Efficiency enhancement of Cu2ZnSn(S, Se)4 solar cells by addition a CuSe intermediate layer between Cu2ZnSn(S, Se)4 and Mo electrode

A CuSe intermediate layer (IL) is prepared between CZTSSe and Mo electrode to decay the carrier recombination on the rear surface of the CZTSSe absorber. The power conversion efficiency (PCE) can be increased from 7.52% to 10.09% by optimizing the thickness of CuSe IL. The increased PCE comes from improvement in filling factor (FF), short-circuit current density (J(SC)), and open-circuit voltage (V-OC), and their contribution percent is calculated to be 63.08%, 24.83%, and 12.09%, respectively. It is demonstrated that boosted FF is mainly due to decreased reverse saturation current density (J(0)), raised J(SC) owing to higher photogenerated current density (J(L)), and enhanced V-OC caused by decreased J(0) and higher J(L). The contribution percent of (ideal factor (A), J(0)), J(L), R-s, and shunt resistance (R-sh) to increased PCE is calculated to be 60.84%, 27.41%, 10.33%, and 1.42%, respectively. By experimental characterization and SCAPS-1D simulation, it is suggested that decreased J(0) results from the formation of passivation field and high electron potential barrier at the rear surface of CZTSSe due to the addition of suitable thickness CuSe IL, higher JL from the increase in width of the depletion region of CZTSSe/CdS, lower R-s from decrease in thickness of Mo(S, Se)(2), and bigger R-sh from improved crystal quality of CZTSSe absorber. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A CuSe intermediate layer is added between CZTSSe and Mo electrode to reduce carrier recombination and improve power conversion efficiency. By optimizing the thickness of CuSe intermediate layer, the power conversion efficiency is increased from 7.52% to 10.09%. The improvement in power conversion efficiency is mainly attributed to the enhancement in filling factor, short-circuit current density, and open-circuit voltage.