Construction of Polyoxometalate‐Based Material for Eliminating Multiple Pb‐Based Defects and Enhancing Thermal Stability of Perovskite Solar Cells

• Published in: Advanced functional materials Vol. 31; no. 52
• Main Authors: Wang, Wei, Zhang, Jian, Lin, Kaifeng, Dong, Yayu, Wang, Jiaqi, Hu, Boyuan, Li, Jiao, Shi, Zhe, Hu, Yanjing, Cao, Wei, Xia, Debin, Fan, Ruiqing, Yang, Yulin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.12.2021
• Subjects: Crystal defects; defects passivation; Energy conversion efficiency; Fourier transforms; Grain size; Infrared analysis; Materials science; Metal-organic frameworks; Oxidation; perovskite solar cells; Perovskites; Photovoltaic cells; polyoxometalates; Polyoxometallates; Precursors; Solar cells; Solvent effect; stability; Thermal stability; Thermogravimetry
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202105884

The high‐quality perovskite film with few defects plays an important role in the power conversion efficiency (PCE) and long‐term stability of perovskite solar cells. Here, an efficient strategy is proposed to eliminate Pb0 and passivate Pb2+ simultaneously by employing a stable polyoxometalate‐based material CoW12@MIL‐101(Cr) in the precursor solution of perovskite. The controllable oxidation ability of CoW12 is optimized through the interaction with metal–organic frameworks, resulting in a doped perovskite film with regular morphology, large grain size, and low defects density. The solvent effects and formation of intermediate materials in the precursor solution are further investigated by an in situ thermogravimetry‐Fourier transform infrared spectroscopy analysis. In addition, the champion doped‐device showed enhanced PCE to 21.39% and excellent stability, maintaining 85% and 89% of the original PCE after heating at 85 °C in N2 atmosphere and stored in ambient conditions (25 °C, 40% humidity) for 1000 h, respectively. A polyoxometalate‐based material CoW12@MIL‐101(Cr) is applied as an effective dopant to eliminate Pb0, passivate Pb2+ defects, and speeds up the volatilization of organic solvents during the crystallization of perovskite, resulting in a uniform and dense perovskite film. The doped device demonstrates an enhanced power conversion efficiency of 21.39% and excellent humid and thermal stability.