利用靜電紡絲法製備高比表面積多層次二氧化鈦奈米管及其在染敏太陽能電池上之應用

High Surface Area Electrospun Hierarchical TiO2 Nanotube and its Application in Dye-Sensitized Solar Cells

李苑菁(Yuan-Ching Lee)

指導教授 ： 陳玉惠

中原大學/理學院/化學研究所/碩士(2014年)

https://doi.org/10.6840/cycu201400693

摘要

在染料敏化太陽能電池光陽極研究上，一般多使用奈米粒子做為工作電極層材料，然而奈米粒子結構是相當不利於傳遞電子，因此發展出1-D奈米結構，利用其結構優勢加快電子傳遞速度，但其缺點為表面積較低且不易貼附於導電基板上，因此對於染料敏化太陽能電池之效率提升相當有限。綜觀上述1-D奈米結構表面積低且與基板貼附性不良而粒子結構不利傳遞電子等缺點，本研究利用靜電紡絲法製備出表面帶有奈米粒子之高比表面積多層次二氧化鈦奈米管做為工作電極層材料，使其保有1-D結構，同時改善材料表面積低與基板貼附性等問題，並探討其對染料敏化太陽能電池效率之影響。
　　首先利用靜電紡絲法製備二氧化鈦奈米管，再將此材料進行水熱反應，以得到二氧化鈦奈米管為主體，表面帶有奈米粒子之多層次二氧化鈦奈米管。其次，利用SEM、XRD、TEM與BET等方法對其形貌進行分析與鑑定。結果顯示，多層次二氧化鈦奈米管具有良好結晶性與粗糙之表面形貌等性質，除了增加比表面積，提高對光的反射能力，更因其多層次結構，與導電玻璃亦有很好的貼附性。將此多層次結構二氧化鈦奈米管運用於染料敏化太陽能電池上，獲得6.36%之轉換效率，此效率相較於二氧化鈦奈米粒子、二氧化鈦奈米纖維與二氧化鈦奈米管，分別各提升了～32.5%、～59%與～29.8%。此外，本研究另以IMPS/IMVS與EIS測試，探討光陽極之電子傳遞速度、生命週期與阻抗表現，顯示出其為有潛力之光陽極材料。

關鍵字

染敏太陽能電池 ； 靜電紡絲

並列摘要

The studies of Dye-sensitized solar cells (DSSCs) often use the TiO2 nanoparticles (〜20 nm diameter) as the working electrode material, but the nanostructure limits transmission of the photoexcited electrons. Therefore, one-dimensional (1-D) nanostructure TiO2, materials have been used for the photoanode because of their effective pathways, facilitating the electron transport. In practice, even though an efficient electron transport rate in 1-D nanostructures is available, the performance of these 1-D TiO2-based DSSCs is still not good enough due to their smooth surfaces, leading to low surface areas and poor adhesion. Since high surface area is one of the key factors for improvement of the performance of DSSC, in this study, the 1-D backbone with a hierarchical nanostructure formed by the primary nanoparticles were prepared to enhance the surface area. The as-prepared 1-D hierarchical TiO2 nanotube not only significantly provided effective pathways for electron transport but also greatly increased the surface area, leading to a significant improvement in the power conversion efficiencies in DSSC.
　　In the study, a hierarchical anatase TiO2 nanotube (HTNT) has been synthesized via an electrospinning method followed by a hydrothermal process. It is found that the dense nanoparticles were grown on the HTNT. The materials with different morphologies were characterized by the SEM、XRD、TEM and BET measurements. The results indicated that the surface morphologies and surface area were varied with different structures. The result display the HTNT with superior crystalline phase, more dye loading, higher light scattering ability, faster electron transport, and greater charge collection efficiency. For application as the photoanode material of DSSC, the device fabricated with HTNT showed higher power conversion efficiency (6.36 %) than that with TNF, TNT, and P25. Besides, the significant improvement in DSSC efficiency was confirmed by the investigation of intensity modulated photocurrent spectroscopy (IMPS), intensity-modulated photovoltage spectroscopy (IMVS) and electrochemical impedance spectroscopy (EIS) measurements. In all, the HTNT prepared in this study exhibited the largest improvement performance of DSSC, hence, it is believed that HTNT nanofibers will be a high potential photoanode materials of DSSC.

並列關鍵字

electrospun ； dye-sensitized solar cells

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