Yazar "Ekinci, A." seçeneğine göre listele

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    Dynamic 1H NMR Studies of Schiff Base Derivatives
    (Springer, 2016) Koylu, M. Z.; Ekinci, A.; Boyukata, M.; Temel, H.
    The spin-lattice relaxation time T (1) and the spin-spin relaxation time T (2) of two Schiff base derivatives, N,N'-ethylenebis(salicylidene)-1,2-diaminoethane (H2L1) and N,N'-ethylenebis (salicylidene)-1,3-diaminopropane (H2L2), in DMSO-d(6) solvent were studied as a function of temperature in the range of 20-50A degrees C using a Bruker Avance 400.132 MHz H-1 NMR spectrometer. Based on the activation energy (E (a)) and correlation time (tau(c)), we believe that the Schiff base derivatives perform a molecular tumbling motion.
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    Effect of Ce doping on the characteristic properties of CdS nanoparticles
    (S.C. Virtual Company of Phisics S.R.L, 2020) Ekinci, A.; Horoz, S.; Şahin, Ö.
    In our present study, Ce doped CdS nanoparticles were synthesized in room temperature environment by using chemical co-precipitation technique which is cheap in cost. Ce doped CdS nanoparticles (average particle size: 3.7 nm) were found to have cubic structure as a result of XRD measurements. It has also been clearly observed that Ce dopant ions do not alter the structure of the host semiconductor CdS. Using the spectrum obtained as a result of UV-Vis measurement, the energy band gap of Ce doped CdS nanoparticles was determined as 2.73 eV. This value was observed to be higher than the energy band gap of bulk CdS (2.42 eV). Thus, it can be said that this change in the energy band gap is due to the quantum confinement effect. The maximum IPCE value was 27% for Ce doped CdS nanoparticles while the IPCE values was 4% for pure CdS nanoparticles, respectively. The IPCE of the solar cells improves with the Ce dopant ion. Moreover, the spectral response range of Ce doped CdS nanoparticles widens with the Ce dopant ion. This is attributed to the long lifetimes of the Ce3+ excited states that facilities the transfer of the charge carries to the photoelectrode. © 2020, S.C. Virtual Company of Phisics S.R.L. All rights reserved.
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    EFFECT OF Ce DOPING ON THE CHARACTERISTIC PROPERTIES OF CdS NANOPARTICLES
    (Natl Inst R&D Materials Physics, 2020) Ekinci, A.; Horoz, S.; Sahin, O.
    In our present study, Ce doped CdS nanoparticles were synthesized in room temperature environment by using chemical co-precipitation technique which is cheap in cost. Ce doped CdS nanoparticles (average particle size: 3.7 nm) were found to have cubic structure as a result of XRD measurements. It has also been clearly observed that Ce dopant ions do not alter the structure of the host semiconductor CdS. Using the spectrum obtained as a result of UV-Vis measurement, the energy band gap of Ce doped CdS nanoparticles was determined as 2.73 eV. This value was observed to be higher than the energy band gap of bulk CdS (2.42 eV). Thus, it can be said that this change in the energy band gap is due to the quantum confinement effect. The maximum IPCE value was 27% for Ce doped CdS nanoparticles while the IPCE values was 4% for pure CdS nanoparticles, respectively. The IPCE of the solar cells improves with the Ce dopant ion. Moreover, the spectral response range of Ce doped CdS nanoparticles widens with the Ce dopant ion. This is attributed to the long lifetimes of the Ce3+ excited states that facilities the transfer of the charge carries to the photoelectrode.
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    EFFECT OF Mo DOPING ON THE PHOTOVOLTAIC PROPERTIES OF Mo DOPED Cd1-xZnxS (x= 3 %) QUANTUM DOTS SYNTHESIZED BY SILAR
    (Virtual Inst Physics, 2018) Ekinci, A.; Sahin, O.; Horoz, S.
    Cd1-xZnxS (x=3 %) and Mo-doped Cd1-xZnxS (x=3 %) quantum dots (QDs) with different Mo concentrations were synthesized at room temperature using successive ionic layer adsorption and reaction (SILAR) method. The aim of the study is to determine the optimum Mo concentration in Mo-doped CdZnS QDs using the incident photon to electron conversion efficiency (IPCE) measurements. To be obtained IPCE% values of samples, Cd1-xZnxS (x=3 %) and Mo-doped Cd1-xZnxS (x=3 %) QDs with different Mo concentrations were grown on TiO2 coated onto FTO conductive glass substrates. As a last part of the study, the structural, elemental and optical properties of Mo-doped Cd1-xZnxS (x=3 %) QDs containing optimum Mo content were investigated, respectively. Consequently, it appears that Mo-doped Cd1-xZnxS (x=3 %) QDs have a higher efficiency than Cd1-xZnxS (x=3 %) QDs and that Mo content plays an important role in this improvement.
