A highly efficient n-CdS/p-Ag2S/p+-SnS thin film solar cell: Design and simulation

Silver sulfide (Ag₂S) chalcogenide compound can be a viable absorber in the applications of thin film solar cells owing to its optimum bandgap of 1.1 eV and high absorption coefficient. Herein, we propose a novel Ag₂S-based n-CdS/p-Ag₂S/p⁺-SnS double-heterojunction solar cell. The numerical analysis of the device has been performed with SCAPS-1D (Solar Cell Capacitance Simulator). In the case of single heterojunction, n-CdS/p-Ag₂S manifests an efficiency of 19.75%, where V_OC = 0.66 V, J_SC = 36.99 mA/cm² and FF = 81.50%. However, Ag₂S-based double-heterojunction device with optimized structure provides the efficiency of 29.51% with V_OC = 0.81 V, J_SC = 42.81 mA/cm² and FF =85.24%. The noteworthy augmentation of V_OC and J_SC in double-heterojunction results from the reduction in surface recombination velocity and rise in built-in voltage in the p-Ag₂S/p⁺-SnS hetero-interfaces that promote the higher efficiency of the device. These theoretical insights indicate a path for fabrication of an efficient Ag₂S based thin film solar cell.