Experimental and numerical study of the CIGS/CdS heterojunction solar cell

In this paper, we have performed a complementary and comparative analysis between an experimental and simulation study of the CIGS/CdS bulk heterojunction solar cell. The electrical parameters of this heterojunction modeled by a diode in the presence of parasitic resistances (Rs; Rsh), are determined by studying the properties of the (I-V) characteristic in the dark, and at different temperatures from 130 K to 300 K. We used the (ALM) method to determine the parasitic resistances. Also, by using the thermionic emission theory, we have determined other parameters, like ideality factor n, the barrier height phi B, and the mobility mu, and we compared these parameters with those determined by using Cheung's method. The ideality factor values at different temperatures which is greater than unity provided us with information about the electronic transport mechanism in the heterojunction. To complete our study, we performed a numerical simulation of the CIGS/CdS structure to determine the efficiency of the solar cell at different temperatures, taking into account the values of the parasitic resistances that we identified earlier. We also explored ways to improve the efficiency of our cell, in particular by using a HTL (NiO) layer. This layer increased the efficiency of the cell from 9.89% to 19.55% at a temperature of 300 K, a significant improvement for the advancement of thin film solar cell technology. In sum, this study makes a valuable contribution to the research field by demonstrating the positive impact of using HTL layers to improve the efficiency of thin film solar cells.