Engineering of embedded star-shaped plasmonic nano rods for enhancing the silicon solar cell performance

Abstract In this study, we present a design for plasmonic silicon solar cells (SCs) that leverages sub-wavelength light-trapping nanostructures to significantly enhance broadband absorption in ultra-thin (1 μ m) silicon layers. The approach involves embedding periodic star-shaped metallic nanorods within the silicon active region and incorporating a dual-layer antireflection coating of Si₃N₄ and SiO₂. The structure is modelled using the finite-difference time-domain method, and its electrical behaviour is evaluated through drift-diffusion simulations. By carefully optimising the geometry of the plasmonic nanostructures, we have effectively tailored the absorption spectrum to maximise light harvesting and improve overall photovoltaic performance. Results demonstrate an impressive absorption efficiency exceeding 84.5% across the 300 nm–1600 nm range under the AM1.5 G spectrum. The optimised cell achieves a short-circuit current density of 43.28 mA cm −2 and a power conversion efficiency of 23.04% in the wavelength range (300–1127 nm). Analyses of the electric field distribution and carrier generation rate confirm strong light confinement and enhanced photogeneration within the silicon layer. This work highlights a promising strategy for developing high-performance thin-film plasmonic SCs through advanced nano-photonic engineering.