CdTe solar cells have reached efficiencies comparable to multicrystalline silicon and produce electricity at costs competitive with traditional energy sources. Recent efficiency gains have come partly from shifting from the traditional CdS window layer to new materials such as CdSe and MgZnO, yet substantial headroom still exists to improve performance. Thin film technologies including Cu(In,Ga)Se₂, perovskites, Cu₂ZnSn(S,Se)₄, and CdTe inherently have many grain boundaries that can form recombination centers and impede carrier transport; however, grain boundary engineering has been difficult and not practical. In this work, it is demonstrated that wide columnar grains reaching through the entire CdTe layer can be achieved by aggressive postdeposition CdTe recrystallization. This reduces the grain structure constraints imposed by nucleation on nanocrystalline window layers and enables diverse window layers to be selected for other properties critical for electro‐optical applications. Computational simulations indicate that increasing grain size from 1 to 7 µm can be equivalent to decreasing grain‐boundary recombination velocity by three orders of magnitude. Here, large high‐quality grains enable CdTe lifetimes exceeding 50 ns.

中文翻译：

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在纳米晶CdSe，MgZnO或CdS层上获得大的柱状CdTe晶粒并延长使用寿命

CdTe太阳能电池已经达到了与多晶硅相当的效率，并且以与传统能源竞争的成本发电。最近的效率提高部分来自从传统的CdS窗口层向新材料（例如CdSe和MgZnO）的转变，但是仍然存在很大的净空以提高性能。薄膜技术包括Cu（In，Ga）Se ₂，钙钛矿，Cu ₂ ZnSn（S，Se）₄和CdTe固有地具有许多晶界，这些晶界可以形成重组中心并阻碍载流子传输。但是，晶界工程一直很困难，而且不切实际。在这项工作中，证明了通过积极的后沉积CdTe重结晶可以实现穿过整个CdTe层的宽柱状晶粒。这减少了成核作用施加在纳米晶体窗口层上的晶粒结构限制，并能够为各种对电光应用至关重要的特性选择不同的窗口层。计算模拟表明，将晶粒尺寸从1 µm增加到7 µm等效于将晶界复合速度降低三个数量级。在这里，高质量的大晶粒可使CdTe的寿命超过50 ns。