White Light-Emitting Electrochemical Cell

We report a light-emitting electrochemical cell (LEC) with air-stable electrodes and a solution-processed single-layer active material that emits warm-white light (CIE coordinates = (0.39, 0.43); color rendering index =83) with significant brightness (B) at a low voltage. The carefully tuned trichromatic device exhibits a short turn-on time (∼5 s to B > 100 cd/m²), high efficiency (3.1 cd/A at B = 240 cd/m²) and good operational stability (17 h at B > 100 cd/m²). We also report a blue LEC with a highly respectable set of device properties in the form of a turn-on time of ∼5 s, an efficiency of 3.6 lm/W and 5.6 cd/A, and an uninterrupted operational lifetime of 25 h. Finally, by analyzing data from trichromatic and monochromatic devices as well as from the constituent fluorescent CPs, we are able to point out a viable path toward further improvements in the performance of the white-emitting LEC.