Modeling and simulation of highly efficient ultra-thin CIGS solar cell with MoSe2 tunnel

Abstract

The main objective of this research work is to improve the efficiency of CIGS solar cells in ultra-thin approach. A detail numerical analysis on the insertion of a thin MoSe2 tunnel layer between the ultra thin CIGS absorber and the back contact in ultra-thin CIGS solar cell is investigated by using a solar cell simulator wxAMPS. The MoSe 2 layer between CIGS absorber and Mo back contact provides an additional hole tunneling action that forms a quasi ohmic contact near the back surface region and BSF action also. The quasi ohmic contact improves the efficiency of carrier collection and BSF action reduces the back surface recombination. From the above-mentioned discussions, it can be clearly showed that the efficiency obtained by the conventional CIGS cells is lower if compared to the values reached by the proposed ultra-thin CIGS solar cells with an additional MoSe 2 layer (at the level of 25%). Conversion efficiency of 21.20 % has been achieved for the conventional ultra thin CIGS structure (1μm CIGS lower) and improved conversion efficiency of 25.46 % has been gained for the proposed ultra-thin cell with an additional thin layer of MoSe 2 . Thermal stability of the proposed ultra thin CIGS solar cell has also been investigated.