高效率小分子太陽能電池之分子結構設計與研究

Abstract

本計畫希望可以合成一系列可應用於塗佈製成的共軛小分子，並探討分子結構對有太陽能電池的效率影響。我們將以文獻高效率小分子(DR3TBDTT)為基礎，利用我們提出的幾個常見的推 電子單元，以及自行設計的拉電子單元，對此高效率小分子進行改良，希望可能建立起對分子能隙與能階調控的能力，讓分子能更有效的吸收太陽光並且與碳球有適當的能階差。另一方面， 我們將對改變小分子上長碳鏈的位置或是數目，研究側鏈修飾在分子堆疊與排列上的影響，期望可以建立對DR3TBDTT系列小分子的晶體形貌的操控能力。最後我們將結合元件，測試計 畫中和成的小分子其光伏元件特性，利用同步光源與電子顯微鏡等設備，分析分子在主動層中的排列與相分離，並整理出調控最佳主動層形貌的方法。

In this project, we would like to investigate structure-properties of solution-processed small molecules and the performances of their organic solar cells. Herein, we base a high efficiency small molecules, DR3tBDTT, as a start point, which consisted of consisting of benzodithiophene as central core, terthiophene as π-conjugated spacers, and an acceptor, 3-ethylrhodanine, as end-capping moieties. We select some donor units that have been used in conjugated polymers to act as the central core. Furthermore, we also design some novel acceptor units to replace 3-ethylrhodanine. By combing new donors and acceptors, we can tuning the absorption spectra and energy levels of molecules, and thus synthesizing a molecule which match solar spectrum well and has ideal energy offset respecting to. fullerenes. On the other hand, we would chain the alkyl chain position and density of molecules, and then it can help us to figure out the effects of side-chain engineering of molecules. Finally, we would test the photovoltaic properties of molecules and the optimal condition of fabricating devices; therefore, we can analyze the relationship between device performance and molecular structure.