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
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（12）
• 页码范围: 558-565
• 页数: 8页
• 语种: 英文

摘要

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.