Multifunctional Iodide-Free Polymeric Ionic Liquid for Quasi-Solid-State Dye-Sensitized Solar Cells with a High Open-Circuit Voltage

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• 作者：Yi-Feng Lin ; Chun-Ting Li ; Chuan-Pei Lee ; Yow-An Leu ; Yamuna Ezhumalai ; R. Vittal ; Ming-Chou Chen ; Jiang-Jen Lin ; Kuo-Chuan Ho
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：June 22, 2016
• 年：2016
• 卷：8
• 期：24
• 页码：15267-15278
• 全文大小：632K
• 年卷期：0
• ISSN：1944-8252

文摘

A polymeric ionic liquid, poly(oxyethylene)-imide-imidazolium selenocyanate (POEI-IS), was newly synthesized and used for a multifunctional gel electrolyte in a quasi-solid-state dye-sensitized solar cell (QSS-DSSC). POEI-IS has several functions: (a) acts as a gelling agent for the electrolyte of the DSSC, (b) possesses a redox mediator of SeCN^–, which is aimed to form a SeCN^–/(SeCN)₃^– redox couple with a more positive redox potential than that of traditional I^–/I₃^–, (c) chelates the potassium cations through the lone pair electrons of the oxygen atoms of its poly(oxyethylene)-imide-imidazolium (POEI-I) segments, and (d) obstructs the recombination of photoinjected electrons with (SeCN)₃^– ions in the electrolyte through its POEI-I segments. Thus, the POEI-IS renders a high open-circuit voltage (V_OC) to the QSS-DSSC due to its functions of b–d and prolongs the stability of the cell due to its function of a. The QSS-DSSC with the gel electrolyte containing 30 wt % of the POEI-IS in liquid selenocyanate electrolyte exhibited a high V_OC of 825.50 ± 3.51 mV and a high power conversion efficiency (η) of 8.18 ± 0.02%. The QSS-DSSC with 30 wt % POEI-IS retained up to 95% of its initial η after an at-rest stability test with the period of more than 1,000 h.