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  • 學位論文

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

指導教授 : 韓建中

摘要


能源匱乏,已經是近年來最嚴重的問題,更有學者指出,到2050年,人類的最大問題是能源,其次才是水以及食物,而目前的能量來源,除了較環保的風力發電以及水力發電外,火力發電以及核能發電都會對環境造成相當程度的破壞,然而,太陽每天照射到地表的能量,足夠全人類30年能源需求,且太陽能是一個完全無汙染的能源,因此如何善用太陽能,是目前全人類所共同關注的焦點。 目前主流的太陽能電池以矽晶元為主,不過其價格過於昂貴,因此也發展出其它有機太陽能電池,其中又以染料敏化太陽能電池最受矚目,其成本較為低廉,且也有不錯之光電轉換效率,而染料敏化太陽能電池又有以有機金屬或純有機化合物做為染料的兩種類型,純有機染料分子對環境較不會產生重金屬的汙染,且價格較為便宜,故我們選用純有機分子來做為太陽能電池之染料。 本論文選用尾端苯環四苯胺寡聚物來做為有機染料之主體,並利用同步還原取代反應與不同碳數硫醇進行碳-硫鍵合成,我們分別以1-丁硫醇、1-己硫醇、1-辛硫醇做為反應試劑,使主鏈接上具有不同碳數的alkylthio側鏈,其中側鏈上的硫孤對電子能與二氧化鈦形成配位鍵結,可協助電子有效的轉移到二氧化鈦上,而當側鏈碳數越多時,較長的側鏈結構可有效抑止電流直接流向電解質,可減少暗電流之產生,其光電轉換效率也較高,其光電轉換效率分別為0.0108 %、0.0197 %、0.0262 %,可發現當碳數不同時,其光電轉換效率可相差到一倍之多。同時也利用四丁基氟化銨催化合成碳-碳鍵,並以硝基甲烷及丙二腈作為反應試劑,可合成出含alkyl側鏈之結構,而由於此兩種側鏈結構分子較小,且無較長的碳鏈可抑止暗電流之產生,因此光電轉換效率較差,其效率分別為0.0156 % 以及0.0154 %。由實驗結果得知,當側鏈的碳數越多時,可有效抑止暗電流,可有最佳之光電轉換效率。

並列摘要


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.

並列關鍵字

無資料

參考文獻


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