Dielectric shells as resonant mode tuners: unlocking superior visible-spectrum photon capture in plasmonic perovskite solar cells

Abstract

A critical barrier to commercializing perovskite solar cells (PSCs) is the trade-off between the efficiency of thick absorbers and the stability of thin films. Advanced light management is essential to resolve this, yet the optimal nanophotonic strategy remains debated. Here, we resolve this debate by systematically comparing planar, dielectric, bare plasmonic, and core–shell architectures within a unified multi-physics framework. We find the core–shell plasmonic design is clearly superior, with the champion CoreAu architecture achieving 21.61% efficiency, a 43% relative enhancement over the 15.11% planar baseline, driven by a J_sc increase from 18.22 to 26.34 mA cm⁻². The core physical insight is that the dielectric shell acts as an active resonant tuner, enabling the excitation of powerful, higher-order plasmonic modes inaccessible to bare nanoparticles. This unique capability facilitates a strategic shift from specialist near-infrared light trapping to a more effective broadband anti-reflection in the visible spectrum, where solar flux is highest. This work establishes a new design principle for plasmonic PSCs: the shell must be co-optimized as an active optical element to prioritize visible-spectrum photon capture, providing a clear pathway toward ultra-high-efficiency, stable thin-film photovoltaics.