The numerical simulation of CIS/CISSe graded band gap solar cell using SCAPS-1D software

In this paper, two types of single absorber layer solar cells, Mo/p-CIS/n-CdS/Al-ZnO and Mo/p-CISSe/n-CdS/Al-ZnO, are simulated using the solar cell simulation software (SCAPS-1D), and the effect of the thickness of the absorber layer on the photovoltaic performance of the solar cells is investigated. In addition, the total thickness of the CIS/CISSe gradient bandgap absorber layer was specified to be 2.5 mu m in the SCAPS-1D simulations, and the structure of the gradient bandgap solar cell was composed of Mo/p-CISSe/p-CIS/n-CdS/Al-ZnO. Using CdS and SnS2 buffer layers, respectively, the optimal photoelectric conversion efficiency (eta) of the CIS/CISSe gradient bandgap solar cell is 23.23% and 23.52% at a CIS/CISSe layer thickness ratio of 1 mu m/1.5 mu m, which means that SnS2 can be used as a buffer layer for Cd-free solar cells. With the increase in carrier concentration in the buffer layer, the carrier transport mechanism changes from a leakage current mechanism to tunneling current mechanism. As a result, optimal open-circuit voltage (Voc), short circuit current (Jsc), filling factor (FF), and eta of Mo/p-CISSe/ p-CIS /n-SnS2/Al-ZnO solar cell are 0.7809 V, 35.31 mA/cm2, 85.29%, and 23.52%, respectively, which uses the best impact parameters including CIS/CISSe absorption layer thickness ratio of 1 mu m/1.5 mu m, working temperature 300 K, and the carrier concentration of 1E + 18 cm-3.