Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Author: search.filters.author.Sarı, Emre

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  • Master Thesis
    Desing Strategies for Solar Car Parks: a Case Study for Iztech Library Parking Lot
    (Izmir Institute of Technology, 2020) Bursa, Enes; Sarı, Emre
    The world’s need for renewable resources is growing as a result of the global climate crisis. In order to overcome this issue. The Paris Agreement was signed by the nations as a step for solution to this issue. In it, targets for future were set, and the nations pledged to meet these targets. Nowadays investments in energy production from renewable sources are increasing. When compared to 2019, the amount of energy produced from renewable sources grew by 12.5% in 2020. Photovoltaic systems are receiving more investment as a result of their growing efficiency. In 2020, photovoltaic system production climbed by 20.5 percent. Turkey is increasing their investment in photovoltaic systems. It is crucial for universities to be pioneers in energy production from renewable sources. The studies carried out by universities should be taken into account in terms of both increasing knowledge in this area and having people resource who are trained in it. In this study, the open parking area of the library building of the Izmir Institute of Technology were covered with a roof in order to simulate and analyze the installation of photovoltaic solar panels on the roof. These simulations and calculations were done using software called Enact Systems. PVWatts is utilized by Enact system for climate and photovoltaic calculations infrastructure. 560 panels have been installed on the 835 m2 covered parking lot. The installed power of the panels is 224 kW, and they can generate about 302 gWh of electricity annually. This amount is equal to 51% of library consumption. With this production, the amortization period of the investment is calculated as 8 years.
  • Master Thesis
    Fabrication of Perovskite Solar Cells Using Ultrasonic Spray Coating
    (Izmir Institute of Technology, 2022) Ceyhan, Eray; Sarı, Emre
    Perovskite solar cells (PSCs) are one of the most prominent research field for the last decade in photovoltaic technology. From 3.8 percent in 2009 to 25.7 percent in 2021 in single-junction architectures, and to 29.8 percent in silicon-based tandem cells, solar cell efficiencies of laboratory-scale devices using these materials have increased, surpassing the maximum efficiency achieved in single-junction silicon solar cells. Therefore, as of now, perovskite solar cells represented the solar technology that was developing the fastest. Perovskite solar cells have gained commercial appeal thanks to their extremely low production costs and promise for even higher efficiency. Their short- and long-term stability are key issues and research topics. In this context, the development of scalable perovskite solar cell fabrication has become essential. A novel ultrasonic spray casting technique is employed by incorporating hot nitrogen gas blowing as a scalable deposition method. We tried to optimize the perovskite film crystallization by applying our technique. With the help of our hot nitrogen gas blowing pipe we are able to enhance the nucleation process and at a desired levels. These investigations are supported by characterization tools such as optical microscope, scanning tunneling microscope, and current-voltage measurement. MAPb(I1-xBrx)3 precursor solution containing DMF and DMSO as solvent was used in our experiments. We examined the effect on the surface roughness change by adjusting the DMF and DMSO ratios. Finally, we construct a device of FTO/ c-TiO2/ m-TiO2/ MAPb(I1-xBrx)3/Spiro-OMeTAD/Au architecture and able to investigate the electrical characteristic of under dark and illumination.
