Affiliation:
1. Humboldt Centre for Nano‐ and Biophotonics Department of Chemistry University of Cologne Greinstr. 4–6 50939 Köln Germany
2. Organic Semiconductor Centre School of Physics and Astronomy University of St Andrews North Haugh St Andrews KY16 9SS UK
Abstract
AbstractElectrochemiluminescence (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.
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献