Synergetic Effects of Zn Alloying and Defect Engineering on Improving the CdS Buffer Layer of Cu2ZnSnS4 Solar Cells.
Synergetic Effects of Zn Alloying and Defect Engineering on Improving the CdS Buffer Layer of Cu2ZnSnS4 Solar Cells.
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DOI：
10.1021/acs.inorgchem.2c01575
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发表时间：
2022-07
影响因子：
4.6
通讯作者：
Liangli Chu;Jinping Zhang;Huiwen Xiang;Sixin Wu;Yu Jia;Chengyan Liu
中科院分区：
文献类型：
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作者：
Liangli Chu;Jinping Zhang;Huiwen Xiang;Sixin Wu;Yu Jia;Chengyan Liu
Cu 2 ZnSnS 4/CdS（CZTS/CdS）异质结的界面电学性能较差，导致开路电压（Voc）损失严重，严重制约了CZTS太阳能电池器件的光伏效率。在这里，第一性原理计算表明，Zn合金化CdS缓冲层反转不利的悬崖状导带偏移（CBO）的CZTS/CdS的理想的尖峰状CBO的CZTS/Zn0.25Cd0.75S，抑制载流子非辐射复合，并阻止电子回流。此外，通过In、Ga和Cl掺杂可以增强Zn0.25Cd0.75S的减弱的n型导电性，而不会引入有害的深能级缺陷和严重的带尾态，这通过促进CZTS/Zn0.25Cd0.75S异质结的吸收侧处的强能带弯曲和大的准费米能级分裂来提高CZTS太阳能电池的Voc。研究发现，Zn合金化和缺陷工程对CdS缓冲层的协同效应有望克服CZTS太阳能电池长期存在的Voc缺陷问题，了解优化的界面电性能为提高半导体器件的效率提供理论指导。
The inferior electrical properties at the interface of the Cu2ZnSnS4/CdS (CZTS/CdS) heterojunction resulting in the severe loss of open-circuit voltage (Voc) highly restrict the photovoltaic efficiency of CZTS solar cell devices. Here, first-principles calculations show that the Zn-alloyed CdS buffer layer reverses the unfavorable cliff-like conduction band offset (CBO) of CZTS/CdS to the desirable spike-like CBO of CZTS/Zn0.25Cd0.75S, which suppresses carrier nonradiative recombination and blocks electron backflow. In addition, the weakened n-type conductivity of Zn0.25Cd0.75S can be enhanced by In, Ga, and Cl doping without the introduction of detrimental deep-level defects and severe band-tail states, which improves the Voc of CZTS solar cells by promoting strong band bending and large quasi-Fermi-level splitting at the absorber side of the CZTS/Zn0.25Cd0.75S heterojunction. This study finds that the synergetic effects of Zn alloying and defect engineering on the CdS buffer layer are promising for overcoming the long-standing issue of the Voc deficit in CZTS solar cells, and understanding the optimized interfacial electrical properties provides theoretical guidance for improving the efficiency of semiconductor devices.