| 摘要: | 染料敏化太陽能電池 ( Dye-Sensitized Solar Cells, DSSCs ) 由於具有透光性、可撓曲性、良好的光電轉換效率與低製造成本等優點，是目前相當熱門的研究領域之ㄧ。在 DSSC 中最常使用的是I-/I3-電解質，但I-/I3-沒有辦法經由結構修飾來增加元件效率。因此，使用鈷金屬錯合物電解質來提高元件的Voc是常用的策略。但是鈷金屬錯合物電解質容易與 TiO2 上的電子產生再結合，影響元件的光電轉換效率。本研究是從本實驗室所合成出的一系列染料中，選擇了尾端具有碳鏈的染料 SJW-B18 和 CYC-B11H 來搭配鈷金屬錯合物電解質組裝成染料敏化太陽能電池，探討釕金屬錯合物結構上加入了長碳鏈是否可以有效的避免鈷金屬錯合物和 TiO2 上的電子再結合，進而提高元件的光電轉換效率。將 SJW-B18 分別和鈷錯合物電解質以及碘系統電解質組裝成元件。在使用鈷錯合物電解質的元件，因為鈷錯合物的還原電位較低，因此元件的Voc值較高（0.814 V，相對於使用I-/I3-的0.781 V）。此外，為了進一步了解染料結構上碳鏈數對鈷電解質的影響，將本實驗室所合成出的另一個高效率染料 CYC-B11H 也搭配鈷電解質組裝成 DSSC 元件並測試其光電表現。實驗結果顯示，使用輔助配為基上具有四個烷基的SJW-B18為敏化劑時，由於染料在二氧化鈦電極上的覆蓋度較好，避免了鈷金屬錯合物與 TiO2 上的電子產生再結合，元件的Voc值損耗較少，讓元件有較高的Voc（0.814 V）及光電轉換效率（7.08%），而最優化的鈷錯合物電解質的組成為0.2 M Co(II), 0.02 M Co(III), 0.5 M TBP和 0.1 M LiClO4配置在乙腈溶劑中。;Dye-sensitized solar cells (DSSCs), one of the third generation solar cells, are getting more popular these days, due to their light weight, low cost and easy to make. In DSSCs, electrolyte plays the role of re- generating the oxidized dye, transferring hole to the counter electrode and determining the theoretical Voc of the devices. The most common electrolyte used in DSSCs is iodide/triiodide (I-/I3-) redox couple. However, I-/I3- redox system has some disadvantages, such as the fixed redox potential and the structure of the electrolyte can not be modified, which limits it development. Many scientists are now looking for new electrolytes to increase the efficiency of DSSCs. Cobalt based electrolyte, due to it adjustable potential which can be used to increase the Voc of DSSCs, is one of the potential electrolytes. However, cobalt based electrolyte has the disadvantage of easily capture the electron on TiO2 electrode, increasing the dark current, therefore reducing Voc of the device. We use the SJW-B18 and CYC-B11H with long alkyl chain on their ancillary ligand developed by our lab to avoid the charge re- combination. In the study, we found that compared to CYC-B11H dye using SJW-B18 dye, which has 4 terminal alkyl chain, as a sesitizer can protect the surface of TiO2 electrode, increase the resistance between dye adsorbed on TiO2 electrode and electrolyte, prevent the dark current, increase the life time of the electron on TiO2 electrode and decrease the loss of Voc. The highest efficiency of the device based on SJW-B18 dye combined with cobalt electrolyte is 7.08%. The optimal composition of the electrolyte is 0.2 M Co(II), 0.02 M Co(III), 0.5 M TBP and 0.1 M LiClO4 in acetonitrile. |
