Stabilization of All-Slot-Die-Coated Perovskite Solar Cells by MXene Nanospheres Unleashes Thousand-Hour Operational Lifetimes

: Halide perovskite solar cells (PSCs) have emerged as highly promising photovoltaic technologies. However, their commercialization is impeded by rapid degradation at interfaces due to intrinsic defects and corrosive decomposition products. Here, we demonstrate the use of spherical Ti3C2Tx MXene nanoparticles synthesized by femtosecond laser ablation as stabilizing additives for all-slot-die-coated PSCs. Unlike conventional MXene flakes, these nanoparticles exhibit improved colloidal stability, uniform dispersion, and facile integration into thin-film layers. Incorporation of MXene nanoparticles into electron transport layers notably enhances charge carrier dynamics, yielding an increased power conversion efficiency from 17.4 to 18.2%. Moreover, operational stability under continuous illumination extends from 400 h to over 1700 h owing to MXene nanoparticles. Structural and photophysical analyses suggest that MXene nanoparticles mitigate interfacial degradation by passivating ionic defects and improving energy-level alignment. This scalable nanoparticle-based strategy offers a versatile pathway toward stable, efficient, and commercially viable perovskite photovoltaics and opens new prospects for MXenes in advanced optoelectronic applications.