Chemically and morphologically distinct grain boundaries in Ge-doped Cu2ZnSnSe4 solar cells revealed with STEM-EELS
Chemically and morphologically distinct grain boundaries in Ge-doped Cu2ZnSnSe4 solar cells revealed with STEM-EELS
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利用 STEM-EELS 揭示了 Ge 掺杂 Cu2ZnSnSe4 太阳能电池中化学和形态上不同的晶界
DOI：
10.1016/j.matdes.2017.02.077
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发表时间：
2017
影响因子：
8.4
通讯作者：
K. Leifer
中科院分区：
文献类型：
--
作者：
T. Thersleff;S. Giraldo;M. Neuschitzer;P. Pistor;E. Saucedo;K. Leifer
关键的Cu 2 ZnSnSe 4（CZTSe）材料的未来发展是一个全面的理解的基本纳米级机制，负责降低性能。调查这些机制是具有挑战性的，因为它们出现在纳米尺度上，但在宏观区域表现出来。在这里，我们提出了一个分析研究相结合的扫描透射电子显微镜（STEM），样品制备和高光谱电子能量损失光谱（EELS）映射技术，以满足这一挑战。我们将我们的方法应用于Ge掺杂的CZTSe样品，测得的效率为10.1%，揭示了它的微观结构主要由两种不同类型的晶界。第一种类型出现在分离大颗粒的吸收器的上半部分。这些都是铜富集，硒贫乏，并有不同数量的O。第二种类型的晶界基本上平行于基底，并且主要出现在吸收体的下半部分，其中锌黄锡矿材料的Cu/Zn比略低。这些晶界包含空隙和Sn氧化物纳米颗粒，表现出高浓度的Na、Cd和S，并且Cu呈现较高的价态。最后，我们讨论的性质和可能的技术影响，这些晶界在这个系统中。
Critical to the future development of Cu2ZnSnSe4(CZTSe) materials is a comprehensive understanding of the underlying nanoscale mechanisms responsible for reduced performance. Investigating these mechanisms is challenging since they arise on the nanoscale, yet manifest themselves over macroscopic regions. Here, we present an analytical study combining Scanning Transmission Electron Microscopy (STEM), sample preparation, and hyperspectral Electron Energy Loss Spectroscopy (EELS) mapping techniques to meet this challenge. We apply our method to a Ge-doped CZTSe sample with a measured efficiency of 10.1%, revealing that its microstructure is dominated by two distinct types of grain boundaries. The first type appears in the upper half of the absorber separating large grains. These are Cu-enriched, Se-poor, and have varying amounts of O. The second type of grain boundary is largely parallel to the substrate and appears predominately in the lower half of the absorber where the Cu/Zn ratio of the kesterite material is slightly lower. These grain boundaries contain voids and Sn oxide nanoparticles, exhibit high concentrations of Na, Cd, and S, and Cu assumes a higher valence state. We conclude with a discussion on the nature of and possible technological implications of these grain boundaries in this system.
影响因子：
27.8
作者：
Bourdais, Stephane;Chone, Christophe;Dennler, Gilles
通讯作者：
Dennler, Gilles