tested. Gram-positive bacterial species were found more sensitive than Gram-negative species. In comparison, the highest antibacterial activity was displayed against Clavibacter michiganensis subsp. michiganensis and Bacillus subtilis subsp. subtilis, the lowest antibacterial activity was recorded for Pseudomonas corrugata. The present research findings suggest that the green synthesized ZnO-NPs have a prospective to be used as optoelectronic materials and antibacterial agents against plant pathogenic bacterial disease.Öğe Enhanced hydration detection properties of nanostructured CuO films by annealing(Elsevier Science Bv, 2016) Sahin, B.; Kaya, T.This work reports the effects of annealing on the material properties and sweat sensing behavior of nanostructured CuO-based films. CuO films were grown on glass substrates via SILAR (Successive Ionic Layer Adsorption and Reaction) method. Films were annealed at 200 degrees C and 400 degrees C in ambient air for 45 min. Scanning electron microscopy analysis confirmed the plate-like morphology of CuO nanostructures with average plate thickness increasing from 30 nm to 70 nm with increasing annealing temperature. X-ray diffraction studies of the films revealed that the average crystallite sizes were around 17-22 nm. The bandgap values were calculated from the UV-visible absorbance spectrum and it was determined that the annealing process lowered the bandgap valued from 1.46 eV to 1.38 eV suggesting that the resistivity would also decrease. The prospect of sweat electrolyte sensing properties of CuO films was studied by drop cast application of different concentrations of artificial sweat solutions. We found that annealing process increases the sensitivity of sweat electrolyte level detection for particularly low concentration artificial sweat solutions. (C) 2016 Elsevier B.V. All rights reserved.Öğe Fabrication and characterization of Mn-doped CuO thin films by the SILAR method(Elsevier Sci Ltd, 2013) Gulen, Y.; Bayansal, F.; Sahin, B.; Cetinkara, H. A.; Guder, H. S.Thin films of un-doped and Mn-doped CuO nanostructures have been deposited on glass substrates via the SILAR method. The morphological, compositional, structural and optical properties of the films have been investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis and UV vis spectrophotometry. The analyzed results indicate that the obtained films consist of plate-like nanostructures. From the EDS analysis it is seen that Mn-doping concentration affects the shapes of the nanostructures. XRD results show that all of the films have monoclinic structure. From the room temperature UV-viS analysis it is found that the optical band gap of the films increases with increasing Mn-doping concentrations. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Öğe Facile fabrication and characterization of SnxCu(1-x)O composite films by the SILAR method on glass substrates(Elsevier Science Sa, 2016) Bayansal, F.; Yuksel, M.; Sahin, B.CuO composite thin films with Sn-doping are deposited on glass substrates by the SILAR method. All the films are characterized by metallurgical microscopy, scanning electron microscopy, energy dispersive Xray spectroscopy, X-ray diffraction, UV-Vis. spectroscopy and Raman spectroscopy. Metallurgical microscopy and scanning electron microscopy results revealed that homogeneity of the film surface distorts and particle size decreases from 110 to 43 nm with increasing Sn-doping. Energy dispersive X-ray spectroscopy evidences the amount of Sn in CuO films, which increases with increasing Sn concentration in the growth solutions. X-ray diffraction patterns showed that the mean crystallite size of the films is decreasing from similar to 14 to similar to 9 nm with increasing Sn-doping. Moreover, increase in Sn concentration results new peaks belong to SnO2 phases. UV-Vis. analysis showed that the transmittance and optical band-gap energy values of the films are increasing with increasing Sn-doping. Raman spectrum was also confirmed the phase formation of CuO nanostructures and it was seen that the Sn-doping caused shifts in Raman active modes. (c) 2015 Elsevier B.V. All rights reserved.Öğe Facile synthesis of group-I elements (K, Li and Na)-doped nanostructured CdO films(Taylor & Francis Ltd, 2014) Sahin, B.; Bayansal, F.In this study, we report an application of facile and low-cost successive ionic layer adsorption and reaction method to investigate nanostructured CdO films. We have tried to enhance some physical properties of nanostructured CdO films by group-I (K, Li and Na) elements doping. The crystal structures, morphology, absorption, transmittance, reflectance behaviour and optical band gap values of CdO films were characterized by using X-ray diffraction (XRD), scanning electron microscopy and ultraviolet-visible spectroscopy techniques. XRD analysis reveals formation of CdO cubic crystalline structure. From these characterizations, it was seen that there are important distinctions in the structural, morphological and optical properties of undoped and K-, Li- and Na-doped nanostructured CdO films.