- 學位論文
微波-水熱法製備二氧化鈦在染料敏化太陽能電池之應用
Microwave-assisted Preparation of Nanocrystalline TiO2 for Dye-sensitized solar cells
摘要
染料敏化太陽能電池與其他太陽能電池相比，具有低成本、可撓性及高轉換效率等優點，因此已引起各國相關企業與學者的注目。奈米二氧化鈦在染料敏化太陽能電池上是一種理想的多孔性薄膜材料，其優點包括能隙與染料相近、染料吸附能力、低廉的價格與容易製備的特性。 本研究的目的在於合成奈米二氧化鈦顆粒新製程的開發，利用微波技術的特性，增進溶膠-凝膠法中二氧化鈦前驅物的溶解度，進而增加其水解效果，並結合水熱法以製造出具有良好結晶性質的銳鈦礦奈米二氧化鈦顆粒。在本研究中，我們探討了微波處理的時間及功率對於合成奈米二氧化鈦顆粒的影響。結果顯示，使用約200 W的微波功率及適當的處理時間，可以得到較高比表面積的銳鈦礦奈米二氧化鈦，且顆粒尺寸不會隨著處理時間再增加而變大。與傳統的水熱製程相比，新開發的微波水熱製程可以將合成時間由五天縮短至一天，且晶體結構與顆粒尺寸的均勻度佳。 之後利用刮塗法將傳統水熱製程與微波水熱製程的奈米二氧化鈦材料製作成電極，並組裝成染料敏化太陽能電池以進行特性分析。量測結果顯示微波水熱製程與傳統水熱製程的奈米二氧化鈦在效率上皆可達到6.9%的光電轉換效率，在入射單色光光電轉化效率(IPCE)上，微波水熱製程的效果優於傳統水熱製程，而在電化學頻譜阻抗分析(EIS)上，微波水熱製程有較高的暗反應電阻、電子擴散長度及電子壽命。
並列摘要
The dye sensitized solar cells (DSSCs) have attracted many industries and researchers because of their advantages such as low cost, flexible, and high conversion efficiency. Titanium dioxide (TiO2) is one of promising materials as a nano-porous thin film for working electrode in DSSCs, due to its appropriate energy band gap, dye adsorption ability, low cost, and easy preparation. This study developed a new method to prepare anatase TiO2 nanoparticles. By microwave technology, the dissolution of TiO2 precursor in sol-gel process is increased, which improves the hydrolysis efiiciency and fabricates anatase TiO2 with good crystal characteristic in combination with hydrothermal method. The influence of microwave power and treatment time on the crystal size and crystallinity of TiO2 nanoparticles is discussed in this study. The results show that anatase nano TiO2 with high specific surface area can be fabricated by microwave-hydrothermal process with 200 W microwave power and appropriate treatment time. Moreover, the size of TiO2 particles was unchanged even for more treatment time. Comparing to traditional hydrothermal process, new microwave-hydrothermal process decreases the synthesis time from five days to one day. Furthermore, the crystal structures and particle sizes are uniform by this method. Although photoelectron energy conversion for both TiO2 working electrodes, prepared by forgoing methods, was measured to be 6.9 %, microwave-hydrothermal TiO2 electrode inherited higher photo-to-current conversion, RK, and Ln. τ.