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Impact of Precursor Compositions on the Structural and Photovoltaic Properties of Spray‐Deposited Cu 2 ZnSnS 4 Thin Films
Author(s) -
Nguyen Thi Hiep,
Fujikawa Shotaro,
Harada Takashi,
Chantana Jakapan,
Minemoto Takashi,
Nakanishi Shuji,
Ikeda Shigeru
Publication year - 2016
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.201600641
Subject(s) - thin film , annealing (glass) , impurity , materials science , stoichiometry , acceptor , thiourea , chemical engineering , solar cell , analytical chemistry (journal) , inorganic chemistry , metallurgy , nanotechnology , chemistry , organic chemistry , physics , optoelectronics , condensed matter physics , engineering
Pure sulfide Cu 2 ZnSnS 4 thin films were fabricated on Mo‐coated glass substrates by facile spray deposition of aqueous precursor solutions containing Cu(NO 3 ) 2 , Zn(NO 3 ) 2 , Sn(CH 3 SO 3 ) 2 , and thiourea followed by annealing at 600 °C. When a precursor solution containing a stoichiometric composition of Cu, Zn, and Sn was used, the resulting Cu 2 ZnSnS 4 thin film contained a Cu 2− x S impurity phase owing to the evaporation of Sn components during the annealing process. The Cu 2− x S impurity in the Cu 2 ZnSnS 4 thin film was removed by reducing the concentration of Cu in the precursor solution. This resulted in an improvement of the structural features (i.e., grain sizes and compactness) as well as the electric properties such as acceptor densities, the nature of the acceptor defects, and carrier lifetimes. A solar cell based on the Cu 2 ZnSnS 4 film with an empirically optimal composition showed conversion efficiency of 8.1 %. The value achieved was one of the best efficiencies of Cu 2 ZnSnS 4 ‐based cells derived from a non‐vacuum process.