Selenium passivates grain boundaries in alloyed CdTe solar cells
Selenium passivates grain boundaries in alloyed CdTe solar cells
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DOI：
10.1016/j.solmat.2022.111595
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发表时间：
2022-05
影响因子：
6.9
通讯作者：
T. Fiducia;A. Howkins;A. Abbas;B. Mendis;A. Munshi;K. Barth;W. Sampath;J. Walls
中科院分区：
文献类型：
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作者：
T. Fiducia;A. Howkins;A. Abbas;B. Mendis;A. Munshi;K. Barth;W. Sampath;J. Walls
尽管吸收层颗粒尺寸小于10μm，因此具有非常高的晶界密度，但碲化镉太阳能电池的效率已达到22%以上。最近的研究表明，这是可能的，因为在广泛使用的氯化镉处理过程中，晶界被部分钝化，而CdTe的硒合金化使晶内缺陷被钝化。在这里，最先进的基于电子显微镜的阴极发光成像被用来表明，除了晶粒内部，硒还钝化了Cd(Sex，Te_(1-x))合金材料(CST)的晶界。具体地说，我们发现在CST晶界的复合比在CdTe晶界低一个数量级。这进一步解释了硒梯度CdTe器件的优异性能，并为进一步提高效率和降低太阳能发电成本提供了潜在的新途径。
Cadmium telluride (CdTe) solar cells have achieved efficiencies of over 22%, despite having absorber layer grain sizes less than 10 μm and hence a very high density of grain boundaries. Recent research has shown that this is possible because of partial passivation of grain boundaries during the widely used cadmium chloride treatment, and passivation of grain interior defects by selenium alloying of the CdTe. Here, state-of-the art TEM-based cathodoluminescence imaging is used to show that, in addition to grain interiors, selenium also passivates grain boundaries in alloyed Cd(Sex,Te1-x) material (CST). Specifically, we find that recombination at CST grain boundaries is up to an order of magnitude lower than at CdTe grain boundaries. This further explains the superior performance of selenium graded CdTe devices and provides potential new routes for further efficiency improvement and solar electricity cost reduction.