Dual-Interface Modulation with Covalent Organic Framework Enables Efficient and Durable Perovskite Solar Cells

Dual-interface modulation including buried interface as well as the top surface has recently been proven to be crucial for obtaining high photovoltaic performance in lead halide perovskite solar cells (PSCs). Herein, for the first time, the strategy of using functional covalent organic frameworks (COFs), namely HS-COFs for dual-interface modulation, is reported to further understand its intrinsic mechanisms in optimizing the bottom and top surfaces. Specifically, the buried HS-COFs layer can enhance the resistance against ultraviolet radiation, and more importantly, release the tensile strain, which is beneficial for enhancing device stability and improving the order of perovskite crystal growth. Furthermore, the detailed characterization results reveal that the HS-COFs on the top surface can effectively passivate the surface defects and suppress non-radiation recombination, as well as optimize the crystallization and growth of the perovskite film. Benefiting from the synergistic effects, the dual-interface modified devices deliver champion efficiencies of 24.26% and 21.30% for 0.0725 cm(2) and 1 cm(2)-sized devices, respectively. Moreover, they retain 88% and 84% of their initial efficiencies after aging for 2000 h under the ambient conditions (25 & DEG;C, relative humidity: 35-45%) and a nitrogen atmosphere with heating at 65 & DEG;C, respectively.

Automated summary

Functional covalent organic frameworks (COFs), namely HS-COFs, are used for dual-interface modulation, enhancing the photovoltaic performance of lead halide perovskite solar cells (PSCs). The buried HS-COFs layer improves resistance against ultraviolet radiation and releases tensile strain, leading to enhanced device stability and improved perovskite crystal growth. The HS-COFs on the top surface effectively passivate surface defects, suppress non-radiation recombination, and optimize perovskite film crystallization and growth. The dual-interface modified devices achieve high efficiencies and maintain them under different conditions.