The Multiple Roles of Na Ions in Highly Efficient CZTSSe Solar Cells

Wentong Yang; Yixiong Ji; Wangxian Chen; Yining Pan; Zifei Chen; Shaoyang Wu; Salvy P Russo; Yang Xu; Trevor A Smith; Anthony Chesman; Paul Mulvaney; Fangyang Liu

doi:10.1002/smll.202307807

The Multiple Roles of Na Ions in Highly Efficient CZTSSe Solar Cells

Small. 2024 Feb 11:e2307807. doi: 10.1002/smll.202307807. Online ahead of print.

Authors

Wentong Yang^{1

2}, Yixiong Ji³, Wangxian Chen^{1

2}, Yining Pan^{1

2}, Zifei Chen³, Shaoyang Wu³, Salvy P Russo⁴, Yang Xu³, Trevor A Smith³, Anthony Chesman⁵, Paul Mulvaney³, Fangyang Liu^{1

2}

Affiliations

¹ School of Metallurgy and Environment, Central South University, Changsha, 410083, China.
² Engineering Research Centre of Advanced Battery Materials Ministry of Education, Central South University, Changsha, 410083, China.
³ ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Melbourne, Victoria, 3010, Australia.
⁴ ARC Centre of Excellence in Exciton Science, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia.
⁵ CSIRO Manufacturing, Clayton, Victoria, 3168, Australia.

PMID: 38342673
DOI: 10.1002/smll.202307807

Abstract

Sodium (Na) doping is a well-established technique employed in chalcopyrite and kesterite solar cells. While various improvements can be achieved in crystalline quality, electrical properties, or defect passivation of the absorber materials by incorporating Na, a comprehensive demonstration of the desired Na distribution in CZTSSe is still lacking. Herein, a straightforward Na doping approach by dissolving NaCl into the CZTS precursor solution is proposed. It is demonstrated that a favorable Na ion distribution should comprise a precisely controlled Na⁺ concentration at the front surface and an enhanced distribution within the bottom region of the absorber layer. These findings demonstrated that Na ions play several positive roles within the device, leading to an overall power conversion efficiency of 12.51%.

Keywords: CZTS; kesterite; non-radiative recombination; sodium distribution; sodium doping; solar cell.

Abstract

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