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- MakaleYalnız künye2022Scopus SJRQ1Morpho-structural and optoelectronic properties of diamond like carbon–germanium (DLC-Ge) composite thin films produced by magnetron sputtering
Aslan, Naim; Kurt, Mustafa Şükrü; Mehmet Koç, Mümin
Diamond-like carbon films have found various areas of application due to their particularly durable characteristics. To enhance the electrical and optoelectronic characteristics of the material, diamond-like carbon was co-deposited with Ge on p-type Si wafer using the DC magnetron sputtering technique, from which diamond-like carbon-germanium nanocomposites were obtained. The structural properties of the nanocomposites were assessed using electron microscopy techniques. The chemical structure of the nanocomposite films was confirmed using energy dispersive spectroscopy and Raman spectroscopy. The electrical properties of the nanocomposite films were investigated via various electrical parameters as determined through current-voltage, capacitance–voltage, and conductance–voltage graphs. Photoresponsive and photosensitivity properties were also assessed using a solar simulator at various illumination intensities. It was concluded that nanocomposite thin films were responsive to light, where photosensitivity and photoresponsivity increased with increasing illumination intensity. The electrical characteristics of the nanocomposite films were associated with the frequency of the AC voltage applied.
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İncele - MakaleYalnız künye2022Scopus SJRQ2Fe3O4 nanoparticle decorated novel magnetic metal oxide microcomposites for the catalytic degradation of 4-nitrophenol for wastewater cleaning applications
Hasanoğlu Özkan, Elvan; Aslan, Naim; Koç, Mümin Mehmet; Kurnaz Yetim, Nurdan; Sarı, Nurşen
Co3O4, NiO and ZnO microparticles were decorated with Fe3O4 nanoparticles where novel Co3O4@Fe3O4, NiO@Fe3O4 and ZnO@Fe3O4 microcomposites were obtained with significant magnetic properties. Decorating microparticles with Fe3O4 nanoparticles helped us to obtain microcomposites with outstanding magnetic characteristics, since Fe3O4 nanoparticles were decorated on the upper shell of the microstructures where the magnetic characteristics of the composites were not suppressed, and good catalytic performance was obtained. SEM was used to assess the physical morphology of the microparticles which indicate that microparticles were in flower or ball-like shape. Magnetic properties were checked using VSM which revealed that magnetic composites are in ferromagnetic characteristics. Optic characteristics of the particles were checked by UV–Vis spectrometry to assess bandgap energies which indicate that doping microparticles with Fe3O4 slightly alters the bandgap energies of microparticles. The catalytic role of microparticles and microcomposites for the catalytic reduction of 4-nitrophenol to 4-aminophenol was studied.
AtıfScopus21WoS22OpenAlex18İncele - MakaleYalnız künye2022Scopus SJRQ2Structural, biocompatibility, and antibacterial properties of Ge–DLC nanocomposite for biomedical applications
Arslan, Mehmet Enes; Kurt, Mustafa Şükrü; Aslan, Naim; Kadi, Abdurrahim; Öner, Sena; Çobanoğlu, Şeymanur; Yazici, Ayşenur
Integrative production of new nanocomposites has been used to enhance favorable features of biomaterials for unlocking ultimate potential of different molecules. In the present study, advantageous properties of diamond like carbons (DLC) and germanium (Ge) like greater biocompatibility and antibacterial attributes were aimed to combined into a thin film. For this purpose, 400 nm DLC–Ge nanocomposite was coated on the borosilicate glasses via the magnetron sputtering and surface characteristics was analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and The Raman spectrum. Biocompatibility analysis were performed by 3-(4,5-Dimethylthiazol-2-yl) (MTT) cell viability assay and Hoechst 33258 fluorescent staining genotoxicity assessments on the human fibroblast cell line (HDFa). Finally, antibacterial properties of DLC–Ge nanocomposite coatings were investigated by Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923) bacterial attachment analysis. As a result of magnetron sputtering coating, nearly 400 nm thick DLC–Ge nanocomposite film showed a smooth, a non-porous, and a dense characteristic. Cell viability analysis showed that Ge–DLC coatings permits %95 cell surface growth of fibroblast cells. Also, there were no significant difference in aspect of nuclear abnormalities compared to the (−) control which showed nonmutagenic features of the thin film. Finally, antibacterial attachment analysis put forth that Ge–DLC coatings inhibits bacterial adhesion as %40 and %25 rates for P. aeruginosa and S. aureus bacterial strains, respectively. From these results, DLC–Ge nanocomposites could be proposed as a potential new biomaterial for various biomedical applications.
