含有反式二苯乙烯發色團的雙偶極有機材料應用於染料敏化太陽能電池

Abstract

我們設計並合成一系列含有反式二苯乙烯為架橋結構的分子，並分別以對位或間位共軛為連接組成共軛系統，與兩端的電子予體及電子受體形成一雙偶極染料分子，應用於染料敏化太陽能電池。理想的架橋應該是要能作為促進電子從電子予體傳遞至受體時的管道，並且抑制反方向的電子再合併。為了瞭解對位及間位共軛在結構上不同的效應，我們討論其光物理性質和元件效率；另外也將離子性液體電解質和改變染料浸泡溶劑作為製備元件的變因，觀察其特性。 由於間位共軛的電子耦合本質上就相較於對位共軛弱，然而近來發現在電子激發態時它們是不相上下的，尤其間位共軛較長的激發子生命期使得電子再合併不易，有利於提升元件效率；然而因為間位共軛使得分子共軛系統較短，造成光電流形成的低落，仍然是影響元件效率的主因，並且還有待改善，可以從調整分子結構來著手。在我們實驗的結果顯示，化合物(PP)展現了最好的光電轉換效率5.34%；含有間位共軛的化合物(PPM)則展現了不錯的2.89%效率。A series of trans-stilbene moiety dyes were designed and synthesized based on the donor-bridge-acceptor (D-B-A) system for the application of dye-sensitized solar cells. Besides typically para-conjugated, the meta-bridge dyes were developed in order to examine the difference of structural effect. The ideal bridge would promote electron transfer from donor to acceptor while resisting electron transfer in the reverse direction and thus suppressing charge recombination. In addition the ionic liquids electrolytes and different dye baths have been used to investigate the performance and the characteristics. It is inherently that electronic coupling through a meta-bridge is weaker than through a para one, however recent meta-bridge undergoes enhanced electronic coupling in the excited state. The meta-bridge isomers shorten conjugation system, to cause the photocurrent transport trapped inevasible and low JSC. Thence the meta conjugation effect should be further study in terms of molecular structure, and looking forward to overcome this drawbacks. In our study the well-known dye (PP) shows a prominent solar-to-energy conversion efficiency (η) 5.34%, and meta conjugated dye(PPM) also shows 2.89%.