| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 99 === In this study, we compared the adsorption properties and photovoltaic performance among five ruthenium complex dyes having different number of carboxyl groups, denoted as Ru-1A, Ru-11A, Ru-2A, Ru-3A and N3, which have one, two, two, three and four carboxylic groups, respectively.
First, the dyes were characterized by NMR and FTIR. And their optical properties in ACN/t-BuOH solution were studied by UV-VIS spectrascopy. From the UV-Vis spectra, the MLCT absorption peak of the dyes blue-shifts with decreasing the number of carboxylic groups.
The adsorption mechanism of the dyes were studied by TEM, DLS, AFM and adsorption/desorption test, which can be concluded by the following results: (1) The dye molecules in the solutions tend to form micelles, which deposited on TiO2 surface in micelle form; with increasing time, the dye molecules lead to a homogeneous surface with an approxmate height of one molecule. (2)Due to N3 had four carboxylic groups, it easily lied in flat form on the TiO2 surface,and thus has the smallest adsorption amount. Other dyes containing one-side carboxyl groups would attach to the TiO2 surface with a tilt and have larger adsorption amount.
For the performance of DSSCs with MPN liquid electrolyte, N3, Ru-3A, Ru-2A, Ru-11A, Ru-1A attained power conversion efficiency of 7.53%, 6.72%, 6.08%, 4.20%, 3.39%, and the Jsc were 19.6mA, 17.9mA, 14.9mA, 10.8mA, 6.59mA with decreasing the number o f carboxyl groups. The IPCE, EIS, IMVS, IMPS, Voltage-decay tests also supported the results of Jsc and efficiency.
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