Favorable electronic structure for organic solar cells induced by strong interaction at interface
Favorable electronic structure for organic solar cells induced by strong interaction at interface
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DOI：
10.1063/1.4829905
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发表时间：
2013-11
影响因子：
3.2
通讯作者：
Shenghao Wang;T. Sakurai;X. Hao;W. Fu;S. Masuda;K. Akimoto
中科院分区：
文献类型：
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作者：
Shenghao Wang;T. Sakurai;X. Hao;W. Fu;S. Masuda;K. Akimoto
为了阐明缓冲层在有机太阳能电池（OSCs）中的作用，采用紫外光谱、高分辨率x射线光谱、角度分辨x射线光谱和近边x射线吸收精细结构（NEXAFS）光谱等方法，系统研究了bathocuproine (BCP)/Mg界面的电子性质。结果表明，BCP与Mg的相互作用导致界面处存在间隙态。在界面处发现了Mg-N键的形成。NEXAFS测量结果表明，1-2层单层的BCP分子是平铺在衬底上的，而厚层的BCP分子是随机定向的。推测薄BCP层的间隙态和高有序取向是BCP缓冲层和低功函数金属阴极提高OSC性能的原因。
To clarify the role of buffer layer in organic solar cells (OSCs), the electronic properties of bathocuproine (BCP)/Mg interface were systematically investigated by using ultraviolet photoemissions spectroscopy, high-resolution X-ray photoemission spectroscopy, angle-resolved X-ray photoemission spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The results show there are gap states at the interface, which are caused by the interaction between BCP and Mg. The formation of Mg-N bond was found at the interface. The NEXAFS measurements show that BCP molecules for 1-2 monolayers are lying-down on the substrate, whereas orient randomly for thick BCP layer. It was supposed that the gap states and the highly-ordered orientation of thin BCP layer are the reasons for improving the performance of OSC with BCP buffer layer and low work function metal cathode.