含 1,3-環己二烯的有機染料敏化太陽能電池

Abstract

本論文設計合成出三個 D-π-A 型式的有機雙極性染料（DM132、DM141、DM157），接上三苯胺（triarylamine）作為推電子端，羧酸根或氰基丙烯酸根作為拉電子端和錨固基團，中間以 thieno[3,2-b]thiophene（TT）接上1,3-環己二烯或苯環作為共軛片段，連結推拉電子基團。針對三個染料的物理性質及電化學性質，利用紫外光-可見光吸收光譜、螢光放射光譜和循環伏特安培法進行詳細的探討。 同時將其製作成染料敏化太陽能電池的元件，利用 AM 1.5 irradiation（100 mW/cm2）太陽光模擬進行效能測試。 在 AM 1.5 irradiation（100 mW/cm2）效能測試結果顯示，DM141 具有最佳的光電轉換效率 η = 2.86%（Jsc = 7.63 mA/cm2、Voc = 608 mV、ff = 0.62），而含有 1,3-環己二烯基團的 DM132 為 η = 1.37%，效果不如預期推測可能原因是：電荷分離效果不明顯、電子再結合速度過快、染料之間堆疊嚴重，導致整體效率下降。透過本論文對於染料結構和電池效能之間相關性的研究，希望未來能設計出更高效能的光吸收染料。Three new organic dipolar D-π-A dyes（DM132, DM141, DM157）with triarylamine as the electron donor, carboxylic acid or cyanoacrylic acid as an electron acceptor as well as an anchoring group, connected with thieno[3,2-b]thiophene and a π-conjugated spacer 1,3-cyclohexdiene or phenyl between the electron donor and acceptor. The photophysical and electrochemical properties of the three dyes were studied in details by UV/ Vis, fluorescence spectroscopy, and cyclic voltammetry. The cell performances of cells assembled from these light-harvesting dyes have been evaluated using the AM 1.5 simulated solar light. The results showed that DM141 has the best power conversion efficiency of 2.86 %（Jsc = 7.63 mA/cm2, Voc = 608 mV, ff = 0.62）under AM 1.5 irradiation（100 mW/cm2）whereas DM132（η= 1.37%）with 1,3-cyclohexdiene moiety within the π-framework was not as effective as expected perhaps due to non-effective charge separation, fast charge recombination and aggregation, which leads a low overall efficiency. A general correlation between the structural factors and the cell performances are currently under investigation aiming to provide a guideline for future design of high performance light-harvesting dyes.