Improvement of Cu2ZnSn(S, Se)4 Solar Cells by Adding N, N‐Dimethylformamide to the Dimethyl Sulfoxide‐Based Precursor Ink. Issue 8 (1st April 2019)

• Record Type: Journal Article
• Authors: Ge, Sijie; Gao, Heng; Hong, Ruijiang; Li, Jianjun; Mai, Yaohua; Lin, Xianzhong; Yang, Guowei
• Is Part Of: ChemSusChem. Volume 12:Issue 8(2019)
• Page Start: 1692
• Page End: 1699
• Publication Date: 2019-04-01
• Subjects: CZTSSe -- kesterite -- solar cells -- solution processing -- solvent engineering; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201803009
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Cu2 ZnSn(S, Se)4 (CZTSSe) solar cells based on dimethyl sulfoxide (DMSO) Cu‐Zn‐Sn‐S precursor ink have seen tremendous progress in recent years. However, the wettability between the ink and Mo substrate is poor, owing to the high viscosity of the highly concentrated Cu‐Zn‐Sn‐S ink. Herein, a solvent engineering process is proposed in which N, N ‐dimethylformamide (DMF) is added into the DMSO‐based Cu‐Zn‐Sn‐S ink for the deposition of CZTSSe thin‐film absorbers in air. The addition of DMF significantly improves the wettability between the precursor ink and Mo substrate. The DMF/(DMF+DMSO) ratio also plays a critical role in determining the crystal quality of the resulting CZTSSe absorber and the device performance. The grain size of CZTSSe thin films increases with increasing DMF/(DMF+DMSO) ratio. Particularly, large grains through the whole cross section can be achieved with 20 % DMF addition. Accordingly, the power conversion efficiency of the device increases from 6.5 % to 8.6 % under AM 1.5G illumination. However, the efficiency decreases to 5.4 % when the DMF content is further increased to 30 %. Interface recombination and back contact barrier are found to be the main limitations of these devices. Abstract : Ink it in : The DMF/(DMSO+DMF) ratio in Cu‐Zn‐Sn‐S ink plays a critical role in improving the wettability of the precursor ink with Mo substrate, the crystal quality of the resulting Cu2 ZnSn(S, Se)4 (CZTSSe) absorber, and the device performance. The power conversion efficiency of the device can be increased from 6.5 % to 8.6 % by using 20 % DMF but decreases to 5.4 % when the DMF content is further increased to 30 %.