Improving the performance of light-emitting diodes via plasmonic-based strategies

Light-emitting diodes (LEDs), featuring long lifetime, small size, and low energy consumption, are increasingly popular for displays and general light sources. In the past decades, new light-emitting materials and novel device configurations are being continuously investigated to obtain highly efficient LEDs. Nevertheless, the unsatisfying external quantum efficiency severely limits their commercial implementation. Among all the approaches to boost the efficiency of LEDs, the incorporation of plasmonic structures exhibits great potential in increasing the spontaneous emission rates of emitters and improving the light extraction efficiency. In this Perspective, the methods to deal with challenges in quantum-well-based LEDs and organic LEDs by employing plasmonic materials are described, the mechanisms of plasmonic-based strategies to improve the light generation and extraction efficiency are discussed, and the plasmonic control over directional emission of phosphors is introduced as well. Moreover, important issues pertaining to the design, fabrication, and manipulation of plasmonic structures in LEDs to optimize the device performance, as well as the selection roles in finding appropriate plasmonic materials and structures for desired LED devices, are explained. This perspective lists the challenges and opportunities of plasmonic LEDs, with the aim of providing some insights into the future trends of plasmonic LEDs.