以奈米級碳材料作為染料敏化太陽能電池對電極之研究

Investigations on the Application of Nanoscale Carbon Materials as Counter Electrodes of the Dye-Sensitized Solar Cells

許家彰(Chia-Chang Hsu)

指導教授 ： 戴念華 ； 李紫原

國立清華大學/工學院/材料科學工程學系/碩士(2009年)

https://doi.org/10.6843/NTHU.2009.00414

摘要

本研究利用奈米級碳材料作為染料敏化太陽能電池之對電極，藉由交流阻抗、循環伏安法、穩態伏安法與光電轉換特性等方法，研究各式碳極對碘離子/三碘錯離子氧化還原對之還原能力。實驗結果發現，碳極的表面積會強烈影響介面電荷轉移阻抗、I3－離子還原效率與光電轉換效率。由電子轉移控制與質傳控制之互動關係得知，奈米碳粉電極具有催化電解液能力，而多壁奈米碳管電極和少壁奈米碳管電極僅為輔助催化電解液，藉由分析奈米碳粉/少壁奈米碳管複合電極特性得知，奈米碳粉電極催化電解液能力不及鉑金屬。
本研究使用熱沉積鉑金屬為對電極，所得的光電轉換效率為4.136 %，以少壁奈米碳管電極作為對電極其光電轉換效率為3.156 %。由此結果可推論，奈米碳材料有機會取代鉑金屬作為染料敏化太陽能之對電極。使用鉑/少壁奈米碳管復合電極，以鉑金屬顆粒作為催化活躍位置，藉由少壁奈米碳管的高表面積，提升光電轉換效率。
最後，本研究提出一套完整的對電極分析方法與流程，並且探討碳材料的結構、表面形貌、表面積與缺陷等因素對電極的導電性、催化活性與穩定性的關係，並提出碳材料應用於染料敏化太陽能電池對電極的準則。

關鍵字

染料敏化太陽能電池 ； 對電極 ； 碳材料 ； 催化

並列摘要

We utilize nanoscale carbon materials as the counter electrodes of dye-sensitized solar cells (DSSCs) to explore how the catalytic ability of carbon electrodes responds to iodium/triiodide redox. We find that the surface area of carbon electrodes has markedly influences on the charge transfer resistance, the efficiency of catalytic process of I3－ ions, and the energy conversion efficiency. Through the relationship between charge transfer and mass transfer control, nanocarbon electrodes possess the ability to catalyze electrolyte; on the other hand, both MWNTs and LWNTs only play the role of assistance. Moreover, according to the experimental result, the catalytic ability of nanocarbon electrodes is inferior to the Pt electrode.
The energy conversion efficiency of thermal deposited Pt and LWNTs counter electrodes are 4.136 % and 3.156 %, respectively, which indicates that LWNTs has the potential to substitute Pt as counter electrodes of DSSCs. This energy conversion efficiency of the Pt/LWNTs electrode can be enhanced due to increasing surface areas of LWNTs and employing Pt particles as the active sites of catalysis.
This work proposes a thorough method to analyze counter electrode and shows how the parameters such as structure, morphology, surface areas, and defects of materials, affect the electric conductivity, catalytic activity, and stability of the electrode. Furthermore, this study also establishes a criterion for the application of carbon materials as counter electrode in DSSCs.

並列關鍵字

dye-sensitized solar cells ； counter electrodes ； carbon materials ； catalysis

參考文獻

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