Unveiling the Selenization Reaction Mechanisms in Ambient Air‐Processed Highly Efficient Kesterite Solar Cells

The selenization annealing process is vital for highly efficient kesterite solar cells. Generally, SnS is added during the selenization process, but excessive S and related defects are introduced. Meanwhile, the path of supplementing Sn has never been elucidated. Herein, in order to solve the above...

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Bibliographic Details
Published in:Advanced energy materials 2023-05, Vol.13 (19), p.n/a
Main Authors: Yu, Zixuan, Li, Chuanhao, Chen, Shuo, Zheng, Zhuanghao, Fan, Ping, Li, Yingfen, Tan, Manlin, Yan, Chang, Zhang, Xianghua, Su, Zhenghua, Liang, Guangxing
Format: Article
Language:English
Subjects:
Chemical Sciences
Circuits
Crystal defects
efficiency
kesterite
Optimization
Photovoltaic cells
Reaction mechanisms
selenization
Solar cells
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Summary:The selenization annealing process is vital for highly efficient kesterite solar cells. Generally, SnS is added during the selenization process, but excessive S and related defects are introduced. Meanwhile, the path of supplementing Sn has never been elucidated. Herein, in order to solve the above problems, a combination of strategies involving SnS and Sn or SnSe or SnSe2 is put forward. And the composition of the vapor inhibiting Sn loss (gaseous SnSe3) and the pathway through which SnSe3 facilitates the formation of Cu2ZnSn(SxSe1‐x)4 (CZTSSe) are clarified. When SnSe2 is added to SnS in the selenization process, grain fusion is effectively promoted. The high crystalline quality kesterite absorber makes the band bending at the GBs optimal and the interface recombination be effectively suppressed. Moreover, cation disorder is remarkably reduced. Therefore, the open‐circuit voltage (Voc) is significantly elevated from 508 to 546 mV with increased fill factor (FF) and short‐circuit current density (Jsc). A state‐of‐the‐art ambient air‐processed kesterite device with 12.89% efficiency is achieved, and the unveiled reaction mechanisms have guiding significance for further optimizing selenization atmosphere and elevating the efficiency of CZTSSe solar cells. A combination strategies involving the use of SnS and Sn or SnSe or SnSe2 during the selenization annealing process is proposed. The pathway of inhibiting Sn loss by gaseous SnSe3 is first clarified. When SnSe2 is added to SnS, grain fusion is effectively promoted and carrier recombination is effectively suppressed, and thus a state‐of‐the‐art ambient air‐processed kesterite device with 12.89% efficiency is acheived.
ISSN:1614-6832
1614-6840
DOI:10.1002/aenm.202300521