Enhanced efficiency and stability of carbon-based CsPbI2Br perovskite solar cells by introducing metal organic framework-derived Fe3O4@NC interfacial layer

Carbon-based CsPbI2Br perovskite solar cells (C-PSCs) have the advantages of low cost and stable performance, but the poor contact and energy mismatch between the perovskite layer and the carbon electrode lead to low power conversion efficiency (PCE). In this work, uniform spindle-shaped Fe3O4@NC composites have prepared by calcining Fe-based metal organic framework (Fe-MOF) NH2-MIL-88B(Fe), which has synthesized by sol-vothermal reaction using 2-aminoterephthalic acid as nitrogen and carbon sources. Using Fe3O4@NC composite and UV-Ozone treated Fe3O4@NC composite (Fe3O4@NC UVO) as the interfacial layer between the perovskite layer and the carbon electrode, the devices with a structure of FTO/SnO2/CsPbI2Br/interfacial layer/Carbon exhibit a maximum PCE of 12.25%, which is about 19.28% higher than that of the pristine device. The improved optoelectronic performance is mainly attributed to more matched energy level, denser interface contact, better carrier separation performance and better conductivity. After 19 days of storage at room temperature and ambient humidity, Fe3O4@NC UVO device has retained 87% of the initial PCE. This work provides a simple and effective strategy to improve the PCE and stability of carbon-based CsPbI2Br PSCs with Fe-MOFs-derived carbon materials.