Date

2013

Author

Koç, Mehmet

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Density functional theory (DFT) calculations within the gradient-corrected approximation (GGA) have been carried out on three models of ETS-10 with the aim to elucidate the effect of ion exchange on the structural, electronic and vibrational properties of the Ti-O-Ti quantum wire. Our data are reveal the presence of two inequivalent Ti-O bonds along the chain in the ETS-10 sodium form, in agreement with past theoretical and experimental studies. The nature and spectral position of the ligand-to-metal charge transfer transition experimentally observed at 4.02 eV is also well accounted for by our DFT calculations. Partial and full exchange of Na+ cations with alkaline, earth-alkaline and transition metal ions affect both structural, electronic and vibrational properties of the quantum wire. The theoretical results have been rationalized and compared with recent experimental data. In order to clarify the theoretical data revealed from DFT studies, experimental setup was arranged. Experimental data show significant similarities with simulation results. Effect of ion-exchange at ETS-10 was discussed both experimentally and theoretically. Effects of different cations with very broad range of physical properties were discussed. In the guidance of theoretical and experimental analyses, solar cell studies were discussed. Important variancesin the application part, which is very challenging to explain experimentally, was tried to reveal. Theoretical studies and solar cell results reveal that ETS-10 has a tunable band gap with ion exchange process, while charge cycle of ETS-10 in DSSC geometry should be improved.

Subject Keywords

Ion exchange., Solar cells., Nanostructured materials., Nanowires., Zeolites., Titanosilicate.

URI

http://etd.lib.metu.edu.tr/upload/12616291/index.pdf
https://hdl.handle.net/11511/22931

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Graduate School of Natural and Applied Sciences, Thesis