Determining the optimum morphology in high-performance polymer-fullerene organic photovoltaic cells.
Determining the optimum morphology in high-performance polymer-fullerene organic photovoltaic cells.
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DOI：
10.1038/ncomms3867
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发表时间：
2013
影响因子：
16.6
通讯作者：
Samuel, Ifor D. W.
中科院分区：
文献类型：
--
作者：
Hedley, Gordon J.;Ward, Alexander J.;Alekseev, Alexander;Howells, Calvyn T.;Martins, Emiliano R.;Serrano, Luis A.;Cooke, Graeme;Ruseckas, Arvydas;Samuel, Ifor D. W.
本体异质结有机光伏电池的形态控制着器件的许多性能特征。然而，由于有机材料的长度尺度小且对比度低，测量这种形态具有挑战性。在这里，我们使用纳米级光电流测绘、超快荧光和激子扩散来观察 PTB7:PC71BM 高性能混合物的详细形态。我们表明，优化的共混物由细长的富含富勒烯和富含聚合物的纤维状域组成，其宽度为 10-50 纳米，长度为 200-400 纳米。这些细长的区域为定向电荷扩散提供了浓度梯度，有助于以 80% 的效率提取电荷对。相比之下，具有团聚富勒烯域的共混物的电荷提取效率要低得多，约为 45%，这是由于电子和空穴传输较差。我们的结果表明，窄而细长的域的形成对于高效的本体异质结太阳能电池是理想的。 有机太阳能电池的形态对其性能至关重要，但难以测量。 Hedley 等人使用各种探针。绘制聚合物富勒烯太阳能电池的形态图，发现细长的纤维状聚合物和富含富勒烯的域对于高性能来说是理想的。
The morphology of bulk heterojunction organic photovoltaic cells controls many of the performance characteristics of devices. However, measuring this morphology is challenging because of the small length-scales and low contrast between organic materials. Here we use nanoscale photocurrent mapping, ultrafast fluorescence and exciton diffusion to observe the detailed morphology of a high-performance blend of PTB7:PC71BM. We show that optimized blends consist of elongated fullerene-rich and polymer-rich fibre-like domains, which are 10–50 nm wide and 200–400 nm long. These elongated domains provide a concentration gradient for directional charge diffusion that helps in the extraction of charge pairs with 80% efficiency. In contrast, blends with agglomerated fullerene domains show a much lower efficiency of charge extraction of ~45%, which is attributed to poor electron and hole transport. Our results show that the formation of narrow and elongated domains is desirable for efficient bulk heterojunction solar cells. The morphology of organic solar cells is crucial to their performance but is difficult to measure. Using a variety of probes, Hedley et al. map the morphology of polymer-fullerene solar cells and find that elongated fibre-like polymer- and fullerene-rich domains are desirable for high performance.
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影响因子：
19
作者：
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通讯作者：
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