合成含側鏈取代基之苯胺寡聚物及其在有機敏化太陽能電池的應用

• Main Author: 盧正庭
• Other Authors: 韓建中
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/85716197107087883520

碩士 === 國立清華大學 === 化學系 === 99 === Lack of energy has been the most serious problem in recent years. Research has showed that until 2050, the biggest problem faced by human beings is the lack of energy, which is much more urgent than the water and food problems. Among all the energy resource, wind energy and water energy are more environmentally friendly while thermal power and nuclear power will certainly cause environmental damage to some extents. On the other hand, the energy radiated from sun to the earth-surface in one day can provide the energy demand of human beings sufficient for 30 years. Solar energy has no pollution, thus, how to fully utilize solar energy should become the main focus of all human kinds. For the time being, the mainstream of solar cell is silicon chip. However, the price is too expensive. Therefore, scientists have explored for organic solar cells as alternative approaches. Among them, the dye-sensitized solar cells (DSSC) wins the greatest attention, because they are cheaper and cost less energy to build. There are two types of dyes used for dye-sensitized solar cell – organometallic complex and organic conjugated molecules. The organic dyes are free of heavy metal pollution and cheaper in price, thus we choose to explore new organic dyes for the dye-sensitized solar cells. In this thesis, phenyl end-capped tetraaniline is used as the main structure of the organic dyes, and the CRS reaction is used to bring in the alkylthio substituent. We use 1-butanethiol, 1-hexanthiol and 1-octanthiol as reagent to react with the oxidized form of phenyl end-capped tetraaniline, allowing its backbone to attach with different lengths of alkylthio groups. The sulfur of the alkylthio side chain can coordinate with TiO2 to assist the electron transfer from the excited dye molecules to TiO2. The result indicated that when the length of side chain increased from butylthio, through hexylthio to octylthio, the efficiency of the corresponding solar cell also increased from 0.0108 %, through 0.0197 % to 0.0262 %, respectively. Apparently, as the dye molecule become less polar, it can better suppress the current to flow to the electrolyte so as to reduce the dark current and increase the efficiency. In this work, we have also used tetrabutylammonium fluoride as organic catalyst to assist the coupling reaction between the oxidized form of the phenyl end-capped tetraaniline and the reagent of nitromethane and malononitrile to help bring in the alkyl substituent bearing with stronger anchoring groups. Since these two side chain groups are smaller, it can't suppress the generation of dark current efficiently. The efficiency turns out to be poorer than expected values - the efficiency is 0.0156 % and 0.0154 %, respectively. The results indicate that the longer length of carbon side chain and stronger anchoring groups are both important for gaining high photoelectric conversion efficiency.