An Exciplex‐Based Light‐Emission Pathway for Solution‐State Electrochemiluminescent Devices

Abstract

Electrochemiluminescence (ECL) allows the design of unique light‐emitting devices that use organic semiconductors in a liquid or gel state, which allows for simpler and more sustainable device fabrication and facilitates unconventional device form‐factors. Compared to solid‐state organic LEDs, ECL devices (ECLDs) have attracted less attention due to their currently much lower performance. ECLD operation is typically based on an annihilation pathway that involves electron transfer between reduced and oxidized luminophore species; the intermediate radical ions produced during annihilation dramatically reduce device stability. Here, the effects of radical ions are mitigated by an exciplex formation pathway and a remarkable improvement in luminance, luminous efficacy, and operational lifetime is demonstrated. Electron donor and acceptor molecules are dissolved at high concentrations and recombined as an exciplex upon their oxidization/reduction. The exciplex then transfers its energy to a nearby dye, allowing the dye to emit light without undergoing oxidation/reduction. Furthermore, the application of a mesoporous TiO2 electrode increases the contact area and hence the number of molecules participating in ECL , thereby obtaining devices with a very high luminance of 3790 cd m−2 and a 30‐fold improved operational lifetime. This study paves the way for the development of ECLDs into highly versatile light sources.

Electron-Accelerator-Induced Fast Electron Transfer for Enhancing Electrochemiluminescence of Gold Nanoclusters and Its Bioanalysis Application: A Novel Avenue for Developing High-Efficient Emitters

“…Nevertheless, the universal sluggish electron transport kineticscaused inefficient electrochemical redox of MNC emitters has not been effectively solved, which still severely limited the further improvement of the ECL performance of MNCs and hindered its application in efficient optoelectronic devices. 21,22 Thus, it is greatly important to propel the electron transport for exploiting highly efficient MNC-based ECL emitters. To conquer this issue, herein, a new avenue of electronaccelerator-induced fast electron transfer for ECL enhancement was proposed.…”

Enhanced Aggregation-Induced Delayed Electrochemiluminescence Triggered by Spatial Perturbation of Organic Dots

“…Electrochemiluminescence (ECL) is a light-emitting phenomenon in which excited species (R*) formed under high-energy electron transfer between electrochemical-active species can be converted into light by the radiative transition − and has been one of the most exciting hot spots in contemporary chemistry, playing crucial roles in various fields, such as immunoassays, − single-entity microscopy imaging, , as well as optical displays. , According to the quantum statistics, the distribution of R* at the lowest singlet excited states (S 1 ) and triplet excited states (T 1 ) is about 25% and 75%, respectively . Limited by the weak spin orbit coupling (SOC) effects, conventional organic dye-based ECL emitters possess intrinsically low ECL efficiency (Φ ECL ) as a result of the only utilization of the excited species at S 1 ( 1 R*) to emit light .…”