Effect of Mg doping on Cu2ZnSnS4 solar cells prepared by DMF-based solution method

Abstract

In this paper, magnesium was successfully introduced into CZTS using the DMF-based solution method, and CZMTS solar cell was prepared. The effects of Mg doping on the morphology, crystal structure, and electronic properties of the CZTS absorber were investigated in detail. The crystal structure of the CZMTS absorber and the chemical valence states of the other elements (Cu, Zn, Sn, and S) were not changed as shown by XRD, Raman, and XPS analyses. The results show that Mg doping can improve the electronic properties and microstructure of CZTS absorbers, thus enhancing the PCE from 2.91% to 4.10%. This performance enhancement is associated with good crystal quality, reduced cation-disordering defects, and high external quantum efficiency at the longwave region caused less recombination and open circuit voltage loss. Therefore, Mg doping has a positive effect on improving the performance of CZTS solar cells. • The feasibility of the DMF-based solution method to achieve Mg doping is demonstrated. • Mg doping can reduce recombination and open-circuit voltage loss of CZTS solar cells. • After Mg doping, the PCE of CZTS solar cells is increased from 2.91% to 4.10%.