Correlation between Distribution of Polymer Orientation and Cell Structure in Organic Photovoltaics.
Correlation between Distribution of Polymer Orientation and Cell Structure in Organic Photovoltaics.
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DOI：
10.1021/acsami.8b10460
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发表时间：
2018-09
影响因子：
9.5
通讯作者：
M. Saito;T. Koganezawa;I. Osaka
中科院分区：
文献类型：
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作者：
M. Saito;T. Koganezawa;I. Osaka
半导体聚合物的主链取向是决定电荷传输进而决定光电器件性能的重要结构因素之一。在这里，我们研究了两组噻吩-噻唑并噻唑聚合物，它们主要形成边上和面上取向，分别称为“边上聚合物”和“面上聚合物”；两种取向类型在其聚合物/富勒烯共混薄膜中共存。有趣的是，我们发现，在具有倒置结构和传统结构的光伏电池中，光敏层厚度对填充因子的依赖性在边缘聚合物中非常明显。然而，这在面对面聚合物中并不明显。通过掠入射 X 射线衍射分析进行的深入研究表明，在边缘聚合物中，正面/边缘比率在膜厚度上分布不均匀，而在正面聚合物中则均匀分布。主链取向分布的差异与厚度对填充因子的依赖性的差异相关。因此，我们建议主链取向的分布是了解聚合物基光伏电池性能的重要因素，并且应通过考虑分布来仔细选择电池结构以最大化性能。
The backbone orientation of semiconducting polymers is one of the important structural factors that determines the charge transport and thus the performance of optoelectronic devices. Here, we study two sets of thiophene-thiazolothiazole polymers, which primarily form edge-on and face-on orientations, termed "edge-on-polymers" and "face-on-polymers", respectively; both orientation types co-exist in their polymer/fullerene blend films. Interestingly, we find that the dependence of the photoactive layer thickness on the fill factor in the photovoltaic cells, with the inverted and conventional structures, is quite distinct in the edge-on-polymer; however, this is not evident in the face-on-polymers. An in-depth study by grazing incidence X-ray diffraction analysis reveals that the face-on/edge-on ratio is unevenly distributed through the film thickness in the edge-on-polymers, while it is evenly distributed in the face-on-polymers. The difference in the distribution of the backbone orientation correlates with the difference in the thickness dependence on the fill factor. We thus propose that the distribution of the backbone orientation is an important factor to understand the performance of polymer-based photovoltaic cells and that the cell structure should be carefully selected by considering the distribution for maximizing the performance.