Organic‐Hydrochloride‐Modified ZnO Electron Transport Layer for Efficient Defect Passivation and Stress Release in Rigid and Flexible all Inorganic Perovskite Solar Cells

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-08, Vol.20 (32), p.e2312230-n/a
• Main Authors: Xu, Wenjie, Tang, Xiaoxuan, Xiong, Jie, Xu, Weiwei, Zhou, Heng, Yu, Chaohan, Lou, Yanhui, Feng, Lai
• Format: Article
• Language: English
• Subjects: CsPbI2Br perovskite; defect passivation; Defects; Electron transport; Interface stability; Modulus of elasticity; Passivity; Perovskites; Photovoltaic cells; rigid and flexible devices; Solar cells; Stress concentration; stress release; Substrates; Thermal resistance; Thermal stability; Thermal stress; Zinc oxide; ZnO electron transport layer
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202312230

All inorganic CsPbI2Br perovskite (AIP) has attracted great attention due to its excellent resistance against thermal stress as well as the remarkable capability to deliver high‐voltage output. However, CsPbI2Br perovskite solar cells (PeSCs) still encounter critical challenges in attaining both high efficiency and mechanical stability for commercial applications. In this work, formamidine disulfide dihydrochloride (FADD) modified ZnO electron transport layer (ETL) has been developed for fabricating inverted devices on either rigid or flexible substrate. It is found that the FADD modification leads to efficient defects passivation, thereby significantly reducing charge recombination at the AIP/ETL interface. As a result, rigid PeSCs (r‐PeSCs) deliver an enhanced efficiency of 16.05% and improved long‐term thermal stability. Moreover, the introduced FADD can regulate the Young's modulus (or Derjaguin‐Muller‐Toporov (DMT) modilus) of ZnO ETL and dissipate stress concentration at the AIP/ETL interface, effectively restraining the crack generation and improving the mechanical stability of PeSCs. The flexible PeSCs (f‐PeSCs) exhibit one of the best performances so far reported with excellent stability against 6000 bending cycles at a curvature radius of 5 mm. This work thus provides an effective strategy to simultaneously improve the photovoltaic performance and mechanical stability. It is reported on a facile strategy to modify the ZnO electron transport layer (ETL) with formamidine disulfide dihydrochloride (FADD). It is found that the FADD modification leads to efficient defects passivation and stress dissipation at the CsPbI2Br/ZnO interface. As a result, the inverted devices exhibit good photovoltaic performance and high thermal/mechanical stability on both rigid and flexible substrates.