Strong coupling in a microcavity LED.

Thin films of polyelectrolyte/J aggregate dye bilayers with high absorption coefficient (6 nm thick with alpha approximately equal to 1.0 x 10(6) cm(-1)) inserted in an optical microcavity enable the cavity quantum electrodynamic strong coupling limit to be reached at room temperature with a coupling strength (Rabi splitting) of 265 +/- 15 meV. By embedding these films in a resonant cavity organic LED structure, we demonstrate the first emissive electrically pumped exciton-polariton device.