Plasmonic Core–Multishell Nanowire Phosphors for Light-Emitting Diodes

White LEDs have replaced traditional incandescent lamps in many places. They are extensively studied to increase the efficiency to even greater values. In this work, we proposed and studied theoretically core–shell metal–semiconductor nanowires as phosphor components in white LEDs. Due to the coupling of the optical density of states to the surface plasmon resonance in the metal, the emission in the core–shell nanowires studied demonstrated a 5-fold enhancement for red phosphors and a 120-fold enhancement for green phosphors, compared to the bare semiconductor nanowires. Due to the coupling of the plasmon resonance oscillations at the metal surface with the electric fields of the incident light, the studied core–shell nanowires also show an absorbance of 0.6–0.9 for blue light compared to the absorbance of 0.2–0.4 observed in the core–shell quantum dots. We have predicted that the external quantum efficiency (EQE) can be enhanced by almost 11 times for red phosphors, by 36 times for yellow phosphors, and as high as 4 orders of magnitude for the green phosphors relative to the bare semiconductor nanowires, when carefully choosing the semiconductor and metal materials and dimensions. Finally, we have also explored the concept of core–shell–shell nanowires and have shown that these nanowires improve values of the EQE values by as much as 60% relative to the core–shell nanowires for red phosphors and 3 times for yellow phosphors, due to the addition of another enhanced electric field from the semiconductor core to the Purcell factor.