Stable for over 6000 hours! Highly stable tin based perovskite solar cells

• A new group of pyrrole pyrrole based (PPr) polymers doped with thioalkylated/alkylated thiophene (SBT/BT) are used as hole transport materials (HTMs) for Sn based perovskite solar cells (TPSCs). Eric Wei Guang Diau of Yangming Jiaotong University in Taiwan, China, China, and Ming Chou Chen of Central University in Taiwan synthesized a group of new pyrrolopyrrolyl (PPr) polymers combined with thioalkylation/alkylation dithiophene (SBT/BT).
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• Three dithiophenyl spacer groups with thioalkylated hexyl (SBT-6), thioalkylated tetradecyl (SBT-14), and tetradecyl (BT-14) chains were used to examine the effect of alkyl chain length. Among them, tin based perovskite solar cells were manufactured using PPr-SBT-14 as a hole transport material through a two-step method, achieving a power conversion efficiency of 7.6% and significant long-term stability over 6000 hours. This is the first report on the longest stability of tin based perovskite solar cells based on non PEDOT: PSS.

  
  

  
  

  The PPr-SBT-14 device remains stable for 5 hours under maximum power point (MPP) in air (50% relative humidity) illumination. The highly planar structure of SBT, strong intramolecular S (alkyl) ··· S (thiophene) interactions, and extended π conjugation make PPr-SBT-14 devices superior to standard P3HT and other devices. The longer thiotetradecyl chain in SBT-14 limits molecular rotation and strongly affects molecular conformation, solubility, and film wettability. Therefore, this study provides a promising model for the design of efficient and stable tin based perovskite solar cells in the future as an undoped polymer hole transport material.

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• Kuan, C.-H., Balasaravanan, R., Hsu, S.-M., Ni, J.-S., Tsai, Y.-T., Zhang, Z.-X., Chen, M.-C. and Diau, E.W.-G. (2023), Dopant-Free Pyrrolopyrrole-based (PPr) Polymeric Hole-Transporting Materials for Efficient Tin-based Perovskite Solar Cells with Stability over 6000 h. Adv. Mater.. Accepted Author Manuscript 2300681.

  
  

  Source:

  https://doi.org/10.1002/adma.202300681

  https://onlinelibrary.wiley.com/doi/10.1002/adma.202300681