Plasmonic Nanocavity Organic LightEmitting Diode with Significantly Enhanced Light Extraction, Contrast, Viewing Angle, Brightness, and LowGlare

or high light extraction inorganic LEDs (fl ip-chip with metallic high refl ectivemirror). [ 10 ] All current methods for good contrast uses the methods that absorb the ambient light (e.g., circular polarizers, light absorbing layers, destructive-interference buffer layers, and low light refl ection black cathode) [ 22–24,26–34 ] but also degrade the light extraction substantially. The light extraction degradation is often as large as a factor of 2 (i.e., lossing a half of the total light that is otherwise being extracted). In other words, the most current LED structures cannot have high light extraction and high ambient light absorption (i.e., low ambient light refl ection) at the same time; they are either a good light radiator or a good ambient light absorber, but not both. Resonant-cavity LEDs with dielectric mirrors can be a good light radiator and absorber, but only in a few nanometer wavelength range and in a particular direction, [ 37,40 ] hence suffering similar low contrast and large glare as other LED structures in display applications. Moreover, in conventional LEDs, the viewing angle is fi xed by the Lambertian radiation pattern unless using lenses or resonant cavities; [ 41 ] and the ambient light refl ection often follows Fresnel’s law, hence having large glare. Metals have many unique properties over dielectric counterparts. One of them is the generation of surface plasmon polariton (SPP), which can, under certain conditions, enhance the light radiation rate (Purcell Effect), alter the radiation intensity and pattern, and improve the light extraction. [ 42,43,55,56 ] Yet, the implementation into LEDs with a single layer of metallic (plasmonic) structures (either nanostructures or a planar thinfi lm) [ 44 ] or two layers of planar metallic thin-fi lms has achieved only limited improvements in LED light extraction. [ 36 ] The general concept of using a plasmonic microcavity with nanoperforated metal cladding for improving light extraction was fi rst proposed and discussed theoretically by Barnes, [ 43 ] and was implemented experimentally, with limited enhancements, to the optical pumped inorganic LEDs with a metal nanograting Plasmonic Nanocavity Organic Light-Emitting Diode with Signifi cantly Enhanced Light Extraction, Contrast, Viewing Angle, Brightness, and Low-Glare