Fig. 1: Schematics of the classical and modified light-emitting diode (LED) device (not to scale).

a Cross-sectional cartoon of a standard LED (including its electrical contacts), where an epoxy lens/casing encapsulates the semiconductor LED chip. Light emitted from the p–n junction escapes into the epoxy lens as long as the incident angle is less than the critical angle θ_c. b Side-view and c 3D view of the proposed new design for enhanced light extraction with a 2D array (“meta-grid”) of nanoparticles (NPs) embedded in the epoxy material at a height h from the LED-chip surface. d Four-layer-stack theoretical model for analysing the optical transmission through the proposed system, where the NP array is represented by an effective film of thickness d, whose properties are derived from the effective medium theory (see section: “Theoretical Formulation”)