| Summary: | 博士 === 國立臺灣師範大學 === 化學系 === 98 === We have explored three topics in this study. In the first topic, we synthesized eight organic dyes (4a、4b、4c、9、14a、14b、16、45 ) for dye-sensitized solar cells (DSSCs) applications. Their physical properties were investigated. Except for dyes 16 and 45, which serve as model compounds, the other dyes all possess 1,3-cyclohexdiene conjugated units in the structural skeleton. One obvious advantage of employing 1,3-cyclohexadiene unit in the framework of light-harvesting dyes is the essential planar conformation in the structural skeleton which yields more dense packing of the dyes adsorbed on TiO2 surface. All of these compounds were characterized by UV/vis, fluorescence spectroscopy, and cyclic voltammetry. The cell performances and incident photo-to-current efficiencies of these compounds were inspected using the AM 1.5 simulated solar light and irradiation of monochromic light system. The highest conversion efficiency of the DSSCs based on dye 14a can reach up to 4.4 %. (70 % of the standard N719 dye, η= 5.87 %)
In the second topic, we designed dye 32 as a model for assessing the role of the twisted intramolecular charge transfer (TICT) state played in the conversion efficiency of the DSSCs. TICT state allows the efficient charge-separation and slows down the unwanted charge-recombination processes. Their physical properties were detailed investigated and correlated the TICT state with the photovoltaic process of DSSCs.
Finally, we designed two types of D-D-π-A organic dyes for DSSCs. Different carbazolyl groups were inserted to the structure to form the D-D-π-A compounds. On one hand, we expected that the absorption region can be extended and the molar extinction coefficient can be enhanced comparing with the D-π-A structure. On the other hand, these dyes may benefit from lower tendency to aggregate and display better thermo-stability.
|
|---|
