Understand the microstructure development of high-performance perovskite battery crystallization

• Solution crystallization in thin film devices has attracted widespread interest in various fields such as perovskite solar cells. However, due to the difficulty in in-situ observation of grain cluster growth during annealing, the detailed crystallization kinetics of perovskite are still unclear.

  
  

  Here, Professor Liu Shengzhong from Shaanxi Normal University, Ran Chen, and Jiaxue You from City University of Hong Kong demonstrated the development of an in-situ laser scanning confocal polarization microscope with a temperature controlled stage for observing the nucleation and growth of perovskite crystal clusters.

  
  

  Research has found that the interaction between liquid crystals and perovskite is enhanced, forming a new intermediate complex that induces diffusion controlled growth according to the Avrami equation. The delayed cluster growth (63 nm/s) is due to the increase in diffusion activation energy to 40 kJ/mol during annealing, while the diffusion activation energies of the control film are 152 nm/s and 37 kJ/mol.

  
  

  Finally, optimized perovskite thin films with enhanced crystallographic and optical properties were applied to solar cells, achieving a champion efficiency of 24.53%, an open circuit voltage (VOC) of 1.172 V, and a filling factor (FF) of 82.78%. Bare devices without any protection maintain their initial efficiency of 89% after aging for 6600 hours in the environmental environment. This work means that in-situ observation using a fluorescence microscope is crucial for understanding the crystallization kinetics in thin film devices.

• 

• Yabin Ma, et al, Understanding microstructural development of perovskite crystallization for high performance solar cells, Adv. Mater. 2023

  
  

  DOI: 10.1002/adma.202306947

  
  

  https://doi.org/10.1002/adma.202306947