Single-Emitter White OLEDs via Microcavity Spectral Engineering

White organic light-emitting diodes (WOLEDs) are promising candidates for next-generation lighting and display technologies. However, conventional WOLED fabrication often relies on complex doping schemes or multiple color stacked emitting layers, complicating device design, and fabrication. Here, a simple approach for fabricating ITO-free WOLEDs with a single-component, using a planar aluminium microcavity, is presented. By engineering the cavity and surface plasmon polariton modes around the emission resonance of the high-efficiency blue thermally activated delayed fluorescence emitter DMAC-DPS, electroluminescence that is spectrally broadened to white light, with a tunable color temperature ranging from 3790 to 5050 K, is achieved. The WOLEDs are top-emitting and reach an external quantum efficiency of >5%. The results are supported by optical simulations and transient emission measurements, providing insights into the emission kinetics.