Sustainable Stabilization of Perovskite Solar Cells Using Multifunctional Ammonium Alginate for over 26% Efficiency
Abstract
ABSTRACT Metal halide perovskite solar cells have emerged as a revolutionary photovoltaic technology due to their exceptional optoelectronic properties and low‐cost fabrication processes. However, the commercialization is significantly hindered by insufficient operational stability. The inherent ionic character of the perovskite lattice renders it susceptible to degradation under thermal and environmental stresses, primarily initiated by the loss of volatile organic cations and ion migration. Although defect passivation strategies have been extensively explored, a solution that effectively addresses the thermodynamic instability of the organic cation lattice site remains highly desirable. Herein, we first introduced ammonium alginate, a benign biopolymer, as a multifunctional stabilizer, which are proposed to suppress the deprotonation of formamidinium cations, thereby anchoring the A‐site, while the carboxylate groups can efficiently passivate undercoordinated Pb 2+ ions, reducing defect states. The synergistic effect, combined with the induced preferential crystallographic orientation and suppressed ion migration, significantly enhanced the device's photovoltaic performance‐increasing the power conversion efficiency from 24.05% to 26.12%, with the fill factor improved from 80.2% to 85.1%. Meanwhile, the devices have also exhibited an exceptional thermal and ambient stability, retaining over 80% of their initial efficiency under accelerated thermal aging and ambient exposure.