Öğe A green approach for the preparation of nanostructured zinc oxide: Characterization and promising antibacterial behaviour(Elsevier Sci Ltd, 2021) Tasdemir, A.; Aydin, R.; Akkaya, A.; Akman, N.; Altinay, Y.; Cetin, H.; Sahin, B.In the present study, nanostructured zinc oxide (ZnO) films have been successfully synthesized using fruit extract of Viburnum opulus L. (VO) on glass slides by successive ionic layer adsorption and reaction (SILAR) procedure. The impact of VO concentrations on the structural, morphological, optical, electrical, and antibacterial attributes of ZnO films has been investigated in detail. The samples' XRD patterns present a hexagonal crystal structure with a preferential orientation along the (002) plane. The crystallite size values of ZnO samples were found to be in the ranges from 14.88 to 9.23 nm. The supplementation of VO to the synthesis solution remarkably affected the surface morphological features of the ZnO films. The optical results demonstrated that band gap energy values of the ZnO films at room temperature were decreased from 3.20 to 3.07 eV as a function of VO content in the bath solution. The films' electrical properties were determined by impedance analysis in the frequency range of 20 Hz -1 MHz. Impedance-frequency measurements showed VO insertion to ZnO thin films cause an increase in impedance value at the low frequencies. Cole-Cole plots with a single semi-circle confirmed the contribution of grain and grain boundary for the electrical conduction process. The agar disk diffusion method was used to test the antibacterial properties of ZnO/VO inserted ZnO and inhibition zones were measured. VO inserted ZnO showed a stronger inhibitory effect on gram-positive bacteria Staphylococcus aureus (ATCC 25923) and gramnegative bacteria Escherichia coli (ATCC 35218) than ampicillin antibiotic used as a control group. In line with the promising bactericidal results of a new generation, VO inserted ZnO, the nanostructured product with this study, it can also be applied in multidrug-resistant clinical isolates obtained from patients.Öğe Hydration detection through use of artificial sweat in doped- and partially-doped nanostructured CuO films(Elsevier Sci Ltd, 2015) Sahin, B.; Alomari, M.; Kaya, T.A new method of sweat sensing based on nanostructured Copper Oxide (CuO) films is presented. Films were developed by the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The morphological, structural and electrical properties of the CuO films were investigated by scanning electron microscopy, X-ray diffraction analysis, and room temperature current voltage measurements, respectively. We doped CuO films with artificial sweat during the film growth process. We also drop cast the surface of the intrinsic CuO films with artificial sweat to investigate the effect of partial doping. Our results showed that partial doping indeed gave results consistent with those of actual doping. The resistivity of the partially doped films was decreased with increasing artificial sweat concentrations. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Öğe Improved optical performance of CdO films prepared with CTAB as surfactant(Taylor & Francis Ltd, 2014) Sahin, B.The influence of surfactant cetyl trimethyl ammonium bromide (CTAB) on structural, morphological and optical properties of CdO films has been investigated. Five series of CdO films were successfully prepared by successive ionic layer adsorption and reaction method with the assistance of CTAB. These CdO films were characterized by X-ray diffraction, scanning electron microscopy and UV-vis spectroscopy. The CTAB caused in a decrease in crystallite size but an increase in the optical band gap of CdO films. From the optical investigations, it was observed that the transmittance of the pure film was about 2% and it increased dramatically to 37% for 2M% CTAB added CdO films at the wavelength of 1100 nm. The results show that the amount of CTAB played an important role in determining the physical properties of the CdO nanostructures.Öğe Influence of annealing to the properties of un-doped and Co-doped CdO films(Elsevier Sci Ltd, 2014) Sahin, B.; Bayansal, F.; Yuksel, M.; Cetinkara, H. A.Un-doped and Co-doped CdO nanostructures were deposited on glass substrates by successive ionic layer adsorption and reaction (SILAR) method and annealed at 300 and 400 C. Morphological, structural and optical properties of the films were investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD) and ultra violet-vis (UV-vis) spectrophotometry. The analyzed results indicate that Co-doping concentration and annealing temperature affect the properties of nanostructure cadmium oxide (CdO) films. XRD results showed that all of the films are polycrystalline cubic CdO with good crystallinity levels. With UV-vis. analysis at the room temperature it was found that the doping and annealing temperature changed optical properties of CdO films. (C) 2013 Elsevier Ltd. All rights reserved.