Stabilization of lead iodide perovskite through defect control and composition engineering

• The phase instability poses a serious challenge to the commercialization of solar cells and optoelectronic devices based on lead formaldehyde iodide (FAPbI3 ). Zheng Rongkun, Liang Yuhang, Li Feng, Cui Xiangyuan, and JunHuang from the University of Sydney combined density functional theory with machine learning molecular dynamics simulations to explore the occurrence of FAPbI3 α-δ The mechanism of phase transition.

  
  

  The ubiquitous iodine vacancies and gaps can significantly accelerate the dynamics of structural transformation by inducing strong covalences in transition states. From an external perspective, the adverse effects of atmospheric moisture and oxygen on the degradation of FAPbI3 perovskite phase have also been reasonably explained. It is worth noting that we have discovered the principle of composition design through classification, that is, a-site engineering mainly controls thermodynamics, while b-site doping can effectively manipulate the phase transition kinetics of FAPbI3, highlighting lanthanide ions as promising b-site alternatives. A-B mixed doping is an effective synergistic stabilization method α- The strategy of FAPbI3 has been experimentally proven to have higher initial photoelectric properties and significantly enhanced phase stability compared to Cs doping.

  
  

  This study provides scientific guidance for the design and optimization of long-term stable solar cells and other optoelectronic devices through defect control and collaborative composition engineering. Photoinduced phase segregation is one of the main issues that constrain the efficiency and stability of wide bandgap perovskite solar cells (WBG PSCs ). Organic small molecules with abundant functional groups can passivate various defects, thereby inhibiting ion migration channels for phase segregation.

  
  

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• Liang, Y., Li, F., Cui, X. et al. Toward stabilization of formamidinium lead iodide perovskites by defect control and composition engineering. Nat Commun 15, 1707 (2024).

  
  

  https://doi.org/10.1038/s41467-024-46044-x