We
demonstrate a hybrid light-emitting device (LED) employing a
chemical-vapor-deposition grown, centimeter-scale monolayer of WS2 (mWS2) as the active luminescent material embedded
within conductive organic layers. The active area of the hybrid LED
is composed of mWS2, located within the organic host matrix,
sandwiched between the hole- and electron-transporting organic layers.
The mWS2 shows fast exciton decay and efficient light outcoupling
compared to the organic dyes used for OLEDs, whereas organic layers
enable a precisely controlled, large-area fabrication process. As
a result, LEDs with an average external quantum efficiency of 0.3
± 0.3% and with the highest efficiency of 1% were achieved. Also,
we show that negatively charged excitons, also known as trions, are
generated in the mWS2 with the injected current, causing
an efficiency roll-off at high current densities. Our result introduces
a means for incorporating a range of emissive inorganic thin films
into an organic device structure, thereby taking advantage of the
positive attributes of both material systems.