應用於染料敏化太陽能電池之新穎紫質染料的元件最佳化工程與光電特性研究

Abstract

本研究首先進行二氧化鈦漿料的製備以及DSSC元件組裝的條件測試，並從其中歸納出影響元件光電壓、光電流與轉換效率之各項因素。我們與中興大學葉鎮宇老師合作進行一系列新穎紫質染料的光電特性研究。紫質染料的羧基團可從meso-或□-位置聯結，我們探討染料中羧基團的數目對於連結二氧化鈦薄膜表面的差異性，並在紫質分子中導入推電子基團，討論推電子基團對於DSSC元件光電特性的影響。我們發現紫質染料YD1有較佳的元件效能，因此後續的研究則以YD1分子為基本雛型，改變紫質染料結構的Donor與Bridge之修飾對於元件效能的影響。實驗結果顯示在紫質染料Donor處導入長烷鍊推電子基團(diarylamino)的YD2分子有最佳的光電效率表現。之後，我們研究紫質染料的Bridge處變化為phenyl、naphthalene和anthracene基團 (YD11-YD13)，藉由這些基團的修飾可使得染料的吸收光譜產生紅位移的現象，此現象導致YD12在DSSC元件的IPCE光譜較YD11更為寬廣，使其短路電流略高於YD11，整體光電轉換效率也較佳。此外，我們研究電解液添加物4-tert-butylpyridine (TBP)對於紫質DSSC元件的影響，我們分別量測YD12和YD12CN在不同TBP濃度的電解液條件下，對於元件效能的影響，實驗中發現TBP可以有效的提升開路電壓，但對於短路電流則有不同程度的影響，實驗中，我們也利用電子注入與電荷收集動力學來探討他們之間的差異性。

In this thesis, we the preparation of TiO2 pastes and photovoltaic measurement of DSSC devices. We tried to understand how the quality of the TiO2 pastes and the composites of the device affecting the device performance. The investigations were collaborated with Prof. Chen-Yu Yeh (NCHU). Novel porphyrin meso- or β- substituted porphyrins with a carboxyl group have been tested as sensitizers for DSSC. The results suggested that the photovoltaic properties of the DSSC can be affected by either the position of a bridge connecting the porphyrin ring and the number of carboxylic acid group. Because YD1 device showed the prominent performance the other porphyrin molecules were designed based on the structure of YD1. We investigated the effect of electron-donating group attached on a meso-position. The results show that the porphyrin with as alkyl-substituted diaryamino group (YD2), has higher stability and superior device performance. Then, we studied porphyrins with different types of bridges (YD11-13) for porphyrin-sensitized solar cell. The IPCE spectrum of YD12 has a Q-band shoulder slightly extended to longer wavelengths, resulting in a greater Jsc and higher power efficiency for YD12 than for YD11. In the last part, we studied the influence of electrolyte additives 4-t-butylpyridine (TBP) for porphyrin sensitized solar cell. We measured the device performance of YD12 and YD12CN with electrolytes containing different ratios of TBP. The additive TBP showed a significant influence on promoting the Voc of device. However, the effects of TBP additive on the device performance are different for YD12 and YD12CN. Electron-injection and charge-collection kinetics were reported to discuss the observed discrepancy.