title: Effects of bis(imidazolium) molten salts with different substituents of imidazolium cations on the performance of efficient dye-sensitized solar cells.
abstract: Bis(imidazolium) iodides (bis-Im(+)I(-)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'-methylene bis(3-imidazolium) diiodide (MIDI), 1,1'-methylene bis(3-n-methylimidazolium) diiodide (MMIDI), and 1,1'-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 (Jsc), higher open-voltage (Voc) 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.
authors.affiliation: School of Physics and Technology, Key Laboratory of Artificial Micro/Nano Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China.
authors.forename: Sihang
authors.initials: S
authors.lastname: Bai
authors.forename: Chenghao
authors.initials: C
authors.lastname: Bu
authors.forename: Qidong
authors.initials: Q
authors.lastname: Tai
authors.forename: Liangliang
authors.initials: L
authors.lastname: Liang
authors.forename: Yumin
authors.initials: Y
authors.lastname: Liu
authors.forename: Sujian
authors.initials: S
authors.lastname: You
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Yu
authors.forename: Shishang
authors.initials: S
authors.lastname: Guo
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Zhao