Researchers from Osaka University managed to create multi-color Mechanochromic Luminescent (MCL) materials. The materials were found to exhibit efficient TADF emission, and the researchers developed an efficient OLED device based on these new materials.

MCL materials change their color in response to a change in their environment - for example pressure or temperature. Most MCL materials can only change between two colors, but the new materials can switch between yellow, red and orange. The color shift occurs in response to heating, fuming, and grinding. 

 

The researchers say that these new materials may find application in OLED emitters and also in pressure sensors and temperature sensors. It's not clear what are the advantages (if any) compared to other TADF emitters and whether these materials can be stable enough to be used to commercial OLEDs.(From：OLED-info)