Bottom-up Growth of Hierarchical Electrodes for Highly Efficient Dye-Sensitized Solar Cells

详细信息    查看全文

• 作者：Youngshin Lee ; Chang-Yeol Cho ; Su-Jin Ha ; Hye-Na Kim ; Jun Hyuk Moon
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2012
• 出版时间：July 25, 2012
• 年：2012
• 卷：4
• 期：7
• 页码：3589-3595
• 全文大小：457K
• 年卷期：v.4,no.7(July 25, 2012)
• ISSN：1944-8252

文摘

The nonconventional bottom-up growth of TiO₂ was first demonstrated in the preparation of hierarchical TiO₂ electrodes for use in highly efficient dye-sensitized solar cells. The simple immersion of a substrate in a precursor solution enabled the growth of TiO₂ particulate films. Here, we have implemented a hierarchical growth strategy in which two stages of controlled growth yielded first macroscale TiO₂ particles, followed by mesoscale TiO₂ particles. We successfully fabricated electrode films up to 20 渭m thick via a growth rate of 0.3 渭m/min. The specific area of the electrodes was controlled via the deposition of mesoscale TiO₂ particles. The deposited particles displayed a rutile phase with an average size of several tens of nanometers in diameter, as confirmed by XRD and high-resolution TEM imaging. After depositing the second layer of mesoscale TiO₂ particles, the photocurrent density increased by a factor of 3. A maximum efficiency of 6.84% was obtained for the hierarchically structured TiO₂ electrodes under 1 sun illumination. The hierarchical TiO₂ electrodes were compared with macroporous TiO₂ electrodes, revealing that the higher photocurrent density could be attributed to a longer electron recombination lifetime and a high specific area. The longer recombination lifetime was supported by the presence of fewer defective TiO₂ surfaces, as confirmed by the XPS spectrum.

Keywords:

hierarchical structures; solution deposition; TiO₂; macroporous; recombination lifetime; dye-sensitized solar cells