Current matching and filtered spectrum analysis of wide-bandgap/narrow-bandgap perovskite/CIGS tandem solar cells: A numerical study of 34.52 % efficiency potential

Perovskite (PVK) materials with wide-bandgap (W_BG) play a crucial role in achieving high-performance tandem devices but phase segregation and open-circuit voltage (V_OC) loss hinders in surpassing the efficiency of single-junction solar cells. Present work discloses a numerical simulation which has been carried out using a W_BG material CH₃NH₃PbI_3-xCl_x of bandgap (E_g) 1.65eV as an absorber layer of the top cell (T_CELL) and a Cu(In,Ga)Se₂-based cell having narrow-bandgap (N_BG) of E_g (1.27eV) has been used as bottom cell (B_CELL). The T_CELL utilizes polyethyleneimine ethoxylated (PEIE) interfacial layer to promote charge-collection and charge-tunneling. The T_CELL and B_CELL have been optimized by various optimization processes such as simultaneous thickness variation of active-region with defect density (DD), variation of interface defect density (IDD) with solar-cell parameters a commendable power conversion efficiency (PCE) of 27.06 %, and 26.77 % has been achieved for respective solar-devices. Variations of numerous electron transport layer (ETL) and hole transport layer (HTL) have also been performed to acquire highly optimized T_CELL. Thus, a perovskite/CIGS tandem solar cell (PVK/CIGS-TSC) device has been obtained using filtered-spectra analysis and current-matching (method which display a promising photovoltaic (PV) parameter with a high V_OC of 2.29 V, short-circuit current density (J_SC) of 17.41 mA/cm², fill factor (FF) of 86.45 % and PCE of 34.47 %. These discoveries hold significant promise for the future development of TSCs.