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    HYDROGEN GENERATION BY HYDROLYSIS OF NaBH4 WITH EFFICIENT Co-La-W-B CATALYST FOR PEM FUEL CELLS
    (Virtual Inst Physics, 2020) Ekinci, A.; Horoz, S.; Baytar, O.; Sahin, O.
    In this study, Co-B based quaternary alloy catalysts were synthesized for use in NaBH4 hydrolysis. Lanthanum (La) and tungsten (W) metals were added to Co-B catalyst by chemical reduction method. The effect of metal content (La and W), NaBH4 concentration, NaOH concentration, catalyst amount and temperature parameters were investigated in NaBH4 hydrolysis. Activity results show that the hydrolysis reaction rate first increases and then decreases with increasing NaBH4 concentration as well as NaOH concentration. The activation energy of the hydrolysis for Co-La-W-B catalysts was calculated as 39.2 kJ / mol. The maximum value of hydrogen generation rate was 3280 ml / min. In terms of application, hydrogen produced in the presence of the Co-La-W-B catalyst was used in PEM fuel cell application. Average yield value according to power and ideal voltage and maximum power value of the system were determined as 57%, 73% and 1.4 Watt, respectively. This original study demonstrates that the Co-La-W-B catalyst can be used as an ideal catalyst for PEM fuel cell applications.
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    Hydrogen Generation by Hydrolysis of NaBH4with Efficient Co-La-Mo-B Catalyst for PEM Fuel Cells
    (Pleiades Publishing Inc, 2020) Ekinci, A.
    In this study, Co-La-Mo-B catalyst used for hydrogen production by hydrolysis of sodium borohydride (NaBH4) solution was synthesized by chemical reduction method. Characterization of the synthesized catalyst was carried out with EDX and XRD. In hydrolysis experiments, the effect of parameters such as molybdenum, NaOH and NaBH(4)concentration, catalyst amount and temperature were investigated. The best Mo concentration was found to be 5%. In the presence of the Co-La-Mo-B catalyst in NaBH(4)hydrolysis, hydrogen initial production rate was found to be 9508 mL g(-1)min(-1). The activation energy of NaBH(4)hydrolyses was determined as 39.5 kJ/mol. The effect of hydrogen gas obtained using the Co-La-Mo-B catalyst in NaBH(4)hydrolysis on fuel cell efficiency was determined by measuringI-Vvalues. Average efficiency values according to power and ideal voltage were found as 60 and 80%, respectively. From the results, it can be said that the Co-La-Mo-B catalyst is an ideal catalyst for PEM fuel cell applications.
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    Synthesis and characterization of Fe:MgZnO/AC as a prospective high photocatalytic material
    (Virtual Co Physics Srl, 2021) Cevik, M. S.; Horoz, S.; Baytar, O.; Sahin, O.; Ekinci, A.
    The motivation of our current study is to carry out photocatalytic degradation experiments of methylene blue in the presence of Fe doped MgZnO/AC (Fe:MgZnO/AC) and MgZnO/AC catalysts and thus to examine the effect of the Fe-dopant metal on the photocatalytic activity of the catalysts. In this context, both catalysts (MgZnO/AC and Fe:MgZnO/AC) are synthesized by hydrothermal technique. Structural (XRD analysis) and optical (UV-Vis) properties of the synthesized catalysts are discussed. How the Fe-dopant metal affects the crystallite size and energy band gap of the MgZnO/AC catalyst is examined and the experimental data obtained are interpreted.
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    SYNTHESIS OF CE-DOPED ZNS NANOPARTICLES BY CHEMICAL PRECIPITATION METHOD AND INVESTIGATION OF THEIR STRUCTURAL, OPTICAL AND PHOTOVOLTAIC PROPERTIES
    (Inst Materials Physics, 2018) Gunbat, M.; Horoz, S.; Sahin, O.; Ekinci, A.
    The synthesized Ce-doped ZnS nanoparticles by chemical precipitation method were dropped on TiO2 coated on FTO conductive glass substrates. The photovoltaic property of the obtained Ce-doped ZnS/TiO2/FTO structure was investigated by measuring current density (J) voltage (V) and incident photon to current efficiency (IPCE), respectively. Power conversion efficiency of nanoparticles was calculated using the recorded J-V curve. Thus, both IPCE and J-V measurements have been shown experimentally that Ce-doped ZnS nanoparticles can be used as promising sensitizers in photovoltaic applications. Morever, the structural, elemental and photovoltaic properties of Ce-doped nanoparticles were studied by x-ray diffraction (XRD), energy dispersive x-ray (EDX), optical absorption and photoluminescence (PL) measurements, respectively. The characterization results were discussed.
