On the limited operational lifetime of light-emitting electrochemical cells

Light-emitting electrochemical cells offer efficient light-emission but suffer from short operational lifetimes. The latter is demonstrated to stem from photoinduced chemical reactions involving the conjugated polymer in the light-emitting p-n junction region, as evidenced by, e.g., optical and Raman microscopy (see figure). It is possible to alleviate the extent of these side reactions, and accordingly improve the operational lifetime, by improved heat control of the junction region.