Adsorption Behavior of Bipyridyl Dyes on Hydrothermally Treated TiO2 Nanotube-Array with Different pH Conditions and Its Applications on Dye-Sensitized Solar Cell

• Main Authors: Li, Tze-Huei, 李姿慧
• Other Authors: Chien, Chao-Hsin
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/61755699915922864178

碩士 === 國立交通大學 === 電子研究所 === 100 === In this work, hydrothermally treated titanium dioxide nanotube is studied. To apply the hydrothermal treatment, pre-sintering over 400℃ is required to prevent collapse of the nanotubes during the treatment. X-ray diffraction pattern showed that the titanium dioxide nanotubes after the hydrothermal treatment maintained anatase phase. By raising pre-sintering temperature or increasing the volume of the solution in the hydrothermal treatment, the crystallinity of the titanium dioxide nanotubes, the amount of adsorbed dye, and thus the performance of dye-sensitized solar cell were enhanced. Also, the influence of the pH of hydrothermal solution was studied. According to Fourier Transform Infrared spectroscopy and X-ray photoelectron spectroscopy, after the hydrothermal treatment at higher pH or at lower pH the amounts of Ti-OH and Ti-OH2 on the nanotube surface were increased and the amount of Ti-O- was decreased, and due to the transformation of the surface ends decreased dye adsorption and degraded solar energy harvesting efficiency were hence resulted. In addition, the characteristics of two different dyes, N3 and N719, adsorbed on hydrothermally treated nanotubes were compared. In general, solar cell using photoelectrode of N3 dye adsorbed on hydrothermally treated nanotubes had better performance than that of N719 dye. In spite of the differences on the molar extinction coefficients and the molecular sizes of the dye molecular, the performance difference between N719 and N3 could be further influenced by TBA+ from N719, which more easily occupied hydrothermally treated TiO2 nanotube surface at higher or lower pH and lead to deterioration of dye adsorption.