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

摘要

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 cm~2), hence scalable to wallpaper size.