不同尺寸二氧化鈦奈米結構的合成與鑑識及其在染料敏化太陽能電池上之應用

Abstract

一維奈米結構材料一直是在提升染料敏化太陽能電池(DSSC)電子傳遞效能方面廣泛研究的主題。在此論文中，我們將藉由雙界面活性劑搭配溶膠－凝膠法和水熱法，合成出具有一維形貌的二氧化鈦奈米棒結構。調整不同的實驗參數，由掃描式電子顯微鏡觀測的結果來監測二氧化鈦奈米棒生長過程中各種形貌轉變的特徵。為了更加了解此類奈米棒的成長機制，我們設計實驗探討界面活性劑F127在奈米棒成長上所扮演的角色。另外，在含有界面活性劑的水熱過程中，我們利用具螯合劑功用的三乙醇胺(TEOA)來達到延緩鈦前驅物的目的，水解速率進而成功的合成出針葉狀的二氧化鈦奈米棒 (NL-NR)。除了探討TEOA如何去影響NL-NR自組裝的生長機制外，我們也將此NL-NR應用於DSSC中的光陽極結構。為了能符合高品質DSSC的光陽極結構之設計，我們將結合擁有高比表面積和最佳染料分子吸附量的二氧化鈦奈米粒(NP)以及具有快速電子傳遞特性的二氧化鈦奈米棒(NR)，並以此NP和NR做為建構複合多層(multi-layer)光陽極結構以達成元件效能最佳化的結果。最後我們藉由奈米粒/奈米棒/散射層，之多層結構的設計，使C106光電轉換元件之效率達到10.5%的最佳化結果。

One dimensional nanostructured materials have been the subject of extensive research to enhance the electron transport characteristic for dye-sensitized solar cell (DSSC). In this thesis, one dimensional TiO2 nanorods (NR) were synthesized with two surfactants through sol-gel and hydrothermal methods. Scanning electron microscopic (SEM) images show various structural features for growing TiO2 NRs under different experimental conditions. To further understand the growth mechanism of TiO2 NRs in the binary surfactant system, we carried out the experiment to examine the role of F127 during the growing process. Triethanolamine (TEOA) was used as a chelating agent to retard the hydrolysis of Ti precursor in the surfactant-assisted hydrothermal process. Accordingly, successfully developed a novel needle leaf-like TiO2 NR (NL-NR) used as photoanode for DSSC. Combining the effects of high surface area with high dye-loading amount of nanoparticles (NP) and rapid electron transport characteristics of NR, the photoanode composed of NP and NR in a multi-layer configuration required function to meets the construct a highly efficient DSSC. Finally, high device performance was achieved by applying the novel TiO2 nanostructures reported herein using C106 as a photo-sensitized. The optimized device featured short-circuit current density (JSC /mAcm-2) 18.98, open-circuit voltage (VOC / V) 0.757, fill factor (FF) 0.729, giving an overall power conversion efficiency η＝10.5%.