可交聯光敏劑與雙成份離子溶液電解質在染敏太陽能電池光電性質之研究

Photovoltaic performance of dye-sensitized solar cells based on cross-linkable sensitizers and binary ionic liquid electrolyte system

文克剛(Ke-Gang Wen)

指導教授 ： 林金福

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.03139

摘要

本論文的研究主題專注於可交聯光敏劑Ru(4,4’-dicarboxylic acid) (4,4'-bis((4-vinylbenzyloxy)methyl) -2,2'- bipyridine)(NCS)2(簡稱 Ru-S),與離子溶液電解質系統在染料敏化太陽能電池的光電性質研究。本論文分成兩部分，第一部分著重於探討單成份(PMImI)、雙成份(PMImI/EMIDCA)離子溶液電解質系統和交聯與未交聯Ru-S染料敏化太陽能電池的表現。第二部份，將Ru-S與三種分子量的trimethylolpropane ethoxylate triacrylate(TET) 交聯後(分子量=428、604、912;依序簡稱RuS-co-TET428、RuS-co-TET604 and RuS-co-TET912) 做成太陽能電池元件，分析不同分子量的交聯劑對光電轉換效率的影響。第一部分，在染敏太陽能電池單成份離子溶液電解質系統中，將RuS 以不同濃度triethyleneglycodimethacrylate (TGDMA)進行交聯，可提升電池效率達4.84%。將低黏度的EMIDCA與PMImI以1:1 (體積比)方式混合成雙成份離子溶液(PMImI/EMIDCA)電解質，元件的開路電壓與短路電流都有顯著提升；接著調整雙成份離子溶液電解質中I2與LiClO4濃度均能有效提升元件的短路電流，而元件效率可提升到6.52 %，並藉著交流阻抗分析元件，得知影響效率的因素。
在第二部份，將三種分子量的TET交聯劑，分別以不同濃度與RuS交聯後，當TET濃度介於10-3~10-4 M(與RuS形成單層交聯網)，元件效率有優異表現，以RuS-co-TET912為例,元件效率高達7.2 ％。同時利用Voltage decay-Charge extraction 實驗分析元件的電位與電量關係，發現有較高的電子/染料貢獻比，電子生命周期也較長。最後，將RuS與TET912交聯後,應用在染料敏化太陽能電池之雙成份離子溶液電解質系統，量測元件的長效穩定性，於室溫下經過960hr，元件的效率仍可保有原先水準的表現。

關鍵字

可交聯光敏劑 ； 染敏太陽能電池 ； 離子溶液電解質 ； 光伏 ； 電化學阻抗

並列摘要

In this thesis，we focus on the photovoltaic performance of dye-sensitized solar cells (DSSCs) based on ionic liquid electrolyte systems and cross-linkable sensitizer Ru(4,4’-dicarboxylic acid) (4,4'-bis((4-vinylbenzyloxy)methyl)-2,2'-bipyridine) (NCS)2, denoted as RuS. There are two parts in this thesis. In the first part, the photovoltaic performance depending on 3-propyl-1-methylimidazolium iodide (PMImI) and binary PMImI/1-ethyl-3-methylimidazolium dicyanamide (EMIDCA) ionic liquid electrolyte systems for DSSCs with non-crosslinked and crosslinked RuS was investigated. In the second part, RuS on TiO2 mesoporous layer was crosslinked with three different molecular weights (Mw = 428、604、912) of trimethylolpropane ethoxylate triacrylate (TET), denoted as RuSco-TET428、RuSco-TET604 and RuSco-TET912, respectively for fabricating DSSCs. The influence of molecular weight for TET on power conversion efficiency was evaluated.
In the first part, the power efficiency of DSSCs using RuS crosslinking with different concentrations of triethyleneglyco- dimethacrylate (TGDMA) and PMImI ionic liquid electrolyte systems reached 4.84 ％. By using binary ionic liquid electrolyte systems comprised of PMImI and low viscosity EMIDCA (1:1 (v/v)), the short-circuit photocurrent (Jsc) and open-circuit photovoltage (Voc) of the device were higher than those using PMImI ionic liquid electrolyte systems. As we optimized the contents of I2 and LiClO4 in binary ionic liquid electrolyte, the device exhibited higher efficiency of 6.5 % resulted from the increase of Jsc. The photovoltaic properties were also investigated by electrochemical impedance spectroscopy (EIS).
In the second part, the DSSCs based on RuS-co-TET428、RuS-co-TET604 and RuS-co-TET912 and a binary ionic liquid electrolyte gave an impressive efficiency, especially when the concentrations of TET in acetonitrile were enough (10-3 ~10-4 M) to form a single layer network with RuS. Take RuS-co-TET912 as a example, the device exhibited an excellent power conversion efficiency of 7.2 %. According to voltage decay-charge extraction measurement, the increase of cell performance was attributed to the higher electron/dye ratio and longer electron lifetime. Finally, the DSSCs based on RuS-co-TET912 in binary ionic liquid electrolyte exhibited good stability with the power efficiency remaining unchanged after 960hr at room temperature.

並列關鍵字

crosslinkable sensitizer ； DSSC ； ionic liquid electrolyte ； photovoltaic ； electrochemical impedance

參考文獻

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