本文主要之目的為利用四級銨鹽為基礎之室溫離子液體作為染料敏化太陽能電池之電解質。現今文獻中依然是傳統液態電解質才能達到約11% 的最佳光電轉換效率，其理由大致上為液態電解質具有擴散速率快、導電度高、黏度低等優勢。但是這些有機溶劑都具有高的揮發性，會造成電池的壽命減短、電池漏液的問題而進一步汙染環境。然而，四級銨鹽為基礎之室溫離子液體只需要運用簡單的物理混合就可以製備，同時也具備了價格便宜的特點。所以本實驗直接利用數種四級銨鹽(quaternary ammonium salt)和可以提供氫原子(hydrogen bond donor)之醇類以適當的比例混合即可製備出此種離子液體。這一系列的離子液體也具備低蒸氣壓及熱穩定性的優點，所以理當能夠改善傳統液態電解液的缺點。
將上述的離子液體配製成電解液並進行離子導電度分析、黏度、極限擴散電流密度的測量來了解添加不同濃度的碘對於電解質中離子擴散的速率以及是否能快速地進行氧化還原反應於光電極(TiO2)以及白金對電極之間。為了能再提升整體光電轉換效率的數值，於陽極上添加散射層(scattering layer)以及四氯化鈦後處理(TiCl4 treatment)兩種程序來增加光電流密度(Jsc)。
由於碘離子本身具有較大的極性易產生聚集，為了能讓碘離子更容易解離；故使用新型四級銨鹽( AcetylCholine Iodide, ACI) 來改善之。其本身陽離子具備不對稱性且不具吸水性的性質進而製備一系列低黏度離子液體。接著改變碘化鋰(LiI)之濃度由0.3M至1.0M的範圍，同時經由單一波長光電轉換效率分析(IPCE)和電化學交流阻抗分析(EIS)的確認可得知在本實驗的最佳條件下，使用有機染料(D-149)在入射光強度為100 mW/cm2下其光電轉換效率(η)可達3.36%、短路電流密度(Jsc)為8.57 (mA/cm2)、開環電壓(Voc)為0.645 V、填充因子(FF)為0.61。在其餘實驗條件設定相同的原則下，使用乙腈為溶劑之液態電解質其轉換效率(η)可達4.3%。故離子液體電解質之效率已經可達到其78%的程度。

In this thesis, quaternary ammonium salt-based ionic liquids are used to serve as a low-volatility solvent for electrolytes in dye-sensitized solar cells (DSSCs). There are three main advantages for the use of volatile organic solvents for electrolytes, including fast diffusion rates, high ionic conductivities, and low viscosities. However, because of the high volatility of the electrolyte solvent, the cell performance decreases when the solvent vapor leaks.
In this thesis, a series of quaternary ammonium salts-based ionic liquids are prepared from heating mixtures of quaternary ammonium salts and hydrogen bond donors. This series of liquids has the advantages of cost-effectiveness, easy preparation, low volatility, and excellent ionic conductivity when used as the solvents for electrolytes in DSSCs.
A new quaternary ammonium salts (Acetylcholine iodide, ACI) is developed in this thesis. When used in DSSCs, constructed from P25 powders and D149 dye
(a metal-free iodoline dye), the electrolyte gives a Jsc of 8.57 (mA/cm2), a Voc of 0.645 (V), a fill factor of 0.61, and an efficiency of 3.36%, which is 78% of that achieved by using the AN based electrolyte (efficiency of 4.3%) under the same measurement condition.

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