離子摻雜，添加劑與不同溶劑對塊材異質界面高分子/富勒烯碳球太陽能電池主動層形態之影響

Abstract

高分子太陽能電池的元件製程中對高效率元件開發以及未來商品化有著重要的影響力。元件製程的技術和元件的主動層形態之間具有密切關係，而且是直接和複雜的。但是高分子太陽能電池的元件製程對目前欲使用新合成的共軛高分子和富勒烯碳球衍生物製造高效率元件僅只於多方面的製程嘗試，無法直接使用具有不同官能基材料配對而直接利用製程技術針對主動層的形態家以控制達到高效率元件的目的。目前最受注視的“添加劑”製程應用於高效率高分子太陽能電池中，其具有的潛力吸引了大量的學術研究在這方面的重視，“添加劑”的工作機制目前缺乏一個完整的分析模型；同時由於製程中溶劑是主要的步驟幾乎直接決定共軛高分子/富勒烯碳球衍生物混合的現象，元件主動層成分組成分佈的趨勢和製程使用的溶劑，兩者間的關係尚須要進一步的釐清。 因此首先，我們使用離子性混合物作為添加劑在高分子太陽能電池的主動層，並利用電化學方式施加偏壓電場即時P-I-N結構形成機制，以提高高分子太陽能電池元件效率。添加入三氟甲基磺酸锂/聚環氧乙烷的離子混合物之MEH-PPV/PCBM元件相對於未添加之MEH-PPV/PCBM元件增加了40％光電轉換效率。接下來，利用雙碘烷(diiodoalkane)作為添加劑並專注在添加劑烷基鏈長度對高分子太陽能電池元件效率的影響，並證明PBTTPD/PC71BM作為主動層薄膜之元件的光電轉換效率可從5％提高到7.3％，發現當一個合適的烷基鏈長度的雙碘烷添加劑(diiodohexane)，可最大幅度地對元件效率提升45％。最後，使用同步輻射加速器的即時同步小角/廣角 X射線散射（GISAXS / GIWAXS），分析利用不同製程溶劑對共軛高分子(PBTC12TPD)的結晶和富勒烯碳球衍生物(PC61BM和ThC61BM)聚集團簇的大小之影響；和穿透式電子顯微鏡結合電子能量損失能譜儀分析不同溶劑製程所製造出的元件橫截面碳元素組成分佈，藉以了解元件垂直方向中共軛高分子和富勒烯碳球自我分佈趨勢。

The process of polymer solar cell plays an important role for the high efficiency device and the commercialization. But the processes of polymer solar cell do not understand enough to well controlling the morphology of active layer with new synthesized conjugated polymer and fullerene derivatives with different functional groups for high performance device. And the high performance polymer solar cell process with “additives” attracts large amount of the researchers in this area and the working mechanism of the “additives” is only proposed by model without fully analyzed. At the same time, the opinions of active layer composition distribution are also widely divided and the relation with processing solvent is most needed to be researched deeply due to the solvent is the main step to decide the mixing phenomena of the polymer/fullerene. In the first, we use ionic liquid as additive in the active layer of polymer solar cell and deduced the mechanism of the formation of p–i–n junction through in situ electrochemical doping is a promising way to enhance the performance of polymer photovoltaic devices. In the second, we examine the alkyl chain length effect of diiodoalkane additives and demonstrate that the power conversion efficiency of a device with a PBTTPD/ PC71BM film as the active layer can be improved to 7.3 % from 5%, a relative increase of 45%, when an additive with suitable alkyl chain length, diiodohexane, was incorporated during the solution processing. Finally, we used simultaneous synchrotron grazing-incidence small-/wide-angle X-ray scattering to elucidate the crystallinity of the polymer PBTC12TPD and the sizes of the clusters of the fullerenes PC61BM and ThC61BM and transmission electron microscopy/electron energy loss spectroscopy to decipher their cross-section distributions and C-ratios in PBTC12TPD/fullerene films processed with different solvents.