Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395

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  • Article
    Citation - WoS: 2
    Citation - Scopus: 1
    Fully Inorganic Colloidal CsPbBr3 Perovskite Nanocrystals with Zn-Doping and Metal Oxide Encapsulation for Luminescent Display Panels
    (Amer Chemical Soc, 2025-11-07) Khorasani, Azam; Soheyli, Ehsan; Mutlugun, Evren
    Perovskite nanocrystals (PeNCs) are emerging as exceptional materials due to their high photoluminescence quantum yield, tunable bandgap, and excellent charge carrier mobility, enabling a wide range of colors and promising applications in optoelectronics and photovoltaics. Despite their advantages, PeNCs face stability challenges caused by environmental factors. In the presented study, a facile and versatile colloidal hot-injection method was used to apply the beneficial aspects of Zn-doping in cesium lead bromide (CsPbBr3) PeNCs. The uniform platelet-shaped Zn-doped CsPbBr3 PeNCs were prepared by doping with a 0.1 molar ratio of zinc-oleate solution in the perovskite precursors during synthesis. Then, zinc-oxide (ZnO) and nickel-oxide (NiO) coating layers were utilized separately to effectively reduce surface defects, encapsulate PeNCs, and improve their stability issues. To fabricate the coated PeNCs with metal oxides, zinc acetate and nickel(II) acetate tetrahydrate solutions were prepared individually and added to the crude perovskite solutions. The quantum yield of Zn-doped CsPbBr3 (CsPb1-xZnxBr3) PeNCs coated with ZnO increased from 50% for bare CsPbBr3 to over 84%, while NiO-coated PeNCs exhibited a higher yield of 90% both of which remarkably enhanced the emission stability. Moreover, NiO coatings represented a proper protection against surface imperfections and improved resistance to external stimuli. The combination of facile/effective preparation method, excellent emission efficiency, and reliable emission stability nominates the prepared colloidal composite for display pixels, detectors, and lasers.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Light-Controlled Electrostatic Self-Assembly of Quantum Dots
    (Amer Chemical Soc, 2025-04-11) Akrema; Phul, Ruby; Yazici, Ahmet Faruk; Senel, Zeynep; Erdem, Talha
    Electrostatic self-assembly is one of the important self-assembly mechanisms that found use in optoelectronics. Although this method enables realizing unconventional architectures, producing complicated architectures in large areas requires local control over the self-assembly process. One of the ways to achieve this control is to provide enough kinetic energy to the self-assembling nanoparticles so that they can escape electrostatic attraction. We hypothesize that this energy can be delivered to the nanoparticles by treating them with light that can be absorbed by the particles. Here, we test this idea to tailor the electrostatic self-assembly of semiconductor quantum dots (QDs) using a laser. Employing fluorescence and atomic force microscopy, we demonstrate that the QDs are not attached to the substrate in regions where they are exposed to light while they are coated in the absence of optical excitation. We further conduct theoretical analysis to show that elevated temperatures indeed allow the QDs to escape the electrostatic attraction of the charged polymers on the surface. We also demonstrate that increasing the temperature during the coating process without irradiating the sample gives similar results as the case when the sample was irradiated. Finally, we fabricate an uncoated region on the self-assembled QD film with dimensions of similar to 200 mu m x 0.5 cm to demonstrate the feasibility of our approach to control the bottom-up self-assembly. We believe that our results may pave the way for a cost-effective and sustainable approach for the fabrication of nanoelectronic and optoelectronic devices.
