Hydrazide Derivatives for Defect Passivation in Pure CsPbI3 Perovskite Solar Cells

• Published in: Angewandte Chemie International Edition Vol. 61; no. 33; pp. e202205012 - n/a
• Main Authors: Che, Yuhang, Liu, Zhike, Duan, Yuwei, Wang, Jungang, Yang, Shaomin, Xu, Dongfang, Xiang, Wanchun, Wang, Tao, Yuan, Ningyi, Ding, Jianning, Liu, Shengzhong (Frank)
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 15.08.2022
• Edition: International ed. in English
• Subjects: Benzamide; Bonding strength; Chemical bonds; Coordination; CsPbI3; Defect Passivation; Density; Hydrazide; Hydrazine; Hydrazines; Hydrogen bonds; Iodine; Lead; Perovskite; Perovskites; Photovoltaic cells; Solar Cells; Stability; CsPbI3 defect passivation hydrazide perovskite solar cells
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202205012

All‐inorganic CsPbI3 perovskite presents preeminent chemical stability and a desirable band gap as the front absorber for perovskite/silicon tandem solar cells. Unfortunately, CsPbI3 perovskite solar cells (PSCs) still show low efficiency due to high density of defects in solution‐prepared CsPbI3 films. Herein, three kinds of hydrazide derivatives (benzoyl hydrazine (BH), formohydrazide (FH) and benzamide (BA)) are designed to reduce the defect density and stabilize the phase of CsPbI3. Calculation and characterization results corroborate that the carboxyl and hydrazine groups in BH form strong chemical bonds with Pb2+ ions, resulting in synergetic double coordination. In addition, the hydrazine group in the BH also forms a hydrogen bond with iodine to assist the coordination. Consequently, a high efficiency of 20.47 % is achieved, which is the highest PCE among all pure CsPbI3‐based PSCs reported to date. In addition, an unencapsulated device showed excellent stability in ambient air. A new passivator—benzoyl hydrazine (BH) with carboxyl, hydrazine and phenyl groups was developed to effectively passivate defects in CsPbI3 through synergetic effects of these groups. Consequently, a highest efficiency of 20.47 % with a high open‐circuit voltage and stability is achieved in a BH‐CsPbI3 solar cell, the highest efficiency among all pure CsPbI3‐based devices reported to date.