本研究中發展出兩步驟的陽極氧化法，並藉由草酸之選擇性溶解，能獲得獨立式雙開孔之二氧化鈦奈米管陣列薄膜，且此薄膜具備大面積，不捲曲，銳鈦礦相的特性，操作流程簡單、製備容易。二氧化鈦奈米管陣列擁有一維的垂直通道能使電子順暢傳輸，以及管狀結構散射光線能有效提升光的利用率，故其光電化學特性皆優於傳統的二氧化鈦奈米顆粒。因此我們將獨立式雙開孔之二氧化鈦奈米管陣列薄膜應用至染料敏化太陽能電池、量子點敏化太陽能電池中，並且也直接將陽極氧化在鈦金屬板上的二氧化鈦奈米管陣列，應用於太陽光水分解產氫反應。在太陽能電池方面，我們利用溶膠凝膠法合成之二氧化鈦奈米顆粒作為黏著劑，將獨立式雙開孔之二氧化鈦奈米管陣列轉移至FTO導電玻璃上，並應用於正光照射模式之染料敏化太陽能電池中，先比較不同長度變因之二氧化鈦奈米管陣列，在吸附N719染料後，於AM 1.5模擬太陽光照射下（100 mW/cm2），得到最佳效率之光電轉換效率為7.82 %；其管長為35 μm，接著藉由光電流－電壓（I-V）曲線、入射單色光子-電子轉化效率的量測（IPCE）以及電化學阻抗分析（EIS）證實獨立式雙開孔之二氧化鈦奈米管陣列薄膜電極，能有效提高光的吸收與電子的收集能力，進而比單開孔之二氧化鈦奈米管陣列薄膜增加了66 %的光電轉換效率，由4.7 %提升至7.82 %。我們再將獨立式雙開孔之二氧化鈦奈米管陣列應用於量子點敏化太陽能電池上，如同DSSCs之實驗方法進行其光電轉換效率的量測，在經由改變沉積硫化鎘次數以及改變二氧化鈦奈米管陣列長度之變因後，得到最佳光電轉換效率的樣品為經由連續離子層吸附反應（SILAR）法沉積硫化鎘七次，並加入氧化鋅層保護硫化鎘以避免其被電解液所腐蝕，所量測的光電轉換效率為1.57 %；而單開孔之二氧化鈦奈米管陣列的光電轉換效率為0.94 %，相較之下也提升了67 %。最後我們直接將陽極氧化在鈦金屬板上的二氧化鈦奈米管陣列，應用於太陽光水分解反應，在經由改變沉積硫化鎘次數以及二氧化鈦奈米管陣列長度之變因後，並測量其水分解之光電轉換效率，得到最佳光電轉換效率的樣品為經由SILAR法沉積硫化鎘五次，管長為20 μm，所量測的平衡電流密度（J-0.4V）為6.98 mA/cm2，光電轉換效率為 6.8 %。

In this study, we report an effective method to produce large-area, free-standing, crystallized and opened-end TiO2 nanotube arrays (TiNT-array) by two-step anodization and oxalic acid selectively dissolve. TiO2 nanotube arrays have one-dimensional channel for transporting electrons and efficiently harvesting the energy from the light that bring in superior than TiO2 nanoparticle derivatives in term of photoelectrochemical performance. Therefore we have applied the prepared TiNT-array to use in dye sensitized solar cells (DSSCs), quantum dot sensitized solar cells (QDSSCs) and solar water splitting. In DSSCs, the free-standing and opened-end TiNT-array was adhered onto FTO glass by sol-gel TiO2 nanoparticles paste. The transparent photoanod consisted of the opened-end TiNT-array film for DSSCs were obtained. As compare to the different tube lengths of TiNT-array. After sensitizing with N719 dye, the optimum solar conversion efficiency is 7.82 % under AM 1.5 simulated sunlight with front-side illumination. Furthermore, we utilized photocurrent – voltage curves, incident photon-to- current conversion efficiency (IPCE) measurement and electrochemical impedance spectroscopy (EIS) to analysis the photoelectron characteristic of TiNT-array. To contrast the closed-end TiNT-array, the used of opened-end TiNT-array exhibited an increase in efficiency from 4.7 % to 7.82 %, corresponding to 66 % enhancement due to its better mass transport as well as enhanced light harvesting and electron collection efficiency. When using free-standing and opened-end TiNT-array in QDSSCs, the maximum efficiency of 1.57 % was obtained by CdS quantum dots via 7 times SILAR process and ZnO protective layer. To contrast the closed-end TiNT-array, the used of opened-end TiNT-array exhibited an increase in efficiency from 0.94 % to 1.57 %, corresponding to 67 % enhancement. Finally, in the solar water splitting, considerably high photoconversion efficiencies of 6.8% and stable photocurrentdensity of 6.98 mA/cm2 was obtained by the CdS quantum dots sensitized TiNT-array/Ti , which was prepared by 5 times SILAR process.

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