Photodoping of spiro-OMeTAD for highly stable and efficient perovskite solar cells

• A widely used component in high-efficiency perovskite solar cells (PSCs ) is the molecular hole transport material (HTM ) spiro-OMeTAD . Such organic solids require p-doping to obtain sufficient hole conductivity.

  
  

  However, conventional doping methods using LiTFSI in air are slow, environmentally sensitive, and can cause PSC deterioration due to accidental oxidation or dopant migration. Therefore, there is a great need to develop fast doping methods to avoid exposing PSCs to ambient air and easily mobile doping ions.

  
  

  Kai Zhu of the National Renewable Energy Laboratory (NREL ), Michael Grätzel, Jacques-E. Moser of Ecole Polytechnique de Lausanne, and Nam-Gyu Park of Sungkyunkwan University and others believe that the light absorption of spiro-OMeTAD itself triggers a hitherto ignored Redox Photochemistry. Surprisingly, Y(III) or La(III)-tBP complexes catalyze the symmetry-breaking charge separation of photoexcited spiro-OMeTAD , leading to efficient p-doping of HTM. Using this photoredox process, PSCs with greater stability than cells using conventional doping were achieved, with cells that did not degrade under more than 1,000 hours of continuous illumination.

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• Seul-Gi Kim, George C. Fish, Etienne Socie, Aaron T. Terpstra, Dong-Am Park, Kai Zhu, Michael Grätzel, Jacques-E. Moser, Nam-Gyu Park,Photo-doping of spiro-OMeTAD for highly stable and efficient perovskite solar cells,Joule,2024,2542-4351

  https://doi.org/10.1016/j.joule.2024.03.012.

  https://www.sciencedirect.com/science/article/pii/S2542435124001478