Self‐Organized Small Molecules in Robust MOFs for High‐Performance Perovskite Solar Cells with Enhanced Degradation Activation Energy

• Published in: Advanced functional materials Vol. 32; no. 33
• Main Authors: Wang, Jiaqi, Zhang, Jian, Gai, Shuang, Wang, Wei, Dong, Yayu, Hu, Boyuan, Li, Jiao, Lin, Kaifeng, Xia, Debin, Fan, Ruiqing, Yang, Yulin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.08.2022
• Subjects: Activation energy; additive; Additives; Benzene; crystallization kinetics; Degradation; Fourier transforms; Infrared analysis; Materials science; Metal-organic frameworks; Organic chemistry; perovskite solar cells; Perovskites; Photovoltaic cells; Solar cells; Stability; Tetrazoles; Thermogravimetry; Zinc
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202203898

A brand new strategy to improve the volatility and disordered arrangement of small organic molecule additives within doped perovskite solar cells through the construction of metal–organic frameworks (MOFs) is proposed. The Zn‐TTB, self‐assembling from Zn2+ and 1‐(triazol‐1‐ly)‐4‐tetrazol‐5‐ylmethyl)benzene (TTB), inherits and arranges triazole and tetrazole groups and forms a long‐chain structure surrounding metal nodes. The perovskite precursors grow along with the skeleton of Zn‐TTB and produce a macromolecular intermediate phase via the MOFs‐perovskite interconnection, subsequently forming superior perovskite films with enhanced stability with respect to molecular additives, as evidenced by in situ thermogravimetry‐Fourier transform infrared spectroscopy measurements. Thermal analyses suggest MOF‐doping increases degradation activation energies by up to >174.01 kJ mol–1 compared to the reference sample (162.45 kJ mol–1). Zn‐TTB‐modified devices exhibit promising efficiencies (up to 23.14%) and operational stability in unencapsulated state, even under constant solar light illumination. A metal–organic framework‐modulated grain growth strategy to optimal crystallization process of perovskite and obtain highly efficient and stable perovskite solar cells is proposed. Benefitting from the long chain structure and ordered passivation sites of Zn‐TTB (1‐(triazol‐1‐ly)‐4‐tetrazol‐5‐ylmethyl)benzene), the Zn‐TTB‐modified perovskite films show improved crystallinity and fewer defects, which enable significantly higher device efficiency and stability.