Electrical and optical parameters optimization and interface engineering for efficiency improvement of double CIGS absorber based solar cell

In this paper, we present a numerical simulation of double CIGS absorber based solar cell to enhance solar cell performance. The performance characteristics such as open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and power conversion efficiency (PCE) were quantitatively analyzed using SCAPS-1D software. Ultrathin WSSe is used as buffer layer due to low reflectance and high bandgap which are favorable for photon transmission from front side to CIGS absorber layer. Optimization of energy bandgap of both CIGS absorbers layer has been done by varying the gallium content in Cu(In1-xGax)Se2 structure. The output characteristics measured here consist of the recombination velocity (S) at the WSSe/ Cu(In0.6Ga0.4)Se2 interface and doping concentration of the buffer and absorber layer. The PCE of double CIGS absorber based solar cell with gallium (Ga) content x = 0.4 of Cu(In0.6Ga0.4)Se2 layer along with Ga content x = 0.7 of Cu(In0.3Ga0.7)Se2 layer represents the record efficiency of 29 %. The results reveal that, it is possible to achieve PCE to 29 % and beyond and provide a promising solution towards the fabrication of highly efficient thin film CIGS photovoltaic cell.

Automated summary

In this paper, a numerical simulation of double CIGS absorber based solar cell is presented to enhance its performance. The use of ultrathin WSSe as a buffer layer and the optimization of energy bandgap of both CIGS absorber layers led to a record efficiency of 29% in the PCE.