Covalent Organic Framework as a Precursor Additive Toward Efficient and Stable Perovskite Solar Cells

Abstract

In recent years, there has been significant progress in the use of organic–inorganic hybrid perovskites for photovoltaic applications. Engineering the compositions and/or morphology of perovskites has become the most effective method to address the challenges related to photovoltaic efficiency and stability. Herein, an amino-functionalized covalent organic framework (NH2-COF) as a precursor additive to modulate the crystallization of perovskites is incorporated. The NH2-COF is found to decrease the defect concentration, reduce the nonradiative recombination within the perovskite layer, and further promote carrier transport. Correspondingly, the solar cells based on the NH2-COF-modified perovskites deliver a champion power conversion efficiency of 22.13% with a fill factor of 0.773 under AM 1.5G 100 mW cm−2 illumination. Furthermore, the device retains approximately 81% of its initial efficiency after 1000 h of aging under ambient conditions at a temperature of 30 °C and relative humidity ranging from 45% to 55%. It is believed that this work would provide a facile and efficient strategy to prepare high-quality perovskite films for efficient and stable solar cells.