Double side passivation of phenylethyl ammonium iodide for all perovskite tandem solar cell with efficiency of 26.8%

All-perovskite tandem solar cells are regarded as the next generation of devices capable of enhancing the solar energy utilization rate. Unlike single-junction perovskite solar cells (PSCs), the efficacy of tandem cells is contingent upon the performance of both the top and bottom cells. In this study, we employed a simultaneous co-modification strategy to incorporate phenylethylammonium iodide (PEAI) at both the top and bottom interfaces of the perovskite film, aiming to boost the top cell's performance. Both experimental and theoretical findings indicate that PEAI not only elevates the perovskite film quality through chemical interactions but also mitigates nonradiative recombination within the device. Consequently, the efficiency of the wide-bandgap (1.77 eV) PSCs based on nickel oxide (NiO_x) attained a level of 16.5%. Simultaneously, the all-perovskite tandem solar cells achieved an efficiency of 26.81% and demonstrated superior stability.