FBE- Fizik Mühendisliği Lisansüstü Programı - Yüksek Lisans
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Sustainable Development Goal "none" ile FBE- Fizik Mühendisliği Lisansüstü Programı - Yüksek Lisans'a göz atma
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ÖgeRole of growth parameters on electrochromic behavior of tungsten oxide thin films grown by RF magnetron sputtering(Fen bilimleri Enstitüsü, 2020) Nuhoğlu, Duygu ; Özkan Zayim, Esra ; 644363 ; Fizik MühendisliğiChromogenic materials are the materials that change their optical properties with the influence of external stimulus such as temperature, potential difference, electromagnetic radiation, and that they revert into their initial state when the effect of external stimulus disappears. Chromogenic technology has a very important place in vehicle glazing, siding of architecture, and even in printed electronics. The materials that change their optical properties under applied potential are called electrochromic (EC) materials and they have the area of usage increasing day by day. The major advantages of EC materials are: they only need electricity during switching (small switching voltage around 1-5V); they can keep their state without any applied potential; they can be integrated on any surface like paper, plastic, or glass. Rear-view mirrors that provide a more comfortable view during day and night are the most commercially developed electrochromic products to date, yet applied in siding in architecture, in window applications (smart glass) providing heat control by means of decreased transmittance and reflectance too. Electrochromic (EC) smart glasses have a very large and developing place in the world market. This market started with Schott-Donnely LLC Smart Glass Solution production of EC glass continues with SAGE Electrochromic's introduction of electrochromic glasses at National Home Builders (USA) at 2000. And it continues to grow with companies such as View Dynamic Glass, E-Control and PPG Industry (Pittsburg Plate Glass) which produce and market electrochromic smart glass technology on flat glass as siding in architectural structures. Since the Sisecam Glass Company is the biggest glass company in Turkey and the biggest float glass producer in Europe, it is very likely to take its place in the EC market in later times. For this reason, laboratory studies have started. Almost all of these devices that perform electrochromic property rely upon vacuum deposition for their electrodes or themselves. Sometimes, different processes such as sol-gel, chemical vapor deposition or other technics are used to make all or portions of EC devices. Among the electrochromic materials, tungsten oxide is the most preferred one owing to its processible nature, stabile nature, and excellent electrochromic performance. Tungsten oxide as a starting point is a good idea because of the companies that produce EC glazing with inorganic materials are using tungsten containing compounds. In this thesis study, it has been aimed to investigate tungsten oxide as an electroactive layer in Sisecam Science and Technology Center. Tungsten metal target was sputtered with RF magnetron sputtering method. In order to create an eco-friendly structure, gallium zinc oxide coated glass was used as a conductor layer since indium tin oxide is poisonous. The effect of power, pressure, reactive gas contents on electrochromic, optical, and structural properties of tungsten films was investigated. Long cycle measurements were made to examine the degradation of films over 900 cycles. Electrochromic characterization was performed for all films and three electrode methods were used. The optical transmittance of the films was measured by spectrophotometer versus wavelength. AFM images to examine the surface roughness of the films, XRD analysis to examine the crystal structures, ellipsometric measurements for the measurement of optical parameters, and the densities of the films were obtained by XRR analysis. Although tungsten oxide is the most investigated material among the electrochromic materials, this study is unique in terms of making coatings in the low power range (45, 60, 75, 90W) and achieving the best performance at a low power of 45W, compared to the literature. After that, coatings were made to see the effect of pressure with 45W sputtering power. Sputtering pressure of 5, 7, 10, 13 mTorr was studied in these coatings and the films were characterized. It was observed that the films coated at 10 mTorr pressure among the pressure values worked with 45W power had the best electrochromic properties. The last study is to investigate the effect of oxygen partial pressure on electrochromic properties.