A dielectric SiO₂ nanosphere array-assisted optical confinement strategy for high-efficiency and lead-reduced MAPbI₃...

Perovskite solar cells (PSCs) are currently limited by a critical trade-off between the need for thick absorber layers (1000-1500 nm) to ensure sufficient light absorption and the environmental concerns regarding high lead (Pb) toxicity. While metal-based general light-trapping strategies like plasmonics or surface texturing have been explored, they often involve complex fabrication or offer marginal gains with high reflective loss. In this work, we present a high-performance, lead-reduced strategy using an optimized array of SiO₂ dielectric material-based nanospheres which can confine and scatter light with almost zero loss. By embedding a 61 nm diameter three-sphere array 50% into the FTO layer, we achieve significant optical confinement via angular scattering. This mechanism allows a thin 300 nm MAPbI₃ layer to achieve a 10.7% enhancement in average absorption, raising the short-circuit current density (J _sc) to 29.11 mA cm^-2 and the power conversion efficiency (PCE) from 22.58% to 24.61%. Crucially, this architecture enables a 73.78% reduction in lead content without sacrificing performance. This approach provides a scalable and eco-friendly pathway for the development of stable, high-efficiency, and low-toxicity next-generation photovoltaics.