Nanoantenna‐Enhanced Light‐Emitting Diodes: Fundamental and Recent Progress

Abstract

Light‐emitting diodes (LEDs) are a promising solution for energy‐saving illumination, terminal display technology, and visible light communication. Driven by the vast markets of these emergent applications, the everlasting demand for LED devices is to continuously improve the luminous efficiency and lifetime while minimizing costs. The luminous efficiency of LEDs can be improved from various perspectives including materials, nanofabrication, encapsulation, and other fields, mainly to increase the internal quantum efficiency of the active layer, the light extraction efficiency, the directionality of luminous emission, and the photoluminescence of color‐converting layer. A nanoantenna is a delicately designed functional structure with strong capabilities in decay rate enhancement, light regulation, and other unique optical and electrical characteristics, which fully meet the needs of LED emission enhancement. Starting from the mechanism of nanoantennas, how to enhance LEDs by nanoantennas made of metals, dielectrics, and mixtures of both is discussed. By considering some practical cases, the review of the enhanced functionalities of LEDs under the function of nanoantenna are provided. On top of that, the great potential of nanoantennas for the use in micro‐ and nanostructures, layered structures, and other new LED geometries, and for the active control of LEDs using reprogrammable nanoantennas is also put forward.

Mode-dependent energy exchange between near- and far-field through silicon-supported single silver nanorods

“…10,11 Simultaneous control over the excitation and emission processes facilitates further investigation of plasmon-based light-emitting devices and other nanoscale light sources, especially those of high energy efficiency, superior brightness, and specific directionality. [12][13][14][15] In previous works, the excitation and emission processes are mostly mediated by a single plasmon mode, for instance, the longitudinal dipole plasmon mode of individual plasmonic nanorods, [16][17][18] or the gap dipole plasmon mode of bowtie and nanoparticle-on-mirror (NPoM) systems. [19][20][21] If a plasmonic nanoparticle is regarded as an optical nanoantenna, a specific plasmon mode can be understood as a communication channel between nano-emitters (near-field) and freespace light (far-field).…”

“…10,11 Simultaneous control over the excitation and emission processes facilitates further investigation of plasmon-based light-emitting devices and other nanoscale light sources, especially those of high energy efficiency, superior brightness, and specific directionality. 12–15…”

Monolayer WS2 electro- and photo-luminescence enhancement by TFSI treatment

“…These are consistent with the angular plots of full 3d systems (lower inset of figure 8) and predict an optimal cavity with N P = 3 and relative normal emissivity enhancement of ×16. Further enhancement mechanisms can also be considered, such as plasmonic cavities and/or antenna-coupling [139][140][141][142][143][144][145], as well as dielectric domes on top of the device to further boost extraction.…”

Efficient monodisperse upconversion composite prepared using high-density local field and its dual-mode temperature sensing

“…[13][14][15] When the position of the surface plasmon resonance (SPR) peak overlaps with the emission band or excitation band of the upconversion material, 16,17 coupling between the emission field or excitation field and the LSPR will considerably enhance the density of the photonic local states on the metal surface, thus allowing increased luminescence and considerable emission enhancement. [18][19][20][21] These mechanisms can be simply described as enhanced excitation intensity or accelerated radiation attenuation rates via band matching. 22,23 However, the loss problem associated with reflection or scattering is serious in plasmonics/UCNPs hybrid systems, e.g., some systems even experience a loss of up to 60%.…”