Effects of Bis(imidazolium) Molten Salts with Different Substituents of Imidazolium Cations on the Performance of Efficient Dye-Sensitized Solar Cells

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• 作者：Sihang Bai ; Chenghao Bu ; Qidong Tai ; Liangliang Liang ; Yumin Liu ; Sujian You ; Zhenhua Yu ; Shishang Guo ; Xingzhong Zhao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：April 24, 2013
• 年：2013
• 卷：5
• 期：8
• 页码：3356-3361
• 全文大小：316K
• 年卷期：v.5,no.8(April 24, 2013)
• ISSN：1944-8252

文摘

Bis(imidazolium) iodides (bis-Im⁺I鈥?/sup>s) are synthesized with different substituents and used as electrolytes in dye-sensitized solar cells (DSSCs). Three kinds of low-volatility electrolytes are prepared by using 1,1鈥?methylene bis(3-imidazolium) diiodide (MIDI), 1,1鈥?methylene bis(3-n-methylimidazolium) diiodide (MMIDI), and 1,1鈥?methylene-bis(3-n-ethylimidazolium) diiodide (MEIDI) as the iodide sources. The effects of these substituents on the photovoltaic performance of the cells are investigated. It is found that the device shows a lower short-circuit photocurrent (J_sc), higher open-voltage (V_oc) and fill factor (FF) with the increased cation size in electrolyte. These results are explained by electrostatic interactions between the solvated Im⁺ and the negatively charged species. Meanwhile, the explanation is supported by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), open circuit voltage decay (OCVD), and dark current measurements.

Keywords:

triiodide/iodide redox couple; bis(imidazolium) iodide; low-volatility electrolyte; electrostatic interaction; dye-sensitized solar cells