| 摘要: | 染料敏化太陽能電池 (Dye-Sensitized Solar Cells, DSSCs)，具有透光性、良好的光電轉換效率、容易製程、對環境較無害以及低製造成本等優點，為現今太陽能電池發展的重點之ㄧ；由於染料在染敏太陽能電池中為主要吸光層，所以染料結構的設計是研究的一大方向。除了釕金屬為主的錯合物染料外，有機光敏染料因具有較高的莫爾消光係數、結構設計上較有彈性以及簡單合成等優點，而受到各國研究學者的注意。
在我的研究中，我成功地合成出一系列具有三級胺結構的染料，藉由中心的三級胺之乙基來連接不同數量的D-π-A片段 (各別為一、二以及三個)，而得到染料TD01、TD02與TD03。Donor為Triphenylamine具有強推電子能力與不共平面性，並且在對位接上叔丁基 (t-butyl) 增加片段間的立體障礙，以減少染料的堆疊，thiophene作為架橋來增加染料分子的共軛長度。隨著D-π-A片段的增加 (TD03>TD02>TD01)，可以增強染料在可見光光譜的吸收強度，預期可以吸收到更多的光子並且轉換成電子，進而提升Jsc。
當染料吸附在TiO2薄膜時，預期TD03的三個固著基團都能與TiO2鍵結，並且因為結構中的碳鏈連接，而限制了染料分子內的D-π-A片段在空間中的自由度，所以能降低染料的堆疊，利用乙基來阻擋電解液與TiO2接觸，降低暗電流的發生以提高Voc。總體而言，期望能藉由染料分子內D-π-A片段的增加，來增進元件之光電轉換效率。
;Dye-sensitized Solar Cells (DSSCs) have attracted intense interest due to their environmental friendly nature, low cost of production, and easy fabrication. The sensitizer is a key component of DSSC and have been studied widely due to its important effects in light harvesting, charge separation, and power conversion efficiency. In addition to Ru-based dyes, metal-free organic dyes have also received great attention for their unique advantages such as higher molar extinction coefficients, low cost of materials, facile molecular designs, and easy syntheses process.
In my research, a series of tertiary amine dyes (TD01, TD02, and TD03) consisting of different number (one, two, and three, respectively) of D-π-A units which are connected through oxygen of donor group to alkyl moiety of tertiary amine have been synthesized. Presumably, the increased D-π-A fragment of each dye could enhance the absorption intensity in UV-visible spectrum of the respected dye, having a chance to transform more absorbed photons into electrons, and thus improve Jsc.
The dye TD03 with its three D-π-A units in three directions from central amine core, is expected to spread over effectively and bind to TiO2 surface and minimize the dye aggregation if any. Further, the bridging ethyl groups between D-π-A division and central nitrogen can be served as a barrier at TiO2-electrolyte interface, thereby retarding electron recombination and enhancing Voc. |
