Integrated strategy unlocks 29.76% efficiency for all-perovskite tandem solar cells

Two stacked layers comprise tandem solar cells (TSCs), with each subcell absorbing different wavelengths of sunlight, which makes TSCs more efficient than single-layer solar cells. All-perovskite TSCs hold great promise for next-generation photovoltaics, with a theoretical efficiency exceeding 40%. However, their practical performance is hampered by mismatched crystallization kinetics between their wide-bandgap (WBG) and narrow-bandgap (NBG) subcells, leading to phase segregation and defect accumulation.