AEM: Photodegradation pathways of organic solar cells revealed by spectrally resolved accelerated lifetime analysis

• Micro robots have attracted the attention of scientists because of their unique characteristics that they can complete tasks in parts that are difficult to reach. Micro robots can be precisely driven and manipulated individually or in groups for sampling, surgery and imaging applications. In addition, micro robots are also used in environmental departments (such as water treatment). In addition, the latest progress of three-dimensional (3D) printers makes it possible to manufacture micro robots with high resolution, providing users with limited micro manufacturing skills with faster design production turnaround time.

  
  

  Thomas Heum ü ller and Paul Weitz of Erlangen Nuremberg University proposed a method for testing the stability of organic solar cells (OSC). This method aims to provide more unique insights into the causes of the degradation mode of OSC.

  
  

  The method includes using monochromatic light to accelerate the isolated degradation mechanism under high radiation dose, and monitoring the equipment with a series of in situ steady-state and transient electrical measurements. The experimental results were accompanied by drift diffusion simulation in a local degradation way. PM6: Y6 based OSC has been tested by the author. It is known that its lifetime is related to device architecture, material batch or degradation conditions, and the range is quite wide. The experiment reveals the degradation mechanism that leads to the increase of trap state density in PM6: Y6 layer. Transient simulation shows that these states are formed at or around the interface between PM6: Y6 and the electron transport layer. In addition, the striking main effect of the illumination wavelength on the degradation mode has been confirmed.

  
  

  Finally, the degradation rate of the device is linearly proportional to the light intensity, so high intensity and spectral selective degradation are the most promising methods to accelerate stability testing, which is helpful to develop stable OSC more quickly.

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• References:

  Weitz, P., Le Corre, V. M., Du, X., Forberich, K., Deibel, C., Brabec, C. J., Heumüller, T., Revealing Photodegradation Pathways of Organic Solar Cells by Spectrally Resolved Accelerated Lifetime Analysis. Adv. Energy Mater. 2022, 2202564.

  DOI: 10.1002/aenm.202202564

  https://doi.org/10.1002/aenm.202202564