以交聯劑及陽離子表面改質交聯型釕金屬染料強化固態染料敏化太陽能電池性能之研究

Abstract

本研究利用合成出帶有苯乙烯基官能基的可交聯型釕金屬染料Ru (4,4’-dicarboxylic acid) (4,4'-bis((4-vinylbenzyloxy)methyl)- 2,2'-bipyridine-(NCS)2 (RuS) 經鑑定後應用至固態染料敏化太陽能電池。與N3染料相比開路電壓(Voc)和短路電流(Jsc)皆有明顯提升，惟填充因子受介面電阻較大而降低，效率值僅1.24%。經改良多孔二氧化鈦厚度至1.7µm可使效率提升至1.49%。為改良介面性質以4,4’-Bis((4-vinylbenzyloxy)methyl)-2,2'-bipyridine (ligand)作為交聯劑改變RuS化學結構，染料脫附測驗顯示鹼液浸泡後工作電極上可保留77%的染料，並初步檢驗元件效率可達到2.12%，其他光電特性也一併提升。接著以帶有lithium和1-ethyl-3-methylimidazolium離子之化合物吸附於經交聯ligand的RuS上，結果除了吸附lithium bis(trifluoromethylsulfonyl)imide (LiTFSI)能提升Voc和Jsc並讓效率達到2.55%外其他無法增進元件表現，照光交流阻抗證實吸附後電阻降低。下一步利用苯甲酸鎂與鈣吸附在經ligand交聯的RuS表面上，兩者之Jsc皆比吸附LiTFSI得到更大幅度的提升，吸附苯甲酸鎂後效率值更達到2.66%，照光交流阻抗分析中介面電阻比未吸附下降許多，也證實具有改良介面之效。再利用乙醯丙酮鎂、鈣、鋇吸附在ligand上作成元件，其中吸附乙醯丙酮鎂能得到最大的效率2.82%，交流阻抗中介面電阻也比吸附苯甲酸鎂小。最後以螢光光譜數據分析經交聯ligand的RuS吸附離子後放光能力下降，證明吸附的離子能加速被激發染料的電荷再生速率，FTIR光譜結果也說明吸附離子後會使未吸附二氧化鈦表面之羧酸基訊號產生紅位移，同時使雙吡啶官能基訊號增強，表示吸附離子確實產生鍵結並改善RuS與固態電解質間的介面相容性。

In this study the crosslinkable ruthenium complex with styryl groups, denoted as RuS, was synthesized and characterized and applied to solid-state dye sensitized solar cell. The resulting open circuit voltage (Voc) and short circuit current (Jsc) were substantially enhanced compared to N3 dye, but efficiency was only 1.24% due to large interface resistence, leading to lower filled factor. After optimizing the thickness of titanium oxide to 1.7µm, the efficiency was slightly increased to 1.49%. To improve the interface, 4,4’-Bis((4-vinylbenzyloxy)methyl)-2,2'-bipyridine (BVP) ligand was introduced to crosslink with RuS. The crosslinked dye which attached on titanium oxide was more sustainable according to the desorption test. The efficiency rose to 2.12% with enhancement of all the photovoltaic properteis. Then the compounds which consist of Li+ and EMI+ were adsorbed onto the BVP-crosslinked RuS. The efficiency increased to 2.55% as LiTFSI was adsorbed. Not only Voc and Jsc increased, but the interfacial resistence in light condition dramatically decreased. Next, magnesium benzonate and calcium benzonate were individually adsorbed onto the BVP-crosslinked RuS. Both of them could increase the device efficiency, especially for magnesium benzonate. The efficiency was up to 2.66. It is owing to the interface resistence drastically decreased compared to the unadsorbed device. After that, magnesium, calcium and barium acetylacetonate salts were individually adsorbed onto the BVP-crosslinked RuS. By using the optimized amounts of magnesium acetylacetonate, efficiency raised to 2.82%. Compared to magnesium benzonate, the interface resistence with magnesium acetylacetonate was even smaller. Finally, the PL spectra showed that the adsorbed ion could acclerate dye regenegation in view of the decreased PL intensity of dye. IR spectra also showed that the carboxylate signal of RuS became red shift and bpyridine signal enhanced. This results indicated that the ions indeed had the strong interactions with BVP-crosslinked RuS and improved the compatibility between RuS and solid-state electrolyte.