Secondary crystallization strategy for highly efficient inorganic CsPbI2Br perovskite solar cells with efficiency approaching 17％

作者：Jing Ma; Zhenhua Lin; Xing Guo; Long Zhou; Jian He; Zhou Yang; Jincheng Zhang; Yue Hao; Shengzhong Liu; Jingjing Chang

来源：能源化学, 2021, 63(12): 558-565.

• CsPbI2Br
• Low temperature
• Secondary crystallization
• High performance

Inorganic CsPbI2Br perovskite solar cells (PSCs) have a tremendous development in last few years due to the trade-off between the excellent optoelectronic properties and the relatively outstanding stability.Herein,we demonstrated a strategy of secondary crystallization (SC) for CsPbI2Br film in a facile planar n-i-p structure (ITO/ZnO-SnO2/CsPbI2Br/Spiro-OMeTAD/Ag) at low-temperature (150 ℃).It is achieved through the method of post-treatment with guanidinium bromine (GABr) atop annealed CsPbI2Br film.It was found that the secondary crystallization by GABr can not only regulate the crystal growth and pas-sivate defects,but also serve as a charge collection center to effectively collect photogenerated carriers.In addition,due to the excess Br ions in GABr,the formation of the Br-rich region at the CsPbI2Br perovskite surface can further lower the Fermi level,leading to more beneficial band alignment between the per-ovskite and the hole transport layer (HTL),while the phase stability was also improved.As a result,the champion cell shows a superb open-circuit voltage (Voc) of 1.31 V,a satisfactory power conversion efficiency (PCE) of 16.97％ and outstanding stabilities.As far as we know,this should be one of the highest PCEs reported among all-inorganic CsPbI2Br based PSCs.

• 单位
  陕西师范大学; 西安电子科技大学