Manipulating Buried Interface via Aromatic Amino Acid Derivatives for Wide-Bandgap Perovskite Solar Cells and Tandem...

All-perovskite tandem solar cells (TSCs) constructed by wide-bandgap (WBG) and narrow-bandgap (NBG) perovskites represent promising future to exceed the Shockley-Queisser limit due to the differential absorption of spectrum. However, the WBG perovskite sub cell suffers from substantial open-circuit voltage (V_OC) losses and poor photovoltage performance caused by the severe phase segregation in the bulk, high defects density and non-radiative recombination losses at the buried interface. Herein, this work introduces a buried interfacial engineering by inserting N-Benzoyl-(2R,3S)-3-phenylisoserine (NBP) molecule between [4-(3,6-dimethyl-9H-carbazol-9-yl) butyl] phosphonic acid (Me-4PACz) and WBG perovskite layer, which simultaneously enhances film quality and energy level alignment. Additionally, experimental investigations demonstrate that the C═O and N─H groups in NBP exhibit significant effects in fixing uncoordinated Pb²⁺ ions and passivating iodide vacancies, suppresses halide phase segregation and reduces defect state density at the buried interface. Eventually, NBP-modified WBG PSCs achieved a power conversion efficiency (PCE) of 20.81% with V_OC of 1.371 V. Notably, the device exhibited exceptional photostability, retaining 85.3% of its initial PCE after 1000 h of maximum power point tracking (MPPT). Moreover, integrating the NBP-modified WBG sub cell with 1.25 eV NBG sub cell obtains a two-terminal (2T) TSCs with an impressive PCE of 29.05%.