二氧化鈦奈米管於染料敏化太陽能電池之探討

呂怡萱(I-Hsuan Lu)

指導教授 ： 諸柏仁

國立中央大學/理學院/化學系/碩士(2006年)

摘要

本研究主要目的為探討使用二氧化鈦奈米管應用於薄膜電極對於染料敏化太陽能電池效能的影響且對此議題建立研究方法。於此提出一簡便、低製備成本且具有高產率、均一性及熱穩定性佳之二氧化鈦奈米管的製作方式，其可直接採用商業化的二氧化鈦顆粒(微米級)於強鹼的環境下經由迴流合成的方式製備出二氧化鈦奈米管。
由XRD、SEM及TEM的鑑定可知二氧化鈦奈米管在450℃煅燒過後的表面型態不會有所改變亦維持中空管狀結構，且為銳鈦礦的晶相，亦形成有利於工作電極之狀態。然而，經由IR、XPS、UV-vis及ASAP的分析得知二氧化鈦奈米管表面具有較多的OH官能基、高比表面積及高孔隙度的特性，使得二氧化鈦奈米管上可吸附染料分子的數量增加。且由XPS檢測染料吸附於二氧化鈦表面後之束縛能，可知染料分子與二氧化鈦奈米管表面產生化學吸附，能夠有利於染料的激發電子轉移至二氧化鈦導帶，以產生較大的電流值(Isc)達25mA。
奈米級的電極材料容易因為表面電荷作用而造成聚集的情況產生，因此使用硝酸水溶液對二氧化鈦奈米管表面進行修飾以增加奈米管間的靜電作用力，使得材料在鍍液中的分散效果較佳，有利於得一表面較為平整的薄膜電極，但因薄膜電極的孔徑減小，造成電解質於薄膜內部擴散不易而無法使電流值有顯著的提升，僅可達7mA。
在元件方面，主要比較二氧化鈦奈米管與一般常用的Degussa P25奈米顆粒為主的薄膜電極。由實驗結果顯示，可知經元件設計改良過後的測試條件下，使用二氧化鈦奈米管取代Degussa P25的染料敏化太陽能電池之光電轉換效率最佳可達到6.58%。

關鍵字

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並列摘要

The study is mainly to discuss the effects of the titanium dioxide nanotube(TiNT) applied in thin film electrode on the performance of the dye-sensitized solar cell and to set up a research method for the study. The method of producing the TiNT is within the simple way, low fabrication cost, uniformly size, and highly thermal stable. Moreover, the yield is higher than the previous art. The titanium dioxide nanotube(TiNT) can be directly fabricated from commercial titanium dioxide particle(micro-level) under the strong base condition via reflux reaction.
After being calcined at 450℃, by XRD, SEM, and TEM images , the TiNT surface morphology would not be changed and still keep anatase phase, which is favorable to the performance of work electrode. However, many hydroxyl groups on the TiNT surface, high surface area and high porosity characteristic be able to increase the amount of adsorbed dye molecules on the TiNT, by IR, XPS, UV-vis and ASAP. From XPS, it is clear to see that the excited electron of dye from bipyridyl ring transfers to the TiO2 conduction band, producing great magnitude of short circuit current to reach 25mA.
The electrode material in the Nano-scale makes it easier to create the accumulation due to the surface charge interaction; on the basis of electrostatic force, HNO3 solution is used to modify the TiNT to enhance dispersion. Hence, the electrode material causes better dispersion in TiO2 paste and advantageous to form a smoother thin film electrode. Because of the small pore size in thin film electrode, the electrolyte becomes hard to diffuse into the interior of thin film, and in addition, it’s unable to enhance the short circuit current. It only may reach 7mA.
In the devices, when we compared the thin film electrode composed of the TiNT to the Degussa P25-used one, the experiment data demonstrated that TiNT-used device has the best efficiency to achieve 6.58%.

並列關鍵字

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