Panasonic Electric Works announced that they developed a new highly efficient OLED device - featuring 128 lm/W efficiency. This was achieved using a semi-spherical highly-refractive lens to enhance light extraction. The OLED panel is small - only 2x2 mm, and according to Panasonic this is the world's most efficient white OLED.
PEW says that in order to achieve this high efficiency, they inserted a light extraction layer composed of a highly-refractive material between the emissive layer (EML) and the glass substrate. The back side uses a high-reflectivity metal material. Detailed calculations were performed to minimize the internal reflection - this doubled the light extraction efficiency to 40%. This panel uses all-phosphorescent materials, and PEW says that this technique is actually similar to the technique used by Universal Display when they developed the 102 lm/W device back in 2008.
The company also fabricated a large panel (25 cm2) - which achieved a luminous efficiency of 56 lm/W at a brightness of 1,000cd/m2 and a CRI of 91. The lifetime is more than 150,000 hours. This device used a blue fluorescent material and red and green phosphorescent materials. Using all-phosphorescent materials upgraded the efficiency to 80 lm/W, but the lifetime is only 10,000 hours.
The OLED device was developed as part of project funded by Japan's New Energy and Industrial Technology Development Organization (NEDO). A few weeks ago, Panasonic announced that Panasonic Idemitsu OLED Lighting (PIOL), their joint-venture with Idemitsu Kosan, started shipping OLED panels.
