Browsing by Author "Wang, Yu-Shiuan"

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Electrochromism of rutile nanowires, vertically aligned along the [001] direction, due to alkali metal ion intercalation
(2011)
Yang, Min-Han
;
Chen, Ting-Ting
;
Wang, Yu-Shiuan
;
Chiu, Hsin-Tien
;
Lee, Chi-Young
Rutile nanowires were grown along the [001] direction and perpendicular to the fluorine doped tin oxide coated glass substrate (R(perpendicular to)) by a solvothermal process using titanium isopropoxide as the precursor in acidic solution. The edge length of the nanowires obtained in isopropyl alcohol is ten times less than that of the nanowires obtained in water. Due to the high ionic diffusion rate along the rutile [001] direction and good optical transmittance, R(perpendicular to) was used as an electrochromism electrode. When -2 V was applied, the color of the electrode became blue with a 60% change in the transmittance for 30 s due to the cathodic polarization potential in LiClO(4)/PC electrolyte (where PC is propylene carbonate). The lithium ion intercalated/extracted densities of R(perpendicular to), P25-coated and rutile nanowires-coated electrodes are 138.6/129.1 mC cm(-2), 93.6/83.2 mC cm(-2) and 31.7/15.9 mC cm(-2) respectively. After 50 cycles, the R(perpendicular to) electrode still performs very well. Furthermore, a large amount of sodium cation intercalation into TiO(2) was observed for the first time at -1.0 V. According to these results, the R(perpendicular to) electrode is a promising candidate to be a multi-function device.
SrTiO3/TiO2 Hybridstructure as Photoanode in Dye-Sensitized Solar Cell
(2013-12-01)
Wang, Yu-Shiuan
;
Chen, Ting-Ting
;
Huang, Yi-Jen
;
Huang, Tzu-Ping
;
Lee, Yin-Yu
In dye-sensitized solar cells (DSSCs), the charge recombination at the TiO2/dye/electrolyte interface greatly influences the photoelectron conversion efficiency. Hybrid semiconductor materials with matched band potentials are designed to reduce the charge recombination. In this study, SrTiO3/TiO2 hybridstructure was synthesized by using TiO2 nanoparticles as template in a hydrothermal, showing a negative shift in the flat band potential. The DSSC with the SrTiO3/TiO2 anode exhibits an increased photovoltage and a reduced photocurrent. The suppression of charge recombination at the TiO2/dye/electrolyte interface was observed in the electrochemical impedance spectroscopy, causing an improvement in the photovoltage. However, the SrTiO3/TiO2 system shows an obstructed electrons injection from the dye to SrTiO3/TiO2, limiting the photocurrent performance. The photoelectrochemical properties of the SrTiO3/TiO2 system are discussed in detail herein.