本研究中採用二次陽極處理製備雙開孔的二氧化鈦奈米管陣列,將一次陽極處理的二氧化鈦奈米管陣列經不同退火溫度後,利用化學蝕刻的方式將二次陽極處理成長的二氧化鈦奈米管陣列去除,獲得雙開孔的二氧化鈦奈米管陣列,並應用於正面照光方式染料敏化太陽電池(Dye-sensitized solar cell; DSSC)之光陽極。使用場發射掃描式電子顯微鏡(FE-SEM)、X光繞射儀(XRD)、紫外與可見光譜(UV-vis)、光電轉換效率分析及交流阻抗圖譜作分析。透過XRD分析發現不同退火溫度有不同的銳鈦礦晶相,藉由SEM分析發現在280度退火溫度下,經由化學蝕刻20分鐘可獲得雙開孔二氧化鈦奈米管陣列。透過UV-vis分析不同管長的染料吸附量,其中以管長28um的染料吸附量為最高。在不同奈米管管長15 μm、 21 μm、 28 μm製作出正面照光方式染料敏化太陽能電池,使用太陽光模擬器光功率為AM 1.5 100 mW/cm2中量測,獲得光電轉換效率分別為4.82 %、5.08 %、4.85 %。將管長為20 μm之光陽極經過30分鐘的四氯化鈦處理後,可獲得最佳效率為5.63 %。透過IPCE分析發現在540nm時,經過30分鐘的四氯化鈦處理後的IPCE值從50.6%上升至74.2%。以交流阻抗分析儀量測做元件之內部阻抗分析,發現電子再結合的電荷傳輸阻抗(Rk)隨著四氯化鈦處理時間增加而越大,四氯化鈦處理時間越長使得染料吸附量增加導致染料激發之電子增多,但黏附層鬆散使得過多的電子不易傳輸,導致電子在結合率的增加,使得電阻值上升。
In this study, we used secondary anodized to prepare open-end TiO2 nanotube (TNT) arrays transferred onto FTO conductive glass and then applied on front-illuminated dye-sensitized solar cells. The TNT arrays and solar cells were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), I-V character-istic analyses, Ultraviolet-visible spectroscopy (UV-vis), and incident Photon conversion effi-ciency (IPCE) to study the effect of open-end TiO2 nanotube arrays on the photoelectrodes for front-illuminated dye-sensitized solar cells. XRD patterns found the TNT arrays will form anatase phase while the annealed temperature greater than 250°C. In FE-SEM analysis, TiO2 nanotube arrays under 280°C annealed temperatures and immersed H2O2 for 20 minutes can be obtained open-end TNT arrays. In UV-vis analysis, the highest adsorption amount in length of 28 μm. The conversion efficiency with different length of TNT arrays photoelectrodes were 4.82 %, 5.08 %, 4.85 % with the length of 15 μm, 21 μm, 28 μm, respectively. After TiCl4 post-treatment, the efficiency of TNT arrays photoelectrode with the length of 21 μm for dye sensitized solar cell can be improved up to 5.63 %. In the IPCE analysis, the value of IPCE increased from 50.6 to 74.2 % after 30min of TiCl4 post-treatment at 540 nm. In the EIS analysis, the value of Rk (charge transfer resistance related to recombination of electrons) increased along with the time of TiCl4 post-treatment increased, the primary cause is related with the compactness of adhesive layer. It may be due to the adhesive layer more loosely, resulting in the increase of the Rk.