Self‐Healing Ionogel Dual‐Network Enables Synergistic Defect Passivation and Strain Relief for High‐Efficiency Robust Perovskite Photovoltaics

ABSTRACT

The simultaneous realization of high efficiency and long‐term stability remains the central challenge for the commercialization of perovskite photovoltaics. The solution processing of perovskite films, while offering significant advantages, inevitably introduces deep‐level defects and residual strain, fundamentally limiting both the achievable open‐circuit voltage and the device's operational durability. Here, we introduce a molecular design concept that concurrently addresses these pervasive issues by engineering a cross‐linked multifunctional ionogel, [HA‐AA][EMIES], which is incorporated into the precursor solution. This approach leverages the ionogel's extensive dynamic bond networks and its intrinsic matrix toughening mechanism, achieved through molecular‐scale bond energy dissipation, to orchestrate the crystallization process and manage mechanical stress. Consequently, we achieve a near two‐fold enhancement in carrier diffusion length, surpassing 8 µm within the polycrystalline film. The resulting [HA‐AA][EMIES]‐based devices demonstrate superior efficiencies of 26.45% for rigid substrates and 25.14% for flexible devices, while exhibiting exceptional resilience against both ambient air exposure and mechanical bending. This work establishes a direct route to eliminate deleterious defects and residual strain in perovskites, offering a promising pathway to accelerate the development and commercial deployment of large‐area, stable perovskite photovoltaics.