Öğe Influence of coumarin as an additive on CuO nanostructures prepared by successive ionic layer adsorption and reaction (SILAR) method(Elsevier Science Sa, 2013) Bayansal, F.; Sahin, B.; Yuksel, M.; Biyikli, N.; Cetinkara, H. A.; Guder, H. S.The effect of coumarin doping during the growth of CuO nanostructures by SILAR method has been studied. It was found that coumarin consider ably influences the growth process, manipulates the band-gap and modifies the crystallite size of the films. XRD experiments evidenced that with higher coumarin concentrations in the growth solution, the microstrain and dislocation density increased, while the crystallite size of the films decreased. SEM images revealed that the thicknesses of the plate-like nanostructures decreased with increasing coumarin concentration. By UV/vis spectrophotometer analysis it is found that the coumarin concentration affects both the optical band gap and the transmission rate: both the band gap and spectral transmittance values of the films decreased for higher coumarin content. (C) 2013 Elsevier B. V. All rights reserved.Öğe Influence of manganese concentration and annealing temperatures on the physical properties of CdO films grown by the SILAR method(Taylor & Francis Ltd, 2014) Sahin, B.; Bayansal, F.; Yuksel, M.Undoped and doped Cadmium oxide (CdO) films with different Mn concentrations were prepared on glass substrates by the successive ionic layer adsorption and reaction method and annealed at two different temperatures. Structural, morphological and optical conditions were performed by XRD, scanning electron microscope (SEM) and UV-vis spectrum measurements. The deposited films were dense and they adhere well to the glass substrates. From the SEM photographs, it was seen that Mn doping concentration and annealing process affect the morphologies of the nanostructures. It was found that the growth process modifies the microstructures of the CdO films. XRD results and UV-vis analysis reveal that the crystal structure and optical band gap of the films could be adjusted by varying the Mn concentration and annealing temperature. The results also indicate that there is a direct dependence of the physical and optical properties of the metal oxide films on doping concentration and annealing process.Öğe Li:Ce co-doped CdO films synthesized by SILAR method: Effects of rare earth element Ce content on the physical attributes(Elsevier Sci Ltd, 2018) Aydin, R.; Sahin, B.Undoped, Li-doped (Li0.02Cd0.98O) and Li:Ce co-doped (Ce-x Li0.02Cd0.98-xO (x = 0.005, 0.01 and 0.02)) CdO nanofilms were prepared by a successive ionic layer adsorption and reaction (SILAR) process. The effects of the Li and Li:Ce doping on the main physical properties such as crystal structure, surface morphological characteristics and optical features like bandgap and transmittance of obtained these films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis spectrophotometer respectively. X-ray diffractogram analysis verified that the synthesized CdO films pertain to the cubic structure. XRD analysis indicated the growth of CdO with polycrystalline form for preferential orientation along the (111) and (200) plane. It is obviously seen from the SEM micrographs that Li doping and Li:Ce co-doping induce remarkable changes in the CdO surface morphology. The UV-Vis spectroscopy analysis results show that the (2.0% Li + 1.0% Ce) Li:Ce co-doped CdO films exhibits maximum transmittance (27%) in the range between 300 and 1100 nm and high optical bandgap energy (E-g = 2.92 eV).Öğe Light-weight and flexible Ni-doped CuO (Ni:CuO) thin films grown using the cost-effective SILAR method for future technological requests(Springer, 2022) Aydin, R.; Akkaya, A.; Sahin, B.Products based on nanostructured flexible thin films, which are anticipated to make their way into our lifetimes in the near future. Therefore, nanostructured metal-oxide thin-film materials grown on flexible substrates are anticipated to meet emerging technological requests. In this article, we present a promising light-weight and flexible thin-film material using un-doped and Ni-doped CuO samples. Ni:CuO flexible thin-film materials were fabricated by using the cost-effective SILAR method on cellulose acetate substrates and the effects of both Ni doping and bending on the change in electrical and optoelectronic performances were investigated. It is observed that Ni doping has a great impact on the main physical properties of flexible CuO samples. The optical bandgap value of the un-doped CuO film improves with increasing Ni ratio in the growth bath. Also, sheet resistance values of the un-doped and Ni:CuO samples are a little affected due to bending of samples for bending radius similar to 20 mm. These flexible all solution-processed nanostructured CuO samples are promising candidates for use in future optoelectronic applications.
