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Öğe Ce/Sm co-doped hydroxyapatites: synthesis, characterization, and band structure calculation(Springer, 2020) Kaygılı, Ömer; Vural, Gülay; Keser, Serhat; Yahia, İ.S.; Bulut, Niyazi; Ateş, Tankut; Köytepe, Süleyman; Temüz, Mehmet Mürşit; Ercan, Filiz; İnce, TuranIn this paper, Ce/Sm co-doped hydroxyapatites (HAps) were synthesized by a wet chemical route. The amount of Ce was kept at constant at the value of at.% 0.4, and the second dopant of Sm was used at different amounts of at.% 0, 0.6, 1.2, and 1.8, respectively. The effects of these co-dopants on the crystal structure, morphology, and thermal properties of HAp were determined experimentally using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Furthermore, the band structure of the prepared samples was modeled theoretically using the quantum calculations of the density of states and band structure. A gradual increase from 26.56 to 36.23 nm in the crystallite size was observed. Although the amounts of the co-dopants of Ce and Sm did not affect the thermal stability and microstructure of HAp, its crystal structure-related parameters were affected by the amount of these co-additives. The partial substitution of both co-dopants was detected. The 0.4Ce-1.2Sm-HAp sample may be considered as the best crystal structure with a steady-state. It was seen that the band structure and density of states were also affected by these co-dopants. The bandgap value decreased gradually from 4.6078 to 4.0477 eV due to these dopants.Öğe Effects of solvents on photonic and fluorescence properties of PtOEP phosphorescent material: Experimental and computational analysis(Elsevier, 2020) Gündüz, Bayram; Bulut, NiyaziThe effects of different solvents (chloroform, tetrahydrofuran, toluene, methanol, acetone and chlorobenzene) on photonic and fluorescence properties of the PtOEP organic phosphorescent material were investigated with experimental and advanced computational techniques. Many parameters such as angle of incidence/refraction, contrast, optical conductance, electrical conductance, peak absorbance, peak emission, stokes shift, fluorescence quantum yield and sensitivity have been obtained. Theoretical and experimental photonic and fluorescence properties of the PtOEP material for different solvents have been compared. It was found that maximum absorbances for experimental and theoretical calculations are quite similar at a value of around 389 (nm) and depending on the solvents used here they slightly shifted to larger wavelength.Öğe Experimental characterization and theoretical investigation of Zn/Sm co-doped hydroxyapatites(Elsevier, 2022) Hssain, Ala Hamd; Bulut, Niyazi; Ateş, Tankut; Köytepe, Süleyman; Kuruçay, Ali; Kebiroğlu, Hanifi; Kaygılı, ÖmerIn this study, the wet chemical method was used to synthesize Zn-doped hydroxyapatite (HAp) samples, and the effects of varying the amount of Sm addition on structural, thermal, and biocompatibility in vitro properties were studied. In addition, a density functional theory was used for modeling the as-synthesized samples to obtain the theoretical calculation results. XRD results confirmed the formation of biphasic compositions for all samples, and FTIR data supported the formation of the functional groups of hydroxyl and phosphate. More than 98% of samples showed the formation of the HAp phase. The addition of Sm resulted in an increase in the secondary phase of the ?-TCP from 0.60% to 1.49%. The lattice parameters (aandc),unit cell volume (V), lattice strain(?), and lattice stress? varied when Sm was added as a dopant. The crystallite size and crystallinity decreased as the Sm content increased, however, the anisotropic energy density gradually increased. Thermal analysis results confirmed that all samples seemed to be thermally stable. The addition of Sm did not result in any notable morphological modifications. Cell viability values of theZn-based HAp sharply decreased as a result of an increase in the Sm additive. Theoretical studies show that when the amount of Sm in the Zn-based HAp structure increases, the bandgap energy decreases from 4.68 to 4.40eV. An increasing density and decreasing unit cell volume have been observed, as confirmed by the theoretical results. In addition, there was a decrease in crystallinity as well as an increase in anisotropic energy density.