Polymer light-emitting electrochemical cell performance

Ionic liquid has been used in polymer light-emitting electrochemical cells and high performance devices have been successfully demonstrated with long lifetime. With the excellent solubility, good thermal stability, and relatively wide chemical window, ionic liquids can be part of the electrochemical devices. It is believed that more and more ionic liquids and blend systems involving ionic liquids will be discovered. 

Tables 6-9 give the device structures and performance metrics for monochromatic OLEDs that utilize organometallic emitters. Eigures 38-42 show the molecular structures for the various materials used in these devices. White OLEDs have also been prepared with these materials, but these will be discussed in a later section. Light-emitting electrochemical cells are treated in a separate section as well, since the finished devices have different operating characteristics than either of the other solution or vapor processed devices. Table 6 lists devices made solely with discrete molecular materials, while Table 7 gives data for devices made using polymeric materials. The only exception to the use of discrete molecular materials in Table 6 is for devices that use a conducting polymer, poly(3,4-ethylenedioxythiophene polystyrene sulfonate) (PEDOT), as a material to enhance the efficiency for hole injection into the organic layer. The mode of preparation for a given device is listed with the device parameters in the...

The other way to produce EL devices is based on a pn junction [63,64]. Apw junction with conjugated polymers was realized by electrochemical doping of the polymer in an electrochemical cell [65]. The working principle and the performance of such a light-emitting electrochemical cell (LEG) is described at the end of this section. 

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