Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Quantitative Phase Analysis in Lensless Digital Inline Holographic Microscopy(01. Izmir Institute of Technology, 2021) Tekin, Hüseyin Cumhur; Varlıklı, Canan; Tekin, Hüseyin Cumhur; Varlıklı, Canan; 03.01. Department of Bioengineering; 04.04. Department of Photonics; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyComputational imaging modalities replace the bulky, complex, and expensive optical components of traditional imaging procedures with numerical reconstruction steps. Digital holographic microscopy is one of the most prominent ones with the possibility of obtaining quantitative phase information by measuring the phase shift change caused by the refractive index of objects. In the lensless digital holographic microscopy system, a pinhole and a light-emitting diode are sufficient to create a holographic pattern on the camera sensor. Here, the optimization of a digital lensless inline holographic microscopy setup was performed to obtain optimal phase value. Also, to retrieve the lost phase information during the recording step, the numerical solution was performed with the single and multi-shot phase retrieval methods. Then, human breast adenocarcinoma (MDA-MB-231) and human myeloid leukemia (U937) cells were analyzed to obtain phase shift, perimeter, and circularity values. These parameters were used to obtain a quantitative differentiation model to replace the traditional labeling or visual confirmation steps with a direct analysis manner. The analysis of respective cells with the classification, object detection, and conditional generative adversarial models can be used directly with pre-trained weights to lessen the computational workloads. With this study, the quantitative analysis with lensless holographic microscopy setup was shown to be a label-free differentiation mechanism to separate cancer cells from monocytes cells which could be used for the early diagnosis of cancer. Also, the proposed method has the potential to be used to identify other cells with links to the diagnosis of different diseases.Master Thesis Emission Characteristics of a Solution Processed, Single Layer White Organic Light Emitting Diode(01. Izmir Institute of Technology, 2020) Varlıklı, Canan; Varlıklı, Canan; Gültekin, Burak; 04.04. Department of Photonics; 04. Faculty of Science; 01. Izmir Institute of TechnologyWhite organic light emitting diodes (WOLEDs) are getting more attention day by day because of their some superior properties like viewing angle, refresh rate, flexibility, easy production process and consequently relatively cost-effective natures. Within the scope of this thesis, WOLED has been prepared and characterized by using the single emitter layer prepared by solution process method. In the emission layer, the host material is used for both obtaining the blue region of the visible spectrum and for efficient energy transfer to the green and orange-red guest material. Poly(N-vinylcarbazole) (PVK): 2-(4-Biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD) or 1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl] phenylene (OXD-7) matrices are used as host for orange-red emitting material of N,N'-bis(2-ethylhexyl)perylene-3,4,9,10-dicarboxylic diimide (PDI) and green emitting material of perylene-3,4,9,10-tetracarboxy tetrabutylester (PTE). Electron and hole mobility, L-V-J characteristics and morphologies of two different host matrix of PVK:PBD and PVK:OXD-7 were examined. As a result of these evaluations, the appropriate host was determined as PVK:PBD. Host:PTE and Host:PDI emission characteristics were examined and exciplex, electroplex formations were detected. After, Host:PTE:PDI configuration were discussed and high white light properties of optimized WOLED are displayed CIE 1931 coordinates (x, y) of (0.34, 0.36), correlated colour temperature of 4916 K and CRI of 96. Finally, lethal time 70 of the latest devices was examined.Master Thesis Photophysical Characterization of Green and Blue Emitting Quantum Dots and Their Application in Qd-Leds(01. Izmir Institute of Technology, 2020) Özgüler, Şahika; Varlıklı, Canan; Varlıklı, Canan; 04.04. Department of Photonics; 04. Faculty of Science; 01. Izmir Institute of TechnologyQLED device construction and characterization studies were carried out in which QD nanoparticles synthesized within the scope of TÜBİTAK project no 115F616, and were used as emission layer. By examining the photo-physical and morphological properties of films prepared with the use of quantum dot (QD) nanoparticles, quantum dot light emitting diodes (QLEDs) which are one of the fields of molecular electronics, were applied as an emission layer using the spin coating technique from wet coating processes. The photo-physical and morphological characterizations of the solution and film phase of blue and green emitted QD nanoparticles were made. For the QDs, the concentration difference in the solution phase was characterized and its effects on film properties were investigated. It has been determined that the increase in concentration does not have a dramatic effect on photo-physical properties but seriously affects film thickness and surface roughness. In this case, performance of blue and green light emitting quantum dot diodes (QLED) prepared by the spin-coating technique, where each QD film is used as the emission layer, have been investigated.Master Thesis A Comparative Study on the Photocatalytic Activity of Dye-Sensitized and Non-Sensitized Graphene Oxide-Ti̇o2 Composites Under Simulated and Direct Sunlight(01. Izmir Institute of Technology, 2019) İlhan, Hatice; Varlıklı, Canan; Demir, Mustafa Muammer; Varlıklı, Canan; Demir, Mustafa Muammer; 04.04. Department of Photonics; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyAmine modified graphene oxide (mGO) and TiO2 composite was synthesized by low temperature hydrothermal method. Characterization of the synthesized material was carried out by using X-ray diffraction, X-ray photoelectron spectroscopy, and BET analysis techniques. The films of mGO:TiO2 and formerly synthesized TiO2, N-TiO2, GO-TiO2 and GO:N-TiO2 were fabricated by doctor blade method and employed as photocatalysts for the photodegradation of Rhodamine-B (RhB) dye under simulated (Xe lamb) and direct sun-light. P25 was also used as reference photocatalyst for all of the synthesized ones. Photodegradation of RhB was monitored by UV-Vis spectroscopy. Among all the catalysts, GO:N-TiO2, the composite of GO and N-doped TiO2, presented the best photocatalytic activity and although the activity of mGO:TiO2 was better than the activities of P25 and TiO2, it presented lower degradation rate constant even than that of the N-TiO2. It is proposed that increased abundance of C-C bonds and decreased number of oxygenated functional groups on mGO:TiO2, in addition to the morphological difference between GO (sheet like) and mGO (dot like) has great influence on their photocatalytic activities. Among the GO containing photocatalysts including mGO:TiO2, specific surface area (SSA) and number of RhB molecules per film volume were the lowest and particle size was the highest for mGO:TiO2. Although the number of RhB molecules per film volume was higher in mGO:TiO2 than that of the N-TiO2, it is thought that approximately 2 folds higher SSA of N-TiO2 allowed better photocatalytic performance. Additionally, the films were sensitized with PTE dye to obtain effective catalysts in visible region and reusability of the films were also tested. Degradation rate constants of all fabricated films have increased under both of the irradiation media and no significant change in rate constants were detected after the reusability tests.