Synthesis and Properties of New Polypyridyl Ruthenium Complexes and Their Application for Dye-sensitized Solar Cells
|Keywords:||染料敏化太陽能電池;短路電流;開環電壓;Dye sensitized solar cells;short current;open circuit voltage||Issue Date:||2010||Abstract:||
本論文主要在探討有機釕金屬染料Ru(4,4’-dicarboxylic acid) (4-nonyl-2,2’-bipyridine)-(NCS)2簡稱Ru-C9、(Ru(4,4’-dicarboxylic acid) (4,4’-dimethyl-2,2’-bipyridine)-(NCS)2) 簡稱Ru-2A、Ru(4-carboxylic acid-4’-Methyl) (4,4’-dimethyl-2,2’-bipyridine)-(NCS)2 簡稱Ru-1A 在染料敏化太陽能電池 (DSSCs)的應用、吸附行為、與其在溶液下奈米結構。
研究可分為兩部份。第一部份主要在探討吡啶官能基上具有單條或雙條烷基長鏈的有機釕金屬分子: Ru-C9、NaRu(4,4’-dicarboxylic acid) (4,4’-dinonyl-2,2’-bipyridine)-(NCS)2簡稱Z907Na、Ru(4,4’-dicarboxylic acid) (4,4’-dinonyl-2,2’-bipyridine)-(NCS)2簡稱Z907三種染料的差異。以NMR、FTIR與UV/Vis光譜鑑定有機釕金屬染料分子，並將三種染料與甲氧基丙腈液態電解質應用於染料敏化太陽能電池中，效率分別可達到6.80 %、6.92 %與6.54 %。 並由交流阻抗分析(electrochemical impedance spectroscopy, EIS)可得知具兩條飽和長碳鏈的Z907Na與Z907相較於只有單一長碳鏈的Ru-C9，有較長的電子生命週期，但卻有較大的界面阻抗值。
第二部份中，將探討吡啶官能基上接有不同羧酸基數目的有機釕金屬分子: Ru2A、Ru1A以及N3三種染料的差異。 同樣以NMR、FTIR與UV/Vis光譜鑑定有機釕金屬染料分子，再將三種染料與甲氧基丙腈液態電解質應用於染料敏化太陽能電池中，效率分別可達到7.02 %、3.39 %與7.82 %。 並由交流阻抗分析、Intensity-Modulated Photovoltage spectroscopy (IMVS) 與Intensity-Modulated Photovoltage spectroscopy (IMPS)可計算出電子收集效率與羧基數目成正比。 同樣利用AFM、TEM與DLS觀察三種染料在溶液中的型態以及吸附於TiO2上的奈米結構。Ru2A、Ru-1A與N3先形成較大的聚集在表面沉降，長時間後皆可均勻覆蓋TiO2表面。 最後以紫外光/可見光光譜定量比較三種染料於TiO2上的吸附量，可發現三種染料大約皆在6小時後，在TiO2上的吸附量便達飽和。 Ru2A以接近直立的方式吸附在TiO2表面上，故單一分子表面積較小，吸附量最大；N3帶有四個羧基化吡啶配位鍵，容易平躺於TiO2表面上，因此單一分子表面積較大，並由於分子間能藉由羧酸基一直疊加吸附，因此N3的吸附量有持續增加的現象，在吸附24小時內可達單層吸附。 而Ru-1A則因為只具有一個羧基，分子不容易直立在TiO2表面，也容易平躺於TiO2表面上，但由於無法緊密吸附TiO2上，故吸附量與分子表面積介在Ru2A與N3之間。
This thesis is to investigate the properties, adsorption behavior, nanostructure and photovoltaic performance of Ru(4,4’-dicarboxylic acid) (4-nonyl- 2,2’- bipyridine)-(NCS)2 denoted as Ru-C9, Ru(4,4’-dicarboxylic acid)(4,4’-dimethyl-2,2’-bipyridine)-(NCS)2 denoted as Ru-2A ,and Ru(4-carboxylic acid-4’-Methyl) (4,4’-dimethyl-2,2’-bipyridine)-(NCS)2 denoted as Ru-1A.
In the first part, we compared the complexes with different numbers of aliphatic side chains, (NaRu(4,4’-dicarboxylic acid)(4,4’- dinonyl- 2,2’- bipyridine)-(NCS)2) denoted as Z907Na, (Ru(4,4’-dicarboxylic acid)(4,4’- dinonyl- 2,2’- bipyridine) -(NCS)2) denoted as Z907and RuC9. Z907Na, Z907 and Ru-C9 were characterized by NMR and FTIR, and their optical property in acetonitrile/tert-butanol was studied by UV-Vis absorption spectroscopy. Then, we investigated the photovoltaic performance of Z907Na, Z907 and Ru-C9 in DSSCs with a methoxypropionitrile liquid type electrolyte and gave conversion efficient of 6.92%, 6.54 % and 6.80% individually. By using electrochemical impedance spectroscopy (EIS), Z907Na and Z907 showed longer electron life time but higher resistance than Ru-C9 due to more aliphatic side chains.
The adsorption mechanism of ruthenium dyes were studied by AFM, TEM and DLS. The results revealed that the adsorption of dye molecules onto TiO2 surface began in micelle form and followed by the dissolution of the condensed dyes located away from TiO2. Increasing the time of adsorption leaded to a homogeneously dye-covered surface. Then, we measured the adsorptive amount of Z907Na, Z907 and Ru-C9 on the TiO2 at different adsorbing time interval with UV-vis absorption spectroscopy. After 12 h adsorption, the adsorptive amount of the three complexes reached saturation. And the TiO2 surface is covered by a monolayer of dye.
In the second part, we synthesized Ru2A and Ru1A with different numbers of carboxylic acid groups which were compared with the commercial N3 in the photovoltaic performance. The two complexes were also characterized by NMR and FTIR and their optical property in acetonitrile/tert-butanol were measured by UV-Vis absorption spectroscopy. For the performance of DSSCs, Ru-2A, Ru1A and N3 with methoxypropionitrile liquid electrolyte attained power conversion efficiency 7.02 %, 3.39 %, and 7.82 % respectively. Then, we used EIS, intensity modulated photocurrent spectroscopy (IMPS) and intensity modulated photovoltage spectroscopy (IMVS) to measure the electron life time and charge collection efficiency. With increasing the numbers of carboxylic acid groups on the Ru complex, the electron life time was longer and charge collection efficiency was higher.
The adsorption mechanism of ruthenium complexes were studied by AFM, TEM and DLS. Ru-2A, Ru-1A and N3 molecules quickly adsorbed onto the TiO2 surface, leading to a homogeneous surface with an approximate height of one dye molecule. We measured the adsorptive amount of Ru2A, Ru1A and N3 on the TiO2 at different adsorbing time interval with UV-vis absorption spectrascopy. Through calculation, we suggested that Ru-2A after 6 h adsorption covered a monolayer with the molecules tilted near vertically with respect to the TiO2 surface. Due to that N3 had four carboxylic acid groups, it easily lied in flat form on the surface of TiO2. This is the reason why the surface of N3 is larger than Ru-2A. The adsorptive amount of N3 on TiO2 surface reached a monolayer within 24 h. Because the N3 molecules tended to interact each other with their carboxylic acid groups, the adsorption might be more than mono layer. Because Ru-1A has only on carboxylic group which was adsorbed to TiO2 in more versatile configuration, the surface area of Ru-1A was in between those of Ru-2A and N3.
|Appears in Collections:||材料科學與工程學系|
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