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İncele - Kitap BölümüYalnız künye2022X-Ray Computed Tomography and Magnetic Resonance Imaging Applications of Magnetic Nanoalloys and Nanocomposites
Aslan, Naim; Koç, Mümin Mehmet
Metallic nanoparticles were used in different medical and biological applications. Such applications can cover targeted drug delivery, biomarking, MRI imaging, CT imaging, magnetic hyperthermia, etc. Metallic nanoparticles show outstanding properties with high electron affinity and good electrical, electronic, and optoelectronic properties with possible magnetic characteristics. In this regard, magnetic nanoparticles and magnetic nanoalloys are found to be a suitable candidate to be used in imaging applications. In this chapter, concepts of X-ray computed tomography imaging and magnetic resonance imaging are briefly discussed. Magnetic nanoparticles, nanoalloys, and nanocomposites used in imaging, diagnostics, and theranostic applications were illustrated.
AtıfScopus2OpenAlex1İncele - MakaleYalnız künye2021Scopus SJRQ2Structural, photovoltaic and optoelectronic properties of graphene–amorphous carbon nanocomposite
Aslan, Naim
Reduced graphene oxide–amorphous carbon nanocomposites were coated on p-Si wafers to prepare graphene-based photodiodes or photodetectors. Electrophoretic deposition was used to prepare electronic devices. Scanning electron microscopy, energy-dispersive spectra, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used in the morphological and structural characterization. Characterization methods confirm that deposited films are in reduced graphene oxide–amorphous carbon nanocomposite structure. Photoresponsive characteristics were checked using I–V, I–t and C–t techniques. It was seen that diodes are responsive to illumination where increased photocurrent and photocapacitance were obtained for increased illumination intensity. Electrical properties were assessed; C–V, G–V properties were found to depend on AC signal frequency. Signal frequency-dependent behavior was attributed to interface states. The density of interface states was calculated, and it was seen that the density of interface states increases with increasing AC signal frequency. It was illustrated that electrical characteristics of photodiodes were affected by signal frequency and the density of interface states.
AtıfScopus15WoS15OpenAlex18İncele - MakaleAçık Erişim2021Scopus SJRQ2Facile preparation of commercial Bi2O3 nanoparticle decorated activated carbon for pseudocapacitive supercapacitor applications
Üner, Osman; Aslan, Naim; Sarıoğlu, Akın; Semerci, Fatih; Koç, Mümin Mehmet
In this work, a facile method to prepare Bi2O3 decorated activated carbon (Bi2O3@AC) composites with high pseudocapacitive properties was presented. The inorganic–organic composites synthesized using commercial Bi2O3 and active carbon with different weight ratio. The composites were assessed using spectroscopic, microscopic, and diffractive techniques. Our assessments confirmed that active carbons were successfully doped with commercial Bi2O3 nanoparticles with different dopant rates. The electrochemical performance of as-prepared materials was researched by cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy in 6 M KOH electrolyte. Higher specific capacitance was achieved for increased Bi2O3 nanoparticle in composites. The 20%-Bi2O3@AC had a maximum specific capacitance of 565 F/g at a current density of 1 A/g. In addition, the symmetrically assembled supercapacitor delivers a high energy density (23.0 Wh kg−1). Moreover, 67% of the initial capacitance is maintained after 1500 cycles at 200 mV/s, suggesting good cycling stability. Due to the synergistic effect of compositing a promising electrochemical performance was observed that was not obtained by bare AC or Bi2O3. As a result, the electrochemical properties of 20%-Bi2O3@AC composite is promising and it may be used as potential electrode for supercapacitor.
AtıfScopus29WoS27İncele - MakaleYalnız künye2020Scopus SJRQ2Metallic nanoparticles as X-Ray computed tomography (CT) contrast agents: A review
Aslan, Naim; Ceylan, Burhan; Koç, Mümin Mehmet; Findik, Fehim
X-ray computed tomography vastly used in both medical purposes and in the research of biological and non-biological materials/samples. Some of the medical applications performed in the clinics requires special protocols where contrast agents may be needed to enhance the contrast. Iodine based contrast agents are commonly used in such applications. Iodine based contrast agents were found hazardous to the environment and some patients has iodine in tolerance due to thyroid origin diseases. Scientists from different fields try to develop contrast agents which can be an alternative to iodine based contrast agents. Metallic nanoparticles have potential to be used as CT contrast agent since metals has high X-ray attenuation and high density. Metal nanoparticles considered as toxic to the living organisms. Covering nanoparticles with organic molecule often reduce toxicity and enhance the biocompatibility. Decoration of nanoparticles with function groups give them targeting properties where special organ and/or tissue can be targeted. Up to now, different studies illustrated the importance of the multipurpose properties of the metallic nanoparticles. In this report, we assessed the metal nanoparticles reported as X-ray computed tomography contrast agent. For the first time in the literature we listed in vivo contrast enhancement, targeted drug delivery and dual/multipurpose imaging properties of each metallic nanoparticles. Therapeutic effects of metallic nanoparticles such as photothermal therapy and magnetic hyperthermia were also addressed. A chart showing relative contrast enhancement properties of the nanoparticles were produced.