  • Master Thesis
    Manufacturing and Characterization of Perovskite Thin Films Using Novel Methods
    (Izmir Institute of Technology, 2020) Bıyıklı, Ozan; Sarı, Emre; Tekin, Hüseyin Cumhur
    Perovskite photovoltaics is a promising technology due to its low-cost fabrication and high efficiency. Since their first demonstration in 2009, efficiencies of perovskite solar cells (PSCs) increased unprecedently fast from 3.81% to 25.2% in 10 years. The most common method for the deposition of the absorber layer of the perovskite solar cells is the spin-coating method, which is not a scalable method, and this method is an obstacle to their commercialization. Efficiencies obtained with scalable methods are currently lower than that of the spin-coating method. In this thesis, among the scalable deposition methods, a novel ultrasonic spray-coating was used by adding antisolvent vapor to the system. The antisolvent quenching technique, that is commonly used to improve the crystalline quality of the film by spin-coating was successfully adapted for ultrasonic spray coating. The interaction between diethyl ether (DE) vapor, which is used as an antisolvent, and MAPb(I(3-x)Brx)3 precursor solution (where the solvent is DMF:DMSO, 4:1) was utilized to improve the crystalline quality of the perovskite film. As a result of this interaction, the intermediate phase was observed. The transition to the intermediate phase is supported by data from characterization methods such as optical microscopy, scanning electron microscopy (SEM), X-Ray diffraction (XRD), and current-voltage measurement. Furthermore, n-i-p devices with the FTO/c-TiO2/m-TiO2/MAPb(I(1-x)Brx)3/Spiro-OMeTAD architecture were produced with different antisolvent vapors and their efficiencies was compared. It was observed that devices using DE vapor reach higher efficiencies than devices without any antisolvent vapor.
  • Master Thesis
    Plasmonic Enhancement of Perovskite Photoluminescence
    (Izmir Institute of Technology, 2020) Tan, Metin; Sarı, Emre; Balcı, Sinan
    Recently emerged perovskite materials show superior features like high efficiency, defect tolerance, facile synthesis, bandgap tunability and wide color gamut over their rivals in photonics applications. On the other hand, metals have interesting characteristics as they go smaller in size. Their absorption and scattering properties are completely different as nanoparticles. Their confined electron oscillations bring peculiar consequences. Due to change in these features, metallic nanoparticles can enhance or quench fields around them. Light-matter interactions determine how we see the world. Understanding quantum nature of light and matter and their interactions can benefit higher efficiencies and can open paths for novel technologies. In accordance with this purpose, this thesis study involves synthesis of cesium lead halide perovskite emitters and investigation of their interactions with silver nanoisland films. It was concluded that direct contact between perovskite layer and nanoislands results in a fluorescence quenching where intensity average lifetime decreases below 1 ns. Separating these layers with an alumina dielectric layer increased photoluminescence intensity after 15 nm and the highest intensity was observed at 18 nm thickness with 78% of PL enhancement. With different spacer thickness values, we achieved to see the change in photoluminescence intensity.
  • Master Thesis
    Fabrication and Characterization of Graphene/Silicon Based Schottky Photodiode
    (Izmir Institute of Technology, 2019) Dönmez, Gülçin; Çelebi, Cem; Sarı, Emre
    This thesis focused on fabrication and characterization of CVD grown p-type graphene and n-type Si Schottky junction photodiode with rectification behavior. The device operated at wavelength range between 390 and 1100 nm at self-powered mode. The device was encapsulated with Epoxy Resin to prevent graphene from atmospheric adsorbates. The electronic and optoelectronic characterizations of the devices were done before and after coating the devices with ER. By encapsulation stability of the device was enhanced in terms of photoresponsivity. The maximum obtained photoresponsivity value of the bare device was 0.56 A/W. Also, time-resolved photocurrent spectroscopy measurements showed that the devices exhibited enhanced photodetector performance in terms of photo-switching characteristics. Furthermore, electrical characteristics of Gr/n-Si Schottky photodiode under various illumination power densities with 850 nm wavelength were investigated. The short circuit current showed linear response to power density. However, open circuit voltage exhibited two phased slow and fast increment with increased power density. Hall effect measurements were conducted in order to investigate hole carrier concentration and mobility of the graphene on n-Si. With increasing the power density the carrier concentration increased and the mobility decreased. Besides, light induced manipulation of the Schottky barrier height of Gr/n-Si photodiode was studied. Schottky barrier height of the graphene measured by KPFM method as 0.4 eV. With increasing power density we found that Schottky barrier height of the device increased from 0.4 eV to 0.5 eV and showed similar trend with the change in open circuit voltage.