Recovery mechanisms in aged kesterite solar cells

• Main Authors: Campbell, Stephen, Duchamp, Martial, Ford, Bethan, Jones, Michael, Nguyen, Linh Lan, Naylor, Matthew C., Xu, Xinya, Maiello, Pietro, Zoppi, Guillaume, Barrioz, Vincent, Beattie, Neil S., Qu, Yongtao
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Materials; Kesterite; Photovoltaics
• Online Access: https://hdl.handle.net/10356/164219
• Institution: Nanyang Technological University

For successful long-term deployment and operation of kesterites Cu2ZnSn(S x Se1-x )4 (CZTSSe) as light-absorber materials for photovoltaics, device stability and recovery in kesterite solar cells are investigated. A low-temperature heat treatment is applied to overcome the poor charge extraction that developed in the natural aging process. It is suggested that defect states at aged CZTSSe/CdS heterojunctions were reduced, while apparent doping density in the CZTSSe absorber increased due to Cd/Zn interdiffusion at the heterojunction during the annealing process. In situ annealing experiments in a transmission electron microscope were used to investigate the elemental diffusion at the CZTSSe/CdS heterojunction. This study reveals the critical role of heat treatment to enhance the absorber/Mo back contact, improve the quality of the absorber/buffer heterojunction, and recover the device performance in aged kesterite thin-film solar cells.