【NATURE】Three-party certification of 27.34%, one of the world’s highest efficiencies for full perovskite stacked cells at both ends

• All-perovskite tandem solar cells are expected to exceed the Shockley–Queisser limit of single-junction solar cells. However, practical applications of these cells are currently hampered by subpar performance and stability issues involving mixed tin-lead (Sn-Pb) narrow-bandgap perovskite subcells in all-perovskite stacks.
  

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• The teams of Fang Guoguo (third from left) and Ke Weijun (second from left) are in the laboratory. Li Sihui/photo

• Recently, Shun Zhou, Shiqiang Fu, Chen Wang, Guojia Fang, Weijun Ke and others from Wuhan University published an article in Nature, reporting that they focused on narrow band gap sub-cells and developed an integrated all-in-one doping strategy.

• Aspartate all-in-one doping strategy enables efficient all-perovskite tandems.

  Aspartic acid fully integrated doping strategy enables efficient all-perovskite tandem solar cells
  

  
  

  Aspartate hydrochloride, AspCl, was introduced into the bottom poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate and bulk perovskite layers, followed by another AspCl post-treatment.
  

  
  

  
  

  Studies have found that a single AspCl additive can effectively passivate defects, reduce Sn4+ impurities, and move the Fermi level. In addition, the strong molecular bonds of AspCl–Sn/Pb iodide and AspCl–AspCl can strengthen the structure and thereby improve the stability of Sn–Pb perovskite.

  
  

  
  

  In Sn–Pb perovskite solar cells, AspCl doping is implemented, the power conversion efficiency of single-junction cells is 22.46%, and the power conversion efficiency of tandem cells is 27.84% (27.62% stable, 27.34% certified), when filled with nitrogen In the glove box, after 2,000 hours of storage, the retention rate is 95%. Research shows that AspCl fully integrated doping is an effective strategy to improve the efficiency and stability of single-junction Sn–Pb perovskite solar cells and their tandem cells.

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• Figure 1: Preparation and mechanism of aspartate hydrochloride, AspCl, in narrow bandgaps, NBG Sn–Pb perovskites.

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• Figure 2: Characterization of narrow bandgap NBG Sn–Pb perovskite films.

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• Figure 3: Single junction narrow bandgap NBG Sn–Pb perovskite solar cells, PSC performance.

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• Figure 4: Performance of two-terminal, 2T all-perovskite tandem solar cells.

  
  

  Related Links:

  https://doi.org/10.1038/s41586-023-06707-z