Our group develops ALD-engineered interlayers optimized for perovskite-based tandem solar cells. By suppressing ion migration, tailoring energy band alignment, and enhancing long-term durability, we achieve record efficiencies with improved operational stability. This research bridges fundamental interface chemistry with scalable thin-film processing. In doing so, we aim to accelerate the commercialization of highly stable tandem photovoltaics for future renewable energy systems.