Researchers from Kyushu University (led by Chihaya Adachi) developed a highly efficient blue OLED TADF (Thermally Activated Delayed Fluorescence) emitter that achieves almost 20% external quantum efficiency - similar to the best blue phosphorescent emitters.
TADF OLEDs are free from the heavy metals used in phosphorescent emitters and so they could be cheaper and better for the environment. The main problem with blue phosphorescent OLEDs is the short lifetime which still makes it impossible to use them in commercial applications. The new TADF blue OLEDs has about the same lifetime as the blue PHOLEDs, but researchers are hopeful that it will be easier to improve the lifetime of the TADF emitters.
