Angew: Record efficiency! Doping-free HTL efficient and stable formal perovskite module

• The use of dopant-free hole transport layers is crucial for stabilizing formal perovskite solar cells. However, these hole transport layer materials are often processed using toxic solvents, which is not ideal for industrial production. When replacing them with green solvents, there is a trade-off between maintaining high crystallinity of the hole transport layer material and ensuring high solubility in the new solvent
  Li Yaowen and others from Suzhou University designed a new linear organic small molecule BDT-C8-3O by introducing asymmetric polar oligomer (ethylene glycol) side chains. This method not only overcomes solubility limitations in green solvents but also enables stacking of conjugated backbones in two modes, further enhancing crystallinity and hole mobility.
  Without any dopants, a formal perovskite solar cell based on a BDT-C8-3O hole transport layer treated with the green solvent 3-methylcyclohexanone achieved 23.53% and a module efficiency of over 20%. The device also exhibits excellent operational stability and high temperature stability, maintaining more than 79.5% of the initial efficiency over 2000 hours. The dopant-free BDT-C8-3O hole transport layer shows significant advantages in large-area manufacturing, Even when using green solvents.
  

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• Cheng, Qinrong, Chen, Haiyang, Chen, Weijie, Ding, Junyuan, Chen, Ziyuan, Shen, Yunxiu, Wu, Xiaoxiao, Wu, Yeyong, Li, Yaowen, Li, Yongfang, Angew. Chem. Int. Ed. 2023, e202312231.

  
  

  https://onlinelibrary.wiley.com/doi/10.1002/anie.202312231