Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Sb2se3 Absorber Layered Solar Cell Fabrication and Characterization(01. Izmir Institute of Technology, 2021) Kurtuldu, Seher Hazal; Aygün, Gülnur; Tarhan, Enver; Tarhan, Enver; Aygün Özyüzer, Gülnur; Tarhan, Enver; 01. Izmir Institute of Technology; 04.05. Department of Pyhsics; 04. Faculty of ScienceThin-film antimony selenide (Sb2Se3) solar cells have gained attention as a high-potential photovoltaic technology around the world. Outstanding features like a high absorption coefficient, a suitable direct bandgap, and good hole mobility make Sb2Se3 a promising absorber material for solar cell applications. It has demonstrated a very rapid growth reaching 9.2% power conversion efficiency (PCE) in only 7 years after intensive studies. In the present thesis, first of all Sb2Se3 thin films were deposited on soda lime glasses (SLGs) and investigated using energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM), spectrophotometry and Raman spectroscopy. Structural and optical studies were carried out depending on the thickness, used argon (Ar) gas flow rate and post-annealing temperature of the Sb2Se3 films in order to optimize the absorber layer to be used in solar cell. This study revealed that key parameters such as band gap energy and crystal structure of the Sb2Se3 thin films affected by the thickness, Ar gas flow rate during deposition and post-annealing temperature. In addition, oxide phase formation was also found to be related to these growth parameters. Finally, SLG/ITO/Zn(O,S)/Sb2Se3/Ag for superstrate configuration and both SLG/Mo/Sb2Se3/CdS/ITO and SLG/Mo/Sb2Se3/CdS/ZnS/ITO devices fabricated for substrate configuration solar cells. Since Zn(O,S)/Sb2Se3 heterojunction has not been studied before in the literature, this study will be the first. At the end of the electrical analysis, the best conversion efficiency of 3.9% was achieved by the solar cell with the substrate configuration.Master Thesis Investigation of Gas Sensing Properties of Nanoparticles Functionalized With Ferrocene Molecules(Izmir Institute of Technology, 2013) Güzelaydın, Abdurrahman Halis; Tarhan, Enver; Tarhan, Enver; Tarhan, Enver; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this study, gas sensing properties of ferrocene functionalized multi-wall carbon nanotubes (MWCNT) and iron oxide nanoparticles were investigated via acoustic wave and electrical based techniques. Commercially obtained multi-wall carbon nanotubes having amine functional groups grafted directly onto their surfaces were covalently functionalized with ferrocene molecules. Iron oxide nanoparticles synthesized by the alkaline coprecipitation of ferric and ferrous salts were functionalized with ferrocene molecules. Dispersions of each modified nanoparticle in 3 mL ethanol were prepared and sonicated for 12 h in order to ensure adequate homogeneity. 5 ï L from each of these dispersions were then drop-cast onto AT-cut gold coated quartz crystal microbalance (QCM) and gold interdigitated (IDE) glass electrodes with 3 ï m interdigit spacing followed by drying on hotplate at 60 °C for 30 min to deposit thin-films. The thin-film coated electrodes were exposed to alternately varying concentration levels of CO, CO2, O2 and humidity ranging from 0 vol% to 100 vol% in predetermined intervals by a computer controlled mass flow meter array in an electromagnetically shielded and hermetically sealed measurement cell specifically designed to acquire QCM and electrical signals from the electrodes. Gas sensor responses of the thin-film coated QCM electrodes were assessed by measuring the frequency shift of the vibrating quartz crystal from its natural resonance frequency and evaluating that value into adsorbed mass according to Sauerbrey relation, whereas, responses from the interdigitated electrodes were assessed by measuring the resistance changes through the thin-film coating under a compliance current value of 1.0000 mA.