Patent ID: 8624485

Claim:
An electroluminescent device comprising: a substrate; two electrodes; a stack disposed between the electrodes that comprises at least two electroluminescent emission layers and at least one interlayer disposed between at least two adjacent layers of the electroluminescent emission layers, wherein each of the electroluminescent emission layers comprise electroluminescent molecules, and wherein the interlayer includes an interface region comprising a mixture of portions of the electroluminescent molecules from each of the at least two adjacent layers separated by the interlayer such that light emission from a first layer of the at least two adjacent layers exhibits a dependence on a voltage applied between the electrodes that is greater than a dependence on the voltage exhibited by light emission from a second layer of the at least two adjacent layers; and a voltage source adapted to vary the voltage applied between the electrodes and thereby tune the light emission from the first layer.