Multidentate\nPolymer-Stabilized Buried Interface for\nEfficient Planar Perovskite Solar Cells

Buried\ninterface engineering is crucial to improve the performance\nand stability of perovskite solar cells (PSCs). Although coordination\nmaterials have been widely used for buried interface modification,\nthey are generally engineered on one surface of the interface through\nmonodentate or bidentate molecules. Here, we propose that a multidentate\npolymer, sodium alginate (SA), acts with both surfaces via numerous\nCO groups to reinforce buried interfaces. SA effectively reduces\nburied interface defects, adjusts the energy level alignment, and\nrefines carrier dynamics. Notably, it also induces the growth of a\nperovskite film that is less tensile stressed and free of voids. Consequently,\nthe champion device efficiency after SA treatment increased from 23.05%\nto 24.98%, along with significant improvements in both light and thermal\nstability. This work offers insights into efficiency and stability\nimprovement from the perspective of multidentate polymer anchoring.