(I)利用氫醌及氫醌衍生物作為染料敏化太陽能的氧化還原對 (II)利用氫醌的電化學特性製作高選擇性的氟離子電化學探針

(I)Dye-Sensitized Solar Cells Based on Hydroquinone/Benzoquinone derivative as a redox Couple (II)A new highly selective OFF-ON electrochemical latent redox ratiometric chemodosimeters for the rapid detection of fluoride

李文詠(Wen-Yung Li)

指導教授 ： 黃聲東

國立臺北科技大學/工程學院/化學工程研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00200

摘要

染料敏化太陽能電池具有低成本及高效率的特性，近幾年來為太陽能領域的研究重點，電解質在染料敏化太陽能電池非常重要，而目前最常使用的電解質通常是碘化物/三碘化物作為氧化還原電對。但是，碘作為氧化還原電對的缺點已被探討出來，包括可見光吸收，金屬反電擊的腐蝕，和碘的昇華。因此，我們使用氫醌/苯醌取代碘作為氧化還原電對，並且進行光電性質的比較，可發現光電轉化效率叔丁基對苯二酚較碘好，而效率與碘非常相近。
　　近年來在氟離子探針的發展與應用上，鮮少有使用電化學來檢測氟離子的例子，使用電化學的方式無法準確得知濃度，只能依據位移作為判斷。因此，我們開發一個具有高選擇性及可定量的氟離子探針(H2Q’ 和 MH2Q’) ，透過使用矽醚保護基隱藏H2Q的電化學信號以獲得探針 H2Q’（OFF狀態) ，氟離子引發Si-O鍵斷裂，將保護基去除，釋放電化學訊號H2Q（ON狀態)，H2Q容易經受電化學氧化還原反應，並在電極表面上顯示它的氧化還原峰，依賴氟化物的濃度，釋放出固定的H2Q濃度。檢測極限（LOD）MH2Q'為2.38 μM ，且H2Q’ 為23.8μM。在檢測的陰離子中，只有氟化物能夠將H2Q’脫保護變成H2Q，產生氧化還原反應，因為矽醚類的氟離子探針在水中有非常好的專一性。且MH2Q’也是具有一個高度選擇性的氟離子探針。

關鍵字

(I)染料敏化太陽能電池 ； 電解液 ； 氫醌(II)氫醌電化學探針 ； 氟 ； 選擇性

並列摘要

Dye-sensitized solar cells are low cost solar cells to carry out the energy conversion from solar light to electricity with high efficiency. Conventionally, Iodide/triiodide (I-/I3-) redox pairs are the most commonly employed electrolyte system in the DSSCs. However, they have several drawbacks such as light absorption, corrosion associated with metal current collectors, sublimation of iodine and mismatch between I-/I3- redox potential and HOMO level of the photosensitizer. Therefore, finding an alternative electrolyte has become considerable attention in the recent years to circumvent these limitations of I-/I3- redox pair. In the present work, we have demonstrated t-butyl hydroquinone substituted hydroquinone/benzoquinone (tBu-HQ/tBu-BQ) as the potential alternative to the I-/I3- redox pair. The tBu-HQ/tBu-BQ presented comparable DSSC performance relative to I-/I3- redox pair in terms of efficiency and incident photon current efficiency (IPCE) which revealing its great potential to be as the electrolyte for the fabrication of versatile DSSCs.
The second part of this thesis is the improving of fluoride detection. We described highly selective OFF-ON electrochemical latent redox ratiometric chemodosimeters (H2Q’ and MH2Q’) for the selective detection of fluoride through simple selective protection/deprotection strategy. The electrochemical signal of hydroquinone (H2Q) moiety within this latent redox probe was masked by protecting its hydroxyl group as silylether that resulted in the formation of latent probe, H2Q’ (OFF). The externally added fluoride ion triggered the deprotection of H2Q’ which leading to the unmasking of H2Q electrochemical property (ON). The amount of liberated H2Q is quantitative and its redox peak currents are linearly dependent with the concentration of fluoride that leading to the ratiometric detection. The LOD observed for the probes are sufficiently lower; 23.8 μM for H2Q’ and 2.38 μM for MH2Q’. The deprotection is highly specific for fluoride over other anions investigated. The probes are highly stable and exhibited rapid response time and promising practical applicability. The proposed strategy holds great promise for the commencement of new H2Q based electrochemical probes by tuning the electronic properties of H2Q through varying the substituents.

並列關鍵字

(I)dye-sensitized solar cell ； electrolytic solution ； hydroquinone(II)hydroquinone ； electrochemical sensor ； fluoride ； selectivity

參考文獻

1.O'Regan, B.; Gratzel, M., A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films. Nature 1991, 353 (6346), 737-740.

2.Yella, A.; Lee, H.-W.; Tsao, H. N.; Yi, C.; Chandiran, A. K.; Nazeeruddin, M. K.; Diau, E. W.-G.; Yeh, C.-Y.; Zakeeruddin, S. M.; Gratzel, M., Porphyrin-Sensitized Solar Cells with Cobalt (II/III)–Based Redox Electrolyte Exceed 12 Percent Efficiency. Science 2011, 334 (6056), 629-634.

3.Gratzel, M., Conversion of sunlight to electric power by nanocrystalline dye-sensitized solar cells. Journal of Photochemistry and Photobiology A: Chemistry 2004, 164 (1–3), 3-14.

4. Mishra, A.; Fischer, M. K. R.; Bauerle, P., Metal-Free Organic Dyes for Dye-Sensitized Solar Cells: From Structure: Property Relationships to Design Rules. Angewandte Chemie International Edition 2009, 48 (14), 2474-2499.

5.Koumura, N.; Wang, Z. S.; Mori, S.; Miyashita, M.; Suzuki, E.; Hara, K., Alkyl-functionalized organic dyes for efficient molecular photovoltaics. J Am Chem Soc 2006, 128 (44), 14256-14257.