| 摘要: | 染料敏化太陽能電池(Dye-Sensitized Solar Cells, DSSCs)由於擁有低製造成本、半透光性、色彩多樣性及可撓曲性等特性，是目前相當熱門的研究主題之ㄧ。過去數十，年研究如何經由染料的分子設計提高元件之短路電流的文獻非常多，但是討論如何經由染料分子設計增加元件開路電壓的文章相對少，因此目前尚沒有明確的染料的設計方向。本研究著重於探討染料分子結構如何影響由其所敏化之染料敏化太陽能電池元件的開路電壓。我們分別藉由在染料分子的輔助配位基尾端接上不同個數的?吩環、加入比碳鏈更強推電子能力的氧烷鏈與硫烷鏈及引入較大分子團等方法，來降低DSSC元件中TiO2上的電子與電解質再結合的機會，提高元件的開路電壓。本論文設計合成SJW-B4、SJW-B8、SJW-B10、SJW-B17，及SJW-B18等五個釕金屬錯合物並搭配先前已發表之CYC-B1、SJW-E1及CYC-B11H，探討由這些染料所敏化之染料敏化太陽能電池元件的光電轉換效率表現，以了解染料結構如何影響元件之光電轉換效率。實驗結果顯示，SJW-B18的輔助配位基為二丁基雙?吩，能有效的改善TiO2表面的覆蓋度，降低DSSC元件中TiO2上的電子與電解質再結合的機會，因此以其所敏化之DSSC元件搭配I-/I3-電解質具有最高的開路電壓，及最高的光電轉換效率。而輔助配位基有四條烷鏈之SJW-B18在TiO2上的覆蓋度較好，使電解質較不易與TiO2接觸，有效降低電子與電解質再結合的機會，因此當以Co(II)/Co(III)做電解質時，在不加共吸附劑下由SJW-B18敏化之DSSC元件的開路電壓可達833 mV。Dye-Sensitized Solar Cell, (DSSC) is one of the hottest research topics in the photovoltaic technology, due to its low production cost, transparent, colorful, and can be flexible. In the past a couple of decades, there are many studies focus on increasing the photocurrent of DSSCs by structural design of the dye molecules. Nevertheless there are very few papers focus on enhancing the open-circuit voltage of DSSC through the design of the sensitizers’ structure. In this study, we investigate the effect of the dye structure on the open-circuit voltage of the corresponding DSSC. The strategy is to avoid the electrolyte to contact TiO2 surface to produce dark current. Five ruthenium based dyes coded SJW-B4, SJW-B8, SJW-B10, SJW-B17, and SJW-B18 in which thiophene derivatives were incorporated to extend the conjugation length of the ancillary ligand, or more electron-donating ability atom (O, S) or a bulky group was incorporated in the ancillary ligand, or add more alkyl chains on the terminal of the ancillary ligand. The results show that SJW-B18 with the ancillary ligand containing 4 butyl chains improves the coverage of TiO2, decreasing the electron recombination between the TiO2 and electrolyte. DSSC sensitized by SJW-B18 with I-/I3- electrolyte has the highest Voc and conversion efficiency. Furthermore, when Co(II)/Co(III) electrolyte was used, DSSC sensitized by SJW-B18 has the highest Voc of 833 mV. SJW-B18 has 4 butyl chains on its ancillary ligand, forming good coverage on TiO2 surface, avoiding the charge recombination between the TiO2 and electrolyte, reducing the dark current, therefore the corresponding DSSC has high Voc. |
