Interfacially embedded BiOBr flakes suppress C60 interfacial non-radiative recombination in inverted perovskite cells

• Presence of C60 -induced nonradiative recombination tends to reduce the overall efficiency of inverted perovskite solar cells (PSCs). To alleviate this problem, Alex K.-Y. Jen of City University of Hong Kong and Huan Wang of Hefei University of Technology embedded ultrathin BiOBr flakes with a unique self-induced internal electric field (SIEF) at the interface between perovskite and C60 .

  
  

  SIEF originates from the uneven charge distribution within the BiOBr lattice, which tends to be perpendicular to the perovskite/C60 heterointerface due to the design of a special (001) plane. This precise arrangement facilitates electron extraction and hole blocking, resulting in field-effect-mediated passivation.

  
  

  Furthermore, the desired surface atomic structure on the BiOBr(001) face can chemically passivate perovskite surface defects through the formation of Pb-O bonds. Combining these dual passivation effects with favorable band bending, the application of BiOBr increases the efficiency of inverted PSCs by 24.36% and significantly improves long-term stability. This work demonstrates an efficient approach to overcome the efficiency and stability limitations of inverted PSCs .

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• Hua Zhang*, Fanglin Wang, Bingxin Li, Man Sun, Kang Li, Huan Wang*, and Alex K.-Y. Jen*,  Overcoming C60-Induced Nonradiative Recombination via Interfacial Embedding of BiOBr Flakes in Inverted Perovskite Solar Cells,  ACS Energy Lett. 2024, 9, 176–185

  https://doi.org/10.1021/acsenergylett.3c02192

  https://pubs.acs.org/doi/abs/10.1021/acsenergylett.3c02192