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Improvement of Cu 2 ZnSn(S,Se) 4 Solar Cells by Adding N , N ‐Dimethylformamide to the Dimethyl Sulfoxide‐Based Precursor Ink
Author(s) -
Ge Sijie,
Gao Heng,
Hong Ruijiang,
Li Jianjun,
Mai Yaohua,
Lin Xianzhong,
Yang Guowei
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201803009
Subject(s) - wetting , dimethyl sulfoxide , materials science , substrate (aquarium) , dimethylformamide , chemical engineering , thin film , energy conversion efficiency , solar cell , solvent , inkwell , nanotechnology , chemistry , organic chemistry , composite material , optoelectronics , oceanography , engineering , geology
Cu 2 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.