Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026Scopus SJRQ2/r/munzur/993
  Structural and optical properties of Bi- and Sn-doped Sb2Se3 thin films prepared by thermal evaporation

  Kök, Mediha; Öztürk, Yunus; Sait Kanca, M.

  In this study, Sb2Se3-based semiconductor thin films, both pure Sb2Se3 and those doped with Bi and Sn, were produced using the thermal evaporation method. The structural, morphological, and optical properties of the obtained films were investigated using XRD, SEM, and UV–Vis spectroscopy. While films without annealing exhibited an amorphous structure, significant crystallization was observed after annealing at 350 °C, especially at high doping levels. SEM analyses showed significant changes in surface morphology and grain structure depending on the doping level. Optical measurements revealed that absorption increased and the band gap changed with increasing doping level. The band gap for the undoped Sb2Se3 thin film was found to be 1.54 eV. An increase due to the Burstein–Moss effect was observed at low additive ratios, while band narrowing was observed at high additive ratios. The results obtained indicate that Bi and Sn additives improve the optoelectronic properties of Sb2Se3 thin films and hold potential for photovoltaic applications.

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• MakaleAçık Erişim2025Scopus SJRQ2/r/munzur/1526
  Impact of sub-eutectoid thermal aging on martensitic transformation, thermo-structural properties, and gamma-neutron shielding performance of CuAlMnFe high-temperature shape memory alloy

  Karaduman, Oktay; Kalay, Ece; Ozkul, Iskender; Kurgun, Mehmet Ali; Canbay, Canan Aksu; Guler, Omer; ALMisned, Ghada; Baykal, Duygu Sen; Tekin, H.O.

  A novel Cu-based high-temperature shape memory alloy (HTSMA) with the composition 70.84Cu–23.80Al–4.14Mn–1.22Fe (at. %) was successfully synthesized via arc melting in this study. The effects of thermal aging duration on the alloy’s martensitic transformation behavior, shape memory effect (SME), and microstructural evolution were systematically investigated. Six samples were prepared from the as-cast ingot: one was homogenized in the β-phase region and quenched into ice-brine to induce a martensitic structure, while five others were subsequently aged at 350 ℃ for varying durations and air-cooled. Thermal and structural characterizations were conducted. These included differential scanning calorimetry (DSC), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and optical microscopy. Prolonged aging altered transformation temperatures and reduced both enthalpy and entropy values. It also promoted the formation of observed precipitates, vacancies, and coarsened 2H martensites. Prolonged aging altered the microstructure and thermal response, leading to partial SME degradation. Additionally, the alloy’s gamma-ray and fast neutron shielding parameters were theoretically estimated using simulation software to explore its potential functional scope. The calculated results indicate that the CuAlMnFe HTSMA is predicted to exhibit favorable attenuation performance across a wide energy spectrum, with appropriate values of mass attenuation coefficient (MAC) and half-value layer (HVL). In particular, the fast neutron removal cross-section was calculated as 0.139 cm−1, which is significantly higher than those of water (0.1023 cm−1), graphite (0.0773 cm−1), and B4C (0.0714 cm−1). In conclusion, the CuAlMnFe HTSMA developed in this study offers a unique profile combining tailorable shape memory behavior with a computationally predicted potential for nuclear radiation shielding. These properties offer novel insights into the alloy’s potential for applications in high-radiation environments that require both mechanical actuation and radiation protection, pending experimental validation of its shielding performance.

  AtıfScopus1·OpenAlex1

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• MakaleAçık Erişim2025Scopus SJRQ2/r/munzur/1312
  High thermal stability and dielectric performance of phenylhydrazine-based Schiff base oligomers obtained via oxidative polycondensation

  Solmaz, Adnan; Kaya, İsmet; Bayır, Erdal

  In this study, the 2-PHMBD Schiff base, synthesized through the condensation of 2,4-dihydroxybenzaldehyde (2,4-DHBA) with phenylhydrazine (PH), was subjected to oxidative polymerization in a basic medium using hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), and molecular oxygen (O2) as oxidizing agents. Three oligomers, designated as o-(2-PHMBD)-P, o-(2-PHMBD)-H, and o-(2-PHMBD)-O, were successfully obtained and comprehensively characterized by FT-IR, 1H-13C-NMR, UV–Vis, CV, GPC, SEM, TGA, and DSC analyses. Spectroscopic results confirmed the successful polymerization, while morphological and thermal analyses revealed the distinct physical characteristics of the oligomers. According to GPC data, o-(2-PHMBD)-H exhibited the highest average molecular weight of 4700 Da, and TGA analysis demonstrated that o-(2-PHMBD)-O had the highest thermal stability with a residue of 46% at 1000 °C. The DSC results showed the highest glass transition temperature of 132 °C for o-(2-PHMBD)-H. UV–Vis and CV measurements indicated reduced optical and electrochemical band gaps compared with the monomer, with the lowest optical band gap determined as 2.74 eV. Dielectric measurements revealed that o-(2-PHMBD)-H displayed the highest dielectric constant of 2.57 and conductivity of 2.49 × 10⁻7 S cm⁻1. These results demonstrate that phenylhydrazine-based Schiff base oligomers possess high thermal stability and favorable dielectric properties, making them promising materials for optoelectronic and dielectric device applications.

  AtıfScopus3·WoS2·OpenAlex4

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• MakaleYalnız künye2022Scopus SJRQ2/r/munzur/2817
  Fe3O4 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.

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  AtıfScopus21·WoS22·OpenAlex18

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• MakaleYalnız künye2021Scopus SJRQ2/r/munzur/2893
  Structural, 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.

  AtıfScopus15·WoS15·OpenAlex18

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• MakaleAçık Erişim2021Scopus SJRQ2/r/munzur/2540
  Facile 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.

  AtıfScopus29·WoS27

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• MakaleYalnız künye2020Scopus SJRQ2/r/munzur/3326
  Structural, 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.

  AtıfScopus42·WoS40·OpenAlex46

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• MakaleAçık Erişim2020Scopus SJRQ2/r/munzur/3118
  The effect of graphene nanoplatelets on technical properties of micro- and nano-sized TiO2 matrix: a comparative research study on electrical and optical characteristics

  Güler, Ömer; Ayhan, Hakan; Başgöz, Öyküm; Yavuz, Çağdaş; Albayrak, M. Gökhan; Evin, Ertan; Safa, Hasan; Yahia, Ibrahim S.

  In this study, titanium dioxide (TiO2)-based graphene nanoplatelets (GNPs)-reinforced composite materials were produced and the electrical and optical properties of the composite materials were investigated. Graphene, which was used as a reinforcing material, was produced by using liquid-phase exfoliation method. While the TiO2 used as matrix material was commercially available for the first group of samples, it was produced by using the sol–gel method for the second group of the samples. Different rates of graphene were added to the TiO2 powders which were commercially available and produced by using sol–gel method. GNPs used as a reinforcing material were subjected to TEM analysis. The resulting composite materials were structurally examined in SEM and XRD. Then, the changes in electrical conductivity of these composites under the impact of temperature were measured. UV–Vis spectrometers of the samples were taken and their optical properties were determined. When temperature-based electrical examination of the produced composite materials was performed, an increase was observed on the electrical conductivity values in both groups of samples as a result of addition of the reinforcing element. In addition, TiO2-containing composites produced by using sol–gel method had lower electrical conductivity comparing with commercially purchased TiO2-containing composites especially at high temperatures. In the optical measurements, it was observed that there was an increase in the optical bandgap energy range values with GNPs reinforcement but a decrease in the reflectance values.

  AtıfOpenAlex2

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