Institute of Nanoscience and Nanotechnology, National Center for Scientific Research DEMOKRITOS,
Keywords: OLEDs, sensor, flexible, food
Summary:Organic light emitting diodes (OLEDs) have now reach a mature level of commercialization due to low material cost and high efficiencies achieved in the state-of-the-art devices. Besides displays and solid-state lighting several other attractive applications are now in their infancy. Among them, OLEDs used as illumination sensors are highly attractive. Here, we report on efficient red LED pixels integrated onto a plastic substrate to act as illumination sensors for food safety. Amines and other volatile products coming from food decomposition adsorb onto the red pixel and react with an inserted dye (into the active layer) hence tuning the EL spectrum to green. As larger amounts of volatile products reach the OLED surface pronounced changes in the dye shift the EL spectrum to blue hence warning not to consuming the food.