Buried interface regulation for efficient and stable perovskite minimodules

Buried interface in perovskite solar cells (PSCs) is currently a highly focused study area due to their impact on device performance and stability. However, it remains a major challenge to rationally design buried interfaces. The properties of the buried interface not only affect carrier recombination and transport of perovskite layers, but also their crystallinity, orientation, and defects. In this work, ligand-modified ZrO₂ nanoparticles (NPs) were introduced as a functional bridging layer at the buried interface of the PSCs. The dense, ultra-thin insulating layer can effectively block holes but allow electrons to pass through the "tunneling" effect, thereby reducing charge recombination between the ETL and the perovskite bulk. In addition, ZrO₂ NPs functionalized with NH₂ groups can reconfigure the substrate to realize oriented growth of perovskite film and minimize bottom defects. This dual modulation of carrier behavior and film physical properties at the buried interface is very effective for improving both device performance and scaling. The efficiency of the champion small-area PSCs (with an active area of 0.0655 cm²) could reach 26.51 %. Moreover, the efficiencies of the PSC minimodules could reach 23.42 % at 23.23 cm² (certified as 22.32 %) and 22.26 % at 87.45 cm², respectively. These devices also showed excellent shelf-life/light soaking stability based on the advanced level of ISOS stability protocols.