Numerical modelling of graded bandgap CIGS solar cell for performance improvement

We simulated the effect of band gap grading in the CIGS absorber layer; in terms of performance parameters of the cell and the electric field across the absorber layer. Band gap grading can be accomplished through variation of Ga composition as a function of thickness across the absorber layer. Based on analysis on four different band gap profiles, it is shown that cell with double graded band gap structure reaches the highest efficiency of 22.52%.