含氟或三氟甲基的輔助配位子之環金屬釕錯合物的合成及其在染料敏化太陽能電池上的應用

Synthesis of Cyclometalated Ru(II) Sensitizers with Fluoro- or Trifluoromethyl- Substituent on the Ancillary Ligands for Dye-Sensitized Solar Cells

江知優(Chih-yu Chiang)

指導教授 ： 吳春桂

國立中央大學/理學院/化學系/碩士(2015年)

摘要

由於全球暖化危機，尋找好的再生能源是目前非常重要的議題，而取之不盡、用之不竭，乾淨且少污染的太陽能是目前最被看好的再生能源。染料敏化太陽能電池 (DSSCs)能將太陽能轉換成電能，是被廣泛研究的新型式太陽能電池之一。此類型電池光電流的來源-染料，是影響電池光電轉換效率與元件長時間穩定性的重要關鍵。許多以釕金屬為中心的錯合物染料具有高效率，如N749，是以一個三牙基terpyridine-carboxylic acid及三個單牙輔助配位基Thiocyanate ligand (NCS)所組成的六配位錯合物，但單牙基的NCS穩定度低。本論文研究重點即設計出新結構三牙基輔助配位基Ligand T2 ~ Ligand T4，以取代三個NCS單牙基，合成出了三個應用於DSSC的釕錯合物敏化劑T2~T4，這三個錯合物染料皆以6-phenylpyridine-2-carboxylate的衍生物為三牙輔助配位子，能與釕形成環金屬 (cyclometalated) 配位，再以terpyridine-carboxylic acid為附著配位基，形成6配位釕金屬錯合物，含環金屬配位基的染料分子其HOMO與LUMO間的能階差較小，使染料有機會能吸收更長波長的光，增加元件之光電流值。另外在輔助配位基中引入了F或CF3基團，降低染料分子的HOMO能階，以利於電解質將氧化態的染料還原再生。在三者中光電性質最佳的T3染料，組裝成電池元件後的短路電流密度 (Jsc)為12.86 mA cm-2，開路電壓 (Voc) 為0.65 V，填充因子 (FF)為0.623，光電轉換效率為5.21%，在相同條件下N749的光電轉換效率為8.87%。

關鍵字

染料敏化太陽能電池 ； 環金屬釕敏化劑

並列摘要

Looking for a renewable energy is one of the currently important issues due to the global warming issue. Solar energy is the most promising renewable energy source because it is inexhaustible, clean and less polluting. Dye-sensitized solar cells (DSSCs) which can convert solar energy into electrical energy, is one of the new generation solar cells under extensive studied. Dye molecules are the source for the photocurrent of DSSC. They also affect the power conversion efficiency and stability of the corresponding devices. In this thesis, we forcus on the synthesis of three new ruthenium dyes, T2, T3, and T4, containing a tridentated ancillary ligand (which is used to replace three NCS ligands to increase the long-term stability of the cell) with O^N^C corrdination sites. Tridentate O^N^C ligand was used to enhance the light harvesting efficiency in the longer wavelength region, because cyclometalated ruthenium complexes have small energy gap. Furthermore, the electron withdrawing groups, such as F- and CF3-, was incorporated in the ancillary ligang to lower the HOMO level of these dyes. Therefore the oxidized dyes can be efficiently regenerated by the electrolyte. The best (amongst the three dyes) photovoltaic performance T3 dye gave a short-circuit photocurrent density of 12.86 mA cm-2, open-circuit voltage of 0.65 V, and a fill factor of 0.623, affording an overall conversion efficiency of 5.21% vs 8.87% for N749 based cell fabricated at similar conditions.

並列關鍵字

Dye-sensitized solar cells ； Cyclometalated Ruthenium(II) Sensitizers

參考文獻

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