染料太陽能電池之染料分析研究及其穩定性探討

The Stability Ananlysis of Dye Molecule in the Dye-Sensitized Solar Cell

陳雅玲(Ya-Lin Chen)

指導教授 ： 楊重光

國立臺北科技大學/工程學院/化學工程所/碩士(2005年)

https://doi.org/10.6841/NTUT.2005.00273

摘要

本研究重點在於利用振動光譜及電子光譜針對染料電池封裝前穩定性的探討，而這些影響穩定性的因素日後勢必也會對封裝後的染料電池之穩定性及效能
造成衝擊。
本研究分為分為四大部份，依檢測方法分為FT-IR、XPS、UV/vis以及Raman Scattering 檢測。在實驗前將染料吸附於P25上，並浸於電解液中，再以原位傅立葉散射-反射紅外光譜技術(DRIFTs)對吸附於TiO2上之染料分子做分析。DRIFT為原位偵測技術專門針對粉末型態的樣品所的特殊配件;由紅外光譜資訊可得染料分子在半導體的鍵結形式、與電解液接觸後之染料分子官能基變化，以及以可見光照射染料分子吸附在TiO2的光劣質化情形，並以XPS檢測染料吸附於P25後的束縛能的變化;以紫外光/可見光譜部份之吸收峰變化觀察電解液中I-/I3-量之多寡和添加劑4TBP(4-tert-butylpyridine)的加入I3-吸收度的改變。在電解液對染料分子的影響部份，由DRIFTs搭配拉曼光譜檢測觀察電解液對染料分子的影響。
從紅外光譜得知染料分子以bidentate chelate/bridging或以一個TBA+和TiO2配位鍵結，不同吸附量鍵結式也不同。經由XPS檢測得知染料吸附量最少的系統其鍵結束縛能提高最多;由紅外光譜及拉曼光譜發現電解液中I3-及水氣會造成染料分子配位基SCN-的損傷，在光劣質化實驗亦是如此，由於文獻指出染料分子配位基(ligand)SCN-在電池中扮演氧化還原之重要角色，因此對SCN-之ν (CN)降解程度做一階動力分析。在電解液部份，添加劑4TBP(4-tert-butylpyridine)的加入可有效抑止I3-對配位基SCN-的損害，在於4TBP可降低I3-的濃度。

關鍵字

染料太陽能電池 ； 二氧化鈦 ； 光敏性染料 ； 化學反應機制

並列摘要

Investigating the stability of dye-sensitized solar cell (nc-DSC) before packaging by vibrational spectroscopy and electronic spectroscopy provides valuable information in the nc-DSC commercial production .
FT-IR, UV/vis, Raman Scattering Spectroscopy and XPS characterize the dye’s (N719) stability and its interaction with TiO2 in electrolyte solution. The dye (N719) adsorbed to TiO2 (P25) and electrolyte was studied by diffuse reflectance infrared spectroscopy (DRIFTs). DRIFTs, a powerful instrument to collect emitted IR spectra from the catalyst surface, provides the information of IR functional group of dye and coordination of the adsorbed dye molecules on TiO2. As a result, photodecomposition occurred on dye-TiO2 during the visible light illumination can be monitored. In addition, XPS was used to determine the interaction between adsorbed dye and TiO2 (P25) surface. The change of I-/I3- intensity in the electrolyte was observed and the decreasing tendency of I3- was noticed after the addition of 4TBP (4-tert-butylpyridine) by UV/vis spectroscopy. Raman spectrum accompanied with DRIFTs provides the estimation of impact between electrolyte and dye molecules.
FT-IR spectroscopy data suggest that a bidentate chelate or bridging coordination was attached to the TiO2 via the pathway of two carboxylate groups or one TBA cation through coadsorbance with dye molecule and TiO2. Consequently, different amounts of chemisorbed dye and different coordination modes were examined. The XPS results show that the dramatic change of binding energy occurred in the case of TiO2 with the least amount of dye adsorbed. To conclude that both triode (I3-) and H2O were found to exchange the SCN- ligand of the dye. The loss of the SCN- ligand in air was accelerated under the irradiation of visible light. Moreover, the SCN- ligand in the dye is believed to play an important role for the reduction of the oxidized dye. It’s suggested that addition of 4-tert-butylpyridine in electrolyte suppresses the loss of the thiocyanato group from the dye due to the decrease of I3- amount.

並列關鍵字

Dye-sensitized Solar Cell ； titanium dioxide ； dye-sensitization ； chemical reaction mechanism

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