AtıfScopus127OpenAlex134İncele - MakaleYalnız künye2020Scopus SJRQ2Structural, electrochemical and optical properties of hydrothermally synthesized transition metal oxide (Co3O4, NiO, CuO) nanoflowers
Yetim, Nurdan Kurnaz; Aslan, Naim; Sarıoğlu, Akın; Sarı, Nurşen; Koç, Mümin Mehmet
In this work, structural, electrochemical and optical properties of the flower-like Co3O4, NiO and CuO nanostructures were investigated. Co3O4, NiO and CuO nanoflowers were prepared using hydrothermal method. Fourier transform infrared spectroscopy was used in the confirmation of the chemical composition of the nanostructures. X-ray diffraction (XRD) was used in the analysis of crystal structures that peaks observed in the XRD analysis confirms good crystallinity of the nanoflowers. Scanning electron microscopy analysis was used to illustrate the flower-like structure of the nanostructures. Cyclic voltammetry (CV) was used in the assessment of the electrochemical properties. It was seen that flower-like Co3O4, NiO and CuO nanostructures have enhanced electrochemical properties. Using CV results, redox reaction processes of the Co3O4, NiO and CuO nanoflowers were determined. Diffusion constants were determined and NiO nanoflowers found to have the highest diffusion constant among those. Nyquist and Bode diagrams were evaluated. Energy band gaps of Co3O4, NiO, CuO nanoflowers were calculated which were found to be 2.10 eV, 2.25 eV and 3.71 eV, respectively.
AtıfScopus42WoS40OpenAlex46İncele - MakaleYalnız künye2020Scopus SJRQ1Structural and catalytic properties of Fe3O4doped Bi2S3novel magnetic nanocomposites: P-Nitrophenol case
Kurnaz Yetim, Nurdan; Aslan, Naim; Koç, Mumin Mehmet
Catalytic properties of Bi2S3 nanostructures, Fe3O4 nanoparticles and novel Bi2S3@Fe3O4 magnetic nanocomposites were investigated. Flower-like Bi2S3 nanostructures were produced using hydrothermal synthesis. Bi2S3 nanostructures were doped with Fe3O4 nanoparticles where Bi2S3@Fe3O4 novel magnetic nanocomposites was obtained. Structural characterization of the nanoflowers were performed using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Microscopic characterization of the nanoflowers was performed using electron microscopy where scanning electron microscope (SEM) and transmission electron microscope (TEM) were used in the characterization which confirms the flower like structures. Vibrating sample magnetometry (VSM) confirmed the magnetic properties of the ferromagnetic characteristics of the magnetic nanocomposites. Optic properties of the nanoparticles were assessed using Ultraviolet - visible (UV-vis) spectroscopy. Band gap energies of the Bi2S3, Fe3O4 and Bi2S3@Fe3O4 were found to be 1.80 eV, 2.0 eV and 2.72 eV, respectively. Catalytic properties of the Bi2S3@Fe3O4 nanoparticles were confirmed using UV spectroscopy where reduction of p-nitrophenol to p-aminophenol was assessed in the presence of NaBH4. It was concluded that Bi2S3 nanostructures and Bi2S3@Fe3O4 nanocomposites showed better catalytic performance than that of Fe3O4 nanoparticles. Such a case was attributed to increased surface area - volume ratio. Results indicate that nanocomposites have the potential to be used in the wastewater treatment.
AtıfScopus55WoS55OpenAlex56İncele - Derleme MakaleAçık Erişim2019Scopus SJRQ2Evaluation of X-ray tomography contrast agents: A review of production, protocols, and biological applications
Koç, Mümin Mehmet; Aslan, Naim; Kao, Alexander P.; Barber, Asa H.
