染料敏化太陽能電池因材料費低廉而受到研究者重視。國外發表以來,效率亦不斷提升,對於組成三明治結構的各層,相繼都有研究指出,不過往往在追求高效率的同時,卻運用耗能設備、稀有金屬材料,來達成高效率的展現。本研究以電泳沉積法製備DSSC光電極以及對天然染料作特性分析。對此兩部分進行探討。 第一部份首先探討電泳沉積法之膠體溶液的搭配與膠體穩定懸浮的控制,實驗結果發現,當TiO2搭配異丙醇(IPA)之膠體添加適量的Mg(NO3)2.6H20可維持膠體的穩定;而電泳法披覆薄膜的最佳製成參數發現,當電場強度40V/cm時可以最高效率達高平整度之薄膜,在表面輪廓儀測試下粗糙度Ra值為1005.725Å。最後,將得到的光電極與DSSC組裝成三明治結構,測試效率與性能。實驗將光電極以不同熱處理方式、多層電泳方式進行改良,提升光電轉換效率。實驗結果發現以400℃高溫熱處理以及經過恆溫階段有助於TiO2薄膜提高緻密性。而多層電泳法可防止薄膜因內部應力的破壞,使得TiO2薄膜增加染料分子吸附量,進而提升DSSC之光電流密度至12.2mA/cm2。因應可撓式DSSC的發展,實驗光電極製備以溫控膠體溶液搭配多層電泳方式有效應用在ITO/PET (Tin-doped Indium Oxide, polyethylene terephthalate)基板上。 第二部份是對天然染料的中各單一色素做成份的認定,以及各色素在DSSC模組中所扮演的角色,進而探討其中的關係。由綠色值物之菠菜與地瓜葉中萃取出天然染料,以UV-vis光譜儀判定色素成份,由菠菜萃取出的染料含有葉綠素-α與β-胡蘿蔔素:而由地瓜葉中萃取出的染料只有葉綠素-α。兩種染料在DSSC的特性表現,雖然菠菜染料有較寬的可見光吸收範圍,但β-胡蘿蔔素不具有光敏特性,可由入射光子-電子轉換效率(incident photon-to- electron conversion efficiency, IPCE)驗證。雖不具光敏化特性的色素分子β-胡蘿蔔素,卻能釋放能量給予將被TiO2表面陷阱捕捉的電子生命力,電子重新反迴導帶上繼續傳導,使得菠菜染料有著比地瓜葉染料有更長的電子生命週期。
The Dye-Sensitized Solar Cell is being paid attention by the researcher because of material is cheap. Since issuing abroad, efficiency has been also improved constantly. There are many study develop for layers of the sandwich structure. However, they are often pursuing high efficiency with equipment of consume energy and rare element. This research use electrophoresis deposition (EPD) method in photo-electrode of DSSC and analysis the characteristic of natural dye. First part, we controlled colloid (TiO2 /IPA) of EPD suspend stable. The result of experimental indicate TiO2/IPA could suspend when it mixed suitable Mg(NO3)2.6H20. These optimum parameters of EPD indicate that electric field intensity 40V/cm could get roughness of thin film about 1005.725Ǻ. After, we assemble the photo-electricity to the sandwich structure of DSSC. We controlled after-treatment include thermal treatment under various method and application multilayer to improve crack. TiO2 layers increase the absorbing amount of dye molecule, and then improve the density of photocurrent to 12.2mA/cm2. On the side, the development of flexible DSSC, experiment photo-electricity used low temperature colloid solution and multilayer electrophoresis coating on ITO/PET. The second part is to analyze ingredient of natural dye and their character in DSSC. Results of experiment, Ingredient analyze with UV-vis spectrum, contained chlorophyll –α and β—carotene. By the method of IPCE (incident photon-to- electron conversion efficiency), we analyzed that the chlorophyll –α had characteristic of sensitization, but β—carotene hadn’t. Although β—carotene hadn’t sensitization characteristic, they could release energy to electron that caught by TiO2 surface trap. Thus, electron could return to conduction band again. The natural dye that involving β—carotene lengthen electronic lifespan cycle.