Ge Ziyi AM: 17.91% record efficiency! Flexible Organic Solar Cells

• High power conversion efficiency (PCE) and mechanical robustness are key requirements for organic solar cells (OSCs) for wearable applications. However, almost all highly efficient photoactive films comprising polymer donors (PDs) and small molecule acceptors (SMAs) are mechanically fragile.
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• In this study, Ziyi Ge et al., Ningbo Institute of Materials, Chinese Academy of Sciences reported the fabrication of highly efficient (PCE = 17.91%) and mechanically robust (crack initiation initial strain [COS] = 11.7%), representing the state-of-the-art flexible OSC.

  
  

  The researchers characterized the photophysical, mechanical, and photovoltaic properties of D18:N3 with different DOAs. By introducing DOA DOY-C4 with longer flexible alkyl linker and lower degree of polymerization, D18:N3:DOY-C4 based device compared with D18:N3 based device (PCE = 17.06%, COS = 7.8%), Flexible OSCs exhibited significantly higher PCE (17.91%) and 50% higher COS (11.7%).

  
  

  Flexible OSCs based on D18:N3:DOY-C4 retained 98% of the initial PCE after 2000 continuous bending cycles, showing higher mechanical stability than the reference device (retaining 89% of the initial PCE). After careful study, the researchers hypothesized that the improved mechanical properties were mainly due to the formation of linking chains or entanglements in the ternary blend films. These results demonstrate the great potential of DOA in realizing high-performance flexible OSCs.

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• Qinrui Ye, et al, Ductile Oligomeric Acceptor-modified Flexible Organic Solar Cells show Excellent Mechanical Robustness and near 18% Efficiency, Adv. Mater. 2023

  DOI: 10.1002/adma.202305562
  

  https://doi.org/10.1002/adma.202305562