Optically pumped amplified spontaneous emission in an ionic liquid-based polymer light-emitting electrochemical cell

Optically pumped amplified spontaneous emission (ASE) is demonstrated in the active layer of the polymer light-emitting electrochemical cells (LECs). The active layer blend of the light-emitting polymer and the ionic liquid retained a high degree of transparency, enabling its use as an optical slab waveguide, allowing a low ASE threshold energy of 4.1 μJ cm−2 to be achieved. We also demonstrate a planar LEC that showed fast turn on, bright linear shape emission in the middle of the two contacts, and a relatively high current density of 36 A cm−2 with a low driving voltage of 6 V.