- 學位論文
以異靛藍素為主的予體-受體交替共軛高分子的合成與性質鑑定以及太陽能電池方面的應用
Synthesis and Characterization of Isoindigo-based Donor-acceptor Alternating Conjugated Polymer for Bulk Heterojunction Solar Cell Application
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摘要
異靛藍素是天然色素，可從植物中提煉，相當環保。以異靛藍素為主的予體─受體低能隙導電高分子擁有卓越的吸光能力、結晶性以及不錯的效率表現。本篇論文致力於發展以異靛藍素為主的予體─受體低能隙導電高分子，應用於高分子太陽能電池。我們選用不同噻吩數量(nT)作為予體，且選用異靛藍素(I)作為受體。我們成功透過Stille 偶聯反應合成出PnTI系列之高分子─P3TI、P4TI、P5TI以及P6TI，並且系統性探討其光電性質、結晶特性以及效率表現。本篇論文主要討論予體支鏈比率、予體共軛長度以及予體對稱性對高分子造成的影響。予體支鏈比率下降時，高分子的光吸收會隨之上升。予體共軛長度增長時，高分子的HOMO以及LUMO會隨之上升。予體結構為中心對稱的P4TI以及P6TI結晶性較予體結構為軸對稱的P3TI以及P5TI好。支鏈比率提升，高分子的結晶能力會隨之下降。結晶性的排列次序為P4TI>P6TI>P3TI>P5TI。P6TI在結晶性與溶解性間達到最佳平衡，以P6TI和奈米碳簇混摻的高分子太陽能電池效率表現高達7.24%。此效率為目前所知的以異靛藍素為主的予體─受體低能隙導電高分子太陽能電池的最高紀錄。我們將繼續為材料以及電池製作最佳化，期望近期內可達到具有商業價值(電池效率高於10%)之電池。
並列摘要
Isoindigo is a kind of nature dye, and it is renewable and available from plants. Isoindigo-based low-band gap conducting polymers have high absorption coefficient, crystallinity, and power conversion efficiency(PCE). We focus on developing this type of polymers for solar cell application. The polymers(PnTI) are designed to have different length of thiophene(nT) as donor unit and iosindigo(I) as acceptor unit. We synthesize four polymers of P3TI, P4TI, P5TI, and P6TI by Stille coupling, characterizing their optical property, electrical property, crystallinity and PCE systematically. The Properties of polymers are affected by the amount of side chain, the length of thiophene, and the symmetry of donor unit. As the amount of side chain on donor unit decreases, the UV-Vis absorption of polymers increases. As the length of thiophene increases, the HOMO and LUMO of PnTI rise. The P4TI and P6TI contain centrosymmetric donor unit, which exhibits higher crystallinity than that of axisymmetry of P3TI and P5TI. When the amount of side chain on donor unit increases, the crystallinity of PnTI becomes lower. Thus, the order of crystallinity is P4TI>P6TI>P3TI>P5TI. The solar cell fabricated from the blend of P6TI and fullerene derivative PC71BM reaches the best PCE of 7.24% among PnTIs. This is the highest record in the field of isoindigo-based polymer solar cell, according to our best knowledge. The PCE is expected to increase to more than 10% of commercial viable value by optimizing the polymer compositions and device structures.
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