Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Fabrication and Characterization of Perylene Diimide Doped Polyfluorene Based Solution Processed Blue Organic Light Emitting Diodes(2023) Varlıklı, Canan; Demir, Mustafa Muammer; 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 TechnologyBlue is considered as the major component in many applications of organic light emitting diodes (OLEDs). Most of the polymeric blue emitters including poli[9,9-di-(2-diethylhexyl)-fluorenyl-2,7-diyl] (ADS231BE) attract attention with their solubility and potential in reducing the application costs, but also suffer from wide electroluminescence resulting in color purity issues. Annealing temperature and solvent choice have great influence on morphology and electronic properties. A typical OLED is fabricated by using ADS231BE as the emitter material and effect of annealing temperature on EL properties is investigated between 60C and 150C. OLEDs produced using toluene have shown better efficiency compared to those using chlorobenzene. Regardless of the solvent used, the efficiencies gradually decreased, but the stability and color purity of the devices increased with increasing annealing temperatures. Surface morphologies were examined, and suitable coating conditions were determined. Small molecule orange-red-emitting N,N'-bis(2-ethylhexyl)perylene-3,4,9,10-dicarboxylic diimide (PDI) derivatives were introduced into the blue-emitting conjugated polymer ADS231BE at a concentration of 0.1 wt.%. Electroluminescence, morphology, photoluminescence and Raman analysis of the developed devices were completed to determine the type of aggregation and conformational change caused by PDI doping. Subsequently, to balance charge and improve the electroluminescent character of the devices, a hole transfer layer (HTL) consisting of Poly (N-vinyl carbazole) (PVK) and PVK:1,3-Bis(N-carbazolyl) benzene (mCP) was added to the device structure. Similar morphological and Raman analyses were performed. Compared to the bare ADS231BE containing devices, without changing the CIE coordinate values, approximately, 10 folds of luminance and more than 5 folds of EQE increments were obtained.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.