Exciplex-enabled high-efficiency, fully stretchable OLEDs

Fully stretchable organic light-emitting diodes (OLEDs), composed entirely of intrinsically stretchable materials, are essential for on-skin displays^1-3. However, their low device efficiency has been a persistent barrier to practical applications for more than a decade⁴. Here we addressed this challenge by incorporating an intrinsically stretchable exciplex-assisted phosphorescent (ExciPh) layer. The elastomer-tolerant triplet-recycling mechanism mitigates exciton energy transfer limitations arising from the insulating elastomer matrix, yielding a light-emitting layer with more than 200% stretchability and an external quantum efficiency (EQE) of 21.7%. To translate this performance to fully stretchable devices, we integrated MXene-contact stretchable electrodes (MCSEs), which feature high mechanical robustness and tunable work function (WF), ensuring efficient hole and electron injection. These advances enable fully stretchable OLEDs with a record EQE of 17.0% and minimal luminescence loss under 60% strain. This approach to designing high-efficiency, mechanically compliant optoelectronics will enable the next-generation wearable and deformable displays.