A Japanese research group from the Kanazawa Institute of Technology has reported a green phosphorescent OLED device with a very high light-emitting efficiency of 210 lm/W, according to an
article on the Nikkei Tech-On website.
The OLED device has the bottom-emission type structure, which extracts light through a substrate made with transparent electrodes. In addition, a 0.7mm-thick glass plate with a refraction index as high as 2.03 is bonded to the substrate. The surface of this glass plate is processed to have a structure of about 0.3mm-pitch optical lens array.
When emitting light at a luminance of 10cd/m2, the device had a light-emitting efficiency of 210 lm/W and a light-extraction efficiency of 56.9%. Without the high-refractive glass plate, the efficiency was only 94.3lm/W, or 2.3 times less.
PNNL uses new materials to boost efficiency of blue OLEDs by 25%
New host materials for a blue phosphorescent OLED boost efficiency by at least 25 percent , filling agap in the development of cost-effective white OLEDs, according to researchers at the Pacific Northwest National Laboratory.