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Date of Award


Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Materials Science and Engineering (MS)

Administrative Home Department

Department of Materials Science and Engineering

Advisor 1

Yun Hang Hu

Committee Member 1

Joshua Pearce

Committee Member 2

Feng Zhao


This study primarily focuses on the synergistic effect between anatase and rutile in the photoanode of dye-sensitized solar cells (DSC), which was evaluated by tuning their phase ratio and crystallite size within the TiO2 photoanode via adjusting the sintering temperature and atmosphere. Hydrogenation of TiO2 powder was performed to increase visible light absorption to compare with air treated powders. Characterization of heat treated powders was performed using XRD, FE-SEM, S-TEM, BET, UV-vis, Fluorescence spectroscopy, and electrochemical I-V testing. The synergistic effect was effectively promoted in air treated TiO2 but was not observed using hydrogenation conditions. The highest energy conversion efficiency of 7.1% was found to occur with the photoanode sintered in air at 600 °C for 2 hours, which possessed a crystallite size of 24.4 nm for anatase and 42.0 nm for rutile with 19.4 wt. % rutile. The highest efficiency obtained using hydrogenated TiO2 was 6.3% with morphology similar to the baseline P25 TiO2 which possessed a crystallite size of 21.4 nm for anatase and 36.4 nm for rutile with 11.6 wt. % rutile. Increased hydrogenation temperature resulted in decreased photovoltaic performance due to vacancy induced recombination centers and deteriorated phase junctions, despite increased visible light absorption measured in UV-vis. Hydrogenation was shown to significantly increase transformation rate of anatase to rutile and crystal growth beyond the transition temperature due to reduced crystal rigidity.