  • Article
    Discovery and in Silico Characterization of Anatolian Water Buffalo Rumen-Derived Bacterial Thermostable Xylanases: A Sequence-Based Metagenomic Approach
    (Amer Chemical Soc, 2025-03-18) Kurt, Halil; Kaya, Dilek Sever; Akcok, Ismail; Sari, Ceyhun; Albayrak, Ebru; Velioglu, Hasan Murat; Surmeli, Yusuf; Sever Kaya, Dilek
    This study involved shotgun sequencing of rumen metagenomes from three Anatolian water buffalos, an exploration of the relationship between microbial flora and xylanases, and in silico analyses of thermostable xylanases, focusing on their sequence, structure, and dynamic properties. For this purpose, the rumen metagenome of three Anatolian water buffalos was sequenced and bioinformatically analyzed to determine microbial diversity and full-length xylanases. Analyses of BLAST, biophysicochemical characteristics, phylogenetic tree, and multiple sequence alignment were performed with Blastp, ProtParam, MEGA11 software, and Clustal Omega, respectively. Three-dimensional homology models of three xylanases (AWBRMetXyn5, AWBRMetXyn10, and AWBRMetXyn19) were constructed by SWISS-MODEL and validated by ProSA, ProCheck, and Verify3D. Also, their 3D models were structurally analyzed by PyMOL, BAN Delta IT, thermostability predictor, What If, and Protein Interaction Calculator (PIC) software. Protein-ligand interactions were examined by docking and MD simulation. Shotgun sequence and Blastp analyses showed that Clostridium (Clostridiales bacterial order), Ruminococcus (Oscillospiraceae bacterial family), Prevotella (Bacteroidales bacterial order), and Butyrivibrio (Lachnospiraceae bacterial family) were found as dominant potential xylanase-producer genera in three rumen samples. Furthermore, the biophysicochemical analysis indicated that three xylanases exhibited an aliphatic index above 80, an instability index below 40, and melting temperatures (T m) surpassing 65 degrees C. Phylogenetic analysis placed three xylanases within the GH10 family, clustering them with thermophilic xylanases, while homology modeling identified the optimal template as a xylanase from a thermophilic bacterium. The structural analysis indicated that three xylanases possessed the number of salt bridges, hydrophobic interactions, and T m score higher than 50, 165, and 70 degrees C, respectively; however, the reference thermophilic XynAS9 had 43, 145, and 54.41 degrees C, respectively. BAN Delta IT analysis revealed that three xylanases exhibited lower B '-factor values in the beta 3-alpha 1 loop/short-helix at the N-terminal site compared to the reference thermophilic XynAS9. In contrast, six residues (G79, M123, D150, T199, A329, and G377) possessed higher B '-factor values in AWBRMetXyn5 and their aligned positions in AWBRMetXyn10 and AWBRMetXyn19, relative to XynAS9 including Gln, Glu, Ile, Lys, Ser, and Val at these positions, respectively. MD simulation results showed that the beta 9-eta 5 loop including catalytic nucleophile glutamic acid in the RMSF plot of three xylanases had a higher fluctuation than the aligned region in XynAS9. The distance analysis from the MD simulation showed that the nucleophile residue in AWBRMetXyn5 and AWBRMetXyn10 remained closer to the ligand throughout the simulation compared with XynAS9 and AWBRMetXyn19. The most notable difference between AWBRMetXyn5 and AWBRMetXyn10 was the increased amino acid fluctuations in two specific regions, the eta 3 short-helix and the eta 3-alpha 3 loop, despite a minimal sequence difference of only 1.24%, which included three key amino acid variations (N345, N396, and T397 in AWBRMetXyn5; D345, K396, and A397 in AWBRMetXyn10). Thus, this study provided computational insights into xylanase function and thermostability, which could inform future protein engineering efforts. Additionally, three xylanases, especially AWBRMetXyn5, are promising candidates for various high-temperature industrial applications. In a forthcoming study, three xylanases will be experimentally characterized and considered for potential industrial applications. In addition, the amino acid substitutions (G79Q, M123E, D150I, T199K, A329S, and G377V) and the residues in the beta 3-alpha 1 loop will be targeted for thermostability improvement of AWBRMetXyn5. The amino acids (N345, N396, and T397) and the residues on the beta 9-eta 5 loop, eta 3 short-helix, and eta 3-alpha 3 loop will also be focused on development of the catalytic efficiency.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Benefiting From Both Ethanol Oxidation and Bidentate Thiol Groups of DHLA Ligands Under Photoirradiation for Synthesis of Au Nanoparticles With Their Catalytic and Peroxidase Like Activity
    (Amer Chemical Soc, 2025-04-08) Temur, Nimet; Dadi, Seyma; Dogan, Ayse Nur; Nisari, Mustafa; Avan, Ilker; Ocsoy, Ismail
    In this work, we rationally synthesized quite stable gold nanoparticles (AuNPs) using dihydrolipoic acid (DHLA) and DHLA-aspartame (DHLA-Asptm) as both reducing and stabilizing agents in a mixture of water/ethanol at RT under photoirradiation in 10 min. The novelty of this work is that benefiting from both the oxidation of ethanol to ethanal and having the bidentate thiol groups of DHLA, stable DHLA@AuNPs and DHLA-Asptm@AuNPs were successfully and rapidly formed without additional reducing reagents. We systematically examined the formation of DHLA@AuNPs and DHLA-Asptm@AuNPs under different pH values and reaction temperatures. Furthermore, the salt tolerance of DHLA@AuNPs and DHLA-Asptm@AuNPs was tested in a series of sodium chloride solutions. We showed the catalytic and peroxidase-like activities of DHLA@AuNPs against 4-nitrophenol and 3,3 ',5,5 '-tetramethylbenzidine. The AuNPs were characterized by UV-vis spectrophotometry, scanning transmission electron microscopy, zeta potential, and dynamic light scattering.