PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/5

Browse

Now showing 1 - 3 of 3

Citation - WoS: 16
Citation - Scopus: 16
Photoluminescence and Piezoelectric Behaviour of Y2zr2o7 Pyrochlore-Based Multifunctional Materials and the Influence of Eu3+ and Sm3+
(WILEY, 2020) Öztürk, Esra; Karacaoğlu, Erkul; Kalem, Volkan
Y2Zr2O7-doped with Eu3+ and Sm3+ phosphors were prepared for the first time as multifunctional smart materials using a solid-state reaction method at 1400(o)C. Thermal behaviour, crystal structure, surface morphology, and elemental analysis were characterized using thermogravimetric (TG) and differential thermal (DTA) analyses, X-ray diffraction (XRD) and scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDX). Experimental results revealed that both phosphors have a pyrochlore structure with a cubic crystal system. Photoluminescence properties were also measured and red emission was observed from Y1.90Eu0.10Zr2O7 and Y1.90Sm0.10Zr2O7 phosphors. Dielectric constant, loss tangent, piezoelectric charge constant, and Curie temperature of all the samples were determined using an LCR-meter, d(33)-meter, and TG/DTA. Eu doping in Y2Zr2O7 resulted in a high dielectric constant (9.61) and low loss tangent (1.67%) values, whereas high piezoelectric charge constant (0.68 pC/N) and high Curie temperature (820 degrees C) could be obtained using Sm-doped Y2Zr2O7.
Citation - WoS: 3
Citation - Scopus: 3
Synthesis of Glucose/Fructose Sensitive Poly(ethylene Glycol) Methyl Ether Methacrylate Particles With Novel Boronate Ester Bridge Crosslinker and Their Dye Release Applications
(Slovensko Kemijsko Drustvo, 2022) Yıldırım, Şeküre; Akyıldız, Hasan; Çetinkaya, Zeynep
In this study, it is aimed to develop glucose/fructose sensitive poly(ethylene glycol) methyl ether methacrylate (PEGMA) particles which can be employed in controlled drug delivery applications. For this purpose, a boric acid based crosslinker was synthesized using 4-vinylphenylboronic acid (VPBA) and its formation was confirmed by H-1-NMR and FT-IR analyses. Sugar-sensitive polymeric particles were then achieved using this crosslinker and PEGMA monomer in single step and surfactant free emulsion polymerization technique. Polymeric particles were characterized by DLS, SEM, and TEM in terms of size and morphology. In order to determine the sensitivity of the particles to sugar molecules, first Rhodamine B dye (as a model drug) loading experiments were performed. Then, the particles were subjected to glucose/fructose rich media and dye release was monitored as a function of time using UV-Vis spectrophotometry. The results of the current study revealed that the PEGMA particles were more sensitive to fructose (similar to 39% release) compared to glucose (similar to 25% release) at pH 7.4 and 310 K.
Citation - WoS: 44
Citation - Scopus: 45
Uv/Visible Light Active Cucro2 Nanoparticle-Sno2 Nanofiber P-N Heterostructured Photocatalysts for Photocatalytic Applications
(ROYAL SOC CHEMISTRY, 2018) Dursun, Sami; Kaya, İsmail Cihan; Kalem, Volkan; Akyıldız, Hasan
CuCrO2 nanoparticle decorated SnO2 nanofiber composites have been prepared as novel p-n heterostructured semiconductor photocatalysts for the degradation of organic pollutants in wastewater. The composite structure was achieved via drop casting of various amounts of hydrothermally derived CuCrO2 nanoparticles on electrospun SnO2 nanofibers. The microstructural and morphological features of each semiconductor and the formation of p-n heterojunctions between them were characterized. In addition, the photo-response and electrochemical properties of the samples were determined. The photocatalytic activity of the heterostructured photocatalysts was investigated systematically as a function of the amount of CuCrO2 nanoparticles in the samples. Experimental results showed that the optimal decoration amount was 0.6 wt% CuCrO2 on SnO2. This composite photocatalyst displayed a 41% higher rate constant value compared to pure SnO2 nanofibers in the degradation of methylene blue dye molecules and reached 83% degradation under UV/visible light irradiation after 1 h. The increase in the photocatalytic activity was ascribed to the incorporation of Cr3+ and Cu+ cations into the SnO2 host lattice and the more effective electron-hole pair separation in the heterostructured sample. The presented data here are highly convincing in comparison to those of UV active p-n heterostructured photocatalysts reported previously in the literature. Therefore, this work opens the way to develop visible light active p-n heterostructured semiconductor photocatalysts using p-type delafossites with n-type oxides.

Browse

Browsing PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collections by Department "Fakülteler, Mühendislik ve Doğa Bilimleri Fakültesi, Metalurji ve Malzeme Mühendisliği Bölümü"