Improvement of Efficiency in Kesterite Solar Cells by Intentionally Inserting a Thin MoS2 Layer into the Back Interface

Su-Zhen Xu; Yan-Ping Song; Bin Yao; Meng-Ge Li; Zhan-Hui Ding; Rui Deng; Heng-Nan Liang; Xiao-Bo Du; Yong-Feng Li

doi:10.1021/acsami.3c18045

Improvement of Efficiency in Kesterite Solar Cells by Intentionally Inserting a Thin MoS₂ Layer into the Back Interface

ACS Appl Mater Interfaces. 2024 Feb 28;16(8):11026-11034. doi: 10.1021/acsami.3c18045. Epub 2024 Feb 16.

Authors

Su-Zhen Xu^{1

2}, Yan-Ping Song³, Bin Yao^{1

2}, Meng-Ge Li^{1

2}, Zhan-Hui Ding^{1

2}, Rui Deng⁴, Heng-Nan Liang^{1

2}, Xiao-Bo Du^{1

2}, Yong-Feng Li^{1

2}

Affiliations

¹ State Key Laboratory of Superhard Material and College of Physics, Jilin University, Changchun 130012, P. R. China.
² Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), College of Physics, Jilin University, Changchun 130012, P. R. China.
³ Key Laboratory of Solid State Optoelectronic Devices of Zhejiang Province, College of Physics and Electronic Information Engineering, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China.
⁴ School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, P. R. China.

PMID: 38361494
DOI: 10.1021/acsami.3c18045

Abstract

A Mo(S,Se)₂ interfacial layer is formed inevitably and uncontrollably between the Mo electrode and Cu₂ZnSn(S,Se)₄ (CZTSSe) absorber during the selenization process, which significantly influences the performance of CZTSSe solar cells. In this work, an ultrathin MoS₂ layer is intentionally inserted into Mo/CZTSSe to reduce the recombination and thus optimize the interface quality. It is revealed that the absorber exhibits a continuous and compact morphology with bigger grains and remarkably without pinholes across the surface or cross-sectional regions after MoS₂ modification. Benefitting from this, the shunt resistance (R_Sh) of the device increased evidently from ∼395 to ∼634 Ω·cm², and simultaneously, the reverse saturation current density (J₀) realized an effective depression. As a result, the power conversion efficiency (PCE) of the MoS₂-modified device reaches 9.64% via the optimization of the thickness of the MoS₂ layer, indicating performance improvements with respect to the MoS₂-free case. Furthermore, the main contribution to the performance improvement is derived and analyzed in detail from the increased R_Sh, decreased J₀, and diode ideality factor. Our results suggest that the Mo/CZTSSe interface quality and performance of CZTSSe solar cells can be modulated and improved by appropriately designing and optimizing the thickness of the inserted MoS₂ layer.

Keywords: CZTSSe solar cells; Mo/CZTSSe interface; MoS2 layer; power conversion efficiency; reverse saturation current density; shunt resistance.