GCRIS

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Green synthesis of silver nanowires and novel assembly technique for iron oxide nanocubes
(01. Izmir Institute of Technology, 2024) Güvenç, Tuğçe Aybüke Arıca; Balcı, Sinan; Adem, Umut
Gümüş nanoteller, mükemmel elektriksel iletkenlikleri, plazmonik davranışları ve esneklikleriyle bilinir ve bu nedenle çeşitli gelişmiş uygulamalar için oldukça uygundurlar. Bu tez çalışması, gümüş nanotellerin hem çevre dostu sentezini, hem de biyomedikal uygulamalarda gelişmiş manyetik nanoyapılar için bir şablon olarak ikili rolünü araştırmıştır. Çalışmanın ilk bölümünde, geçiş metali tuzlarının gümüş nanotellerin morfolojisini kontrol etmedeki etkisi araştırılmıştır. Çevre dostu indirgeyici madde olarak gliserolün kullanılması, belirli geçiş metali tuzlarının nanotel morfolojisini önemli ölçüde etkileyebileceğini göstermiştir. Deneysel koşulların dikkatli bir şekilde optimize edilmesiyle, gümüş nanoteller yüksek en boy oranlarıyla başarıyla sentezlenmiştir. Bu yeşil sentez yaklaşımı, esnek elektronik, sensörler ve daha fazlası için nanoteller üretmek için sürdürülebilir bir yol sağlar. İkinci bölümde, gümüş nanoteller, demir oksit nanoküplerin manyetik hipertermi performansını artırmak için yüksek yüzey alanlı bir şablon olarak sunulmuştur. Demir oksit nanoküpler, manyetik anizotropilerini artırmak için gümüş nanotellerin yüzeyine dekore edilmiştir. Manyetik karakterizasyon ve özgül emilim oranı analizi, bu yapının uygulanan manyetik alan koşullarına bağlı olarak değişen manyetik alanlar altında ısıtma verimliliğini artırdığını ve tek başına demir oksit nanopartiküllerinden daha üstün performans gösterdiğini ortaya koymaktadır.
Synthesis, Properties and Applications of Tungsten Oxide Nanostructures
(01. Izmir Institute of Technology, 2023) Kahraman, Zeynep; Balcı, Sinan; Genç, Aziz
In this study, tungsten oxide nanostructures, which are n-type semicon ductors with a band gap between 2.6-2.8, have been studied extensively. The hydrothermal method was used as the synthesis technique and the phases and morphologies were optimized in a stable and controllable manner. Firstly, sto ichiometric tungsten oxide nanowires with certain ratios were synthesized, and then cobalt doping was made using this synthesis technique. Subsequently, sub-stoichiometric tungsten oxide nanowires, which have oxygen gaps and can show plasmonic properties due to the increased carrier density, were synthe sized, and tungsten oxides with a flower-like hierarchical structure with oxygen gaps were synthesized and grouped according to possible application areas. Accordingly, how oxygen vacancies and hierarchical structures affect pho tocatalysis applications have been examined and it has been seen that ub stoichiometric tungsten oxide works faster until it reaches a certain saturation than stoichiometric tungsten oxide. According to this study, how the system can be manipulated by adding low pH to the system and hydrogen peroxide as an electron acceptor, respectively. It has been observed that it can be done. Hierarchical tunsten oxide has been found to be an ideal catalyst that can work quickly in photocatalysis studies due to its hierarchical structure, which has oxygen vacancies and can absorb light well. Additionally, tungsten oxide attracts attention as a material used in su percapacitor applications. Supercapacitors are long-lasting and fast-reacting electrochemical devices that can provide high power in energy storage and dis charge processes. The use of tungsten oxide in supercapacitor applications can be summarized as follows: when nanoparticles with large surface area are used as electrode material, they increase the interaction with the electrochemical surface and can increase the energy storage capacity. It shows high electro chemical activity as an electrode material. This feature contributes to the high performance of the supercapacitor. Tungsten oxide has a structure suitable for electron and ion conduction. This allows the supercapacitor to have fast charge/discharge capabilities and low internal resistance. Tungsten oxide can show stable performance during electrochemical cycles. This feature ensures the long life of the supercapacitor. In supercapacitor applications, in addition to these features, the electrical conductivity of the material can be increased by increasing the number of electrons carried in the material due to its oxygen gap. Accordingly, we investigated the comparative electrochemical properties and cycling stability of stoichiometric and sub-stoichiometric nanowires. Thanks to its electrochromic properties, the latest application has observed electrochromic changes of oxygen vacancies and cobalt doping

Phd Degree / Doktora

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