High Fill Factor CsPbI2Br Perovskite Solar Cells Via Crystallization Management

Min Ju Jeong, Soo Woong Jeon, Sung Yong Kim, Jun Hong Noh

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Inorganic CsPbI2Br perovskite has a substantial potential for triple-junction tandem solar cells as a top subcell, however it exhibits relative instability in the air compared with organic-inorganic perovskites as well as significantly lower efficiency than the theoretical efficiency limit. To further enhance the air-stability and efficiency of CsPbI2Br-based perovskite solar cells (PSCs), it is vitally crucial to improve the crystallinity and passivate the defects within films that accelerate the phase transformation to the photo-inactive phase in the air. Here, it is reported that crystallization management via incorporating sodium formate (NaFo) in a CsPbI2Br perovskite solution effectively leads to enlarged grain size and the reduced trap density. The Na+ cation and HOOC anion produce a synergistic effect for engineering the defects by acting as cation and pseudo-halide anion passivators, respectively. As a result, the NaFo-incorporating device shows an improved power conversion efficiency (PCE) of 17.7% with a fill factor (FF) of 84.5%. To the best of the authors' knowledge, this progressive FF value is the highest value among CsPbI2Br-based PSCs reported thus far. In addition, the NaFo-incorporated device shows improved air stability compared to the control device, retaining over 95% of its initial PCE for 1000 hours under 10% relative humidity at room temperature without any encapsulation.

Original languageEnglish
Article number2300698
JournalAdvanced Energy Materials
Issue number23
Publication statusPublished - 2023 Jun 16

Bibliographical note

Publisher Copyright:
© 2023 Wiley-VCH GmbH.


  • CsPbI2Br
  • Fill factor
  • P3HT
  • dopant-free
  • stability

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science


Dive into the research topics of 'High Fill Factor CsPbI2Br Perovskite Solar Cells Via Crystallization Management'. Together they form a unique fingerprint.

Cite this