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    SYNTHESIS OF Mo-DOPED ZnS NANOPARTICLES AND INVESTIGATION OF THEIR STRUCTURAL, OPTICAL AND PHOTOVOLTAIC PROPERTIES
    (Virtual Inst Physics, 2018) Gunbat, M.; Horoz, S.; Sahin, O.; Ekinci, A.
    ZnS and molybdenum (Mo) doped ZnS nanoparticles were synthesized at room temperature by co-precipitation method without any capping agent. The crystal structures of the synthesized ZnS and Mo-doped ZnS nanoparticles were determined to be zinc blend by x-ray powder diffraction (XRD). The calculated average crystal sizes are 2.70 and 2.68 nm for ZnS and Mo-doped ZnS nanoparticles, respectively. As a result of optical absorption measurements, it was observed that Mo dopant affects the energy band gap value of ZnS nanoparticles. The band gap value for ZnS and Mo-doped ZnS nanoparticles was determined as 4.07 and 4.17 eV, respectively. EDX measurement indicated that elemental percentages of Zn, S and Mo in the Mo-doped ZnS nanoparticles are 48.91, 50.25 and 0.84, respectively. The photovoltaic properties of Mo-doped ZnS nanoparticles were investigated for the first time in this study. The photon-to-current conversion (IPCE) measurements were carried out for ZnS and Mo-doped ZnS nanoparticles to compare their IPCE (%) values. The obtained result provides a new way to improve performance of ZnS-based solar cell structure.
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    Synthesis of pbs and Ni-doped PbS thin films by CBD method and investigation of their structural, optical and photovoltaic properties
    (S.C. Virtual Company of Phisics S.R.L, 2018) Horoz, S.; Ekinci, A.; Sahin, O.
    In the first part of the present work, the structural, elemental and optical properties of PbS and PbS:Ni(3%) thin films synthesized by chemical bath deposition (CBD) technique on glass substrates at room temperature were analyzed by x-ray diffraction (XRD), energy dispersive x-ray (EDX) and absorption measurements, respectively. It was determined that the particle size of PbS:Ni (3%) thin film in the presence of Ni additive material is smaller than that of PbS although both thin films have the same structure (cubic phase). A similar result was achieved using the data obtained as a result of the optical measurements. Moreover, when the PbS thin film was doped with Ni, its energy band gap was observed to be wider. In the second part; the photovoltaic properties of FTO/Zn2SnO4/PbS and FTO/Zn2SnO4/PbS:Ni(3%) thin films were investigated by performing incident photon-to-current efficiency (IPCE) and current density (J)-voltage (V) measurements, respectively, using Zn2SnO4 coated on FTO conductive glasses instead of glass susbtrates. Based on the data obtained from both measurements, it was observed that the Ni dopant significantly enhance the performance of the PbS-based solar cell devices. © 2018, Virtual Institute of Physics of the Foundation Horia Hulubei. All rights reserved.
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    SYNTHESIS OF PbS AND Ni-DOPED PbS THIN FILMS BY CBD METHOD AND INVESTIGATION OF THEIR STRUCTURAL, OPTICAL AND PHOTOVOLTAIC PROPERTIES
    (Natl Inst R&D Materials Physics, 2018) Horoz, S.; Ekinci, A.; Sahin, O.
    In the first part of the present work, the structural, elemental and optical properties of PbS and PbS:Ni(3%) thin films synthesized by chemical bath deposition (CBD) technique on glass substrates at room temperature were analyzed by x-ray diffraction (XRD), energy dispersive x-ray (EDX) and absorption measurements, respectively. It was determined that the particle size of PbS:Ni(3%) thin film in the presence of Ni additive material is smaller than that of PbS although both thin films have the same structure (cubic phase). A similar result was achieved using the data obtained as a result of the optical measurements. Moreover, when the PbS thin film was doped with Ni, its energy band gap was observed to be wider. In the second part; the photovoltaic properties of FTO/Zn2SnO4/PbS and FTO/Zn2SnO4/PbS: Ni(3%) thin films were investigated by performing incident photon-tocurrent efficiency (IPCE) and current density (J)- voltage (V) measurements, respectively, using Zn2SnO4 coated on FTO conductive glasses instead of glass susbtrates. Based on the data obtained from both measurements, it was observed that the Ni dopant significantly enhance the performance of the PbS-based solar cell devices.