Journal Article

One of the primary challenges of perovskite solar cells (PSCs) towards commercialization is to simultaneously achieve sufficient stability and high power conversion efficiency (PCE). Here, we propose a synchronous modulation of the strength of chemical and electric field-induced passivation strategies to comprehensively heal the imperfect characteristics of perovskite. Two nitrogen-rich small molecules with asymmetric geometry, namely AS-BP and AS-AZO, were designed and synthesized. The target molecule AS-AZO, featuring the most Lewis-base active sites and the largest dipole moment, can effectively passivate defects of perovskite and improve the built-in potential of derived PSCs. Moreover, the most flexible molecular structure of AS-AZO ensures that it acts as a molecular creeper towards the perovskite grain, not only largely relieving the residual strain, but also reinforcing the overall passivation capability. The abovementioned effects of AS-AZO largely stabilize the perovskite and optimize the charge carrier dynamics of derived PSCs, leading to robust stability against humidity, thermal stress and light soaking along with a promising PCE of 25.12% versus that of the control one (21.82%). Our work offers valuable insights for designing molecules featuring sufficient chemical and electric field effects for synchronous passivation capability for assembling robust and efficient PSCs.