Light-emitting electrochemical cells with millimeter-sized interelectrode gap: low-voltage operation at room temperature.

We have prepared and characterized polymer light-emitting electrochemical cells (LECs) containing a binary mixture of the conjugated polymer poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene] and the ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate as the active material. We demonstrate, for the first time, that it is possible to turn on and attain light emission from LECs, with a mm-sized interelectrode gap separating two identical Au electrodes, at a low voltage of 3 V and at room temperature.