CsPb2Br5-assisted direct crystallization of the 3D perovskite phase for highly efficient and stable solar cells

Caiyun Gao, Kun Gao, Bingqian Zhang, Xiuhong Sun, Qiangqiang Zhao, Xiao Wang, Feng Wang, Mingliang Sun*, Guanglei Cui*, Shuping Pang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Improving the crystallization quality of perovskite films is crucial for both the efficiency and stability of perovskite solar cells. However, the solid-state transition of formamidinium lead iodide perovskite thin films from the δ to α phase at high temperatures typically introduces a significant number of lattice defects, which in turn leads to increased carrier recombination rates and reduced humidity stability. Directly growing the α-phase perovskite phase from a precursor solution still remains a challenge. In this work, a low solubility, halogen-rich CsPb2Br5 crystal was introduced into the perovskite solution to regulate the crystallization behavior of the perovskite layer. It was demonstrated that the CsPb2Br5 nanocrystals pre-precipitated and induced the direct crystallization of the α-phase perovskite during the solution processing. The direct formation of the α-phase instead of the δ-phase effectively enhances the crystalline quality and reduces the defect density of the perovskite films. As a result, the corresponding device exhibits an enhanced power conversion efficiency of 25.55%, and the module efficiency with 14 cm2 of active area reaches 22.35% (certified PCE is 21.7%). Thanks to the higher crystalline quality, these unencapsulated devices exhibit excellent operational stability at the maximum power point (∼92% efficiency retention after 1000 h).

Original languageEnglish
Pages (from-to)2734-2742
Number of pages9
JournalEnergy and Environmental Science
Volume17
Issue number8
DOIs
Publication statusPublished - 26 Mar 2024
Externally publishedYes

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