Efficient and Stable Wide-Bandgap Methylammonium-Free Perovskite Solar Cells by Simultaneous Passivation and Cleaning with Diamine

Wide-bandgap perovskite solar cells (WBG-PSCs) are pivotal in achieving high-performance tandem solar cells. However, their power conversion efficiency (PCE) is limited by the losses from the interfacial charge transfer barrier and nonradiative recombination. In this investigation, 1,4-bis(aminomethyl)benzene (PDMA) is employed as a defect passivator for fabricating methylammonium (MA)-free perovskite solar cells (PSCs), thus effectively mitigating nonradiative recombination losses of charge carriers. Meanwhile, PDMA molecules chemically rinse the perovskite film to create a grooved surface, leading to the increase of contact area between the perovskite and electron transport layer to further improve the interfacial charge transfer. As a result, the PSCs based on these surface-passivated and chemically cleaned perovskite films present a champion PCE of 21.23% (E_g = 1.68 eV) compared to the control devices with a PCE of 18.23%, while maintaining over 80% efficiency after 800 h storage in ambient air. This study presents a highly effective approach for one-step passivation and chemical cleaning of wide-bandgap perovskite for efficient and stable solar cells, offering valuable insights for future research in this field.