Multi-functional interface modulation through thiol functionalized covalent organic frameworks for efficient and durable perovskite solar cells†

Abstract

Inhibiting metal electrode corrosion and reducing cathode interface charge loss are of significant importance for achieving stable and efficient p-i-n perovskite solar cells (PVSCs). Herein, two-dimensional (2D) thiol-functionalized covalent organic frameworks (SH-COFs) are used as an advanced barrier layer to provide an integrated solution for the above issues. The SH-COF rich in thiol groups can form close contact with the surface of Ag electrodes due to its strong chemical coordination, thus improving the corrosion resistance of metal electrodes. The inserted SH-COF interlayer also effectively hinders the ion migration and chemical reaction at the perovskite/metal electrode interface. Meanwhile, the SH-COF interlayer provides optimized interface contact and a cascade energy band arrangement, which is beneficial for promoting electron extraction and reducing non-radiative recombination at the cathode interface. Therefore, SH-COF-modified inverted PVSCs achieve power conversion efficiencies (PCEs) of 24.12% and 21.63% for 0.15 cm² and 1 cm²-sized devices. Moreover, the optimized devices retain 93.3% and 90.7% of their initial PCEs after aging at 85 °C for 1200 h and maximum power point tracking at 65 °C for 1000 h, respectively. This work provides a promising strategy for overcoming the performance and long-term stability limitations of p-i-n PVSCs to promote their commercialization by SH-COF-modification.