Microscopic origins of performance losses in highly efficient Cu(In,Ga)Se2 thin-film solar cells
Microscopic origins of performance losses in highly efficient Cu(In,Ga)Se2 thin-film solar cells
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DOI：
10.1038/s41467-020-17507-8
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发表时间：
2020-08-21
影响因子：
16.6
通讯作者：
Abou-Ras, Daniel
中科院分区：
文献类型：
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作者：
Krause, Maximilian;Nikolaeva, Aleksandra;Abou-Ras, Daniel
基于多晶吸收体的薄膜太阳能电池已经达到了高达23- 25%的非常高的转换效率。为了阐明需要克服的限制因素，甚至更高的效率水平，这是至关重要的，以调查这些设备中的损失机制的微观起源。在目前的工作中，高效率（21%，无抗反射涂层）铜铟镓硒（CIGSe）太阳能电池的特点是通过相关的显微镜的方法和证实通过光致发光光谱。通过实验表征获得的值被用作二维器件模拟的输入参数，其中使用了真实的微结构。可以看出，静电势和寿命波动对器件性能没有实质性影响。相比之下，在随机晶界处的非辐射复合可以被识别为CIGSe太阳能电池的显著损耗机制，甚至对于处于非常高性能水平的器件。实现薄膜太阳能电池的更高效率总是需要识别限制因素。Krause等人的研究表明，非均匀分布的净掺杂或寿命几乎没有影响，而晶界处的复合是高性能Cu（In，Ga）Se-2太阳能电池的主要损耗机制之一。
Thin-film solar cells based on polycrystalline absorbers have reached very high conversion efficiencies of up to 23-25%. In order to elucidate the limiting factors that need to be overcome for even higher efficiency levels, it is essential to investigate microscopic origins of loss mechanisms in these devices. In the present work, a high efficiency (21% without anti-reflection coating) copper indium gallium diselenide (CIGSe) solar cell is characterized by means of a correlative microscopy approach and corroborated by means of photoluminescence spectroscopy. The values obtained by the experimental characterization are used as input parameters for two-dimensional device simulations, for which a real microstructure was used. It can be shown that electrostatic potential and lifetime fluctuations exhibit no substantial impact on the device performance. In contrast, nonradiative recombination at random grain boundaries can be identified as a significant loss mechanism for CIGSe solar cells, even for devices at a very high performance level. Achieving higher efficiencies for thin-film solar cells always requires identification of the limiting factors. Here Krause et al. show that inhomogeneously distributed net doping or lifetime have little impact while recombination at grain boundaries is one of the main loss mechanisms for high performance Cu(In,Ga)Se-2 solar cells.