by Jin S. Kim
A group of researchers from the Kanazawa Institute of Technology in Japan succeeded in developing a green phosphor-based OLED. What’s the big deal? The light-emitting efficiency they achieved with this new OLED was 210lm/W (that’s lumens per watt) at 10 cd/m2 (or nits) of luminance. That number is almost a 57% improvement over existing OLEDs.
Based on a bottom-emission type using a 0.7mm glass plate, the light-emitting layer is made up of a host material called “CBP”. An iridium complex is added to it and peak emission wavelengths are between 500 and 550nm, corresponding to the green color.
Without the 0.7mm glass plate that is highly refractive the light-emitting efficiency was only 93.3lm/W. The researchers concluded that the glass plate was responsible for more than doubling the light extraction efficiency.