Intragrain impurity annihilation for highly efficient and stable perovskite solar cells.

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Intragrain impurities negatively impact perovskite solar cell performance and longevity.
• These impurities are difficult to detect using standard characterization methods, hindering research.
• Understanding and addressing these impurities is key to advancing solar cell technology.

Purpose of the Study:

• To investigate the behavior of intragrain impurities in perovskite solar cells under irradiation.
• To reveal the atomic-level mechanisms of impurity transformation and their effects on crystal grains.
• To develop a method for mitigating impurity effects and enhancing device performance.

Main Methods:

• In situ scanning transmission electron microscopy (STEM) to observe impurity behavior at the nanoscale.
• Computational modeling to understand crystallographic transformation modes.
• Device fabrication and testing of formamidinium-cesium perovskite solar cells.

Main Results:

• Intragrain impurity nano-clusters can transform and amend crystalline grains upon irradiation.
• Atomic-scale imaging revealed specific crystallographic transformation modes for impurity annihilation.
• Scanning laser stimulus was found to heal these impurities, improving optoelectronic properties.
• This healing process also reduced intra-crystal strain, enhancing device stability.

Conclusions:

• Irradiation stimuli can trigger the transformation of intragrain impurities in perovskite solar cells.
• Atomic-level understanding of impurity behavior enables targeted device engineering.
• Scanning laser treatment offers a novel strategy to simultaneously enhance perovskite solar cell efficiency and stability.