Solvothermal synthesis of Cu2Zn(Sn1-xGex)S-4 and Cu-2(Sn1-xGex)S-3 nanoparticles with tunable band gap energies

摘要

The performance of Cu2ZnSnS4 based thin film solar cells can be efficiently improved by proper elemental substitution. This paper describes a facile and cost-efficient solvothermal route to synthesize Cu-2(Sn1-xGex)S-3 and Cu2Zn(Sn1-xGex)S-4 (0 <= x <= 1) nanoparticles, using elemental sulfur, GeCl4 and other metal salts as the precursors. To avoid the instability of pure CeCl4 toward the moisture and protic solvents, its acetone solution was prepared to use in the synthesis. The resulting Cu2Zn(Sn1-xGex)S-4 and Cu-2(Sn1-xGex)S-3 materials show tunable Ge/Sn ratios through simply adjusting the amount of metal salts in the starting materials, subsequently leading to composition-dependent band gap engineering. The Hall measurement and photoelectrochemical studies reveal that the synthesized Cu2Zn(Sn1-xGex)S-4 and Cu-2(Sn1-xGex)S-3 materials are p-type semiconductor, and the electrical and photoelectrical properties indicate their application potential in thin film solar cells. (C) 2015 Elsevier B.V. All rights reserved.