Flexible and Metal-Free Light-Emitting Electrochemical Cells Based on Graphene and PEDOT-PSS as the Electrode Materials

We report flexible and metal free light-emitting electrochemical cells (LECs) using exclusively solution processed organic materials and illustrate interesting design opportunities offered by such conformable devices with transparent electrodes. Flexible LEC devices based on chemically derived graphene (COG) as the., cathode and poly(3,4-ethylenedioxythiophene) mixed with poly(styrenesulfonate) as the anode exhibit a low turnon voltage for yellow light emission (V = 2.8 V) and a good efficiency 2.4 (4.0) cd/A at a brightness of 100 (50) cd/m(2). We also find that COG is electrochemically inert over a wide potential range (+1.2 to -2.8 V vs ferrocene/ferrocenium) and exploit this property to demonstrate planar LEC devices with COG as both the anode and the cathode.