Device design and simulation of wide band-gap CsPbBr3 based ETL-free perovskite solar cell

With its high stability, cesium lead bromide (CsPbBr3) has drawn huge attention in tandem solar cells. Here, we report a detailed performance analysis of CsPbBr3-based ETL-free perovskite solar cell (PSCs) via the SCAPS-1D. Optimal device performance occurs with anode and cathode work functions above 5.1 eV and below 4.4 eV, respectively. The power conversion efficiencies (PCEs) decrease when the donor doping density (N-D) of the absorber layer and accepter doping density (N-A) exceeds 10(19) cm(-3) and absorber defect density (N-t) exceeds 10(15) cm(-3). We also calculated the impact of point defect within CsPbBr3, finding that Pb-Br(2+) and V-Cs(1-) significantly impact device performance. The PCE significantly decrease when the N-t of front interface exceeds 10(13) cm(-3). Furthermore, the proper valence band offset (VBO) of -0.3 similar to 0.05 eV and conduction band offset (CBO) of -0.05 similar to 0.4 eV positively affects device performance, indicating that FTO is an appropriate electrode and a suitable HTL remains to be identified. Finally, we investigated the impact of interface recombination velocity and analyze the loss mechanism of V-OC, showing that energy level mismatch, J(SC) and J(0) and defects are the significant reasons for V-OC loss. These results help fabricate highly stable and efficient wide-bandgap PSCs based on CsPbBr3.