Controlled n‐Doping in Air‐Stable CsPbI2Br Perovskite Solar Cells with a Record Efficiency of 16.79%. (7th February 2020)

• Record Type: Journal Article
• Authors: Han, Yu; Zhao, Huan; Duan, Chenyang; Yang, Shaomin; Yang, Zhou; Liu, Zhike; Liu, Shengzhong (Frank)
• Is Part Of: Advanced functional materials. Volume 30:Number 12(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-02-07
• Subjects: CsPbI2Br -- high efficiency -- high open circuit voltage -- inorganic perovskite solar cells -- n‐doping; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201909972
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Cesium‐based inorganic perovskites, such as CsPbI2 Br, are promising candidates for photovoltaic applications owing to their exceptional optoelectronic properties and outstanding thermal stability. However, the power conversion efficiency of CsPbI2 Br perovskite solar cells (PSCs) is still lower than those of hybrid PSCs and inorganic CsPbI3 PSCs. In this work, passivation and n‐type doping by adding CaCl2 to CsPbI2 Br is demonstrated. The crystallinity of the CsPbI2 Br perovskite film is enhanced, and the trap density is suppressed after adding CaCl2 . In addition, the Fermi level of the CsPbI2 Br is changed by the added CaCl2 to show heavy n‐type doping. As a result, the optimized CsPbI2 Br PSC shows a highest open circuit voltage of 1.32 V and a record efficiency of 16.79%. Meanwhile, high air stability is demonstrated for a CsPbI2 Br PSC with 90% of the initial efficiency remaining after more than 1000 h aging in air. Abstract : Herein, calcium chloride is applied to passivate and dope inorganic CsPbI2 Br. It enhances the crystallinity of CsPbI2 Br to decrease trap density and prolong carrier lifetime and to raise its Fermi level to lie very close to the conduction band, leading to a high voltage of 1.32 V, and a record efficiency of 16.79% for CsPbI2 Br cells.