Impact of ZnMnO buffer and SnMnO2 window layer on enhancing the performance of CIGSSe thin-film solar cell

Abstract

A conventional copper indium gallium sulphur diselenide (CIGSSe) thin-film with double buffer layer solar cell structure of Al/MgF2/ZnO: B/ZnO/ZnMgO/CIGSSe/Mo(S, Se)/Mo is simulated. A high conductivity, low cost and minimum absorption coefficient, manganese doped zinc oxide (Zn1-xMnxO) semiconductor material as a buffer-1 layer is used instead of ZnO in the conventional solar cell. It is observed that the new proposed structure increases the efficiency by 28.80%. Smaller energy band-gap and higher absorption coefficient of ZnO: B window layer material does not absorb the short wavelength photons, thus a decrease in the external quantum efficiency (EQE) of conventional cells is observed. To overcome this, a new structure is proposed to have a wide energy band-gap. A tin-doped manganese oxide (Sn1-xMnxO2) is used as window layer material instead of ZnO: B. A new thin-film solar cell (TFSC) design is proposed where SnMnO2 as window and ZnMnO as buffer-1 is proposed, which helps in instantly absorbing the maximum blue light, reducing recombination losses, increasing efficiency and EQE. This new TFSC design provides a better efficiency of 29.40%.