Öğe Fe ve Ti katkılı Çift Fazlı Kalsiyum Fosfatların Sentez ve Karakterizasyonu(Malatya Turgut Özal Üniversitesi, 2021) Ateş, Tankut; İnce,Turan; Acar, Serdar; Kaygılı, Ömer; Bulut, Niyazi; Keser,Serhat; Köytepe, SüleymanBu çalışmada, Ti katkısının Fe esaslı çift fazlı kalsiyum fosfat malzemelerinin yapısal, morfolojik ve termal özellikleri üzerine etkileri araştırılmıştır. X-ışını kırınımı (XRD) analizi, üretilen numunelerin hem hidroksiapatit (HAp) hem de beta trikalsiyum fosfat (?-TCP) fazlarına sahip olduğunu doğrulamaktadır. Ayrıca, Ti katkısındaki artışla ?-TCP fazının miktarının arttığı görülmektedir. Fourier dönüşümlü kızılötesi (FTIR) spektroskopisi sonuçları, numunelerdeki karakteristik fonksiyonel grupların varlığını doğrulamaktadır. Ti miktarı morfolojiyi etkilemektedir. Numunelerin ısıl davranışları birbirine benzerdir ve oda sıcaklığından 1000 °C’ye kadar tüm numuneler termal olarak kararlıdırlar. Bu sıcaklık aralığında numunelerdeki kütle kayıpları % 1,63’e eşit veya altındadır.Öğe Investigation of the effects of Ni-doping on the structural and thermal properties of ZnAl2O4 spinels prepared by wet chemical method(Springer, 2021) Ercan, Filiz; Ateş, Tankut; Kaygılı, Ömer; Bulut, Niyazi; Köytepe, Süleyman; Alahmari, Fatimah; Ercan, İsmail; Hssain, Ala Hamdn this study, a more detailed characterization of the un-doped and Ni-doped ZnAl2O4 spinel structures prepared via a facile wet chemical route was carried out. Significant effects of the additive of Ni on the ZnAl2O4 structure were observed. For all the samples, the ZnO phase was detected as the second phase, and the third phase of NiO was observed for two samples having the highest Ni content. X-ray diffraction (XRD) results showed that the crystallinity percent, lattice parameter, and volume of the unit cell decreased continuously with adding of Ni. Fourier transform infrared (FTIR) spectra verify the formation of the ZnAl2O4 structure for all the samples. The thermal behaviors, including the recrystallization temperature and mass losses, of the ZnAl2O4 structure, were also affected by the amount of Ni. The morphology varied with adding of Ni. These properties were not reported before.Öğe NTCDA compounds of optoelectronic interest: Theoretical insights and experimental investigation(Elsevier, 2021) Hssain, Ala Hamd; Gündüz, Bayram; Majid, Abdul; Bulut, NiyaziStructural, electronic, and spectroscopic properties of 1,4,5,8-naphthalene-tetracarboxylic dianhydride organic semiconductor molecule are reported based on experimental and computational methods. The spectroscopic investigations were carried out via H1 and C13 NMR chemical shifts and UV–VIS spectroscopy. The effects of solvation of NTCDA molecule into different solvents were investigated to explore the effect of polarities of solvents on the absorption peak of the compound. Positive charges on the Carbon atom side were discovered to be more prominent, leading to the conclusion that the NTCDA molecule could be suited for optoelectronic applications with mid-range optical band gaps.Öğe Structural, spectroscopic, dielectric, and magnetic properties of Fe/Cu co-doped hydroxyapatites prepared by a wet-chemical method(Elsevier, 2022) Ercan, İsmail; Kaygılı, Ömer; Kayed, Tarek; Bulut, Niyazi; Tombuloğlu, Hüseyin; İnce, Turan; Al Ahmari, Fatımah; Kebiroğlu, Hanifi; Ateş, Tankut; Almofleh, Atheel; Fırdolaş, Fatih; Köysal, Oğuz; Al-Suhaimi, Ebtesam Abdullah; Ghrib, Taher; Sözeri, Hüseyin; Yıldız, Mesut; Ercan, Filiz; Ateş, TankutIn this study, the effects of Cu and Fe additives on the structural, dielectric, magnetic, thermal and morphology of hydroxyapatite (HAp) samples were investigated and reported in detail for the first time. The prepared systems were also modeled and examined theoretically. It can be said that both additives affect the thermal behavior of the HAp structure. The addition of Cu affected the morphology of submicron-sized particles with spherical-like shapes with a low degree of agglomeration. Diffuse reflection data revealed that the energy band gap values decreased as Cu was added to the Fe-based HAp structure. The dielectric constant (??) had high values at low frequencies in all samples and decreased with increasing frequency. It could be concluded that Fe/Cu incorporation to hydroxyapatites enhanced its thermal, magnetic, and dielectric properties required for mimicking natural HAps to open a successful venue for medical application in the healing regeneration of bone.