Light-Emitting Devices Based on Electrochemiluminescence: Comparison to Traditional Light-Emitting Electrochemical Cells

Abstract

Electrochemical processes can be exploited to operate light-emitting devices with unusual functionality. For example, light-emitting electrochemical cells (LECs) contain a small amount of electrolyte within the organic/polymer light-emitting active layer. The electrolyte in the active layer allows the multiple charge injection layers that are deemed critical for organic light-emitting diodes to be avoided. Very recently, an alternative light-emitting device platform based on electrochemical processes was also suggested. These devices rely on electrochemiluminescence (ECL), a light-emission process based on the charge transfer reaction between reduced and oxidized forms of luminophores. Although the ECL process has been extensively investigated in the field of analytical chemistry, its utilization in electronic devices is a new approach that offers unique opportunities. Despite the interesting opportunities, a good introduction to the subject is not available, particularly with a focus on electronic device applications. Moreover, the operation of ECL devices is often confused with that of LECs, even though they follow distinct working principles. This confusion occurs mainly because the active layers for both ECL devices and LECs contain light-emitting material and electrolyte material (although their compositions are completely different). Therefore, clarifying the difference between the two sister devices would be both necessary and useful. In particular, a comparison of the two sister devices would highlight the unique opportunities for ECL devices and inspire researchers to devise a novel light-emitting device platform, which is the primary goal of this perspective.

Photocrystallographic and spectroscopic studies of a model (N,N,O)-donor square-planar nickel(II) nitro complex: in search of high-conversion and stable photoswitchable materials

“…Chemical compounds exhibiting specific photoactive properties, either in solution or even more importantly in the solid state, have already found versatile applications in solar-energy conversion and other fields ranging from molecular electronics and photocatalysts through light-emitting devices (LEDs) to biolabels (Alibabaei et al, 2013;Kamtekar et al, 2010;Kong et al, 2017;Reineke et al, 2009). Photoswitchable transitionmetal complexes, in which the metal centre (e.g.…”

Electrochemiluminescent Transistors: A New Strategy toward Light‐Emitting Switching Devices

“…Since the light‐emission process by the TPrA co‐reactant and Ru(bpy) 3 2+ luminophore does not require a long ion migration, the whole ECL process is rather free from the slow diffusion of the reactant species in the C‐ECL Gel, resulting in continuous light‐emission under a DC‐bias. [ 37 ]…”

Visco‐Poroelastic Electrochemiluminescence Skin with Piezo‐Ionic Effect

“…The included ionic mixture can exhibit electrochemically generated chemiluminescence or electrochemiluminescence (ECL), as a consequence of a charge transfer reaction between the oxidized and reduced forms of the iTMC. [27,28] See Supporting Information for brief description of ECL process we exploited. We note that for these devices based on ECL, charges are typically transferred by convective process (which involves direct mass transfer for oxidized and reduced iTMC species), [27] whereas charges in their sister electrochemical devices, often referred to as the light-emitting electrochemical cells, [29] charge are transferred by conductive process (which involves hopping of electrons and holes through iTMCs).…”