Light-emitting electrochemical cell
A light-emitting electrochemical cell (LEC or LEEC) is a solid-state device that generates light from an electric current (electroluminescence). LECs are usually composed of two metal electrodes connected by (e.g. sandwiching) an organic semiconductor containing mobile ions. Aside from the mobile ions, their structure is very similar to that of an organic light-emitting diode (OLED). LECs have most of the advantages of OLEDs, as well as additional ones: The device is less dependent on the difference in work function of the electrodes. Consequently, the electrodes can be made of the same material (e.g. gold). Similarly, the device can still be operated at low voltages. Recently developed materials such as graphene or a blend of carbon nanotubes and polymers have been used as electrodes, eliminating the need for using indium tin oxide for a transparent electrode. The thickness of the active electroluminescent layer is not critical for the device to operate. This means that: LECs can be printed with relatively inexpensive printing processes (where control over film thicknesses can be difficult). In a planar device configuration, internal device operation can be observed directly. There are two distinct types of LECs, those based on inorganic transition metal complexes (iTMC) or light emitting