- 學位論文
染料敏化太陽能電池之反電極與天然染料製備
Preparation of thin film of counter electrode and natural dye in Dye-sensitized Solar Cells
摘要
本論文研究主要是探討染料敏化太陽能電池（Dye-Sensitized Solar Cells）反電極薄膜與天然染料花青素萃取物之製備方法、結構與特性分析之研究。對此分為三部份進行探討。 第一部分首先探討利用刮刀塗佈法製備出反電極薄膜，係使用各種碳材料為對電極薄膜，並加入不同比例之乙基丙酮、界面活性劑、去離子水混合成漿料，塗佈在FTO導電玻璃上，並可得反電極薄膜。碳材料係使用單壁及多壁奈米碳管、石墨、碳黑、TiO2-MWCNTs奈米複合粉末製備出染料敏化太陽能電池反電極，並以純化後多壁奈米碳管及TiO2-MWCNTs奈米複合粉末製備出兩層反電極，探討單層與雙層反電極，對其光電轉換效率之影響。 第二部份是利用隔水加熱法製備出天然染料，天然植物染料萃取係用無毒乙醇溶劑及甲醇溶劑、去離子水、醋酸，作為獲得葉綠素及花青素之染料。從石榴葉中萃取葉綠素，從桑葚果實、黑醋栗果實、藍苺果實中萃取出花青素，並探討萃取溫度、萃取時間對光電轉換效率之影響，此外也將萃取所得之葉綠素與花青 素混合成為雞尾酒染料，觀察其光電轉換效率之影響。 第三部份是先利用溶膠凝膠法製備出奈米二氧化鈦顆粒，並將奈米二氧化鈦顆粒披覆在多壁奈米碳管上，而製備出TiO2-MWCNTs奈米複合粉末，可作為染料敏化太陽能電池(DSSCs)中光電極材料。再利用電泳沉積法(EPD)將Degussa P25 TiO2 奈米顆粒混合TiO2-MWCNTs粉末沉積電泳於ITO導電玻璃上，經二次電泳沉積薄膜厚度為17~23 μm之光電極薄膜。 最後，將DSSC封裝檢測完成後可得知開環電壓(Voc)、短路電流(Isc)、填充因子(FF)、光電轉換效率(η)。經由電流-電壓曲線(I-V curve)之檢測結果顯示，以純化後單壁奈米碳管反電極與石榴染料及桑葚染料混合成雞尾酒染料之染料敏化太陽能電池(DSSCs)，其光電轉換效率為0.552％。
並列摘要
This study aims to deal with the film of counter electrode of dye-sensitized solar cells (DSSCs) and the preparation, structure and characteristics of extract of natural dye. The first part deals with the film of counter electrode fabricated by doctor blade (DB). Various kinds of carbon materials are used to serve as the film of counter electrode and different proportion of acetylacetone, surfactant (TritonX-100) and deionized water (DI water) are added to combine into paste to spread on the fluorine-doped tin oxide (FTO) conductive glass to obtain the film of counter electrode. Single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), black lead, carbon black and TiO2-MWCNTs compound nano-powder are adopted to prepare for the counter electrode of DSSCs. Purified MWCNTs and TiO2-MWCNTs compound nano-powder are used to fabricate two-layer counter electrodes and the influence of single-layer counter electrode and two-layer counter electrodes on photoelectric conversion efficiency is dealt with. The second part uses water-resisting heating to prepare for natural dye and employs non-toxic alcohol, methyl alcohol, DI water and acetic acid to act as the dye for chlorophyll and anthocyanin. Chlorophyll is extracted from pomegranate and anthocyanin is extracted from mulberries, black currant and blueberries. The influence of extracting temperature and extracting time on photoelectric conversion efficiency will be dealt with. Besides, the extracted chlorophyll and anthocyanin are blened into the cocktail dye and its photoelectric conversion efficiency will be dealt with as well. The third part uses sol–gel solution (SGS) to fabricate TiO2 nanoparticles. TiO2 nanoparticles are coated on MWCNTs and TiO2-MWCNTs compound nano-powder can serve as the photoelectrodes of DSSCs. And then, eletrophoretic deposition (EPD) is adopted to mix with Degussa P25 TiO2 nanoparticles and TiO2-MWCNTs compound nano-powder to carry out electrophoresis on ITO conductive glass to acquire the film of photoelectrode with the thickness of 17~23 μm by twice EPD. Finally, after the assembling of DSSCs, open-circle voltage (Voc), short-circuits current density (Isc), fill factor (FF) and photoelectron conversion efficiency (η) can be attained. Results of I-V curve show that the photoelectric conversion efficiency of cocktail dye for DSSCs fabricated by the counter electrode of purified MWCNTs, pomegranate dye and mulberry dye can reach 0.552%.