Plasmonic Nanocavity Organic Light‐Emitting Diode with Significantly Enhanced Light Extraction, Contrast, Viewing Angle, Brightness, and Low‐Glare

One central challenge in LEDs is to increase light extraction; but for display applications, other factors may have equal significance, such as ambient‐light absorption, contrast, viewing angle, image sharpness, brightness, and low‐glare. However, current LED structures enhance only some of the factors, while degrading the others. Here, a new organic LED (OLED) structure is proposed and demonstrated, with a novel plasmonic nanocavity, termed “plasmonic cavity with subwavelength hole‐array” (PlaCSH), and exhibits experimentally significant enhancements of all above factors with unprecedented performances. Compared to the conventional OLEDs (the same but without PlaCSH), PlaCSH‐OLEDs achieve experimentally: i) 1.57‐fold higher external‐quantum‐efficiency and light‐extraction‐efficiency (29%/32% without lens, 55%/60% with lens)—among the highest reported; ii) ambient‐light absorption not only 2.5‐fold higher but also broad‐band (400 nm) and nearly angle and polarization independent, leading to lower‐glare; iii) fivefold higher contrast (12 000 for 140 lux ambient‐light); iv) viewing angle tunable by the cavity length; v) 1.86‐fold higher normal‐view‐brightness; and vi) uniform color over all emission angles. The PlaCSH is an excellent optical antenna—excellent in both radiation and absorption of light. Furthermore, PlaCSH‐OLEDs, a simple structure to produce, are fabricated using nanoimprint over large‐area (≈1000 cm²), hence scalable to wallpaper size.