Atomic Scale Structure of (Ag,Cu)2ZnSnSe4 and Cu2Zn(Sn,Ge)Se4 Kesterite Thin Films
Atomic Scale Structure of (Ag,Cu)2ZnSnSe4 and Cu2Zn(Sn,Ge)Se4 Kesterite Thin Films
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DOI：
10.3389/fenrg.2021.656006
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
K. Ritter;G. Gurieva;S. Eckner;Cora Preiß;M. Ritzer;C. Hages;E. Welter;R. Agrawal;S. Schorr;C. Schnohr
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文献类型：
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作者：
K. Ritter;G. Gurieva;S. Eckner;Cora Preiß;M. Ritzer;C. Hages;E. Welter;R. Agrawal;S. Schorr;C. Schnohr
基于锌黄锡矿的材料正在研究和开发，作为薄膜光伏发电中经济实惠、高效且机械灵活的吸收材料。基于 (Ag,Cu)2ZnSnSe4 和 Cu2Zn(Sn,Ge)Se4 的器件在克服进一步提高基于黄锌锡矿的太阳能电池的转换效率方面的一些剩余挑战方面都显示出巨大的潜力。因此，本研究通过掠入射 X 射线衍射和低温 X 射线吸收光谱研究技术相关薄膜的长程晶体结构和局部原子尺度结构。正如预期的那样，晶胞尺寸的变化比元素特定平均键长大一个数量级。对于 Cu2Zn(Sn,Ge)Se4，薄膜吸收体表现出与之前研究的 Cu2Zn(Sn,Ge)Se4 粉末样品非常相似的行为。分析中考虑了薄膜中少量残留的 S，结果表明优先形成 Sn-S 键而不是 Ge-S 键。在 (Ag,Cu)2ZnSnSe4 中，Ag-Se 和 Cu-Se 键长对 Ag/(Ag+Cu) 的依赖性可能表明在某些局部构型的形成中具有能量优势。
Kesterite based materials are being researched and developed as affordable, efficient, and mechanically flexible absorber materials for thin film photovoltaics. Both (Ag,Cu)2ZnSnSe4 and Cu2Zn(Sn,Ge)Se4 based devices have shown great potential in overcoming some of the remaining challenges for further increasing the conversion efficiency of kesterite based solar cells. This study therefore investigates the long range crystallographic structure and the local atomic scale structure of technologically relevant thin films by means of grazing incidence X-ray diffraction and low temperature X-ray absorption spectroscopy. As expected, the unit cell dimensions change about an order of magnitude more than the element specific average bond lengths. In case of Cu2Zn(Sn,Ge)Se4, the thin film absorbers show a very similar behavior as Cu2Zn(Sn,Ge)Se4 powder samples previously studied. Small amounts of residual S in the thin films were taken into account in the analysis and the results imply a preferential formation of Sn-S bonds instead of Ge-S bonds. In (Ag,Cu)2ZnSnSe4, the dependence of the Ag-Se and Cu-Se bond lengths on Ag/(Ag+Cu) might indicate an energetic advantage in the formation of certain local configurations.