Heterojunction lithiation engineering and diffusion-induced defect passivation for highly efficient Sb 2 (S,Se) 3 solar cells

• Published in: Energy & environmental science
• Main Authors: Liu, Cong, Gong, Anweng, Zuo, Chen, Liu, Tao, Liang, Xiaoyang, Ren, Donglou, Shen, Kai, Zheng, Jianzha, Xue, Qifan, Li, Zhiqiang, Schropp, Ruud E. I., Zou, Bingsuo, Mai, Yaohua
• Format: Journal Article
• Language: English
• Published: 2024
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/D4EE03135K

High-quality heterojunctions are crucial for achieving high power conversion efficiency (PCE) in the antimony selenosulfide (Sb 2 (S,Se) 3 ) solar cells. Here, we introduce lithium fluoride (LiF) doping of the precursor solution to improve the conductivity, morphology, and n-type characteristics of cadmium sulfide (CdS) films. In addition, Li-ions have high mobility, which enhances in situ diffusion into the Sb 2 (S,Se) 3 absorber layer during subsequent hydrothermal deposition. Li effectively passivates selenium vacancies (V Se ) and antimony anti-site (Sb S ) defects through the formation of Li–S(e) bonds. This lithiation process not only realizes a twofold optimization of the CdS buffer layer and the Sb 2 (S,Se) 3 absorber layer, but also yields a favorable energy level arrangement and a wider depletion region at the CdS/Sb 2 (S,Se) 3 heterojunction. By this way, we have achieved a champion PCE of 10.76% compared to a certified value of 10.50% for Sb 2 (S,Se) 3 solar cells, which is the highest certified efficiency reported for Sb-based solar cells so far. This study provides a convenient method to optimize dual functional layers and heterojunctions for high-performance Sb 2 (S,Se) 3 solar cells.