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Defect passivation and optical management of triple-junction solar cells

Perovskite/perovskite/silicon-based triple-junction solar cells are a promising low-cost route to surpass the Shockley–Queisser efficiency limit of single-junction photovoltaics, but their performance is constrained by non-radiative losses in wide-bandgap perovskites and sub-optimal light management across the multilayer stack1-3. Here, we introduce a passivating molecule, 4F-POEABr, which strongly suppresses surface-defect-mediated recombination of WBG perovskite films. The ammonium attached and electron-deficient structure of 4F-POEABr provides combined chemical and field-effect passivation, enabling a quasi-Fermi-level splitting of 1.53 eV and an open-circuit voltage of 1.413 V in the WBG sub-cell. In parallel, systematic interference management is used to optimize the current density of the current-limited middle sub-cell, yielding a gain of 0.5 mA cm⁻2 via a tailored tin oxide/indium zinc oxide bilayer structure. As a result, the triple-junction devices achieve certified steady-state power conversion efficiencies of 32.22% for a 1.046 cm2 aperture area and 26.97% for a 15.62 cm2 aperture area, with negligible hysteresis. Robust interconnection layers and engineered perovskite interfaces further enhance operational stability and reduce device-to-device variation. This work demonstrates a synergistic strategy for pushing perovskite/silicon triple-junction solar cells toward their theoretical efficiency limits, enabling scalable, high-performance photovoltaic technologies.

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