X-ray computed tomography is a strong tool that finds many applications both in medical applications and in the investigation of biological and nonbiological samples. In the clinics, X-ray tomography is widely used for diagnostic purposes whose three-dimensional imaging in high resolution helps physicians to obtain detailed image of investigated regions. Researchers in biological sciences and engineering use X-ray tomography because it is a nondestructive method to assess the structure of their samples. In both medical and biological applications, visualization of soft tissues and structures requires special treatment, in which special contrast agents are used. In this detailed report, molecule-based and nanoparticle-based contrast agents used in biological applications to enhance the image quality were compiled and reported. Special contrast agent applications and protocols to enhance the contrast for the biological applications and works to develop nanoparticle contrast agents to enhance the contrast for targeted drug delivery and general imaging applications were also assessed and listed.
AtıfScopus91OpenAlex101İncele - MakaleAçık Erişim2019Scopus SJRQ3The effects of deposition potential on the optical, morphological and mechanical properties of DLC films produced by electrochemical deposition technique at low voltages
Aslan, Naim; Başman, Necati; Uzun, Orhan; Erkovan, Mustafa; Yakuphanoǧlu, Fahrettin
Diamond-like carbon (DLC) films were electrochemically deposited onto indium tin oxide (ITO) substrates using acetic acid and deionized water as electrolyte at low deposition voltages (2.4 V and 60 V). The transmittance of the films was investigated by UV spectrometry. Transmittance measurements versus wavelength revealed that the films transmit 86 % to 89 % light in visible region and band gap of the films varies between 3.87 eV and 3.89 eV. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used for structural characterization to evaluate surface morphology of the DLC films. The grain size and the surface roughness increased for the films prepared at higher deposition potential, while their measured average height decreased. The mechanical properties (hardness H and elastic modulus Er) were determined from load-displacement curves which were obtained by using nanoindentation method. Hardness and elastic modulus of the films increased as the deposition voltage of the films increased from 2.4 V to 60 V.
AtıfScopus9OpenAlex4İncele - MakaleAçık Erişim2019Scopus SJRQ2Electrical characterization of solar sensitive zinc oxide doped-amorphous carbon photodiode
Koç, Mümin Mehmet; Aslan, Naim; Erkovan, Mustafa; Aksakal, Bünyamin; Uzun, Orhan; Farooq, W. Aslam; Yakuphanoğlu, Fahrettin
A new solar-sensitive zinc oxide doped-amorphous carbon diode was fabricated using the electrochemical deposition technique. The current-voltage characteristics of the fabricated Al/ZnO-a:C/p-Si/Al diode were investigated under dark and various lighting intensities using both I-V and C-V methods. The fabricated diode was characterized by XRD, SEM-EDS, FTIR and XPS analysis. Through the analysis, it was determined that the photocurrents increased with increasing intensity of incident light. The capacitance-voltage (C-V) characteristics revealed that the capacitance of the diode depended on voltage, frequency and illumination, indicating the existence of a continuous distribution of interface states. It was found that the capacitance changed drastically with changing frequency and separation was observed in different frequencies, as identified in the reverse bias region. The ideality factor obtained was found to be higher than unity, with the average barrier height and ideality factor of the diode were found to be 0.528 ± 0.0069 eV and 5.24 ± 0.39, respectively. The newly fabricated ZnO-doped amorphous carbon (Al/ZnO-a:C/p-Si/Al) photodiode exhibited good solar sensitivity. The overall results indicated that the fabricated Al/ZnO-a:C/p-Si can be used as a solar sensitive diode in optoelectronic device applications as an alternative to graphene-based materials.
AtıfScopus41OpenAlex46İncele - MakaleAçık Erişim2018Scopus SJRQ3Ti doped amorphous carbon (Al/Ti-a:C/p-Si/Al) photodiodes for optoelectronic applications
Aslan, Naim; Koç, Mümin Mehmet; Dere, Ayşegül; Arif, Bilal; Erkovan, Mustafa; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, Fahrettin
Electrochemical deposition technique was used to fabricate titanium doped amorphous carbon (Ti doped a:C) Al/Ti-a:C/p-Si/Al photodiode. The effects of illumination on the current–voltage (I–V) characteristics of the Al/a:C/p-Si/Al doped Ti diode for optoelectronic applications were investigated. The reverse current of the diode increased with the increasing illumination intensities when the bias voltage was applied. By using the forward bias I–V characteristics, the ideality factor (n) and barrier height (Φb) of Al/Ti-a:C/p-Si photodiode structure was found as 1,84 and 0,50 eV, respectively. In addition, the capacitance–voltage (C–V) and conductance–voltage (G–V) measurements of the diode were studied in the frequency range of 100 kHz–600 kHz. The measured values of the capacitance decreased with the increasing frequency. The photoelectrical properties of Al/Ti-a:C/p-Si/Al device indicates that the photodiode investigated in this paper has great potential to be used in optoelectronic device applications and in industry.
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