Metallic nanostructures for efficient LED lighting

Light-emitting diodes (LEDs) are driving a shift toward energy-efficient illumination. Nonetheless, modifying the emission intensities, colors and directionalities of LEDs in specific ways remains a challenge often tackled by incorporating secondary optical components. Metallic nanostructures supporting plasmonic resonances are an interesting alternative to this approach due to their strong light–matter interaction, which facilitates control over light emission without requiring external secondary optical components. This review discusses new methods that enhance the efficiencies of LEDs using nanostructured metals. This is an emerging field that incorporates physics, materials science, device technology and industry. First, we provide a general overview of state-of-the-art LED lighting, discussing the main characteristics required of both quantum wells and color converters to efficiently generate white light. Then, we discuss the main challenges in this field as well as the potential of metallic nanostructures to circumvent them. We review several of the most relevant demonstrations of LEDs in combination with metallic nanostructures, which have resulted in light-emitting devices with improved performance. We also highlight a few recent studies in applied plasmonics that, although exploratory and eminently fundamental, may lead to new solutions in illumination. Nanoscale metal structures can enhance the performance of light-emitting diodes, making them an efficient replacement for light bulbs. Gabriel Lozano from the Instituto de Ciencia de Materiales de Sevilla, Spain, and his colleagues from France and the Netherlands review how metallic nanoparticles enhance light–matter interactions and improve light emission from semiconducting materials and color converters employed for lighting. Nanostructures made of aluminum, silver or gold can support surface plasmon polaritons, which are formed by the coupling of electrons in the metal with photons. Surface plasmon polaritons can influence the behavior of nearby light sources, altering their emission rates and directionality. The researchers provide an overview of the many combinations of nanostructures and light-emitting materials that have been studied and discuss how this technology could provide an efficient alternative to traditional light sources.