以稠環烴炔基擴張紫質吸收峰及其在敏化太陽能電池上之效應

本論文中，使用cross-coupling 方法合成了一系列應用於染料敏化太陽能電池中的第三丁基稠環烴紫質光敏劑，並且研究探討這些紫質光敏劑的光譜學以及電化學性質。另外，為了減少這些紫質光敏劑吸附在二氧化鈦奈米粒子上所產生的分子堆疊情形，我們以結構立體阻礙較大的紫質分子10,15,20-tris(3,5-di-tert-butyl-phenyl)-porphinato zinc(II) [Zn(t-Bu)TriPP] 作為光敏劑主要發色團。在紫外光-可見光吸收光譜部分，在紫質分子的 meso- 位置以乙炔基作為 spacer group 接上稠環烴取代基後，吸收峰會產生紅移的現象，其中以 anthracene 取代基、tetracene 取代基以及pentacene取代基的紫質光敏劑之光譜變化最明顯。在螢光放射光譜，也觀察到相同趨勢的紅移現象，是因為延長紫質分子的π電子共軛系統所致。在電化學探討部分，接上不同稠環烴取代基的紫質分子之還原電位彼此有明顯差異，表示這些紫質光敏劑的能隙也會有所不同，不同的稠環烴取代基對於紫質分子的電化學變化的確是有一定的影響。紫質光敏劑藉由接上不同稠環烴取代基之後，在測其光電流時，可以發現在接上anthracene所得到的光電轉換效率最高，雖然接上tetracene 取代基以及pentacene取代基的紫質光敏劑的吸收光譜範圍較廣，但是光電轉換效率不及接上anthracene取代基的紫質光敏劑。

關鍵字

染料敏化太陽能電池；稠環烴；紫質染料光敏劑；分子堆疊；光電轉換效率

並列摘要

A series of acene-ethynyl substituted porphyrin photo-sensitizers are successfully synthesized by using cross-coupling method and their UV-Visible absorption and redox properties are studied. In order to avoid the aggregation of porphyrin sensitizers upon adsorbing on nanocrystalline TiO2 films, 10,15,20-tris(3,5-di-tert-butyl-phenyl) porphinato zinc(II) [Zn(t-Bu)TriPP] porphyrin is studied. The UV-Visible absorption spectra of the porphyrin sensitizers have significant red-shift and peak-broadening of the Soret and Q band, especially in the cases of anthracene, tetracene and pentacene substituted porphyrins. Likewise, these porphyrin sensitizers have significant red-shifted fluorescence emission bands. As for the redox properties, the reduction and oxidation potentials of these porphyrins were different to each other. The suggests that different acene-ethynyl substituents have different effects on electrochemical properties of the porphyrin sensitizers. The IPCE (incident photon-to-electron conversion efficiency) of these porphyrins were also measured. We found the porphyrin sensitizers with anthracene-ethynyl group has the best IPCE performance. Although the absorption spectrum of the porphyrin sensitizers with tetracene and pentacene-ethynyl group are more red-shifted but their IPCE values are less than the porphyrin sensitizers with anthracene-ethynyl group.