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

Abstract

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, we report the strategy of using functional covalent organic frameworks (COFs), namely HS-COFs, for dual-interface modulation, and 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 device delivers a champion efficiency of 24.26% and 21.30% for 0.0725 cm2 and 1 cm2 -sized devices, respectively. Moreover, it retains 88% and 84% of their initial efficiency after aging for 2000 hours under the ambient conditions (25°C, relative humidity: 35- 45%) and a nitrogen atmosphere with heating at 65°C, respectively. This article is protected by copyright. All rights reserved.