Öğe Synthesis and Characterization of Co-Doped SnO2 Samples(Bilecik Şeyh Edebali Üniversitesi, 2020) Ateş, Tankut; Kaygılı, Ömer; Bulut, Niyazi; Okur, Havva Esma; Keser, Serhat; Yahia, İ.S.; Köytepe, Süleyman; Seçkin, Turgay; Özcan, İmren; İnce, TuranThe un-doped and Co-doped SnO2 samples having high crystallinity were successfully prepared. The effects of Co content on the structural, thermal and morphological properties of SnO2 were investigated. Changes in the crystallite size and unit cell parameters were detected with adding of Co. The phase composition did not alter with the addition of Co. Both X-ray diffraction and Fourier transform infrared results confirmed the formation of the SnO2 structure for each sample. The thermal stability of the as-produced samples from room temperature to 900 °C was observed. The morphology was affected by Co content, and energy dispersive X-ray results verified the introduction of Co into the SnO2 structure.Öğe Theoretical and experimental characterization of Pr/Ce co-doped hydroxyapatites(Elsevier, 2021) İbrahimzade, Lala; Kaygılı, Ömer; Dündar, Serkan; Ateş, Tankut; Dorozhkin, Sergey V.; Bulut, Niyazi; Köytepe, Süleyman; Ercan, Filiz; Gürses, Canbolat; Ercan, Filiz; Hssain, Ala HamdThis study presents a more extensive report on the experimental and theoretical characterization of the Ce-doped hydroxyapatite (HAp) samples additionally doped with Pr at varying amounts. To achieve this goal, four Ce-containing (a constant amount of 0.35 at.%) HAps additionally doped with Pr at various amounts (0.35, 0.70, 1.05, and 1.40 at.%) were synthesized via a combustion method. Besides, all these samples were modeled theoretically by using a density functional theory (DFT). Theoretical results showed that the bandgap energy decreased continuously from 4.5156 to 4.3097 eV. For all samples, the linear attenuation (or absorption) coefficient increased with the increasing amount of Pr and this parameter had a decreasing trend with the increase in the photon energy. An increase in the theoretical density and the lattice parameter c and a decrease of both the lattice parameter a and the unit cell volume were found. After analyzing the experimental data, the following results were observed: X-ray diffraction (XRD) and Fourier transform infrared (FTIR) data verified the formation of HAp phase (above 94% for all the samples) as the major phase and beta-tricalcium phosphate (?-TCP) as the minor one. The amount of ?-TCP phase was found to increase from 3.4 to 5.9% with the addition of Pr. Similar to the theoretical findings, an increasing trend for the density and decreasing one for the unit cell volume were detected. Both a decrease in the crystallinity and an increase in the anisotropic energy density were found. The results of the thermal analysis supported the thermal stability of all the samples. The cell viability was found to be affected by Pr-content.Öğe Theoretical and experimental characterization of Sn‑based hydroxyapatites doped with Bi(Springer Nature, 2022) Korkmaz, A. Aksoğan; Ahmed, Lana Omar; Kareem, Rebaz Obaid; Kebiroğlu, Hanifi; Ateş, Tankut; Bulut, Niyazi; Kaygılı, Ömer; Ateş, BurhanThis is the first report, including both theoretical and experimental results, on Bi and Sn co-doped hydroxyapatite (HAp) structures. Sn content was kept at a constant amount of 0.22 at.%, and Bi content was changed from 0 to 0.44 at.% by using the steps of 0.11at.%. Theoretical results from density functional theory (DFT) calculations revealed an increase in density from 3.154 g cm?3 to 3.179 g cm?3, as well as gradual decreases in the bandgap from 4.5993 eV to 4.4288 eV and the linear absorption coefficient. The spectroscopic data obtained from both Raman and Fourier transform infrared (FTIR) spectra confirmed the HAp structure for all the samples. The thermal behavior and morphology, as well as all X-ray diffraction (XRD) related parameters, were all considerably impacted by Bi-content. In vitro assays showed that all the samples can be accepted as the biocompatible materials
