Revealing the nanostructure of bulk‐heterojunction (BHJ) photovoltaic blends is a critical task in the field of organic photovoltaics. The complicated morphology, ranging from binary blends to ternary mixtures, shows quite varied structural details that need to be fully characterized in terms of correlating them with device performance. The nonequilibrium nature of the BHJ thin‐film morphology makes the structure optimization difficult, and fundamental principles that relate to chemical structure, processing methods, and device performances have not yet been fully understood. On the other hand, various high‐powered techniques ranging from in‐house instrumentation to synchrotron techniques have been applied to this tremendously difficult research topic. More structural details, including length scale of phase separation, structural ordering, chain/molecular orientation, surface topology, etc., can be obtained in a quantitative manner, which finally allows the structure–property relationships to be determined. Here, the most important characterization techniques in understanding the morphology of BHJ solar cells are summarized, targeting chemists and materials scientists.

中文翻译：

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体异质结太阳能电池的形态表征

揭示体异质结（BHJ）光伏混合物的纳米结构是有机光伏领域的关键任务。从二元共混物到三元混合物，复杂的形态显示出千差万别的结构细节，需要将它们与器件性能关联起来才能充分表征。BHJ薄膜形态的非平衡性质使结构优化变得困难，而与化学结构，加工方法和器件性能有关的基本原理尚未得到充分理解。另一方面，从内部仪器仪表到同步加速器技术的各种高功率技术已被应用到这个极其困难的研究主题中。更多结构细节，包括相分离的长度尺度，结构排序，链/分子取向，表面拓扑等可以通过定量的方式获得，这最终可以确定结构与性质之间的关系。在此，针对化学家和材料科学家，总结了理解BHJ太阳能电池形态最重要的表征技术。