DC-Driven, Sub-2 V Solid-State Electrochemiluminescent Devices by Incorporating Redox Coreactants into Emissive Ion Gels

We demonstrate a DC-driven solid-state electrochemiluminescent (ECL) device based on a solution-processable ion gel containing luminescent complexes and tetrabutylammonium oxalate (TBAOX) as a coreactant. The ECL gel, comprising a polystyrene- block -poly(methyl methacrylate)- block -polystyrene copolymer, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ionic liquid, tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate (Ru(bpy) 3 (PF 6 ) 2 ) and TBAOX, was cast as a film on indium tin oxide-coated glass (anode) by spin-coating, and a top electrode (cathode) was prepared by brush-painting Ag paint. Application of 1.6 V DC bias across the device resulted in the onset of light emission. The maximum luminance was achieved at 1:5 mol ratio of Ru(bpy) 3 (PF 6 ) 2 and TBAOX, and the turn-on voltage was independent of the composition. The simplicity of the ECL device and its low voltage operation characteristics make it potentially attractive as a display element for printed electronic circuits.